A Review and Enhancement of the Cloud Seeding Chapters in the 2007 book, “Human Impacts on Weather and Climate”

Another in a continuing possibly semi-useless series by this author….  This example probably indicates why I am not asked to review manuscripts in my expertise; cloud seeding and ice formation in clouds.  I try to follow in the footsteps of meteorologist and MIT faculty member, Fred Sanders, of whom it was said, “His reviews were sometime longer than the manuscript he was reviewing.”  I bet he didn’t get many manuscripts to review, either!

Oh, well, “we” trudge on.

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Comments and “enhancements” on this work by my friends, William R. “Bill” Cotton and Roger Pielke, Sr., are in red. Necessarily, I am only presenting those portions of Cotton and Pielke’s book (those on cloud seeding) that require an “enhancement” or corrections for the reader and I have attempted to do this delicately.  Fortunately, because both are major scientists, they do not respond to criticism with emotion and are quite happy to see errors in their work corrected.  🙂

For the actual, extensive text leading up to these comments, you’ll have to buy the book.  Dashes are inserted where material, usually extensive,  is skipped to avoid too much copyright infringement.

Summary

The first three chapters are an excellent overall introduction to the topic  of weather modification.  The “Reference” section alone makes it worth the purchase of this book since it covers so much of the climate domain up to 2006.  The weather modification references needed beefing up and are done so here.

Oh, some background on what the climate was doing when this book on climate came out…  

Cotton and Pielke, Sr.’s book, hereafter,  “CP07,” came out during the middle of a hiatus in global warming, discussed a few years later in Science magazine by its reporter, Richard Kerr (2009) in, “What Happened to Global Warming?”  

About the time CP07  was published it also marked a time when the phrase, “global warming” (which was no longer occurring for unknown reasons) began to recede in use and was supplanted by the phrase, “climate  change,” something that is always happening on this great planet.  It made sense to change phrases since “climate change” would always be true whereas “global warming,” as we were learning in the 2000-2010 era, might not be.  (An aside:  I am a believer that CO2 will warm the earth in the decades ahead, but not catastrophically; I am strongly influenced in this belief by “influencers,” Roger Pielke, Jr., climate and policy expert, formerly of the University of Colorado but pushed out,  and Cliff Mass, weather and climate expert, still “intact male” at the University of Washington thanks solely to tenure.

Let us begin the review of CP07 with their acknowledgments which required an insertion by this writer:

Acknowledgments for CPO7

 The study of human impacts on weather and climate continues to be a high- interest topic area, not only among scientists but also the public. Our second edition has continued to build on our funded research studies from the National Science Foundation, the National Aeronautics and Space Administration, the Environmental Protection Agency, the Department of Defense, the National Oceanic and Atmospheric Administration, and the United States Geological Survey. Our numerous research collaborators at the Natural Resource Ecology Laboratory and Civil Engineering at Colorado State University have continued to provide valuable in sight on this subject. Over our multidecadal career, the fundamental insights into weather and climate provided by our education at the Pennsylvania State University have become increasingly recognized. We also want to recognize the perspective on these subjects, and science in general, that Robert and Joanne Simpson have provided us in our careers. Their mentorship and philosophy of research, of course, is but one of their many seminal accomplishments.

Roger Pielke would like to thank everyone who contributed to compiling the information in Tables 6.2 and 11.2 especially Roni A vissar, Richard Betts, Gordon Bonan, Lahouari Bounoua, Rafael Bras, Chris Castro, Will Cheng, Martin Claussen, Bob Dickinson, Paul Dirmeyer, Han Dolman, Elfatih Eltahir, Jon Foley, PavelKabat, George Kallos, Axel Kleidon, Curtis Marshall, Pat Michaels, Nicole Molders, Udaysankar Nair, Andy Pitman, Adriana Beltran-Przekurat, Rick Raddatz, Chris Rozoff, J. Marshall Shepherd, Lou Steyaert, and Yongkang Xue. In addition, Roger would like to thank Dr. Adriana Beltran for her assistance with figures in this edition.

As is always the case, Dallas Staley’s editorial leadership and Brenda Thompson’s assistance in completing the book has been invaluable and is very much appreciated.

However, we are unable to thank Mr. Arthur L. Rangno for his review of this book before it was published because we forgot to ask him.  Mr. Rangno is an acknowledged expert with several peer-reviewed publications on two of the cloud seeding experiments reviewed in this book; those carried out by Colorado State University (the home institution of CP07) at Climax and Wolf Creek Pass, Colorado, and those carried out in Israel conducted by the Hebrew University of Jerusalem.  Namely,  Art didn’t do sh. to improve our book beforehand since we also mostly ignored his scintillating 1997 email concerning the first edition of our book, CP95.  Nevertheless,  we are happy to have him review our 2nd edition (CP07) belatedly, i.e., provide a few review “cow pies” here and there on some of our otherwise excellent work.”  (Fake quote.)

If you would like to see how truly “scintillating” my email was to the lead author, go here

Since Professor Doctor William R. “Bill” Cotton does not thank any reviewers in CP07 while Prof. Doctor Roger Pielke, Sr., thanks many contributors, I am of the belief that the cloud seeding chapters, 1-3 in CP07,  were not reviewed by anyone until now.  Dr. Cotton is on record as favoring commercial  vendors of orographic cloud seeding.

So, off we go!

Chapter 1:  The rise of the science of weather modification by cloud seeding

Throughout history and probably prehistory man has sought to modify weather by a variety of means. Many primitive tribes have employed witch doctors or medicinemen, and human sacrifices to bring clouds and rainfall during periods of drought and to drive away rain clouds during flooding episodes. Numerous examples exist where modern man has shot cannons, fired rockets, rung bells, etc. in attempts to modify the weather (Changnon and Ivens, 1981).

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Seeding of supercooled cumulus clouds produced more controversial results. Dry ice and silver iodide seeding experiments were carried outat a variety of locations with the most comprehensive experiments being over New Mexico. Based on four seeding operations near Albuquerque, New Mexico, Langmuir claimed that seeding produced rainfall over a quarter of the area of the state of New Mexico. He concluded that “The odds in favor of this conclusion as compared to the rain was due to natural causes are millions to one.” Langmuir was evenmore enthusiastic about the consequences of silver iodide seeding over New Mexico. The explosive growth of a cumulonimbus cloud and the heavy rainfall near Albuquerque and Santa Fe were attributed to the direct results of ground-based silver iodide seeding. In fact Langmuir concluded that nearly all the rainfall that occurred over New Mexico on the dry ice seeding day and the silver iodide seeding day were the result of seeding.

The claim by Langmuir was found to be false in an analysis by the Scientific Services Division of the Weather Bureau, represented by Ferguson Hall.  Others chimed in with Hall also publishing in Science magazine:   Gardener Emmons, NYU, Bernard Haurwitz, NYU, Hurd Willett, MIT, and George Wadsworth, MIT.

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Convinced that cloud seeding was a miraculous cure to all of nature’s evils, Langmuir and his colleagues carried out a trial seeding experiment of a hurricane with the hope of altering the course of the storm or reducing its intensity. On October 10, 1947, a hurricane was seeded off the east coast of the United States. About 102 kg of dry ice was dropped in clouds in the storm. Due to logistical reasons, the eye wall region and the dominate spiral band were not seeded. Observers interpreted visual observations of snow showers as evidence that seeding had some effect on cloud structure. Following seeding, the hurricane changed direction from a northeasterly to a westerly course, crossing the coast into Georgia. The change in course may have been a   was the result of the storm’sinteraction with the larger-scale flow field. Nonetheless, General Electric Corporation became the target of lawsuits for damage claims associated with the hurricane.

In summary, Project Cirrus launched the United States and much of the world into the age of cloud seeding. The impact of this project on the science of cloud seeding, cloud physics research, and the entire field of atmospheric science was similar to the effects of the launching of Sputnik on the United States aerospace industry.

This discussion lacks mention of perhaps the most influential paper of all those that motivated cloud seeding throughout the world; that of Kraus and Squires (1947) reporting spectacular results from an Australia seeding experiment.  The KS47 paper, appearing in the high-end journal, Science, purported that two drops of dry ice totaling 250 lbs. into a Cumulus congestus cloud at 23,000 feet spawned a massive, isolated storm that towered to possibly “40,000 feet,” lasted for hours and dropped heavy rains over “20 square miles.”  This was the only cloud that appeared to respond so impressively to dry ice seeding on that flight day.   The Kraus and Squires report was seen as evidence that drought might be alleviated with few hundred pounds of dry ice, and as a result,  widespread cloud seeding took off as entrepreneurs hastily formed cloud seeding companies such as North American Weather Consultants, Atmospherics, Inc., Irving P. Krick Associates, among many others.  The series of photographs of the apparent response of that Cumulus cloud to seeding continued to be published as proof what cloud seeding could do for almost 40 years after KS47 (e.g., Orville 1986). 

Caveat Emptor:

HOWEVER, in independent dry ice seeding tests on Cumulus clouds by the U. S. Weather Bureau (Coons et al. 1949, Coons and Gunn 1951) no explosion of a cloud occurred as KS47 had described after seeding.  Instead, they reported, the seeded Cumulus clouds generally sank back down after dropping up to 100 lbs. of dry ice into them.  Also, they reported that natural precipitation had formed in similar Cumulus clouds in the vicinity.  It wasn’t clear to Coons et al. that dry ice seeding had made a difference.

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Chapter 2:  The glory years of weather modification

  • Introduction

The exploratory cloud seeding experiments performed by Langmuir, Schaefer, Kraus and Squires, and Project Cirrus personnel fueled a new era in weather modification research as well as basic research in the microphysics of precipitation processes, cloud dynamics, and small-scale weather systems, in general. At the same time commercial cloud seeding companies sprung up worldwide practicing the art of cloud seeding to enhance and suppress rainfall, dissipate fog, and decrease hail damage. Armed with only rudimentary knowledge of the physics of clouds and the meteorology of small- scale weather systems, these weather modification practitioners sought to alleviate all the symptoms of undesirable weather by prescribing cloud seeding medication. The prevailingview was “cloud seeding is good!”

  • The static mode of cloud seeding

We have seen that the pioneering experiments of Schaefer and Langmuir suggested that the introduction of dry ice or silver iodide into supercooled clouds could initiate a precipitation process. The underlying concept behind the static mode of cloud seeding is that natural clouds are deficient in ice nuclei.

2For an excellent,  more technical review of static seeding, see Silverman (1986).

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The rime-splinter secondary ice crystal production process may not explain all the observations of high ice crystal concentrations relative to ice nuclei estimates but it is consistent with many of them. Still other processes, such as drop fragmentation during freezing (Korolev et al. 2004, Rangno and Hobbs 2005) and fragmentation of delicate ice particles (e.g.,Vardiman 1978) are not well quantified understood at this time may be operating operate in some cases of observed high ice crystal concentrations relative to ice nuclei concentrations.

The implication of these physical studies is that the “window of opportunity” for precipitation enhancement by cloud seeding is much smaller than was originally thought. Clouds that are warm-based and maritime have a high natural potential for producing precipitation. On the other hand, clouds that are cold-based and continental have reduced natural potential for precipitation formation and, hence, the opportunity for precipitation is much greater, although the total water available would be less than in a warm-based cloud.

This is consistent with the results of field experiments testing the static seeding hypothesis. The Israeli I and II experiments were quite successful in producing positive yields of precipitation in seeded clouds (Gagin and Neumann, 1981). The clouds that were seeded over Israel had relatively cold bases(5-8°C) and were generally continental such that there was little evidence of a vigorous warm rain process or the presence of large quantities of heavily rimed graupel particles.

This paragraph was copied verbatim from the first edition of this book,  CP95.  This paragraph should not have been copied and pasted into CP07 because it was not even valid at the time of CP95.  For example, strong evidence of ice multiplication and warm rain processes that undercut the “ripe for seeding” Cumulus descriptions that made the statistical successes of the Israeli experiments so credible (e.g., Silverman 1986) had appeared in 1988 (Rangno).

CP07 (and CP 95) were not aware of, or chose also not to cite,  Gabriel and Rosenfeld (1990) which published the “crossover” result of seeding for Israeli II for the first time. Crossovers consist of combining the results of random seeding in two targets.  The crossover evaluation had been mandated by the Israeli Rain Committee prior to Israeli II (Silverman 2001).    The important result for Israeli II was -2% effect on rainfall, not statistically significant.    Thus, Israeli II had not replicated Israeli I, as also concluded by Rangno and Hobbs (1995), and Silverman (2001).  For comparison, the Israeli I crossover result had indicated a statistically significant 15% increase in rain (e.g., Wurtele 1971).

The null crossover result in Israeli II was due to apparent increases in rain due to seeding in the north target that were canceled out by indications of a whopping 15% decrease in rainfall on seeded days in the south target.  Numerous questions about the “ripe for seeding” clouds of Israel would have been raised had the results for the south target of Israeli II been reported in a “timely manner” and not hidden from view until 1990.

CP07 acknowledge some of the evidence against the Israeli seeding successes later in this chapter, but not all.  This is an improvement over CP95 that had not cited any counter evidence regarding those experiments.   However,  in CP07 the reader will get two interpretations of the same experiments in one book.

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A number of observational and theoretical studies have also suggested that there is a cold temperature “window of opportunity” as well. Studies of both orographic and convective clouds have suggested that clouds colder than-25°C have sufficiently large concentrations of natural ice crystals that seeding can either have no effect or even reduce precipitation (Grant and Elliot, 1974; Gagin and Neumann, 1981; Gagin et al., 1985; Grant, 1986). It is possible that seeding such cold clouds could reduce precipitation by creating so many ice crystals that they compete for the limited supply of water vapor and result in numerous, slowly settling ice crystals which evaporate before reaching the ground. Such clouds are said to be overseeded.  

There are also indications that there is a warm temperature limit to seeding  effectiveness (Grant and Elliot, 1974; Gagin and Neumann, 1981; Cooper and Lawson, 1984). This is believed to be due to the low efficiency of ice crystal production by silver iodide at temperatures approaching -4 °C and to the slow rates of ice crystal vapor deposition growth at warm temperatures. Thus there appears to be a “temperature window” of about -10°C to -25°C where clouds respond favorably to seeding (i.e., exhibit seedability).

CP07 were not aware of, or chose not cite, the extensive literature that contradicted the claims of Grant and Elliott (1974) concerning a cloud top temperature range in which cloud seeding is supposedly viable. This led CP07 to “cut and paste from CP95 that there is a viable cloud seeding window for clouds (with tops) having a temperature range from -10°C to -25°C.  We note that CP07 do not use the term “cloud top” in this discussion, but that’s what the papers they reference are referring to, not just a temperature range within a cloud deck.

That a viable cloud top temperature seeding window of -10°C to -25°C exists as CP07 purport was dealt a severe blow in the Rockies by several papers in which high (10s to 100 per liter) concentrations of ice particles were reported in wintertime clouds with tops  >-25°C including even a contribution from Grant (leader of the Climax, CO, experiments) in Hobbs (1969).

Some of the overlooked papers are: Auer et al. (1969), Cooper and Vali (1981), Marwitz et al. 1976, Cooper and Marwitz 1980, and ground ice crystal concentration reports by Vardiman 1978, and by Vardiman and Hartzell (1976) in support of the Colorado River Basin Pilot Project, and by Grant et al.’s 1982 airborne study that reported no correlation with cloud top temperatures and ice particle concentrations in stable orographic clouds.   

So, the “window of opportunity” for cloud seeding was, at the time of CP95 and in CP07, known to be much more limited compared to what they were in their books.  I brought some of this counter evidence against this purported seeding window to the attention of the first author of CP07 in an email in 1997 to no avail.

There was also a serious drawback to the Grant and Elliott (1974)  study that CP95 and CP07 depended upon; they did not measure cloud top temperatures in the projects they evaluated.  Instead,  Grant and Elliott used constant pressure surfaces as proxies of cloud tops. The use of a constant pressure temperature was shown to be invalid as an index of cloud top temperatures on several occasions (Rangno 1972, 1986, Bartlett et al. 1975, Elliott et al. 1976, Hobbs and Rangno 1979, Mielke 1979, Hill 1980). These studies also went under the CP95 and CP07 “radar.”

There is a similar drawback to the Gagin and Neumann (1981) study; they measured radar tops, not cloud tops; the latter are higher, and their claim of having measured the top of “every cell” in Israeli II, was not true. It was impossible to see the tops of cells in the north end of the north target of Israeli II, nor even very close by when appreciable rain was falling on the Israel Meteorological Service’s 3-cm wavelength radar that Gagin and Neumann used for this purpose (personal communication, 1987, Mr. K. Rosner, the Israeli experiments’ chief meteorologist).  

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Physical studies and inferences drawn from statistical seeding experiments suggest there exists a more limited window of opportunity for precipitation enhancement by the static mode of cloud seeding than originally thought. The window of opportunity for cloud seeding appears to be limited to:

  • clouds that are relatively cold-based and continental;
  • clouds having top temperatures in the range -10°C to -25°C;

The above sentence about cloud top temperatures is profoundly incorrect because neither in CP95 and in CP07 were the authors aware of, or chose not to cite, the many publications concerning wintertime ice in clouds that contradict the assertion that this temperature range presents a viable cloud seeding window.

  • a timescale limited by the availability of significant supercooled water before depletion by entrainment and natural precipitation

We must also recognize that implementing a seeding experiment or operational program that operates only in the above listed windows of opportunity is extremely difficult and costly. It means that in a field setting we must forecast the top temperatures of clouds to assure that they fall within the -10 – 5°C  to perhaps to -15°C  – 25°C  temperature window.

The temperature range above is adjusted to reflect the modern knowledge of ice in clouds in the Rockies and the improved AgI formulations that work more efficiently at higher temperatures.  However, at the higher cloud top temperatures in this range (-10°C to -15°C) in the high barriers of the Rockies the wintertime clouds tend to be too thin for appreciable modification potential.

In summary, the static mode of cloud seeding has been shown to cause the expected alterations in cloud microstructure including increased concentrations ofice crystals, reductions of supercooled liquid water content, and more rapid production of precipitation elements in both cumuli (Cooper and Lawson, 1984) and orographic clouds (Reynolds and Dennis, 1986; Reynolds, 1988; Super and Boe, 1988;Super and Heimbach, 1988; Super et al., 1988).

The documentation of increases in precipitation on the ground due to static seeding of cumuli, however, has been far more elusive with the Israeli  experiment (Gagin and Neumann, 1981) providing the strongest evidence that static seeding of cold-based, continental cumuli can cause significant increases of precipitation on the  ground.

The above statement shouldn’t have been copied and pasted from CP95 into CP07 considering the published contrary evidence available that was available prior to both editions.

The evidence that orographic clouds can cause significant increases in snowpackis  far more compelling, particularly in the more continental and cold-based orographic clouds  (Mielke et al., 1981; Super and Heimbach, 1988).

By citing Mielke et al. 1981, CP07 indicate a lack of awareness of the published literature regarding the experiments conducted at Climax, CO.  Mielke et al. 1981 stratified their results by 500 mb temperatures, which have no meaning for cloud properties as Mielke (1979) himself reported. For those of us who follow the cloud seeding literature, this was a bizarre occurrence in peer-reviewed literature; the official journal reviewers and journal editor who were responsible for this science oxymoron, take note.

A dark cloud (no pun intended) was cast on all of the Colorado State University cloud seeding reports when Rangno and Hobbs (1987) used independent data reduced by NOAA personnel to evaluate the Climax experiments precipitation and upper-level temperature.  CSU personnel had reduced the data in Climax II to speed reporting of its results.  But this was contrary to the prior statements made by the experimenters about these having been independently made measurements (Mielke 1995).  

Rangno and Hobbs (1987) found that the CSU errors created the replication of Climax I by Climax II .  Moreover,  Climax II’s early tainted success through it’s first two years (reported to the Bureau of Reclamation’s cloud seeding division in Grant et. al. 1969,  helped spur the decision by the BOR to fund the massive seven million dollar Colorado River Basin Pilot Project as well as provide CSU and their consultants with about $500,000 to design that experiment in June 1968.   The Climax II errors had a profound effect; Climax I had been virtually error-free.

Furthermore, Rhea (1983) uncited by CP 95 or by CP07,  showed that the optimistic result by Mielke et al. (1981) for Climax II was due to a mistiming of precipitation gauge readings between the target and the control gauges, and not due to cloud seeding.  Thus Climax II did not replicate Climax I as was widely believed.  (Rhea 1983 was published AFTER he made revisions to his paper as had been suggested by Grant et al. in a “Comment” and “Reply” journal exchange behind the scenes.  However, Grant et al. (1983) did not revise their original “Comment” after Rhea made his revisions, an act that misled readers when reading the published exchange in the journal.  Rhea, in a private communication to me in 1986 considered the Grant et al. “Reply” a “smokescreen.”

But even these conclusions have been brought into question. The Climax I and II wintertime orographic cloud seeding experiments (Grant and Mielke; 1967; Chappell et al., 1971; Mielke et al., 1971, 1981) are generally acknowledged by the scientific community (National Academy of Sciences, 1975 1973; Tukey et al., 1978) for providing the strongest evidence that seeding those clouds can significantly increase precipitation.

Nonetheless, Rangno and Hobbs (1987, 1993) question both the randomization techniques and the quality of data collected during those experiments.  They and concluded that the Climax II experiment failed to confirm that precipitation can be increased by cloud seeding in the Colorado Rockies when the NOAA-published precipitation and upper level data for the Climax II experiment was used to evaluate it. Even so, Rangno and Hobbs(1987) did show that precipitation may have been increased by about 10%in the combined Climax I and II experiments

CP07 did not read Rangno and Hobbs (1993),  The 10% increase in snow  CP07 assume occurred was due to Grant and Mielke (1967) building in a huge seeding effect in Climax I in the high 500 mb temperature storm category via the choice of controls mid-way through Climax I.  This initial act caused the entire Climax experiments to suggest an ersatz 10% increase in snow due to seeding in the high 500 mb temperature category.Moreover, the 10% was not statistically significant via 1000 re-randomizations of the combined experiments CP07 refer (I. Gorodnoskya, personal communication, University of Washington Academic Computing Center, 1987, unpublished result).

Once the controls were hard-wired, no further indications of a seeding effect occurred as can be seen in the diagrams below from Rangno and Hobbs (1993).  One can assume that Grant and Mielke were sincere in their belief that a large cloud seeding induced increase in snowfall was being produced at Climax when they chose their controls at the halfway point, but had they realized that it had ended after their choices, the story of Climax I would have turned out far differently.

should be compared, however, to the original analyses by Grant et al.(1969) and Mielke et al.(1970, 1971)which indicated greater than 100% increase in precipitation on seeded days in the high 500 mb temperature category for Climax I and 24% for Climax II. Subsequently, Mielke (1995) explained a number of the criticisms made by Rangno and Hobbs regarding the statistical design of the experiments, including revealing that CSU personnel, and not independent NOAA ones,  as had been claimed on several occasions, were responsible for the errors in the precipitation and upper- level data that created a false replication of Climax I, in particular the randomization procedures, the quality and selection of target and control data, and the use of 500 mb temperature as a partitioning criteria. It is clear that the design, implementation, and analysis of this experiment was a learning process not only for meteorologists but statisticians as well.

PS to the reader: It was not a learning process for the CSU experimenters as claimed above.

Professor Grant was informed in my presence by three different people (I was not one of them) on three occasions in the early 1970s while I was the Assistant Project forecaster for the CRBPP that the stratifications by 500 mb temperatures by he and his group did NOT index cloud top ones as he was claiming.   These refutations of his claims were based on the statements of the prior Park Range Project contractor in Rhea et al. (1969),  and on the rawinsonde data from the on-going Colorado River Basin Pilot Project (e.g., Rangno 1972, Elliott et al. 1976).  500 mb and cloud top temperatures are, in general, poorly correlated.

So, Grant stopped claiming they were strongly related after he received this information in the early 1970s and learned from it?

 No.

 Grant continued to claim (as in Grant and Elliott 1974, Grant and Cotton 1979, Grant 1986) that the 500 mb temperature was representative of cloud top temperature (see Table 8 in Grant and Elliott 1974).   Strangely believe it, Mielke et al. with Grant as a co-author (1981) again stratified results of seeding in Climax I and II by 500 mb temperatures which Mielke himself knew had no physical meaning re cloud tops or cloud microstructure!

Moreover, the CSU experimenters repeatedly and falsely claimed that a graduate student, Furman (1967), had established a relationship between 500 mb and cloud top temperatures (e.g., as in Grant and Elliott 1974). Furman (1967) says nothing about such a relationship in his master’s thesis that consisted of but three days of vertically pointed 3-cm wavelength radar at Climax (Hobbs and Rangno 1979).  Another CSU graduate student, Hjermstad (1970), to refer to Furman’s study as, “scant” in coverage.  

To the outside community, the experimenters were presenting quite a different picture of what Furman had done.  What do we make of this?

For a naive, idealistic newbie into the weather modification/cloud seeding scene like me in the early 1970s in Durango, CO, this was amazing and troubling stuff to experience! CP07 (CSU folk) try to minimize what happened, I think,  by claiming it was a “learning process” when what actually happened was so counter to what we think of as “science”; i. e., that scientists change their minds when new facts come in that contradict their hypotheses.

The results of the many reanalyses of the Climax I and II experiments have clearly “watered down” the overall magnitude of the possible increases in precipitation in wintertime orographic clouds. Furthermore, they have  revealed that many of the concepts that were the basis of the experiments are far too simplified compared to what we know today. Furthermore, many of thecloud systems seeded were not simple “blanket-type orographic clouds” but were part of major wintertime cyclonic storms that pass through the region.As such, there was a greater opportunity for ice multiplication processes and riming processes to be operative in those storms, making them less susceptible to cloud seeding.

The above is a good summary.

 Two other randomized orographic cloud seeding experiments, the Lake Almanor Experiment (Mooney and Lunn, 1969) and the Bridger Range Experiment (BRE) as reported by Super and Heimbach (1983) and Super (1986) suggested positive results. However,these particular experiments used high-elevation silver iodide generators, which increases the chance that the silver iodide plumes get into the supercooled clouds.  Moreover, both experiments provided physical measurements that support the statistical results (Super, 1974; Super and Heimbach, 1983, 1988). Using trace chemistry analysis of snowfall for the Lake Almanor project, Warburton et al.(1995a) found particularly good agreement with earlier statistical suggestions of seeding-induced snowfall enhancement with cold westerly flow. They concluded that failure to produce positive statistical results with southerly flow cases was likely related to seeding mis-targeting of the seeded material.

The reader should be aware that the results of the second randomized Lake Almanor experiment were not fully reported. The effect of seeding in the so-called “cold westerly” cases where a large seeding effect was suggested in the first Lake Almanor experiment, was omitted in the analyses of the second experiment (Bartlett et al. 1975).

Omittted results are always a sign of concern as happened in the Israeli II experiment.  Also of concern, no one has reanalyzed the first Lake Almanor experiment with its overly large percentage increases in snow, also of “concern.”  They don’t seem realistic to me, an expert in ersatz seeding reports and in cloud microstructure.  Someone gimmee that list of random decisions for Lake Amanor I and I’ll check it out!

These two randomized experiments strongly suggest that higher-elevation seeding in mountainous terrain can produce meaningful seasonal snowfall increase.

Independent scrutiny is needed for both of those experiments to strengthen this conclusion.

We noted above, that the strongest evidence of significant precipitation increases by static seeding of cumulus clouds came appeared to come from the Israeli I and II experiments…until Gabriel and Rosenfeld (1990) reported the full results of Israel II.  

Rosenfeld and Farbstein(1992) suggested that the differences in seeding effects between the north and south target areas during Israeli II that were reported by Gabriel and Rosenfeld (1990) is was the result of the incursion of desert dust into the cloud systems. They argue that the desert dust contains more active natural ice nuclei and that they can also serve as coalescence embryos enhancing collision and coalescence among droplets. Together, the dust can make the clouds more efficient rain-producers and less amenable to cloud seeding.

Note:  This “divergent effects” hypothesis began to gain early traction in the scientific community (e.g., J. Simpson, 1989).

Even these experiments have come under attack by Rangno and Hobbs doubted the Rosenfeld and Farbstein (1992) claims, and he launched a reanalysis of both Israeli experiments in 1992 that was published in 1995 (Rangno and Hobbs). That publication drew numerous critical comments from seeding partisans in 1997   From their reanalysis of both the Israeli I and II experiments, they Rangno and Hobbs argued demonstrated that the appearance of seeding-caused increases in rainfall in the Israeli I experiment was due to “lucky draws” or a Type I statistical error as had first  been “red flagged” in Wurtele (1971) for Israeli I due to the highest statistical significance on seeded days in that experiment having been located in a Buffer Zone that was meant to be unseeded between the two targets.  That it was largely unseeded was stated by the Israeli I chief meteorologist in Wurtele’s paper, Mr. Karl Rosner.  Wurtele’s paper should have been cited in CP95 and CP07.

Gabriel and Rosenfeld (1990) and  Furthermore, they Rangno and Hobbs argued showed that during Israeli II, naturally heavy rainfall fell over a wide region that included both targets on north target seeded days, with Rangno and Hobbs expanding the analysis of Gabriel and Rosenfeld (1990) to  include Lebanon and Jordan.  The widespread heavier rainfall on north target seeded days gave the appearance that seeding caused increases in rainfall over the north target area, but since the seeded days in the north were the control days for the south target  and more ordinary storms happened in the south target on its seeded days, created the impression that seeding had decreased rainfall there.   Namely, the presence of “dust/haze” as claimed by Rosenfeld and Farbstein (1992) had nothing to do with the outcome of the Israeli II experiment as evaluated by Rangno and Hobbs (1995).  The lower natural rainfall in the region  encompassing the south target area gave the appearance that seeding decreased rainfall over that target area:  

Not cited by CP07 in this segment is Silverman (2001) in his major review of numerous static glaciogenic seeding experiments, that included the Israeli experiments.  He concluded, as did Rangno and Hobbs (1995), that the two Israeli experiments no longer were credible in proving that rain had been increased by cloud seeding.

We argued above that the “apparent” success of the Israeli seeding experiments was due to the fact that they are more susceptible to precipitation enhancementby cloud seeding. This is because numerous studies (Gagin, 1971, 1975, 1986; Gagin and Neumann, 1974) have had shown that the clouds over Israel are continental having cloud droplet concentrations of about 1,000 cm-3 and that ice particle concentrations are generally small until cloud top temperatures are colder· than-14°C. Furthermore, there is was little evidence found in those early studies for ice particle multiplication processes operating in those clouds.

See Rangno and Hobbs (1988) for a critique of those early studies by Professor Gagin listed above and why they were unrepresentative of most Israeli clouds.  Also see Rangno (1988) for evidence that those early studies were, indeed, highly erroneous as was verified on numerous occasions in later Israeli cloud studies using aircraft (e.g., Levin et al. 1996) and satellite data.  

Rangno (1988) and Rangno and Hobbs (1995) also reported on observations of clouds over Israel that strongly suggested containing they contain large supercooled droplets and quite high ice crystal concentrations at relatively warm temperatures. In addition, Levin et al.(1996) corroborated the Rangno (1988) and Rangno and Hobbs (1988, 1995) inferences when they found high ice particle concentrations, 10s to hundreds per liter, in convective clouds with tops no colder than -13°C.  presented evidence of active ice multiplication processes in Israeliclouds. This further erodes the perception that the clouds over Israel were as susceptible to seeding as originally thought.

Naturally, the Rangno and Hobbs (1995) paper generated quite a large reaction in the weather modification community. The March issue of the Journal of Applied Meteorology contained a series of comments and replies related to their paper (Ben- Zvi, 1997; Dennis and Orville, 1997; Rangno and Hobbs, 1997a,b,c,d, e, the most important of those “Replies”; Rosenfeld, 1997; Woodley, 1997). These comments and responses clarify many of the issues raised by Rangno and Hobbs (1995). Nonetheless, the image of, what was originally thought of as the best example of the potential for precipitation enhancement of cumulus clouds by static seeding has become considerably tarnished.

What have we learned from this chapter?  Caveat emptor concerning reports by those who conducted a “successful” cloud seeding experiments later telling us how ripe with seeding potential those clouds were.

Amen.  Thanks, guys, for this concluding remark largely due to the present writer’s work and skepticism.  This conclusion should have been placed earlier so the reader is not getting two versions of the of the Israeli experiments in having increased rain.

Chapter 3:  The fall of the funding science of weather modificationby cloud seeding

For nearly two decades vigorous research in weather modification was carried out in the United States and elsewhere. As shown in Fig. 3.1, federalfunding in the United States for weather modification research peaked in the middle 1970s at nearly $19 million per year. Even at its peak, funding for weather modification research was only 6% of the total federal spending in atmospheric research (Changnon and Lambright, 1987) and this amount includedconsiderable support for basic research on the physics of clouds and oftropical cyclones. Nonetheless, research funding in cloud physics, cloud dynamics, and mesoscale meteorology was largely justified based on its application to development of the technology of weather modification.Research on the basic microphysics of clouds particularly benefited fromthe political and social support for weather modification.   •

By 1980, the funding levels in weather modification research began to fall appreciably and by 1985 they had fallen to the level of $12 million. After 1985, funding in weather modification research became so small and fragmented that no federal agency kept track of it. Currently the Bureau of Reclamation has onlyabout

$0.25 million per year that can be identified as weather modification. They have operated a program in Thailand that was supported by the Agency for International Development. Basic research in the National Science Foundation that can be linked to weather modification is on the order of $1 million. Likewise, the Department of Commerce has no budgeted weather modification program but has supported a cooperative state/federal program at about the $3.5 million level. This on again- off again “pork barrel” program is supported by congressional write-insrather than a line item in the National Oceanic and Atmospheric Administration (NOAA) budget. In FY-2003, the Bureau of Reclamation administered this program,but no such funds were earmarked for either the Bureau of Reclamation or NOAA inFY-2004 or FY-2005. In this program, states having strong political lobbying support for weather modification are earmarked for support in this program.Overall the total federal program for weather modification in the United Statesis on the order of 10% of its peak level in the middle 1970s. What caused this virtual crash in weather modification research?

Changnon and Lambright (1987) listed the following reasons for this reduction in funding:

  • poor experimental designs;

Changnon and Lambright, as did CP95 and CP07, did not discuss the Bureau of Reclamation’s Colorado River Basin Pilot Project, the nation’s largest, best-planned, and costliest ever randomized orographic cloud seeding experiment based on the work of CSU cloud seeders. The surviving author, Lambright, did not remember why in his reply to a recent email query by this writer.

  • widespread use of uncertain modification techniques;
  • inadequate management of projects;
  • unsubstantiated Faulty claims of success, published in the peer-reviewed literature, ones that should have been caught in the peer-review of manuscripts.  

The “fall” described by CP95 and again in CP07 didn’t have to happen because with solid reviews; there would have been no rise!  If you would like to read about how to stop faulty cloud seeding claims from appearing in the peer-reviewed literature, go here:

https://cloud-maven.com/cloud-seeding-and-the-journal-barriers-to-faulty-claims-closing-the-gaps/

  • inadequate project funding; and
  • wasteful expenditures

Changnon and Lambright concluded that the primary cause of the rapid decline in weather modification funding was the lack of a coordinated federal research program in weather modification. However, there are other factors that also must

  • weather modification was oversold to the scientific community, public and legislatures due to peer-reviewed literature that appeared to show that cloud seeding had worked;
  • demands for water resource enhancement declined due to an abnormal wet period;

 

Clearly there is a great need to establish a more credible, stably funded scientific program in weather modification research, one that emphasizes the need to establish the physical basis of cloud seeding rather than just a”black box” assessment of whether or not seeding increased precipitation. We need to establish the complete hypothesized physical chain of responses to seeding by observational experiments and numerical simulations. We also needto assess the total physical, biological, and social impacts of cloud seeding, or what we call taking a holistic approach to examining the impacts of cloud seeding similar to those conducted during the latter stages of the Colorado River Basin Pilot Project (e.g., Marwitz et al. 1976).  E.K. Bigg, for example (Bigg, 1988, 1990b; Bigg and Turton,1988) suggested that silver iodide seeding can trigger biogenic production ofsecondary ice nuclei. His research suggests that fields sprayed with silveriodide release secondary ice nuclei particles at 10-day intervals and thatsuch releases could account for inferred increases in precipitation 1-3 weeksfollowing seeding in several seeding projects( e.g., Bigg and Turton, 1988).If Bigg’s hypothesis is verified, an implication of biogenic production ofsecondary ice nuclei is that many seeding experiments have thus been contaminated such that the statistical results of seeding are degraded. This effect would be worst in randomized cross-over designs and in experiments inwhich one target area is used and seed days and non-seed days are selectedover the same area on a randomized basis. Thus, not only is the weathermodification community faced with very difficult physical problems and largenatural variability of the meteorology, but they also are faced with thepossibility of responses to seeding through biological processes. (Bigg’s work is not credible to this reviewer.)

We shall see later that scientists dealing with human impacts on global change are also faced with very difficult physical problems, large natural variability of climate, and the possibility of complicated feedbacks through the biosphere. There is also a great deal of overselling of what models candeliver in terms of “prediction” of human impacts over timescales of decades or centuries.

End of “review and enhancement” of CP07’s weather modification chapters.

———–We interrupt this review for a brief personal presentation———

My self-funded trip to Israel (Rangno 1988) was to expose what I thought were faulty, ripe for cloud seeding cloud reports that were the foundation for the belief that seeding had increased rain.   My findings were first confirmed by Levin (1992), reported again in the journals by Levin et al. (1996) and verified in ensuing years several times in satellite imagery and in other airborne measurements.  Spiking fubball here, of course.  How often do researchers go to another’s lab on their own expense and tell him, “I don’t believe your results? Show them to me.”  Cost me a lot of money, but it was worth it.  At the time I went, the Israeli cloud reports had gone unquestioned (e.g., Silverman 1986).

Just before I hopped on a plane to Israel, my lab chief, Professor Peter V. Hobbs described me as “arrogant” for thinking I knew “more about the clouds of Israel than those who studied them in their backyard.”  But when he submitted my paper to the Quart. J. Roy. Meteor. Soc., 12 January 1987, with a copy to Professor A. Gagin, Professor Hobbs wrote to  Gagin that what I was describing  in my paper was the same as he thought about the clouds of Israel (that they were not as Professor Gagin was describing them).  

Professor Hobbs was not being truthful.  I often wonder many times Professor Hobbs might have said that to others, that what I  was reporting was what he had thought all along, robbing me of my insight, my historical trip and year long effort all paid for from my savings.  When I confronted him about this, he sent me a memo that said not to expect a job in his group in the future.  

But, he did hire me back to the job I loved via the magic of reconciliation (mostly) over past wrongs!

———————– 

The references cited in this “Review and Enhancement” that do not appear in CP07:

Auer, A. H., D. L. Veal, and J. D. Marwitz, 1969: Observations of ice crystalsand ice nuclei observations in stable cap clouds. J. Atmos. Sci., 26, 1342-1343.

Bartlett, J. P., Mooney, M. L., and Scott, W. L., 1975:  Lake Almanor Cloud Seeding Program.  Special Regional Weather Modification Conference, San Francisco, CA, 106-111.

Coons, R. D., and R. Gunn, 1951:  Relation of artificial cloud-modification to the production of precipitation.  Compendium of Meteorology,  Amer. Meteor. Soc., Boston, MA. 235-241. 

Coons, R. D., E. L. Jones, and R. Gunn, 1949: Artificial production of precipitation. Third Partial Report: Orographic Stratiform Clouds–California, 1949. Fourth Partial Report: Cumuliform Clouds–Gulf States, 1949. U. S. Weather Bureau Res. Paper No. 33, Government Printing Office, Washington, 46 pp.

Gabriel, K. R., and D. Rosenfeld: The second Israeli rainfall stimulation experiment: analysis of rainfall on both target areas. J. Appl. Meteor., 29, 1055–1067, 1990.

Cooper, W. A., and J. D. Marwitz, 1980: Winter storms over the San Juan mountains. Part III. Seeding potential. J. Appl. Meteor., 19, 942-949.

Cooper, W. A., and G. Vali, 1981: The origin of ice in mountain cap clouds.J. Atmos. Sci., 38, 1244-1259.

Furman, R. W., 1967:  Radar characteristics of wintertime storms in the Colorado Rockies.  M. S. thesis, Colorado State University, 40pp

Grant, L. O., DeMott, P. J., and R. M. Rauber, 1982: An inventory of icecrystal concentrations in a series of stable orographic storms. Preprints, Conf. Cloud Phys., Chicago, Amer. Meteor. Soc. Boston, MA. 584- 587.

Grant, L. O., J. G. Medina, and P. W. Mielke, Jr.,  1983: Reply to Rhea 1983.   J. Appl. Meteor. and Climate, 22, 1482-1484.

Grant, L. O., Chappell, C. F., Crow, L. W., Mielke, P. W., Jr., Rasmussen, J. L., Shobe, W. E., Stockwell, H., and R. A. Wykstra, 1969:  An operational adaptation program of weather modification for the Colorado River basin.  Interim report to the Bureau of Reclamation, Department of Atmospheric Sciences, Colorado State University, Fort Collins, 98pp.

Hill, G. E., 1980: Reexamination of cloud-top temperatures used as criteria of cloud seeding effects in experiments on winter orographic clouds. J. Climate Appl. Meteor., 19, 1167-1175.

Hobbs, P. V., 1969: Ice multiplication in clouds. J. Atmos. Sci., 26, 315-318.

Hobbs, P. V., and Rangno, A. L., 1979: Comments on the Climax randomized cloud seeding experiments.  J. Appl. Meteor., 18, 1233-1237.

Hobbs, P. V., Lyons, J. H., Locatelli, J. D., Biswas, K. R., Radke, L. F., Weiss, R. W., Sr., and A. L. Rangno, 1981: Radar detection of cloud-seeding effects. Science, 213, 1250-1252.

Korolev, A. V., M. P. Bailey, J. Hallett, and G. A. Isaac, and, 2004:Laboratory and in situ observation of deposition growth of frozen drops. J. Appl. Meteor., 43, 612-622.

Kraus, E. B., and P. Squires, 1947: Experiments on the stimulation of clouds to produce rain. Nature, 159, 489-490.

Levin, Z., 1992: The role of large aerosols in the precipitation of the eastern Mediterranean. Paper presented at theWorkshop on Cloud Microphysics and Applications to Global Change, Toronto. (Available from Dept. Atmos. Sci., University of Tel Aviv). No doi available

Levin, Z., E. Ganor, and V. Gladstein, 1996: The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean.  J. Appl. Meteor., 35, 1511-1523.

Marwitz, J. D., Cooper, W. A., and C. P. R. Saunders, 1976: Structure and seedability of San Juan storms. Final Report to the Bureau of Reclamation,University of Wyoming, Laramie, WY, 324 pp.*

Rangno, A. L., 1972: Case study on some characteristics of the specially monitored storm episodes within the Colorado River Basin Pilot Project. Special Project Report to the Bureau of Reclamation, 105pp.

Rangno, A. L., 1988: Rain from clouds with tops warmer than -10 C in Israel. Quart J. Roy. Meteorol. Soc., 114, 495-513.

Rangno, A. L., and P. V. Hobbs, 1988: Criteria for the development of significant concentrations of ice particles in cumulus clouds. Atmos. Res., 22, 1-13.

Rangno, A. L., and P. V. Hobbs, 1997e: Comprehensive Reply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp .https://carg.atmos.washington.edu/sys/research/archive/1997_comments_seeding.pdf

Rangno, A. L., and P. V. Hobbs, 2005: Microstructures and precipitation development in cumulus and small cumulonimbus clouds over the warm pool of the tropical Pacific Ocean. Quart. J. Roy. Meteorol. Soc., 131, 639-673.

Rhea, J. O., 1983: “Comments on ‘A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments. J. Climate Appl. Meteor., 22, 1475-1481.

Simpson, J., 1989:  Amer. Meteor. Soc. Banquet talk transcript on the occasion of her inauguration as president of that organization, October 4th.

Vardiman, L., 1978: The generation of secondary ice particles in cloudcrystal-crystal collisions. J.  Atmos. Sci., 35, 2168–2180.

Vardiman, L., and C. L. Hartzell, 1976: Investigation of precipitating ice crystals from natural and seeded winter orographic clouds. Final Report to the Bureau of Reclamation, Western Scientific Services, Inc., 129 pp.

Wurtele, Z. S., 1971: Analysis of the Israeli cloud seeding experiment by means of concomitant meteorological variables. J. Appl. Meteor., 10, 1185-1192.

Concluding remark:

The entire CP07 reference list, consisting of several hundred references, is  a great resource for research and demonstrated how knowledgable these two authors are.  However, the list above also indicates how difficult a review of a topic is when the amount of literature that appears in journals today can bury you with important citations being missed.

Review and Enhancement of the Cloud Seeding Portion of the 1995 book, “Human Impacts on Climate and Weather”

I received a copy of this book in 1997 and went into a completely objective tantrum when I read the chapters on weather modification/cloud seeding.  Here’s my unedited 1997 letter to one the authors, with, as usual, candid material and why I was upset.  And, why wasn’t I asked to review this portion of their book?  I coulda improved it.  Still, I highly recommend this book overall.  It is likely that the first author is responsible for the cloud seeding portion of this book.

1997 2-16-18 Cotton, to, critique of his book with Pielke_emotions in cloud seeding_ocr

The comments embedded in this article in red font is NOT a hindsight view, but comments that were appropriate at the time this book was submitted/published with the relevant and available missing citations listed.

https://cloud-maven.com/wp-content/uploads/2024/12/Review-and-Enhancement-of-CP95-Human-Impacts-cloud-seeding-discussions-1.pdf

Sincerely,

Art

PS:  This has been made more difficult since in the intervening 30 odd years, I have become social friends with the two authors.  What to do? Nothing, or go forward?

PPS:  It will be interesting to see if CP95 carried out my admonishments in CP2007, the second edition of Human Impacts on Climate and Weather.  Standby.

Review and Enhancement of a 1979 Review of Weather Modification

Oh, yeah, baby!  1979!  The Sex Pistols with Johnny Rotten and punk bands like Black Flag were on the rise! 

My belated review of “Weather Modification” has to be done, IMO:  i.e., corrections and comments, to complete a peer-reviewed article that was published in the journal, Reviews of Geophysics and Space Physics, using literature available to the authors at the time of the article was submitted/published that they omitted or didn’t know about.  

As an aside, omitting stuff happens a LOT in the domain of “weather modification/cloud seeding.”  A recent example, to go into a minor rant, was in the peer-reviewed article by Benjamini et al. 2023 (J. Appl. Meteor. and Climate)  who reported a null result of randomized cloud seeding in Israel.  Benjamini et al.  could not bring themselves to cite my 1995 article with Prof. Peter V. Hobbs (same journal), that concluded cloud seeding increases previously reported by Israeli scientists at the Hebrew University of Jerusalem were illusory.  Thus, there was no reason to think cloud seeding would work in another randomized experiment.  Sure, it’s painful for them to cite my work, but still….same old same old; omit, omit, omit.  Science is not always what you think it should be!

As an expert in some elements that are addressed in the 1979  article, I am happy to be able to improve and clarify it for readers of historic material, should they find it,  before the Grim Reaper drops by.  Here is the full article, which overall is quite good, except for those areas I am intimately familiar with:

A review and enhancement of the “weather modification” review by Grant and Cotton_1979_one column

I am quite candid about WHY I am doing a series of these “reviews and enhancements” of historic material as you will read above.  I tend to get carried away, and so all the minutiae I discuss might be “painful,” too.  I do my best, though.

Sincerely,

Art

A Review and Enhancement of “A Critical Assessment of Glaciogenic Seeding of Convective Clouds for Rainfall Enhancement”

I submitted a long “review and enhancement” on this article by Dr. Bernard A. Silverman’s 2001 massive (14,000 word) review article in the Bulletin of the American Meteorological Society (BAMS) in March 2002.  My “Comments” were too long, the Bulletin editor said, and so it never even went to peer review.  And, he was right, it was too long.

Silverman’s long review article is here.  It’s well worth reading and there is much we agreed on in those days,  if anyone cares:

2001 Silverman Critical assessment 2001ocr

Most of my “review and enhancement” of Silverman’s excellent, unbiased article despite his pro-cloud seeding stance, concerns the Israeli clouds and cloud seeding experiments.  I am an expert in that domain, having spent 11 weeks in Israel in 1986 studying their clouds, rain and sounding data with the full cooperation of the Israel Meteorological Service.  The ensuing article was published in the J. Roy. Meteor. Soc. in 1988.  The gist of it:  the clouds of Israel were not being described correctly by the leaders of cloud the seeding experiments at the Hebrew University of Jerusalem.  They described them as plump with cloud seeding potential when they were not.

In the early 1990s,  I re-analyzed the Israel-1 and Israel-2 randomized experiments along with my co-author, Peter V. Hobbs, director of the Cloud and Aerosol Research Group at the University of Washington, Seattle.  The article, which concluded that there had been no cloud seeding induced increases in rain in these experiments,  was published in the J. Appl. Meteor. in 1995.  Several cloud seeding-centric scientists commented on that paper in 1997 along with our “Replies.”

When I saw Dr. Silverman’s 2001 article and that he had misdescribed some of my own work, I went into a controlled rage of objectivity (haha),  as scientists do from time to time,  and decided to write a “Comment.”  But, as I added more and more material, my  “Comment” became an article in itself, even a “novella” of sorts.    Eventually those 2002  “Comments” led to a full blown article:  “The Rise and Fall of Cloud Seeding in Israel,” that manuscript submitted in 2017 and rejected by BAMS in 2019 (J. R. Fleming, private communication) after two split reviews.  BAMS did not allow me to respond to the comments of the two reviewers or revise my manuscript.

Well, after all these years, I just re-read my critique of Silverman’s 2001 article and thought it had some merit for those of you interested in 1) cloud seeding, 2) Israel.    So, here it is, as it was submitted with a couple of minor corrections and an update.  Caution:  the subject of scientific misconduct is broached. That didn’t help me in 2002, either, but I’ve left it in anyway.

———————————————————————

  1. Introduction

Silverman (2001, hereafter S01) is to be commended for attempting the prodigious task of making sense of all of the randomized cloud seeding experiments targeting cumuliform clouds during the past 40 years.  In large measure he has succeeded and made a significant contribution to the field of weather modification.  Still, some comments and clarifications are needed .

In his historical overview of cloud seeding, S01 should have mentioned the great effort that an independent agency, the U. S. Weather Bureau (USWB), made in attempting to replicate the early and often spectacular claims of seeding successes that began to appear in the late 1940s (e.g., Kraus and Squires 1947).  The USWB (i.e., Coons et al. 1949; Coons and Gunn 1951) seeded dozens of summertime cumuliform clouds in Ohio and along the U. S. Gulf Coast that were similar to clouds in several of the projects examined by S01 with up to “60 lbs of dry ice per mile.”

They found no evidence of any particular seeding effect.

On the contrary, USWB observers found that the turrets usually dissipated or settled back in altitude after they had been seeded.

The USWB scientists also made an unexpected and important discovery: ice was already forming in clouds with tops as warm as –6°C before they had seeded them.  The occurrence of ice was at far higher temperatures than was expected from ground ice nucleus concentration measurements on which seeding hypotheses were based.  Those ground measurements suggested that ice would not form until clouds reached temperatures of –15° to –20°C.  This stunning USWB observation was to be confirmed in more sophisticated aircraft measurements more than ten years later in Missouri during Project Whitetop (Koenig 1963).

The USWB’s independent seeding trials that showed little evidence of seeding having affected rain on the ground, crude as it was, stands tall today relative to the same conclusions about the seeding of cumulus clouds reached by S01 50 years later.

  1. Why weren’t seeding effects produced in the projects reviewed?

One would think that we know how to seed clouds successfully with indisputable scientific evidence for more rain on the ground after more than 50 years of attempting to do so.  However, the production of seeding effects in rainfall on the ground have been preempted by three crucial cloud factors, particularly so in the projects examined by S01:  1) Due to the relatively warm cloud bases in the projects he examined, natural ice forms in, or can be expected to form, in the targeted clouds either within or soon after their summits ascend above –5° to –10°C, the temperature range where seeding might take place; 2) the formation of ice crystals is vastly increased in the temperature range of –2.5° to –8°C in clouds with warm bases once ice has formed due to an explosion of ice splinters and fragments caused by secondary ice-forming mechanisms associated with large drops; and 3) perhaps most surprising to the Bulletin reader: we don’t yet know what the true concentrations of ice particles are in clouds today due to past instrument limitations that have only recently been overcome.

Today’s knowledge concerning ice in clouds has been limited because of our inability to reliably measure ice crystals smaller than about 100 mm in maximum dimension.  Thus, published concentrations, even as high as they have been, have had to necessarily omit the contribution of very small ice crystals to the total in the cumulus clouds that have been sampled (e.g., Koenig 1963; Rangno and Hobbs 1991, 1994; Levin et al. 1996).  Early measurements with a new probe capable of measuring these small ice crystals suggest that the total ice crystal concentrations in clouds will be several times higher than previously thought (e.g., Lawson and Jenson 1998).  Hence we are once again on the verge of learning what the USWB did more than 50 years ago: there is more natural ice in clouds than we imagined.

Therefore, the seeding experiments discussed by S01 were, in a sense, premature since the experimenters had made, and perhaps unavoidably, erroneously low estimates of the amount of natural ice that formed in clouds.  In essence, they were pouring water into a river without knowing whether there was a flood already in progress.

This fact has been demonstrated by Stith et al. (2002) who found little liquid water in tropical cumuli above the –12°C level and but “traces” of liquid water by –18°C.  The clouds studied by Stith et al. represent the kinds of clouds seeded in several of the projects reassessed by S01, those in tropical regions with warm cloud bases and moderate updrafts.  The liquid water in the clouds studied by Stith et al. had been consumed by the explosive natural ice formation taking place in rising turrets at temperatures before they reached the –12°C level and that were glaciated by –18°C.

  1. Project Whitetop

 Project Whitetop (Braham 1979) still remains as one of the most important, enigmatic, and well designed of all the randomized cloud seeding experiments carried out to this day and it was surprising that it was not mentioned by S01.  It was worthy of discussion because of its design and results, and because of the seeding method employed, which probably constituted its only major design flaw.

  1. What made Project Whitetop so special?

Project Whitetop had the three critical attributes that characterize sound experimental design:  the experiment was 1) randomized, 2) the target area and the specific rain gauges for evaluation purposes were identified before the experiment began, and 3) the results were evaluated contractually by those removed from the conduct of the experiment, the institution carrying it out, and the evaluators had no vested interests in cloud seeding.[1]  The importance of these attributes in the conduct and evaluation of cloud seeding experiments cannot be overemphasized.  We do not know from S01 which, if any of his reviewed experiments, had these essential design attributes.

Project Whitetop stirred great interest and controversy when the initial analyses following its conclusion suggested strong decreases in rainfall had been produced by cloud seeding over a wide area (e.g., Lovasich et al. 1969).  Later analyses, however, found that rain was also less on seeded days over wide areas upwind of the seeding line as well and subsequently, most scientists now believe that the random draw was uneven and produced a false negative (Type II statistical error or “unlucky draw”) and seeding actually produced a null result overall (Braham 1979).

What went wrong in Project Whitetop?  First, just as the USWB scientists had found in similar clouds more than 10 years earlier, natural ice was forming in the Project Whitetop clouds at shockingly high cloud top temperatures, between –5° and –10°C, and clouds glaciated (turned completely to ice) with great rapidity (Koenig 1963; Braham 1964). Without doubt,  “ice multiplication” as this phenomenon was later dubbed by Hobbs (1969), seriously compromised the chances of creating more rain on the ground through cloud seeding.  This is because the purpose of the seeding was to create more ice in clouds that were (erroneously) believed by the experimenters to have little ice.

The warm-based Missouri clouds, like those projects in tropical settings discussed by S01, and also like those in Israel, produce copious quantities of large drops (>23 mm diameter) and even precipitation-sized drops (>200 mm diameter) as they ascend past the freezing level, making them ultra-ripe for the onset of various natural ice multiplication mechanisms (e.g., Hallet and Mossop 1974; Mossop 1985; Hobbs and Alkezweeny 1968).  In themselves, these mechanisms can produce effects similar to those produced by cloud seeding (Rangno and Hobbs 1991, 1994).

  1. Were the clouds seeded effectively in the experiments reviewed?

Again, Project Whitetop has something to say about the projects assessed by S01.  Project Whitetop had, in retrospect, a key design flaw: the seeding method used. Instead of injecting the seeding agent into updraft regions of clouds upwind or over the target as would be done today, the three aircraft used in this experiment dispensed it in lines about 50-km long upwind of the target at a height that was just below the bases of the cumulus clouds that might have been forming in the area.  Suitable cumulus clouds (building ones with, or about to have supercooled tops) with updrafts above the aircraft as they dispensed silver iodide was not a criterion for releasing the seeding agent in Project Whitetop.

Whether the silver iodide released by the aircraft in Project Whitetop ever got into suitable clouds, whether it did so at the right locations upwind or in the target, and in what concentrations if it did, was never established.  In fact, the “patrol” seeding, as it is sometimes called, appeared to be relatively ineffective from the ground measurements of ice nuclei concentrations that were made downwind in the target (Bouqard 1963).

Thus, a crucial link in the chain of events in the seeding process in Project Whitetop was completely missing.  The method of seeding suggests another reason why results of Project Whitetop were doubtful; the seeding hypothesis itself may never have been fully tested.

The questionable seeding method used in Project Whitetop was similar to the one that was adopted in the first experiment in Israel that was begun at about the same time as Whitetop, and this in turn affected the choice of seeding method used in the Puglia experiment (List et al. 1999) that S01 discussed.  Patrol seeding was used in the Puglia experiment because it appeared to the Puglia design team that the first experiment in Israel had been a statistical success, and they wished to replicate exactly in their own experiment the seeding methodology that had apparently brought success in Israel.  Whether, in fact, the first experiment in Israel was a success is now subject to doubt on several accounts (e.g., Rangno and Hobbs 1995, 1997a,b.)

The assumptions about dispersion made by the Project Whitetop design team also represents one of several recurring themes in cloud seeding experiments: an exaggerated view of dispersion, an accompanying lack of dispersion measurements prior to cloud seeding experiments, and an underestimate of the natural ice concentrations in the clouds to be seeded.

  1. The two randomized seeding experiments in Israel

The two randomized experiments carried out in Israel deserve special attention beyond that given by S01 because of their importance for a number of years in convincing the scientific community, even the most skeptical scientists, that randomized cloud seeding experiments had finally produced a measurable result (e.g., Mason 1980, 1982; Kerr 1982; Silverman 1986; Dennis 1989; Young 1993; Cotton and Pielke 1995).  Indeed, many have believed that they were the onlyexperiments in cloud seeding that had demonstrated a seeding success among all those that have been conducted. In this context, S01 must be admired for his ability to move from one who has previously validated the results of the experiments in Israel to one who now believes as the author does that they did not prove cloud seeding effectiveness after all. However, some descriptions by S01 of the Rangno and Hobbs (1995, hereafter RH95) reexamination of these experiments are incomplete and require further discussion.

First, why did the experiments in Israel have such great credibility as successes to such a wide audience?  This was because they seemed to have had, for a time anyway, all of the requisites for unambiguous scientific credibility: a sound design that included randomization, a choice of evenly spaced rain gauges (at least in the first experiment) that was limited to all of the gauges in a pre-existing recording rain gauge network, an apparent confirmation of a statistically significant result in a follow-up confirmatory experiment, and a sound cloud microstructural basis for believing that the statistical successes reported were achievable because the clouds were so deficient in ice.

For example, the experimenters reported over a period of many years that the clouds in Israel achieved rather great depths and low cloud top temperatures (to –21°C) while producing little ice or precipitation (i.e., Gagin and Neumann 1974, 1976, 1981; Gagin 1975, 1980, 1981, 1986, hereafter GN74, GN76, GN81 and G75, G80, G81, and G86, respectively).  This left a wide window (–12° to –21° C) for seeding to initiate ice and precipitation in those clouds.  The higher temperature mentioned above demarcated the highest temperature at which appreciable concentrations of the silver iodide seeding crystals would have begun to nucleate and the lower temperature where it was reported that the natural ice concentrations were high enough that seeding was not required to boost ice content.

With cloud bases regularly at 800 m or so above sea level at 5-9°C (GN74, G75), this meant, according to these reports, that there was a large population of non-precipitating or barely precipitating clouds moving into Israel from the Mediterranean Sea that were as much as several kilometers deep.  Furthermore, in support of this picture, the effects of seeding, according to the experimenters, had been in duration of rainfall, not in intensity (G86), a fact compatible with the kind of seeding done.  From these many reports, it all made sense to outside scientists.

It will surprise and trouble many readers who do not follow the cloud seeding literature closely that the reporting of the results of the experiments by those who conducted them was not apropos according to normal scientific expectations.  This unfortunate element of these experiments, which necessarily impacts the reliability of the body of literature about them, is discussed in Section e.

  1. Seeding logistics and heterogeneities in the two experiments in Israel

Perhaps because the patrol method of seeding described in Section 4 had just been adopted by the United States in its major test of seeding in Project Whitetop, the experimenters in Israel, about to embark on their own major seeding trial at about the same time (in the late winter of 1960-1961), also chose this method.  In fact, patrol seeding was used almost exclusively in the six years of the first experiment (National Academy of Sciences 1973, GN74).[2]

However, the experimenters in Israel used a seeding track that was 65-75 km long, or about 15-25 km longer than the one used in Project Whitetop (Gabriel 1967).  Moreover, they had but a single twin-engine aircraft available to them to seed a longer experimental period over which rainfall was to be evaluated for seeding effects, a 24 h day vs. Project Whitetop’s 14 h experimental period.  Most remarkably, seeding by this method was carried out for an average of only about 4 h of the 24 h experimental day and yet still seemed to have produced statistically significant results (Gabriel 1967; Wurtele 1971; GN74).   The precipitation climatology of Israel, that makes this an astonishing fact, was discussed by RH95.

 Not surprisingly, the experimenters themselves came to realize the inadequacy of coverage of the 4 h per day of patrol seeding by a single aircraft in the first experiment.   When their second experiment began in the fall of 1969, they had added no less than 42 ground generators and a second aircraft with aircrews to man them 24 h a day (National Academy of Sciences 1973).

These new and greatly extended sources of seeding in the second experiment constituted an enormous heterogeneity in seeding coverage in the amount of seeding material released, and a shift in the methodology between the two experiments from solely airborne seeding to mainly ground seeding supplemented by airborne seeding.  Yet, implausibly, according to the partial statistical reports of the experimenters, the enormous increase in seeding and the shift in methodology produced virtually the same seeding result as in the first experiment, a 13% increase in rainfall in the North target (e.g., GN81) compared with the 15% overall increase in both targets of the first experiment when only seeding 4 h per day took place.

  1. The cloud microstructure of Israel does not make a case for seeding having produced statistically significant results in the experiments

A second factor that makes it implausible that the 4 h of seeding produced the statistical results reported in the first experiment, or effects in the second is that the clouds of the eastern Mediterranean are, in fact, largely unsuitable for seeding due to high concentrations of ice and the onset of ice at slightly supercooled cloud top temperatures (e.g., Rangno 1988; Rangno and Hobbs 1988, 1995, 1997a,b; Levin et al. 1996).

However, S01 stated that a “fraction” of the clouds of Israel do not correspond to those required for seeding to be effective.   S01, by using the phrase “a fraction of” the clouds may have been “unsuitable” for seeding, presumably means that some of the clouds making landfall on the Israeli coastline where they were to be seeded already contained high natural ice crystal concentrations and thus had no seeding potential, or had tops that were too warm for seeding to be effective, or were stratiform in nature with no updrafts below them to draw the seeding material upward as was noted in RH95.

However, the word “fraction”, as used by S01, is ambiguous and may inadvertently mislead Bulletin readers by suggesting that it means  “a small amount of.”

In fact, it would be a rare day in which high ice concentrations are not observed in mature and aging cumuliform clouds with tops  >–14°C.  Levin et al. (1996) gathered ice concentrations in clouds with tops warmer than about –14°C on several rather ordinary shower days in Israel and found tens to hundreds per liter in those clouds. The author directs the reader to papers that discuss the cloud microstructure of Israel (Rangno 1988, 2000; Rangno and Hobbs 1988, 1995, 1997a,b).

       2.  The stratifications of seeding effects by the cloud top temperatures in the second experiment are unreliable

S01 repeats the cloud top temperature stratifications that were reported on numerous occasions by the experimenters as having strongly partitioned seeding effects in the second experiment.  The experimenters reported, for example, that the maximum seeding effect in the second experiment was a 46% increase in rainfall compared with control days when the cloud top temperature was in the range of  –15° to –21°C (e.g., GN81).

However, the cloud top temperature stratifications by the experimenters are unreliable for several reasons and should not be quoted (RH95).  Also, in view of the tens to hundreds per liter ice particle concentrations found in the clouds of Israel with tops warmer than about –14°C on rather ordinary showery day situations (Levin et al. 1996), combined with the discovery that rain routinely falls from clouds with tops warmer than –10°C (Rangno 1988), it is no longer scientifically credible that the strongest seeding effect was produced in clouds that had top temperatures between –15° and –21°C where excessive natural ice crystal concentrations already exist.

       3.  Discussion of statistical issues:   Israel-1

S01 stated that RH95 concluded that the results of the first experiment were due to a false positive or Type I statistical error based solely on evidence reported by Wurtele (1971).   RH95 performed a “cradle to grave” analysis of the first experiment and several significant factors, besides the fact that the greatest apparent seeding effect was in a region that was avoided by the seeding aircraft, led us to our conclusion. We direct the reader to our paper and subsequent discussions of this issue (Rangno and Hobbs 1995, 1997a, 1997b; Rosenfeld 1997).

On the other hand, S01 himself offers no explanation in his evaluation of the first experiment about why the statistical significance was highest in the little-seeded Buffer Zone (BZ) that lay between the two targets.  In ignoring this fact S01 does not heed the same large “red flag” that should have raised skepticism about the statistically significant results in the first experiment more than thirty years ago.

No less than the chief meteorologist for the first experiment[3] stated, with notable candor in Wurtele (1971), that the BZ could only have been seeded 5-10% of the time, a conclusion sustained in RH95.  Moreover, GN74, themselves puzzling over this same statistical anomaly in the BZ, concluded that relying on a seeding argument for the BZ anomaly was weak (though they did it anyway) since the statistical significance in the BZ also accrued on seeded days in which the lone seeding aircraft did not even fly!

It would be interesting to learn what knowledge S01 has developed to refute these assessments by the experimenters themselves.       

      b.   Israel 2

Two Type I statistical errors in a row (lucky draws) is a slim possibility as some have noted concerning RH95.  However, two false positives in a row did not occur in the Israeli experiments when the same crossover scheme was used to evaluate both of them as was called for in the a priori design (Gabriel and Rosenfeld 1990, Silverman 2001).

Second, when using the South target gauges as the control for the North target area, as was also specified in the a priori design (e.g., GN74), a null result for the second experiment was produced again (Gabriel and Rosenfeld 1990; RH95).

However, in a third design component of the second experiment, a statistically significant result was evinced when a few rain gauges in a coastal plain upwind of the North target area were used to assess seeding effects in the target (GN81).  The statistical significance so obtained in the third of the three design evaluation components comprises the second statistically significant result in a row that S01 refers to.  Are you following me, reader?

At first glance, perhaps the achievement of any statistical significance in even one of the three design components is an impressive result even if it is outweighed by two null results (both of which went unreported at the time).

However, in a wider analysis than that performed by the experimenters, or by Gabriel and Rosenfeld (1990), RH95 found comparable or even heavier rain that fell on the seeded days in the North target area also fell over a wide region in and outside of northern Israel; namely, in central and southern Lebanon, western Jordan, and in Israel south of the North target area including Jerusalem itself!  Ironically, the experimenters had their offices in Jerusalem and were somehow oblivious to the heavy rain they were receiving when they seeded the North target area some 100 km to the north.

The single exception to this regional pattern of markedly heavier rain on North target area seeded days was in the coastal plain upwind of the North target area that had been pre-selected as a control zone.

The widespread regional pattern of bias in rainfall discovered by RH95 on North target seeded days suggests to meteorologists that the random draw was flawed or compromised by a bias in the weather systems that favored heavier rain over a synoptic scale region on North target area seeded days.

The second point that weakens the statistical significance obtained in the North target area is that those conducting the experiment did not specify the rain gauges for the evaluation prior to the experiment contrary to good scientific design (e.g., Court 1960).  Not naming gauges, or not using all of the established gauges in post analysis allows for “cherry-picking” of those gauges to find whatever result one wanted to find[4].

           c. The delayed reporting of statistical results and other actions by the experimenters constituted scientific misconduct and therefore the body of work by those researchers is inherently compromised

 S01 should be applauded for his valiant attempt in his review to ferret out the misleading reports of statistical significance.  However, there is a far more important test of the reliability of published results that S01 did not consider: if demonstrable scientific misconduct occurs in the reporting of results, then no publication by the wayward author(s) before or after this time can be considered reliable and they should not be quoted.

But what is “scientific misconduct”?

“Drug Maker Admits That It Concealed Tests Which Showed Flaws.”

“The Warner-Lambert Company, one of the nation’s largest drug companies, pleaded guilty yesterday to criminal charges and agreed to pay a $10 million fine for hiding from the Food and Drug Administration faulty manufacturing processes used for several drugs….”

                                                                                                –New York Times,  p1, 29 November 1995

Most readers can recognize egregious scientific misconduct such as concealing data that impact and change the conclusions of an experiment in which only favorable and therefore, deceptive results are published,  as described in the newspaper story above.

Misconduct also occurs when researchers conceal for many years the results of new experiments that contradict those of their previously published “successful” experiments on which the scientific community and public have depended upon.

Misconduct can also be understood to have occurred when a researcher denies access to his “lab” to bonafide workers in his field who have come to study and validate his unique long-published results, results that only his lab in all the world have produced with the “equipment” he has used.

We can all recognize these acts as contrary to the values of science and its pursuit of  truth.  An action such as the latter is particularly odious when the researcher’s much ballyhooed results are later shown to be wholly fictitious.

Very regrettably, all three acts of misconduct occurred in the cloud seeding experiments in Israel.  It is a matter of record that the experimenters chose to conceal the negative statistical results that accrued in the randomly seeded South target area of Israel-2 from the time that experiment ended in the spring of 1975 until 1990. These omitted statistical results, when incorporated into the mandated crossover evaluation of that experiment, resulted in a null (-2%) seeding effect (Gabriel and Rosenfeld 1990).[5]  Thus, the complete second experiment had not replicated the results of Israel-1 as Silverman (2001) also concludes but had been widely believed based on the experimenters’ partial reports limited to the North target area (e.g.,  Tukey et al. 1978, Kerr 1982; Silverman 1986).

The experimenters also chose to conceal from their colleagues the ongoing results of a third randomized cloud seeding experiment, Israel-3, that was taking place in central and southern Israel.  This experiment began in the fall of 1975 and ended in 1994.  The random seeding in this experiment suggested year after year that seeding was having no effect or possibly decreasing the rainfall in the target (e.g., Rosenfeld and Farbstein 1992; Rosenfeld 1998).  The first interim results of the third randomized experiment were not mentioned until 1992, 17 years after it had begun.  This reporting behavior is in contrast to the positive reports that were issued in journals part way through the first and second experiments by Gabriel 1967 and GN74 when the effects of seeding were indicated to be positive.

In summary, during 24 consecutive years of randomized seeding in the south target  in Israel-2 and -3 combined, had less rainfall (about 10%) on seeded days than on the control days.   This contrary knowledge was hidden from the scientific community for more than 15 years.  The original authors of the partial reports passed away before these concealed results were, or could be, reported in journals for the outside community to evaluate.

No one can doubt that the crucial negative statistical results of seeding described above in Israel-2 and -3, would have raised many questions, and should have been made known om a timely manner, first of all, to the experimenters’ own countrymen, to the outside scientific community as a whole, and especially to the scientific community in Jordan downwind of central and southern Israel that might have been impacted by the remote possibility of having their rainfall decreased.

In a third example of misconduct, this writer, known to the leader of the Israeli experiments as a skeptic[6] of the cloud microstructure reports that he had been publishing in journals, was denied access to the experimenters’ two radars during rainy spells to examine the heights (and temperatures) of precipitating clouds during his 11-week visit to Israel in early 1986.  One of the radars, a vertically pointing X-band or 3-cm wavelength radar, was located near the offices of the experimenters at a satellite office of the Hebrew University of Jerusalem.  The second, a C-band or 5.5-cm wavelength radar, was located on the grounds of Ben Gurion Airport to which this writer bicycled to from Tel Aviv for a meeting with the leader of these experiments who forbade him to go there during storms due to “airport security.”

From the rawinsonde data analyzed by me in 1988, and from the airborne data of Levin et al. 1996 we now know why the experimenters did this.

It doesn’t seem possible to conjure up the magnitude of incompetence required on the part of the experimenters to misinterpret so many cloud measurements over so many years from the many measurement sources they had at their disposal:  their own radars, satellite thermal imagery which they used routinely for forecasting cloud seeding opportunities and in their research reports (e.g., Rosenfeld 1980; G80), their own aircraft that for two rainy seasons skimmed the tops of clouds over their vertically pointing radar at Jerusalem (e.g., G80).   And, of course, they also had the Israel Meteorological Service (IMS) rawinsonde profiles launched up to four times a day from Bet Dagan (near Tel Aviv )from which it could be discerned that the clouds were not as they were describing them.

In view of these documentable instances of misconduct by the experimenters, none of the publications regarding cloud seeding, or its potential in Israel or elsewhere by those who participated in these acts, can be considered reliable.  Such publications should not be quoted until the full story concerning the actions of the experimenters is revealed.   Of particular interest is the original list of random decisions for Israel-2 due to the extreme one-sided nature of that draw on seeded days (Gabriel and Rosenfeld 1990).  We need to be sure that the list wasn’t compromised when heavy rain was forecast by the Israel Meteorological Service.  From experience in commercial projects, I know that it’s satisfying to say when someone asks that you seeded when heavy rain falls.

  1. But why discuss misconduct in science? Won’t a discussion of, or a finding of “misconduct” diminish public support of science?  And won’t that, in turn, lessen the job opportunities that we workers in science might have?

In fact, from our own narrow purview, it could be (and will be by some) argued that we should never discuss or even mention misconduct in any area of science.  Rather, we should promote the thought that as scientists, we are not like other people, but, in fact, are superior to them and never do anything wrong or fraudulent because of our training like other people.  Sarcasm here.

Of course, we must not only discuss but eradicate misconduct from our ranks or others will.  And, yes, it is likely that there will be some erosion of public support for cloud seeding in the face of reports of misconduct in that field.  Someone may indeed lose his job.

But from a larger viewpoint, it is an outrage to not consider the question of whether scientific misconduct occurred that resulted in misspent tens of millions of public dollars.

Most worrisome, there are no guarantees that this will not happen again. We do not know, for example, if more data relative to cloud seeding or cloud microstructure are being concealed or consciously misanalyzed by this same group in ongoing efforts to justify what now appears to be a dubious operational cloud seeding program begun by the Israeli government in 1975 that was based on the experimenters’ partial statistical reports of seeding success and descriptions of  fictitious clouds.

Update: Due to the re-analysis of the Israeli experiments in 1995, and the subsequent journal exchanges in 1997, a panel was formed by the Israeli government to independently examine the results operational cloud seeding of the Sea of Galilee (Lake Kinneret) that began with the winter of 1975-76.  The panel found no  viable evidence that cloud seeding had increased runoff into the Sea of Galilee over a 27 year period (Kessler et al. 2006, Sharon et al. 2008).  Israel-4 ended with a null result after seven seasons of randomized seeding (Benjamini et al. 2023).

A reputational dark cloud will hang over the group from which these acts originated until the details are fully known and the data in these papers verified.  An independent panel of inquiry into these matters, while time consuming, can only benefit all parties by lifting this dark cloud so that we can move ahead.

On the other hand, the field of cloud seeding is unique in the atmospheric sciences.  Its past charlatans, quacks, and even misguided, self-deceived but sincere scientists who made ludicrous claims about seeding effects, have been well documented throughout its history (e.g., Fleming 2010).  In the early days of modern cloud seeding we had the USWB with their aircraft and their independent scientists (e.g., Coons and Gunn 1951) to invalidate some of the outrageous claims being made.

Today, it seems, we have only the peer-review process to ensure that the truth is told.  And, from the many reversals of published findings of major, even widely accepted experiment results, some once seen as having “proved” cloud seeding as evaluated by our best scientists (e.g., National Academy of Sciences 1973), we can conclude that peer-review is but a thin “firewall” indeed against this type of more subtle quackery.

Workers in weather modification today, like S01, with their own continuing silence on the matter of the omitted, crucial statistical results of the experiments conducted in Israel, are exhibiting an eerie tolerance for a pernicious kind of science reporting in journals on cloud seeding that, from this author’s viewpoint, threatens to destroy this field altogether.

 

REFERENCES

Benjamini, Y, A.,  Givati, P.,  Khain, Y. Levi, D. Rosenfeld, U. Shamir, A. Siegel, A. Zipori, B. Ziv, and D. M. Steinberg, 2023:  The Israel 4 Cloud Seeding Experiment: Primary Results.   J. Appl. Meteor. Climate, 62, 317-327.  https://doi.org/10.1175/JAMC-D-22-0077.1

Bouqard, A. D., 1963: Ice nucleus concentrations at the ground.  J. Atmos. Sci., 20, 386-391.

Braham, R. R., Jr., 1964: What is the role of ice in summer rain-showers?  J. Atmos. Sci., 21, 640-646.

_______________., 1979:  Field experimentation in weather modification.  J. Amer. Stat.

        Assoc., 74, 57-68.

Coons, R. D., E. L. Jones, and R. Gunn, 1949: Artificial production of precipitation.  Third Partial Report: Orographic Stratiform Clouds–California, 1949.  Fourth Partial Report: Cumuliform Clouds–Gulf States, 1949.  U. S. Weather Bureau Res. Paper No. 33, Government Printing Office, Washington, 46 pp.

_________, and R. Gunn, 1951: Relation of artificial cloud modification to the production of precipitation.  Compendium of Meteorology.  Amer. Meteor. Soc., 235-241.

Cotton, W. R., and R. A. Pielke, 1995: Human Impacts on Weather and Climate, 2nd edition, Cambridge University Press, 288 pp.

Court, A., 1960: Evaluation of cloud seeding trials.  J. Irrig. and Drainage Div., Proc. Am. Soc. Civ. Eng., 86, No. IR 1, 121-126.

Dennis, A. S., 1989: Editorial to the A. Gagin memorial issue. J. Appl. Meteor., 28, 1013.

Fleming, J. R., 2010:  Fixing the Sky:  The Checkered History of Weather and Climate Control.  Columbia University Press,  306pp.

Gabriel, K. R., 1967: The Israeli artificial rainfall stimulation experiment: statistical evaluation for the period 1961–1965.  Proceedings, Fifth Berkeley Symposium on Mathematical Statistics and Probability, Vol. 5, L. M. LeCam and J. Neyman, eds., University of California Press, 91–113.

_______, and D. Rosenfeld, 1990: The second Israeli rainfall stimulation experiment: analysis of rainfall on both target areas.  J. Appl. Meteor., 29, 1055–1067.

Gagin, A., 1975: The ice phase in winter continental cumulus clouds.  J. Atmos. Sci., 32, 1604–1614.

________, 1980:  The relationship between the depth of cumuliform clouds and their raindrop characteristics.  J. Res. Atmos., 14, 409-422.

_______, 1981:  The Israeli rainfall enhancement experiments. A physical overview. J. Wea. Modif., 13, 1–13.

________., 1986: Evaluation of “static” and “dynamic” seeding concepts through analyses of Israeli II and FACE-2 experiments. In Precipitation Enhancement–A Scientific Challenge, Meteor. Monog., 21, No. 43, Amer. Meteor. Soc., 63-70.

_______, and J. Neumann, 1974: Rain stimulation and cloud physics in Israel. Weather and Climate Modification, W. N. Hess, Ed., John Wiley and Sons, 454–494.

________., and J. Neumann, 1976: The second Israeli cloud seeding experiment–the effect of seeding on varying cloud populations. Proc. II WMO Sci. Conf. Weather Modification, Boulder, WMO Geneva, 195-204.

_______, and _________, 1981: The second Israeli randomized cloud seeding experiment: evaluation of results.  J. Appl. Meteor., 20, 1301–1311.

Hallett, J., and S. C. Mossop, 1974: Production of secondary ice particles during the riming process. Nature, 249, 26-28.

Hobbs, P. V., 1969:  Ice multiplication in clouds.  J. Atmos. Sci., 26, 315-318.

__________., and A. J. Alkezweeny, 1968:  The fragmentation of freezing water droplets in free fall.  J. Atmos. Sci., 25, 881-888.

Kerr, R. A., 1982: Cloud seeding: one success in 35 years.  Science, 217, 519–522.

Kessler, A., A. Cohen, D. Sharon, 2006:  Analysis of the cloud seeding in northern Israel. A report submitted to the Israel Hydrology Institute and the Israel Water Management of the Ministry of Infrastructure, In Hebrew with an English abstract). 117pp.  No doi.

Koenig, L. R., 1963:  The glaciating behavior of small cumulonimbus clouds.  J. Atmos. Sci., 20, 29-47.

Kraus, E. B., and P. A. Squires, 1947:  Experiments on the stimulation of clouds to produce rain.  Nature, 159, 489-492.

Lawson, R. P., and T. L. Jensen, 1998: Improved microphysical measurements in mixed phase clouds. Preprints, Conf. Cloud Phys., Everett, WA, Amer. Meteor. Soc. 451-454.

Levin, Z., E. Ganor, and V. Gladstein, 1996: The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean.  J. Appl. Meteor., 35, 1511-1523.

List, R., K. R. Gabriel, B. A. Silverman, Z. Levin, and T. Karacoastas, 1999:  The rain enhancement experiment in Puglia, Italy:  statistical evaluation.  J. Appl. Meteor. 38, 281-289.

Lovasich, J. L., J. Neyman, E. L. Scott, and J. A. Smith, 1969: Wind directions aloft and effects of seeding on precipitation in the Whitetop experiment.  Proceedings, National Acad. Sci., 64, 810-817.

Mason, B. J., 1980:  A review of three long-term cloud-seeding experiments.  Meteor. Mag., 109, 335-344.

___________, 1982:  Personal reflections on 35 years of cloud seeding.  Contemp. Phys., 23, 311-327.

Mossop, S. C., 1985: Secondary ice particle production during rime growth:  the effect of drop size distribution and rimer velocity.  Quart. J. Roy. Met. Soc., 111, 1113-1124.

National Academy of Sciences, 1973: Weather Modification: Progress and Problems. T. F. Malone, ed., 258 pp. (Available from the National Research Council, Washington, D. C.)

Rangno, A. L., 1988: Rain from clouds with tops warmer than –10°C. Quart J. Roy. Meteor. Soc., 114, 495-513.

___________, 2000:  Comments on “A review of cloud seeding experiments to enhance precipitation and some new prospects.” Bull. Amer. Meteor. Soc., 81, 583-585.

____________, and P. V. Hobbs, 1988: Criteria for the development of significant concentrations of ice particles in cumulus clouds. Atmos. Res., 22, 1-13.

_____________, and __________, 1991: Ice particle concentrations and precipitation development in small polar maritime cumuliform clouds. Quart. J. Roy. Met. Soc., 117, 207-241.

___________, and __________, 1994:  Ice particle concentrations and precipitation development in small continental cumuliform clouds. Quart. J. Roy. Meteor. Soc., 120, 573-601.

___________,  and P. V. Hobbs, 1995: A new look at the Israeli cloud seeding experiments.  J. Appl. Meteor., 34, 1169-1193.

___________, and _________, 1997a: Reply to Rosenfeld.  J. Appl. Meteor., 36, 272-276.

___________, and _________, 1997b: Comprehensive Reply to Rosenfeld. Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25 pp.

Rosenfeld, D., 1980:  Characteristics of rain cloud systems in Israel derived from radar and satellite images.  M. S. Thesis, The Hebrew University of Jerusalem, Israel, 129 pp. (Available from the Department of Geosciences, Hebrew University of Jerusalem, Israel)

___________, 1997: Comment on “Reanalysis of the Israeli Cloud Seeding Experiments.” J. Appl. Meteor., 36, 260-271.

___________, 1998: The third Israeli randomized cloud seeding experiment in the south: evaluation of the results and review of all three experiments. Preprints, 14th Conf. on Planned and Inadvertent Wea. Modif., Everett, Amer. Meteor. Soc. 565-568.

___________., and H. Farbstein, 1992: Possible influence of desert dust on seedability of clouds in Israel. J. Appl. Meteor., 31, 722-731.

Sharon, D., A. Kessler, A. Cohen, and E. Doveh, 2008:  The history and recent revision of Israel’s cloud seeding program.  Isr. J. Earth Sci., 57, 65-69.     https://DOI.org/10.1560/IJES.57.1.65.

Silverman, B. A., 1986: Static mode seeding of summer cumuli–a review. In Precipitation Enhancement–A Scientific Challenge, Meteor. Monog., 21, No. 43, 7-20.

_____________, 2001:  A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement.  Bull. Amer. Meteor. Soc., 82, 903-923.

Stith, J. L., J. E. Dye, A. Bansemer, A. J. Heymsfield, C. A. Grainger, W. A. Petersen, and R. Cifelli, 2002:  Microphysical observations of tropical clouds.   J. Appl. Meteor., 41, 97-117.

Turkey,  J. W.,  D. R. Brillinger, and L. V. Jones, 1978b: Report of the Statistical Task Force to the Weather Modification Advisory Board, Vol. II.  U. S. Government Printing Office, pE-3.

Young, K. C., 1993: Microphysical Processes in Clouds.  Oxford University Press, 335-336.

Wurtele, Z. S., 1971: Analysis of the Israeli cloud seeding experiment by means of concomitant meteorological variables. J. Appl. Meteor., 10, 1185-1192.

Footnotes

[1] The University of California Statistical Laboratory under the direction of Jerzey Neyman.

[2] Four ground generators were located in hilly terrain in the extreme northeast portion of the country.

[3] The Chief Meteorologist for the seeding experiments in Israel was misidentified by Wurtele (1971) as a meteorologist with the Israel Meteorological Service.

[4] Rangno and Hobbs (1995) used a subset of rain gauges that whose data were routinely published in monthly or annual summaries by the Israel Meteorological Service and therefore, were “pre-selected” by the Israel Meteorological Service, an agency not affiliated with the seeding experiments.

5 Even then, these “full” statistical results for the second crossover seeding experiment were not published in a vacuum; but only after the leader of the experiments passed away in 1987, and after a letter-writing campaign to Israeli government offices by the former Chief Meteorologist of the experiments urging the experimenters to publish the full results.

[6] My July 1983 submitted article,  asserting that rain was falling from clouds with tops much warmer than could be accounted for by the experimenters’ cloud descriptions was rejected by J. Climate  Appl. Meteor. in 1983 (B. A. Silverman, co-chief Editor, private communication.)  Moreover, the leader of the experiments in Israel had provided a lengthy and perhaps pivotal negative review of that paper (A. Gagin, 1984, private communication.)

The Catalina, AZ, 2023-24 Water Year

Check it out.  We’re still having generally greater totals than we had during those many droughty years of the late 1990s to about 2012 that caused so much speculation about longterm permanent drought here due to global warming (later rephrased to “climate change” after a hiatus in global warming that began around 1999 and lasted more than a decade).    The red line is a quadratic fit to the data.  Let’s hope those greater WY totals of late continue despite overall gradual warming over this whole period.

The Catalina WY record happened to begin in 1977-78 right at the beginning of one of the wettest few years in hundreds of years in the Southwest generally as seen in tree ring records.  The overall Arizona statewide average (unfortunately presented by calendar years by NOAA) doesn’t show much going on over the past 100 years, see lower graphic through 2022, the latest year available.

Catalina Cool Season (October-May) Was Slightly Above Average

Here’s a long term graph with a curve fit of the Catalina October through May precipitation beginning in 1977.

The Catalina record begins with an extraordinary wet spell in 1977-78 through the early 1980s, augmented by El Niñoes and possibly the Pinatubo eruption in the early 1990s. The initial wet spell was  associated with a shift in the so-called “Pacific Decadal Oscillation.”  The red line is a polynomial fit to the data.  It seems to suggest a recovery is underway from the overall drier winters of the early 2000s despite the 2020-21 Oct-May drought.  Will a recovery continue?  Is it real?

A New Decadal Climate Oscillation Detected in Past Data a Long Time Ago? A Fool’s Journey? Namias Reacts

Purpose of this post of ancient, unfinished work with the humorous title:  Could it inspire someone to continue it in a more sophisticated way than I have?

Named climate/weather influencing  “oscillations” have become so numerous in the scientific literature (e.g., Atlantic Meridional Oscillation, Arctic Oscillation, Pacific Decadal Oscillation, El Niño-Southern Oscillation, Atlantic Oscillation, Quasi-Biennial Oscillation, Madden-Julian Oscillation, etc.)  one is tempted to ask humorously, “Doesn’t everyone have one?”

Well, I do, but this research is incomplete.  And it may ne bogus, illusory; it seems to lead to a dead end.  Still, “we” journey on, hoping these early findings, incomplete as they are and needing to be updated, will nevertheless bring someone a Nobel Prize in meteorology.  (Also still waiting for some kind of science prize or medal from Israel for the work I’ve done there in exposing faulty cloud seeding results and descriptions of non-existent clouds supposedly ripe with seeding potential (Rangno and Hobbs 1995, Rangno 1988).  But, as the Prunes sang, I had too much to dream last night.

https://youtu.be/-xRRT92Fpgs

Let us begin this story from the beginning.  Let us explore how a gigantic amount of work, consuming work, really,  thousands of hours of personal effort, can lead to a dead end. Maybe.

The oscillation story begins in an undergraduate  climatology class I took at San Jose State College in the late 1960s.  Each of us was assigned to do a climate research project.  I chose to do something on Los Angeles Civic Center rainfall, something I had been charting since childhood.  I graphed the days with measurable rain over the period of record for the Civic Center  going back to the 1877-78 “rain season.”  In California, the period of July 1 through June 30 is deemed the “rain season.”  That was the way rainfall data were presented in the newspapers.  The California “rain season” is similar to the water year precipitation totals widely used in the western US for the period of October 1 through September 30.  If you are a meteorologist in the West, the calendar year is generally eschewed in place of rain season or water year since the latter capture the character of whole winters and better account for snowpacks in mountains.

I saw an interesting phenomenon in the plot of days with measurable rain; there appeared to be an “instability”; a jump to much wetter conditions after a decades long trend of declining days with measurable rain. After reaching what appeared to a minimum of days with measurable rain, there was a  sudden jump in the next season to one having considerably more than the average.  But, it wasn’t just one season that had many more days with rain!  It was most of the next ten rain seasons that had above average days with rain.  This had happened in my plot on three occasions; the season following 1903-04, the season following 1933-34, and lastly, the season following 1976-77.  Namely, it wasn’t just a one-shot wonder, a season long singularity.

I was EXCITED!  So excited I eventually sent my Los Angeles Civic Center plot to a famous professor of climate and weather at Scripps Institution of Oceanography, Prof. Jerome Namias. I had read his papers in the Monthly Weather Review.  (I had begun subscribing to this journal when I was 13 years old. By this time I had seen that these same three jumps had occurred at San Luis Obispo, Santa Barbara, and San Diego.  There was no evidence of this phenomenon at San Francisco; it faded to the north.

If you’re a Los Angeles or Southern California “precipophile” like me, you might well guess immediately why I wasn’t so much interested in rain totals as with days with measurable rain.  A couple of huge storms can hide the character of a whole rain season, but the character of a rain season would be called out by days with rain.  An extreme example:  on New Year’s Eve, December 1933 into New Year’s Day, 1934, Los Angeles received it’s greatest 24 h rainfall:  7.36 inches!  Approximately half fell in December 1933 and a little more than half in January 1934.   The season’s rainfall total that year was 14.64 inches, or just about average.  HOWEVER, the DAYS with rain was two standard deviations below average! That’s “what done it” for me, that extraordinary rain day and why rain totals might hide the real character of a winter’s rain season.

Naturally, there is pretty high correlation between the days with measurable rain and the season’s total.  But from day one, I was convinced that the days with measurable rain was a better indicator of circulation changes over the years while rain amounts added “noise.”  Here is the correlation between rain amounts and days with rain for Los Angeles Civic Center:

Professor Jerome Namias seemed to be excited, too.  Here is his reply to my graph of LA rain frequency over the period of record.

Here’s the plot that started it all and that Namias and Stidd found interesting.  It didn’t look like “white noise.”

By the time I corresponded with Professor Namias, I had been hired as the Assistant Project Forecaster for the nation’s largest randomized orographic cloud seeding experiment, the Colorado River Basin Pilot Project.   I was living in Durango, CO, where the project’s headquarters were as I continued my research on a possible oscillation.

I was hoping that my work would eventually qualify as a Master’s Thesis from the meteorology department at San Jose State College (despite poor grades in grad school).  As an aside to the reader: I had no business whatsoever in being in grad school taking classes like “numerical methods,” “advanced hydrodynamics.” etc.  But I loved my campus life in those days of campus trash cans set on fire to protest the war, album protest rock, the marches, the demonstrations, the be-ins, the draft card burnings, to pinch a quote from National Lampoon’s “Bob Dylan’s Golden Protest” parody:

Over the next couple of years I added to my Los Angeles dataset with ones from San Francisco, San Luis Obispo, Santa Barbara, and San Diego.  These stations all had records that went back even earlier than the one at Los Angeles.  All but San Francisco, whose record exhibited what one might call, “white noise,” exhibited the trend I had seen in the Los Angeles record!  It was amazing to see.

Below is a running, 3-season average for SLO, SBA, LAC, and SAN through the early 1980s.  Sadly, I was not paying attention when scanning this original diagram and parts are not shown here, such as the abscissa comprised of the rain seasons.  The ordinate is the number of days with measurable rain at these four stations with a running mean of 3 seasons of those totals.  It ends with the 1981-82 season, far right.  For those in the know, the following season,  1982-83 featured a giant El Niño and that, combined with whatever was going on in what I was charting,  produced numbers of days off the chart!  I was so happy!  The Great Salt Lake was about to overflow, too, from this incredible wet spell that accompanied the shift to a more frequently rainy regime.

Since the rain at these locations is associated with cold troughs in the wintertime westerlies, I imagined that the circumpolar westerlies gradually retracted over the years, then hit some kind of tipping point and sprung back to more a more southerly latitude before beginning the same slow retraction over decades.

In the 1950s and 1960s,  the Los Angeles forecast office used the 564 decameter geopotential height contour as a divider of rain; heights at or below that contour was where the rain was and no rain was the rule for heights greater than the 564 decameter contour.   This key contour was used as an aid in forecasting rain as troughs approached and entered California.

The last shift to wetter conditions I found happened after the 1976-77 rain season.  With the 1977-78 rain season, it became much more frequently rainy along the central and Southern California coast for most of the next seven years.

My California rainfall study ended a few years into this transition to wetter conditions due to two elements:  1) NOAA had stopped publishing the “Daily Series, Synoptic Weather Maps, Part 1, Northern Hemisphere Sea-Level and 500 mb Charts and 2) I got very upset over the misleading cloud seeding literature that was being published in journals and jumped ship into reanalyzing previously published cloud seeding literature for most of the rest of my career almost solely on my own time (e.g., Rangno 1979, Hobbs and Rangno 1979, Rangno and Hobbs 1995).

The NOAA surface and 500 mb charts were important because that’s what I had used to track cyclones across the Pacific for five winter seasons before and after a “shift.”   I wasn’t able to do a set of tracks before and after the 1977-78 shift.  It was interesting that about 20 years later, the 1977-78 shift I was studying was discovered as the, “Pacific Decadal Oscillation”  (Wallace et al. 1994).

By the 1973-74 rain season I was so sure a prolonged shift to wetter conditions in the SW was on the doorstep that I was writing to the LA Times science writer, George Getz, the BuRec’s PR person, Hunter Holloway (the BuRec was the sponsor of the cloud seeding experiment I worked on), and to the Durango Herald about this coming shift to wetter conditions.

I was a little too early; the downward trend continued through the 1976-77 winter.  Here’s an example of those writings, one an audacious, self-written “news release” that follows the letter to Mr. Holloway shown here:

The reason I posted the letter above is to PROVE that I really was anticipating “The Shift” BEFORE it happened:

The additional research I carried out went far beyond the rain day graphs:

Pacific cyclone tracks before and after a “shift,”

NH average sea level pressures before and after a shift.

Here are the sea level maps for the 1930s, before and after a shift that occurred with the 1934-35 rain season.  For those not acquainted with the synoptic charts of that 1930s era it was something of a golden age of ship reports before they disappeared on these maps during World War II.  Thus northern hemisphere sea-level pressure and cyclone tracks changes could be reliably charted.

A graphically obtained “delta” map of sea-level pressure changes before and after a shift comprises the third graphic.   Not much can be seen to have happened when looking at these average maps for whole December through March seasons due to having  semi-permanent pressure systems like the low in the Gulf of Alaska, and the “Pacific High.”  I deemed looking at cyclone tracks (the following graphics) as far more useful.  Nevertheless, these are never-before-seen-or-done maps by anyone but me.  Enjoy:

Strangely believe it, the greatest sea level changes were in the domain of the Arctic Oscillation; in the North Atlantic, Greenland and England.  Whodda thunk it?  Not much change in the Pac and West, as expected due to persistent pressure fields even in these extremely frequent days with rain and those with many fewer ones.  I honestly did not know what to make of this change.  Do you?  If not, let’s keep moving….

Before doing the sea level pressure maps, I had charted cyclone centers across the central Pacific to the Rockies for the same winter (Dec-Mar) periods as was done above.  These charts were much more illuminating concerning the shift that happened in days with rain in central and Southern California:

First, the cyclone track “densities” of the five low frequency days with measurable rain winters preceding the shift.  A strong channeling of cyclones was seen during these winters from the lower latitudes of the central Pacific into the Gulf of Alaska and into southern British Columbia to a lesser degree.  This suggests the geographically anchored Asia/western Pacific Ocean jet exit had extruded farther east and into the central Pacific.  (Upper-level maps are not available for this period.). This was to resemble what happened in the low rain frequency seasons of the early and mid-1970s that preceded another shift.

In the figure below are the tracks following the “shift” to higher frequency rain day occurrences in central and Southern California.  The channeling is gone and what appears to be a standard distribution of low centers has replaced it.  Cyclones that developed in the western Pacific moved northeast into the Aleutians relatively close to Japan rather than scooting across the lower latitudes of the central Pacific.  The difference between these two maps is shown in the final map below this one.

The Delta Cyclone Density Map (pardon the skew):

Many more low centers tracked across the extreme eastern Pacific into California and into the Great Basin low pressure cyclogenesis zone in the lee of the Sierras.  This map is more illustrative than the sea-level pressure maps of those changes that happened after the shift to wetter conditions .

Questions:  Did channeled cyclones disrupt the sea surface enough to cause temperature anomalies in real time or later?  Were the El Niños that followed in the late 1930s and early 1940s in part triggered by the lower latitude cyclones racing across the central Pacific? Was this a global change such that Western Europe and northwest Africa saw a shift to wetter conditions after the ones noted in central and Southern California?  Data were not available for this period of study (1930s) except in the Middle East for Jerusalem, Israel.  There was no indication of a long period of decreasing days with measurable followed by a sudden and prolonged shift to more frequently rainy days.

My favorite answer to, “What caused this shift when someone asked was based on the work of E. N. Lorenz at MIT.   Professor Lorenz is famous for bringing our attention to chaos theory where small initial changes in starting conditions can lead to huge differences later.  Today, this concept is used to improve forecasts by introducing minor changes in initial data in the models from that observed to see how much difference results in the model predictions.

There need not be an external cause for climate shifts, he wrote.  It may just that systems shift in and out of favorite modal types without an external  forcing.  Thus, the best answer for what caused the shift I think I detected was, of course, “nothing.”  See Lorenz (1968, Climate Determinism) in the Amer. Meteor. Soc. Monograph Vol. 8, No. 30, on,  “The Causes of Climate Change.”   Strangely believe it, there are no papers on CO2 in this Amer. Meteor. Soc. monograph!   Mauna Loa measurements of C02 had just begun and so there was no awareness of how it was steadily increasing over the years.

——-

Work to be done?

Bringing the days with measurable rain plots up to date, storm tracks in the 1970s, and investigate whether the 564 decameter geopotential height contour shows a global expansion after the 1970s shift after hemispheric geopotential heights became available (beginning in the mid-1940s).   Or is the shift to a high rain frequency along the central and Southern California coast a local phenomenon where a mean upper-level trough recurrs along the West Coast for years at a time?  In a cursory check recently, there seems to be no clear recurrence of the prior three shifts in days with rain.  Boo.

And lastly, one must ask, is what I have done a “scientific mirage,” and expression used by Foster and Huber (1997) to denote illusory science?

I would like the answer to be a sudden global expansion of the polar westerlies (shown in the average hemispheric latitude of the 564 500 hPa geopotential height contour that accompanies a shift, something like the “Bond Cycles” observed in historic ice core data:  a “reset,” if you will, after a long, long period of withdrawing ever so gradually over the decades.  Perhaps our gradually shifting climate to a warmer one has done something to interfere with this “shift” phenomenon?

An obstacle that arose in later years was that climate station at Cal Poly, San Luis Obispo. whose record started in 1868,  started having missing monthly data that never showed up in the “Delayed Data” section in NOAA’s Climatological Data in the June and December issues.   Eventually, NOAA dropped even having a “Delayed Data” segment in the June and December issues!   Boo on that!  Santa Barbara, whose record also went back into the 1860s, too, had missing months that never were reported.  I remember how discouraged I was when these events happened and thought about giving up.  How can stations whose records go back into the 1860s (!) suddenly have incomplete records where observers don’t file reports with NOAA?  Where was the California State Climatologist?  Asleep at the wheel, I suppose.

Maybe you, one of my two readers, will take this research up to see if it goes anywhere?

Sincerely, Art “I’m dreaming” Rangno.   :

Caveat:  My grad advisers at San Jose State and a professor at the U of WA were unimpressed with these works.

A Review of the Israeli Cloud Seeding Experience in the Context of the 2023 Israel 4 Null Primary Result

PROLOGUE

I have written an extensive,  “comment” and “enhancement” of an article by Benjamini et al.  published in the in J. Appl. Meteor.  in January 2023.  The article was about the results of a fourth randomized Israeli cloud seeding experiment, Israel-4.   My “comments” and “enhancement” of Benjamini et al. (2023) posted below would never be published in an Amer. Meteor. Soc. journal.  The words are too strong.  So, I am going this route, a blog post.

Evidence for such a contentious assertion?  Prior experience.

I submitted a paper on the history of Israeli cloud seeding in 2018.  The journal, the Bull. Amer. Meteor. Soc. (BAMS) got but two reviews:  “Accept, important paper, minor revisions” by one Israeli scientist, and the second review, an outright “reject” in  a long review by an Israeli seeding partisan who signed his review. The chief editor of BAMS did not allow me  to revise my manuscript where needed (minor corrections),  nor rebut  the many specious comments by the seeding partisan.

Why is this behavior by the chief editor of BAMS outrageous and in non-compliance with our science ideals?

Replying to the comments of reviewers of manuscripts following peer-review is standard procedure in science after which a final decision on publication is then reached by the editor based on the responses of the author and the revisions made in the submitted manuscript.  This is exactly the process that Prof. Dave Schultz, Chief Editor of the Amer. Meteor. Soc. journal, The Monthly Weather Review,  and I are going through right now with a cloud seeding manuscript on the Colorado River Basin Pilot Project sub omitted to the AMS’ J. Appl. Meteor. and Climate (as of January 2024).

As an acknowledged expert on Israeli clouds, weather, and cloud seeding (e.g., Rangno 1988, Rangno and Hobbs 1995a), I deemed this refusal by the BAMS Chief Editor to allow me to respond to the comments of the two reviewers the sign of a corrupted journal process within the Amer. Meteor. Soc.:  Certain stories about failed science are not to be told, especially if they involve a country people have strong feelings about, as in this case.   My 2018 history describes unimaginably inadequate peer-reviews of the original published reports, those describing ripe for  seeding  clouds and the cloud seeding statistical “successes” that were all scientific mirages crafted by cloud seeding partisans.

The manuscript below has the same elements as the 2018 submission thus guaranteeing its rejection by a partisan AMS leadership.  But I feel strongly that certain things need to be said, and questions asked, to stop seeding partisans in Israel from costing their country so much in wasted cloud seeding efforts as they have over so many decades.  Sound implausible?  Read on…..

Despite what might be considered some “harsh” language at times, I consider myself a friend of Israel and donate to the American-Israeli Cooperative Enterprise, an organization that regularly counters the negative descriptions of Israel in much of the media today in their “Myth vs. Facts” segments.

=========THE MANUSCRIPT==========

ABSTRACT

The result of a fourth long-term randomized cloud seeding experiment in Israel, Israel-4, has been reported by Benjamini et al. 2023.  The seven-season randomized cloud seeding experiment ended in 2020 with a non-statistically significant result on rainfall (a suggested increase in rain of 1.8%).  This review puts the results of Israel-4 in the context of prior independent reanalyses of Israel-1 and -2,  reanalyses that can be said to have anticipated a null result of both the Israel-4 experiment and the lack of evidence that rain had been increased in the 30 plus years of the operational cloud seeding program targeting the Lake Kinneret (Sea of Galilee) watershed discovered in 2006 by an independent panel of Israeli experts.  The published literature that overturned the reports of success in the first two experiments, Israel-1 and Israel-2, was omitted by Benjamini et al., and thus, misled readers concerning those first two experiments.

The lack of cloud seeding success in Israel can be attributed to unsuitable clouds for seeding purposes, ones that form prolific concentrations of natural ice at relatively slight to moderate supercoolings which preclude seeding successes using glaciogenic seeding agents.

The phenomenon of “one-sided citing,” practiced by Benjamini et al. via the omission of relevant contrary literature is addressed.   Several corrections to and enhancements of the Benjamini et al. article are also included.

===================================================

  1. Introduction and Background

The results of the first two randomized crossover cloud seeding experiments in Israel, Israel-1 and Israel-2, discussed recently by Benjamini et al. 2023, as well as the descriptions of “ripe for seeding” clouds in Israel by the seeding experimenters, had an important role in the history of cloud seeding.   For many years it appeared that the viability of cloud seeding to have produced economically important amounts of rain had been established in those two “crossover” experiments conducted by scientists at the Hebrew University of Jerusalem (HUJ) (e.g., Kerr 1982, Mason 1982, Dennis 1989).  In descriptions of the first two benchmark experiments, ones that created the scientific consensus described above, Benjamini et al.  (2023, hereafter, “B23,”) do not tell the whole story in their history of cloud seeding in Israel that preceded their evaluation of Israel-4.

This review is meant to fill in the gaps for the reader left by B23 about those first two experiments that had so much practical impact.  For example, the Israel National Water Authority (INWA) began a several decades-long operational cloud seeding of the watersheds around Lake Kinneret (aka, Sea of Galilee) based on the seemingly favorable results of Israel-1 and those in the “confirmatory” Israel-2 experiment that followed (Gabriel 1967a; b; Neumann et al. 1967; Wurtele 1971; Gagin and Neumann 1974; 1976).  The INWA began seeding Lake Kinneret’s watersheds in November through April, beginning with the 1975/76, the winter season that immediately followed the end of Israel-2.

The statistical results of Israel-1 and -2 were backed by several cloud microstructure reports over the years that underpinned the idea that rain could be increased substantially by seeding Israel’s clouds (e.g., Gagin 1975, 1981, 1986, Gagin and Neumann 1974, 1976, 1981).  These reports caused Science magazine’s reporter, Richard Kerr,  to proclaim in 1982 that those first two Israeli experiments constituted the “One success in 35 years” of cloud seeding experimentation.  Kerr (1982) also wrote:

The Israeli II1 data must still be reanalyzed by other statisticians, but most researchers are also impressed that the results make so much physical sense.  The clouds that Gagin and Neumann hypothesized would be most susceptible to seeding did indeed produce the most additional rain after seeding.”

These statements are compatible with the history that B23 have provided, but it was to be far from the end of the “story.”

Fifteen years after Israel-2 had been completed it was learned that the random seeding of the south target clouds of Israel-2, a crossover experiment as Israel-1 had been, produced the indication that cloud seeding had decreased rainfall by a substantial amount, 15% (Gabriel and Rosenfeld 1990)2.  Gagin and Neumann (1981), however, had claimed that the random seeding that took place in the south target was “non-experimental” and so did not report the results of random seeding there.  No one challenged this claim. 

Until 1981 the result of seeding in the south target seeding had been described as “inconclusive” (Gagin and Neumann 1976), and prior to that, by (Gagin and Neumann 1974) after the first two seasons of Israel-2, that seeding had resulted in a seed/no seed average rainfall fraction in the south target that was “less than 1,” suggesting rain might have been decreased on seeded days.

However, the crossover evaluation of seeding in Israel-2 was not reported until Gabriel and Rosenfeld (1990)2.  The design document, approved by the Israeli Rain Committee and completed before Israel-2 began had, however, mandated a crossover evaluation (Silverman 2001) as had been done for Israel-1.  Nowhere did Gagin (1981) or Gagin and Neumann (1974, 1976, 1981) explain why they did not perform the mandated crossover evaluation of Israel-2.

Instead of Israel-2 crossover evaluation replicating Israel-1, where seeding appeared to have increased rainfall by about 15% when the data from both targets was combined (e.g., Wurtele 1971), the crossover evaluation of Israel-2 indicated a slight decrease in rainfall of 2% (not statistically significant).  Thus, Israel-2 had not replicated Israel-1 in an important way.

But results of Israel-2 were complex, as noted by Gabriel and Rosenfeld (1990) and left questions that they could not resolve.  The most revealing statement in Gabriel and Rosenfeld (1990) in reporting the “full” results of Israel-2 was this enigma (my italics and bold font):

There is a surprising contradiction between this finding and those of the analyses of Tables 4-17.  The difference occurs because the historical comparison of Table 18 ignores the unusually high south precipitation on north-seeded days (as well as the north precipitation on south-seeded days).  In other words, it is what happened when there was no seeding that causes the differences between the two analyses. The different choice of “control” days for the south, whether all the rainy days of 1949-60 or the north-seeded days of 1969-75, is what crucially affects the comparison.  If such large differences-of a magnitude of several standard errors and clearly significant by the usual statistical criteria-occur by chance, then chance operates in unexpected ways on precipitation and historical comparisons become highly suspect (see also Gabriel and Petrondas 1983). Otherwise, one would need to explain why there was so much more rain in the south when the north was being seeded; as of now, no explanation is available, especially as the prevailing wind direction is from the southwest.”

A “Type I statistical error,” the “good draw,” in Israel-2, heavy rains that affected both targets on north target seeded days3, was there for all to see if they wanted to.

Thus, a severe blow to the idea of randomizing cloud seeding experiments occurred in Israel-2 due to the exceptional random draw described by Gagin and Rosenfeld (1990).  Randomization could produce wildly unrepresentative results in which slight, but important, rain increases due to seeding could be forever hidden.

The null result of the combined targets in Israel-2 was due to an apparent decrease in rainfall on seeded days in the south target (~15%) that canceled out apparent increases in rainfall (~13%) in the north target.   Despite the new result and the many questions it raised, the INWA continued the commercial-like seeding of the Lake Kinneret watersheds during the winter rain seasons for more than 20 years after Gabriel and Rosenfeld’s (1990) disclosure of the “full” results of Israel-2.

The continuation of seeding of Lake Kinneret watersheds in northern Israel by the INWA despite the Israel-2 null result may have been due to the hypothesis put forward by Rosenfeld and Farbstein (1992)4; “dust/haze” had interfered with seeding in Israel -2 by creating high natural ice particle concentrations in supercooled clouds and that the presence of “dust/haze” even resulted in collisions with coalescence-formed rain (“the warm rain” process) that does not require the ice phase.  These cloud attributes, they concluded, meant there could be no increases in rainfall due to cloud seeding in the south target nor in the north target when dust/haze was present.  Without “dust/haze,” Rosenfeld and Farbstein argued, the clouds of Israel were as ripe as ever for cloud seeding.

2).    The Motivation for a Reanalysis of Israel-1 and Israel-2

The publication and the hypothesis of Rosenfeld and Farbstein (1992) formed the motivation for the Rangno and Hobbs 1995, hereafter RH95a) reanalyses of Israel-1 and -2.  This writer had spent 11 winter weeks in Israel in 1986 studying the rain-producing characteristics of Israeli clouds and felt Rosenfeld and Farbstein’s hypothesis had little credibility;  a full independent review of Israel-1 and -2 was needed as had been suggested in Science magazine (Kerr 1982).  And it would be done by someone who knew the clouds and weather of Israel (Rangno 1983, rejected by the J. Appl. Meteor.; Rangno (1988), Rangno and Hobbs (1988, hereafter, RH88).

I am also experienced in exposing suspect cloud seeding claims in the published literature (e.g., Hobbs and Rangno 1978, 1979, Rangno 1979, 1986, Rangno and Hobbs 1980a, b, 1981, 1987, 1993, 1995b).  By the time I began reanalyzing the Israeli experiments in 1992 I had also logged more than 400 flights for the University of Washington’s Cloud and Aerosol Group in studies that mostly concerned ice crystaldevelopment in slightly supercooled clouds in polar air masses similar to those that affect Israel (Rangno and Hobbs 1983, 1991, 1994, Hobbs and Rangno 1985, 1990).

3).   The results of the Rangno and Hobbs (1995) benchmark reanalyses of Israel-1 and Israel-2 that went uncited by B23

RH95 concluded that neither Israel-1 nor Israel-2 had produced bona fide increases in rain on seeded days, contradicting the HUJ experimenters’ reports and those contained in B23 that cloud seeding had increased rain in each of these experiments.  The conclusions of RH95 were given support by Silverman (2001) and later, for Israel-2, by Levin et al. (2010).

Moreover, in R88 it was strongly indicated that the “ripe for seeding” clouds described repeatedly by the experimenters (e.g., Gagin and Neumann 1974, 1976, 1981, Gagin 1975, 1981, 1986) did not exist.   The findings in R88 concerning shallow clouds that rained was not news to Israel Meteorological Service forecasters with whom I spoke nor to the Israeli experiments’ “Chief Meteorologist,” Mr. Karl Rosner.  Mr. Rosner wrote to me in 1987 that, “sometimes heavy rain fell from clouds with tops at -8°C.”  Thus, in contrast to the many HUJ experimenters’ reports cited previously, it was widely known by weather forecasters in Israel that rain fell regularly from clouds with tops >-10°C (~3-4 km thick clouds) as was documented in R88.

The HUJ experimenters had also reported, contrary to the above,  that many clouds with radar measured tops between -15°C and -21°C did not precipitate naturally due to a lack of ice in them or that precipitation formed by “warm rain” (collisions with coalescence) process (e.g., Gagin 1981, 1986) did not occur.  Those non-precipitating clouds in this low radar top temperature range were responsible for extra-large increases (46%) in rain on seeded days  (Gagin and Neumann 1981, Gagin and Gabriel 1987).

Seeding, they also reported, had no effect on naturally precipitating clouds, a finding compatible with the “static” seeding method carried out by the HUJ experimenters where small amounts of the seeding agent,  silver iodide are released.   Namely, when seeding took place, it rained for more hours on seeded days than on control days, but it did not rain harder.

B23 also refer to the Israel-2 low radar top temperature partition as having been associated with increases in rain.

(Questions)

Is it possible that Israeli weather forecasters and the “chief meteorologist” of the Israeli cloud seeding experiments had a better idea of which clouds rained in Israel than those whose research careers at the HUJ depended on reliable assessments of their own clouds and their cloud seeding potential?   Ans.  Probably not.

Why?

This writer, while welcomed at the Israel Meteorological Service in January 1986, was denied access to the seeding experimenters’ radar on the grounds of Ben Gurion AP to obtain echo heights  by the leader of the Israeli experiments, Prof. A. Gagin.  He insisted in our meeting that my monitoring of top heights would only confirm his cloud reports; that it took deep and very cold-topped clouds to rain in Israel.

It was also learned during January 1986 at about this same time that no less than six attempts had been proposed by outside groups to do airborne studies of the seemingly unique clouds of Israel, as shown in RH88, ones that had responded so well to cloud seeding (Personal communication, Prof. Gabor Vali, University of Wyoming, 31 January 1986).  Every one of those attempts to study Israeli clouds had been blocked.

Why?  And by whom?

  1. More about Rangno and Hobbs (1995): the most controversial and commented on paper ever published in an Amer. Meteor. Soc. journal and the unusual strategy used by the editor in choosing reviewers

 In a moment of brilliance (in retrospect), the editor for our journal manuscript, L. Randall Koenig, chose three reviewers who would be sure to reject the RH95a manuscript and its negative findings concerning cloud seeding.  But at the same time, Koenig realized that there would be no easy pass on it; no stone would go unturned by the reviewers, and our findings would be severely tested.  In fact, RH95 was significantly better for having cloud seeding partisans, H. Orville, W. Woodley, and D. Rosenfeld, review it (all signed their reviews).

Editor Koenig, himself an expert on weather modification and cloud microphysics (e.g., Koenig 1963, 1977, 1984), was also steeped in the long record of frequent mischief by those in the cloud seeding domain, weighed the arguments of the reviewers and the modifications of RH95a that reflected the reviewers’ criticisms:  He made the choice to publish RH95a.

It took courage for Editor Koenig to do that and recognizing who he felt had the better arguments.  In RH95a were the first two independent re-analyses of Israel-1 and Israel-2, as had been recommended years earlier in Kerr (1982) but ones that were clearly not going to take place.   How many other papers in our journals would be the improved and bogus claims eliminated if editors used the strategy of of Koenig and were as informed about the topic of the manuscript?

Perhaps due to the size of the ox being gored, our paper drew comments by the reviewers of our manuscript and others (1997a, b, c, d, e).   The number of journal pages involved in “Comments” and “Replies” on a single article is still a record for an Amer. Meteor. Soc. journal.   We draw particular attention to our “Replies” to the many, as we showed, specious “Comments” of Dr. Rosenfeld in RH97a and RH97b, and a B23 co-author.

Let the reader decide where truth lies.  We urge the reader to carefully review RH95a and our replies for the considerable evidence we present that the Israel-1 and Israel-2 experiments were both mirages of cloud seeding successes, contrary to the assertions in B23.

  1. Israel-3: enhancing B23’s description

B23 describe the results of the longest randomized cloud seeding experiment ever conducted, Israel-3 (1975-1995), a single target experiment.  However, they omit informing the reader that the remarkable “inconclusive” result was a suggested 9% decrease in rainfall on seeded days compared to non-seeded days (Rosenfeld 1998).  By omitting the sign of the null result, B23 left the reader to speculate on what the sign of the “null” result was.  The suggestion of a decrease in rain on seeded days again points to clouds naturally form precipitation very efficiently in Israel.  With the result of Israel -3 in hand, the reader would now learn, with Israel-2 (Gabriel and Rosenfeld 1990), that over a period of 25 plus years (Israel-2 and Israel-3 combined) decreases in rainfall due to seeding were suggested in central and southern Israel by cloud seeding!

  1. Rectifying B23’s statement concerning operational seeding

B23 state the increase in rainfall during the operational seeding, 1975/76 winter to 1990 reported by Nirel and Rosenfeld (1995) was “6-11%.”  In the abstract of the quoted article, the authors state that rainfall due to cloud seeding was increased by 6%, not “6-11%.”  This same increase in rain (6%) was also quoted by Sharon et al. (2008).

Moreover, the 6% increase in rain (said to be statistically significant by Nirel and Rosenfeld 1995) was not confirmed by Kessler et al. (2006) in their independent evaluation of operational seeding through the same period.  The independent panel reported 4.8% suggested rain enhancement over the same period evaluated by Nirel and Rosenfeld (Figure 1). 

Figure 1. The results of operational seeding on the watersheds of Lake Kinneret (aka, Sea of Galilee) as reported by Kessler et al. 2006.  (a) is that result of seeding on rainfall reported by Nirel and Rosenfeld (1995), b-d are the results found for various periods, including the very same era evaluated by Nirel and Rosenfeld (1995)5.

  1. What triggered the formation of an independent panel to evaluate cloud seeding?

The panel was created after RH95a was published and then followed by extensive journal exchanges by RH97a, b, c, d, e, in “Replies” to various “Comments” in 1997.  The INWA was then inspired to form an independent panel of experts due to these exchanges to evaluate what they were getting from the operational seeding of Lake Kinneret’s (aka, Sea of Galilee) watersheds rather than relying on the evaluations by the seeding promoters at the HUJ (e.g., Nirel and Rosenfeld 1995).  The results found by the panel are shown in Figure 1.

Should the lack of seeding results after 1990 shown in Figure 1 surprise?  I don’t think so.  This sequence of optimistic claims by seeding experimenters concerning their own experiments followed by reanalyses by external skeptics that find the original claims were “scientific mirages” (Foster and Huber 1997, Judging Science) is a pathology within the cloud seeding realm that has dogged it since its earliest days (e.g., Brier and Enger 1952, versus MacCready 1952).

In view of Figure 1, one must ask, “What if there had been no RH95a”?

We suspect that not citing our independent re-analyses of Israel-1 and Israel-2, Silverman’s (2001) conclusions concerning the first two Israeli experiments, and Wurtele (1971) who first drew the attention to a major red flag in Israel-1, combined with the fact that the HUJ experimenters failed to even understand the precipitating nature of their own clouds for decades with all the tools at their command, all pose monumental science embarrassments for Israel, their scientists, and for the prestigious HUJ from which the faulty reports emanated.

Can there be other reasons for not citing the work of external, foreign workers who overturned benchmark experimental science by the home country’s scientists?

  1. Did the background airborne microphysical measurements that preceded Israel-4 justify a new experiment?

B23 cite Freud et al. (2015) as having demonstrated cloud seeding potential in the mountainous north region of Israel through a series of airborne flights; but did it support the idea of strong cloud seeding potential as B23 assert?

No.

I was not asked to review Freud et al. 2015, as one might have expected given my background.  Nevertheless, I carried out a post publication “comprehensive review” that can be found under 2017 here.

Freud et al. 2015 was a “Jekyll and Hyde” read; some of the best reporting by the HUJ’s cloud seeding unit was contained in it.  But it also contained misleading statements.  My recommendation after reading what I considered to be a strongly biased study that was going to mislead the INWA concerning cloud seeding potential: “Don’t do a cloud seeding experiment in northern Israel based on the research of Freud et al. (2015)!”

 As the INWA could have suspected, Freud et al. (2015) would not be the first time that cloud seeding researchers at the HUJ had misled the INWA about the clouds of Israel being filled with cloud seeding potential.  My conclusion regarding the false picture of “abundant” cloud seeding potential in the northern mountains of Israel painted by Freud et al. 2015 was, in essence, affirmed post facto by the “primary” results of Israel 4.  The “abundant” cloud seeding potential in northern Israel described by Freud et al. (2015) was not realized or was imaginary to begin with.

A caveat on airborne sampling:  One can “lie” with aircraft measurements by sampling only newly risen turrets and avoiding those that are maturing or in aged states with appreciable ice particle concentrations.  Gagin and Neumann (1974), for example, stated that they chose only newly risen turrets, narrow ones at that, and flew research flights on mostly dry days, and those choices misled them and the rest of the scientific community regarding the microstructure of Israeli clouds and their cloud seeding potential.  Significant rain days in Israel are comprised of large complexes of convective clouds in various stages of development, “tangled masses,” as they were described by Neumann et al. (1967).  To their credit, Freud et al. informed the reader that they sampled only newly risen turrets when reporting the low (<2 per liter) modal ice particle concentrations in those turrets.

Freud et al.’s measurements could not have been more incompatible with uncited by B23 measurements of Levin (1992: 1994; Levin et al. 1996).  Tens to hundreds per liter of ice particles were found in six flights on four days in clouds having tops >-13°C.   Freud et al. 2015 could not bring themselves to inform their readers of similar high ice particle­­­ concentrations that they likely encountered during their 27 flights (that is, if they did not deliberately avoid those high ice particle concentration regions).  Freud et al. 2015, therefore, may be a first in the evaluation of cloud seeding potential in which measurements of ice particle concentrations in mature and aging clouds were not reported; the absence of such data made their entire report unreliable.

One of the B23 co-authors (DR) has claimed that ice particle measurements measured in their airborne research were “unreasonably high” in Israeli clouds due to probe caused shattering of ice crystals and thus weren’t reliable.  D. Axisa, a representative of the manufacturer, Droplet Measurement Systems, of the CAPS probe used by Freud et al. (2015) stated that this statement was false: “They could have reported accurate ice particle concentrations if they had wanted to.” Dr. Axisa is a former president of the Weather Modification Assoc.  It seems likely that HUJ researchers are once again withholding vital information on the clouds of Israel6.

  1. What do we know about cloud seeding in Israel today?

 What we know today is that if careful, skeptical and independent analyses of Israel-1 and Israel-2 experiments and equally careful evaluations of the clouds of Israel had been done in the first place by independent Israeli scientists or ones outside Israel that are non-partisan cloud seeding scientists (as was carried out by RH95a, R88, and by Silverman 2001), there would not have been 30 plus years of wasted operational cloud as would be found by independent evaluators in the decades ahead (Kessler et al. 2006, Sharon et al. 2008).  Fortunately, we need not guess whether those 10s of millions of dollars were wasted on the seeding of Lake Kinneret watersheds.  They were.   Inexplicably, the INWA drove through the “stop sign” presented by Kessler et al. (2006) and commercially seeded around Lake Kinneret for another seven years after this report came out according to B23.

  1. Why hasn’t cloud seeding worked In Israel?

 Answer:  too much natural ice formation in clouds.

B23 failed to mention that the “ripe-for-seeding” cloud foundation for the statistical results of Israel-1 and Israel-2 no longer exists.  The mythical clouds described by HUJ researchers were critical in the acceptance of the Israeli cloud seeding rain increases by the scientific community, as quoted in Kerr (1982) earlier and by Dennis (1989).

A review of the Israeli cloud microstructure shows that they are “ripe,” but not for cloud seeding, but for an explosion of ice as the tops ascend to temperatures below -5°C and age.  In most cases, precipitation-sized drops have already formed when the Israeli cloud ascend through this level (Gagin and Neumann 1974, Figure 13.4), and the concentration of cloud droplets exceeding the Hallett-Mossop riming-splintering criterion of >23 µm diameter can be inferred to be copious in that -2.5° to -8°C temperature zone.  Furthermore, there is an enhancement of the H-M process when droplets <13 µm are present (Goldsmith et al. 1976, Mossop 1985) and such drops would be present in the semi-polluted air masses; initially, shallow cold layers diluted by the warming of the Mediterranean Sea to depths of 3-9 km on shower/thunderstorm days by the time they reach Israel under cold polar troughs.

Without the “ripe for seeding” clouds, ones with great seeding potential to cloud top temperatures as low as -21°C as described by Gagin and Neumann (1976, 1981 and Gagin 1981), there can be no viable increases in rainfall due to cloud seeding.  This does not mean that some small, slightly supercooled clouds can’t be seeded to make small amounts of rain as noted by the HUJ researchers, Gagin and Neumann (1981), and by Sharon et al. (2008).  However, those small amounts weren’t deemed viable for a cloud seeding operations.

  1. The nature of the reporting of the experiments by the HUJ cloud seeding researchers

 The omission of the south target result (Gagin and Neumann 1976, 1981) was tantamount to the cancer researcher who only reports on the 50 mice his treatment cured while not reporting on the 50 mice that died from the same treatment.  This kind of behavior in virtually every field but weather modification/cloud seeding, would be termed, “scientific misconduct,” specifically of a type called, “falsification” when data are omitted or adjusted (Ben-Yehuda and Oliver-Lumerman 2017, Fraud and Misconduct in Research)6.  Inexplicably, Prof. K. Ruben Gabriel, the Israeli cloud seeding statistician, acquiesced in this omission as a reviewer of Gagin and Neumann’s 1981 paper in which this critical omission occurred.

Moreover, reporting the apparent negative effect on rainfall in the south target of Israel-2 would have raised numerous questions about the clouds of Israel:   How could seeding Israeli clouds, described as being filled with great seeding potential as had been repeatedly described by the HUJ researchers, have resulted in what appeared to be a large decrease in rainfall in the south target on seeded days?  Cloud tops in the south target in Israel average higher temperatures than those in the north (e.g., GN74; RH95a) making findings of decreased rainfall due to cloud seeding (as Rosenfeld 1989, Rosenfeld and Farbstein 1992 suggested) even harder to explain.

Moreover, while interim “positive” reports of cloud seeding increases in rain emanated from the HUJ during Israel-1 and Israel-2, HUJ researchers clearly felt differently about reporting indications of rain decreases in Israel-2 and Israel-3.   For example, the scientific community was not informed of the suggestion of decreased rain due to clouds seeding in Israel-3 by the HUJ experimenters until 17 years after randomized seeding had begun (Rosenfeld and Farbstein 1992).  Is this what the HUJ stands for?  This chronology demonstrates a pattern that HUJ experimenters have had reporting suggestions of decreased rainfall or null results due to cloud seeding and in correcting their flawed cloud microstructure reports to the scientific community and to their countrymen in the years prior to B23.

Moreover when “good draws” or null results are suggested, the HUJ researchers reach for the magic bag to explain why “cloud seeding did it,” not nature.  For example, when the Israel-1 chief meteorologist provided a plume analysis that the buffer zone (BZ) of Israel-1 could not have been appreciably contaminated by inadvertent seeding (a conclusion also supported by Neumann et al. 1967),  Gagin and Neumann (1974), however, countered with an opposite explanation; the BZ had surely been contaminated on Center seeded days.  The reason and data behind these two different explanations for the difference in the two plume analyses was not given except in general unsatisfactory terms.

When a Type I error and massive “good draw” affected the north seeded days of Israel-2 that also brought heavy rain to the south target, the crossover null result was then explained as due to “dust/haze” that produced different cloud microstructures when present in each target, first proposed by Rosenfeld (1989) in an HUJ report.

When RH95a showed that the results of seeding on the coast of Israel in Israel-1 were too close to the cloud base seeding release point to have resulted in rain practically falling on top on the seeding aircraft that flew in a line along the coast, Rosenfeld (1997) wrote a magical explanation filled with conjectures, one requiring nine steps to be fulfilled to explain the troublesome indication of rain increases in the BZ and in the coastal zone on Center seeded days.  Please see my extended “Reply,” p11, to the hypothesis of Rosenfeld (1997) at:

http://carg.atmos.washington.edu/sys/research/archive/1997_comments_seeding.pdf.

When the independent panel, Kessler et al. 2002, could find no viable increases in rain in the seeding of the Lake Kinneret watersheds in their interim report, the HUJ seeding team then asserted that “air pollution” was suddenly( after 1990) decreasing rain as much as cloud seeding was increasing it (Givati and Rosenfeld (2005).  One might ask, “what happened to ‘dust/haze’”?

Ice crystal concentrations measured in Israeli clouds by our best instruments are “unreasonably high” according to B23 co-author, Rosenfeld (private communication, 2018).  Rosenfeld’s statement, however, contrasts with that of Droplet Measurement Technologies (DMT), the manufacturer of the Cloud, Aerosol and Precipitation Spectrometer (CAPS) probe used by the HUJ researchers:  “They could have reported accurate ice particle concentrations if they had wanted to” (D. Axisa, DMT scientist, personal communication, 2018).

With the certainty of dust/haze days and incoming Israeli shower clouds affected by “sea spray” as Freud et al. 2015 described on shower days during the time the HUJ experimenters were flying their research aircraft in the early 1970s, monitoring storms with their radars, or examining rawinsondes during rain spells, we can conclude confidently that the lack of reporting on shallow precipitating clouds that occurred regularly in Israel is one of the more inexplicable and troubling aspects in the reporting of the Israeli cloud seeding experiments.

Deepening this enigma is that for two winter seasons in the late 1970s, the experimenters measured the depth of raining clouds with a vertically pointed 3-cm wavelength radar with research aircraft overflights to verify accuracy (Gagin 1980).  Dr. Rosenfeld, a B23 co-author who studied clouds and radar imagery at this time, is the sole living person who can tell us what happened (Rosenfeld 1980, master’s thesis).  One must necessarily ask if the HUJ experimenters discovered clouds they “didn’t like,” and withheld that information from us as they did the results of seeding in the south target of Israel-2?  Without conjuring up a stupefying degree of incompetence, it seems likely.

It is not science that we are dealing with concerning the reporting by the HUJ cloud seeding researchers.  There will ALWAYS be another problem that prevented seeding from working and if only corrected, seeding will work, as we are sure to learn when the inevitable “secondary” results of Israel-4 are published.

Will I be given a chance to review an Israeli cloud seeding manuscript as an expert in Israeli clouds, weather, and cloud seeding?  It seems unlikely with the journal atmosphere we have today.

  1. The on-going journal problem of “one-sided citing” as seen in B23; the equivalent of today’s “cancel culture” 

The omission of the work by myself and with Prof. Peter V. Hobbs was shocking to see in B23 since all the B23 authors knew of this work.  In human terms, external skeptics from a foreign country that expose faulty science in another country are not going to be exactly welcomed (or apparently cited) by that’s country’s scientists when a scientific embarrassment unfolds, as has happened in Israel concerning cloud seeding.  While this may seem like an outlandish claim, what happened could be interpreted as tinged with nationalism has previously been shown to obfuscate science (Broad and Wade 1982, p114).

For journal readers who are used to “one-sided citing” in partisan media, our scientific journals are supposed to be immune from these acts due to a peer-review “filter” that is supposed to eliminate this practice before an article reaches the publication stage.

        a).  Why do authors, like B23, tell only one side of the story?

In the words of Ben-Yehuda and Oliver-Lumerman (2017) of the HUJ,  such deceptions are, “…a deliberate attempt to create a false reality, persuade audiences that these realities are valid, and enjoy the benefits that accompany scientific revelations, whether those of prestige, money, reputation, or power….”  The effect of one-sided citing on journal readers is well expressed in the U. S. Federal Trade Commission’s (FTC) statement on consumer fraud:

“Certain elements undergird all deception casesFirst, there must be a representation, omission or practice that is likely to mislead the consumer [journal reader].”

For the reader, one-sided citing, if it is not obvious, is purposefully done by authors to hide results that they do not want you to see.  In effect, B23 performed the same act as Gagin and Neumann (1981) did when the latter authors did not report the results of random seeding of the south target of Israel-2, results that they did not want the world to see, and results that would have raised so many questions.

Regrettably, one-sided citing (a form of deception) is widely observed in Amer. Meteor. Soc. journals and in J. Weather Modification articles on cloud seeding/weather modification:

https://cloud-maven.com/journal-citing-practices-in-a-controversial-domain-cloud-seeding/

B23 practiced one-sided citing (defined by Schultz 2009) in their article concerning the Israel-1 and Israel-2 experiments.  Inexplicably, our groundbreaking work (e.g., R88, RH88, who pointed out how anomalous the Israeli cloud reports were compared to other clouds, and RH95a) went uncited by B23.   Our work, in toto, can be said to have anticipated the both the null result of decades of operational seeding of Lake Kinneret (Kessler et al. 2006, Sharon et al. 2008) and the null “primary” result of Israel-4 reported by B23.

B23 repeatedly misled/deceived readers, the “consumers” of journal science, concerning Israel-1 and Israel-2.   If there is something different than what was done by B23 than what is described by the FTC above its not apparent.

Nor did B23 cite Wurtele (1971), Silverman (2001) or mention the critical airborne cloud measurements by one of Israel’s own leading scientists, Levin 1992, 1994, and Levin et al. 1996).  The latter measurements were the first cloud ice measurements in Israel since Gagin (1975).  Those new, independently acquired cloud ice measurements supported the conclusions in R88, RH88, and those in RH95a, all which contravened the many HUJ experimenters’ fictitious reports of “ripe for seeding” clouds whose tops could ascend to ~-20°C without precipitating.

Later measurements of cloud properties via satellite would also confirm the independent cloud measurements and assessments; that the clouds of Israel formed precipitation far more readily and at much higher cloud top temperatures (Ramanathan et al. 2001) than the HUJ experimenters could discern over many decades.

In 2015, the HUJ cloud researchers discovered that “sea spray” in the Mediterranean makes the cumuliform clouds invading Israel precipitate more efficiently and at the high cloud top temperatures like those reported in R88 (Freud et al. 2015).  We can be quite sure that Mediterranean Sea spray has been occurring and affecting clouds that move into Israel for millions of years, and of course, did so during the 1970s when the HUJ scientists were performing their aircraft and radar cloud studies.  Yet, they could not detect, or did not report, on those clouds that would have erased most of their seeding potential.

The shame of one-sided citing in B23 is that the authors could have added a single sentence following their repeated claims of rain increases in Israel-1 and -2:  “However, these results, and the cloud reports that gave the statistical results credibility, have been questioned/overturned,” followed by a string of citations.

But B23 could not bring themselves to do that.

          b) Why should we care about one-sided citing?

 Knowledgeable readers of a specific topic like this writer will know that an article has been skewed to deliberately mislead readers due to omissions of contrary findings that go against what the authors assert.  But less informed readers will not know, and their knowledge will be truncated regarding an important public policy, as when their state or local government considers a­­­­ cloud seeding program.  They will want to know the unabridged findings about the Israeli experiences as a tale of caution about accepting claims by promoters of seeding that have not been closely scrutinized by outside experts.

Moreover, “one-sided citing” sullies the reputations of all the authors even those who may not have agreed with doing it, and likewise sullies the reputations of institutions represented by the authors who practice it by suggesting that those institutions do not uphold standard science practices by those who work there.   It also damages the authors whose work goes uncited since one’s impact in science is measured by citation metrics.  Finally, even the journal in which one-sided citing occurs can be considered to have been damaged since unreliable findings have been published in it.

Nevertheless, it would appear that reviewers, editors, and journal management do not care so much about this issue.  No statement in our Amer. Meteor. Soc. ethics statement addresses the question of the pernicious practice of one-sided citing as seen in B23.  Its intellectually dishonest to omit relevant findings for your science audience just because you don’t like them

              c) Who’s responsible for “one-sided” citing in        journals?

 “One-sided” citing, specifically as observed in B23, is due to poor peer reviews of manuscripts by seeding partisans or reviewers ignorant of the literature they are supposed to know.   However, it is also due to those that do know the literature but do not get those manuscripts to review.  For example, even though I would be deemed an expert on Israeli clouds, weather, cloud seeding, and on cloud microstructure, I was inexplicably not asked to review a manuscript in my specialty; that by B23 which would have made these comments unnecessary.

The reviewers of B23 manuscript were either ignorant of the literature they were supposed to be knowledgeable about or were cloud seeding partisans that also desired that the “other side” of the story for Israel-1 and Israel-2, as represented in the peer-reviewed literature by R88, RH88, RH95a, RH97a, b, c, d, e, Silverman (2001), Wurtele (1971) and Levin’s cloud measurements (e.g., Levin et al. 1996),  be hidden from the journal readers.

At the top of the “responsibility pyramid” for one sided citing in journal articles, however, must reside the editor of the journal who chose the reviewers that allowed this to happen.  Whomever this was at the J. Appl. Meteor. Climate, should not be allowed to be an editor who disburses cloud seeding manuscripts again.

        d) Concluding remarks on one-sided citing

 While all the B23 authors are technically responsible for its misleading content, one suspects some were likely “drug along” by stronger author personalities or authors who have funding power over them.  As is done in Geophys. Res. Letts., the actual contributions of each author to this article should have been listed so we can truly know who was responsible for providing one-sided histories for Israel-1 and Israel-2 and other misleading statements.

We know, too, seeding partisans at the HUJ that have cost their own country so much will not let the “primary” null result of B23 stand; there will be “secondary” and “tertiary” stratifications of Israel-4 data perhaps designed to mislead the INWA into another randomized cloud seeding experiment or to resume operational seeding of Lake Kinneret.

It will be critical that if a new experiment is conducted at the behest of the HUJ seeding partisans, that outside, independent experts conduct it!  It is also critical that prior to a new experiment that new airborne measurements of the clouds of Israel also be undertaken by outside, independent and experienced researchers in view of the problems that researchers at the HUJ have had over several decades, right up to today,  in reporting ice particle concentrations in their clouds and their clouds’ actual seeding potential.

The major question we must now confront to avoid further science mischief by HUJ cloud seeding researchers, is how was it that they were not aware of the natural state of their clouds, namely, that clouds with tops warmer than -10°C that regularly rained, a finding that seriously limits cloud seeding potential?   To date, no explanation has been put forward.  And what evidence will they skew or miss in a likewise manner in the inevitable Israel-4, “secondary” results article?

=========================

Lastly, a note of scientific etiquette for B23 and young researchers: B23 cite the work of French et al. (2018) in demonstrating cloud seeding efficacy via the use of mm-wavelength radar.

The first use of mm-wavelength radar of the type used by French et al. (2018) was used by the Cloud and Aerosol Group at the University of Washington in a “proof of concept” experiment (Hobbs et al. 1981).  Scientific etiquette means citing those that went first (Schultz 2009)   Thus, a citation to the Hobbs et al. (1981) article should have preceded that of French et al. 2018)8.   Our experiment proved that cloud seeding works in limited situations as in those described by French et al. (2018).

=================FOOTNOTES=====================

1The Israeli experiments have had several names over their history.  We use the latest terms for them here, e.g., Israel-1, etc.

2Pressure was applied in 1986 on the HUJ researchers by the Israeli experiments’, “Chief Meteorologist,” Mr. Karl Rosner, who began a letter writing campaign to have the important results of seeding in the south target published by Prof. Gagin.  Mr. Rosner told Professor Hobbs and myself in a Seattle visit that he felt that Prof. Gagin’s co-author, Jehuda Neumann, was “drug along” as a co-author of Gagin’s papers.

3This author believes that it is critical that a certified copy of the list of random decisions for Israel-2 be compared against those days used in the experiment.  The remarkably unlikely random draw described by Gabriel and Rosenfeld (1990) could be explained if the original list was violated by the experimenters: draws were made and assigned to  “seed” days when heavy storms were forecast.

4Rosenfeld (1989) in an unpublished HUJ report argued that the divergent apparent effects of cloud seeding were real.

5The findings of Kessler et al.  were challenged by seeding partisans at the HUJ and who claimed that “air pollution” had decreased rain as much as cloud seeding had increased it after 1990.  While this was a convenient explanation, it was not found credible by many subsequent independent investigators, including by Kessler et al. (2006).

6Ben-Yehuda and Oliver-Lumerman’s 2020 book, Fraud and Misconduct in Research, should be required reading for B23.  Ben-Yehuda and Oliver-Lummerman are professors at the HUJ.

7I suggested the use of our vertically pointed, mm-wavelength radar for cloud seeding use to Prof. Larry Radke and Peter Hobbs, after seeing virga signatures pass overhead of that radar, realizing that creating lines of seeding in supercooled cloud layers that passed over such a radar could prove the viability of cloud seeding in a new way.  I also carried out this experiment as flight scientist/meteorologist in the seeding/monitoring aircraft.  However, I was not credited for this idea by Prof. Hobbs in the Science article.

==================REFERENCES====================

Ben-Yehuda, N., and A. Oliver-Lumerman, 2020:  Fraud and Misconduct in Research.  University of Michigan Press, 266pp. No doi.

Benjamini, Y, A. Givati, P. Khain, Y. Levi, D. Rosenfeld, U. Shamir, A. Siegel, A. Zipori, B. Ziv, and D. M. Steinberg, 2023:  The Israel 4 Cloud Seeding Experiment: Primary Results.   J. Appl. Meteor. Climate, 62, 317-327.  https://doi.org/10.1175/JAMC-D-22-0077.1

Brier, G. W., and I. Enger, 1952: An analysis of the results of the 1951 cloud seeding operations in central Arizona.  Bull. Amer. Meteor. Soc., 23, 208-210.  https://doi.org/10.1175/1520-0477-33.5.208

  Broad, W. J., and N. Wade, 1982: Betrayers of the TruthFraud and Deceit in the Halls of Science. Simon and Schuster, 256pp. No doi.

Dennis, A. S., 1989: Editorial to the A. Gagin Memorial Issue of the J. Appl. Meteor., 28, 1013.

Foster, K. R., and P. W. Huber, 1997:  Judging Science: Scientific Knowledge and the Federal Courts.  The MIT Press, 333pp.   No doi.

French, J.R., Friedrich, K., Tessendorf, S.A., Rauber, R.M., Geerts, B., Rasmussen, R.M., Xue, L., Kunkel, M.L. and Blestrud, D.R., 2018: Precipitation formation from orographic cloud seeding. Proc. Natl. Acad. Sci., 115, 1168-1173.

https://doi.org/10.1073/pnas.1716995115

Freud, E., H. Koussevitsky, T. Goren, D. Rosenfeld, 2015:  Cloud microphysical background for the Israel-4 cloud seeding experiment.  Atmos. Res., 158-159, 122-138.  https://doi.org/10.1016/j.atmosres.2015.02.007

Gabriel, K. R., 1967a: The Israeli artificial rainfall stimulation experiment: statistical evaluation for the period 1961-1965. Vol. V., Proc. Fifth Berkeley Symp. on Mathematical Statistics and Probability, L. M. Le Cam and J. Neyman, eds., University of California Press, 91-113.

___________, 1967b:  Recent results of the Israeli artificial rainfall stimulation experiment.  J. Appl. Meteor., 6, 437-438.

            https://doi.org/10.1175/1520-0450(1967)006%3C0437:RROTIA%3E2.0.CO;2

____________, and R. Baras, 1970: The Israeli rainmaking experiment 1961-1967 final statistical tables and evaluation. Tech. Rep., Hebrew University, Jerusalem, 47pp. No doi.

_____________, and Rosenfeld, D., 1990: The second Israeli rainfall stimulation experiment: analysis of precipitation on both targets. J. Appl. Meteor., 29, 1055-1067.  https://doi.org/10.1175/1520-0450(1990)029%3C1055:TSIRSE%3E2.0.CO;2

Gagin, A. 1975: The ice phase in winter continental cumulus clouds. J. Atmos. Sci., 32, 1602-1614.  https://doi.org/10.1175/15200469(1975)032%3C1604:TIPIWC%3E2.0.CO;2

Gagin, A., 1980: The relationship between depth of cumuliform clouds and their raindrop characteristics. J. Rech. Atmos., 14, 409-422.  No doi.

Gagin, A., 1981: The Israeli rainfall enhancement experiments.  A physical overview. J. Wea. Mod., 13, 1-13.   https://doi.org/10.54782/jwm.v13i1.41

Gagin, A., 1986: Evaluation of “static” and “dynamic” seeding concepts through analyses of Israeli II and FACE-2 experiments. In Precipitation Enhancement–A Scientific Challenge, Meteor. Monog.,21, No. 43, Amer. Meteor. Soc., 63-70.

https://doi.org/10.1175/0065-9401-21.43.63

_______., and K. R. Gabriel, 1987: Analysis of recording gage data for the Israeli II experiment Part I: Effects of cloud seeding on the components of daily rainfall. J. Appl. Meteor., 26, 913-926.

 https://doi.org/10.1175/1520-0450(1987)026%3C0913:AORRDF%3E2.0.CO;2

_______, and J. Neumann, 1974: Rain stimulation and cloud physics in Israel. Climate and Weather Modification, W. N. Hess, Ed., Wiley and Sons, New York, 454-494. No doi.

_______, and _______, 1976: The second Israeli cloud seeding experiment–the effect of seeding on varying cloud populations.  Proc. 2nd WMO Scientific Conf. on Weather Modification, Boulder, 195–204.  World Meteor. Organization, 41 Ave. Giuseppe Moffs, Geneva 2, Switzerland.) No doi.

________, and ________, 1981: The second Israeli randomized cloud seeding experiment: evaluation of results. J. Appl. Meteor., 20, 1301-1311.

https://doi.org/10.1175/1520-0450(1981)020%3C1301:TSIRCS%3E2.0.CO;2

Givati, A., and Rosenfeld, D., 2005: Separation between cloud-seeding and air pollution effects. J. Appl. Meteor. Climate, 44, 1298-1314.

https://doi.org/10.1175/JAM2276.1

Goldsmith, P., Gloster, J., and C. Hume, 1976:  The ice phase in clouds.  Preprint Volume, Intern. Conf. on Cloud Physics, Boulder, Amer. Meteor. Soc., Boston, MA. 163-167.

Hobbs, P. V., and A. L. Rangno, 1978: A reanalysis of the Skagit cloud seeding project.  J. Appl. Meteor., 17, 1661–1666.

         https://doi.org/10.1175/1520-0450(1978)017%3C1661:AROTSC%3E2.0.CO;2

_________, and _________, 1979: Comments on the Climax randomized cloud seeding experiments.   J. Appl. Meteor., 18, 1233-1237.

     https://doi.org/10.1175/1520-0450(1979)018%3C1233:COTCAW%3E2.0.CO;2

_________, and __________, 1985: Ice particle concentrations in clouds. J. Atmos. Sci., 36, 2523-2549. https://doi.org/10.1175/1520-0469(1985)042%3C2523:IPCIC%3E2.0.CO;2

_________, and ___________, 1990: Rapid development of ice particle concentrations in small polar maritime cumuliform clouds. J. Atmos. Sci., 47, 2710-2722.

     https://doi.org/10.1175/1520-0469(1990)047%3C2710:RDOHIP%3E2.0.CO;2

 

_________, Lyons, J. H., Locatelli, J. D., Biswas, K. R., Radke, L. F., Weiss, R. W., Sr., and A. L. Rangno, 1981:  Radar detection of cloud-seeding effects.  Science, 213, 1250-1252.  https://doi.org/10.1126/science.213.4513.1250

Kerr, R. A., 1982: Cloud seeding: one success in 35 years.  Science, 217, 519–522.    https://doi.org/10.1126/science.217.4559.519

Kessler, A., A. Cohen, D. Sharon, 2006:  Analysis of the cloud seeding in northern Israel. A report submitted to the Israel Hydrology Institute and the Israel Water Management of the Ministry of Infrastructure, In Hebrew with an English abstract). 117pp.  No doi.

Koenig, L. R., 1963:  The glaciating behavior of small cumulonimbus clouds.  J. Atmos. Sci., 20, 29-47.

https://doi.org/10.1175/1520-0469(1963)020%3C0029:TGBOSC%3E2.0.CO;2

__________, 1977:  The rime-splintering hypothesis of cumulus glaciation examined using a field-of-flow cloud model.  Quart. J. Roy. Meteorol. Soc., 103, 585-606.

https://doi.org/10.1002/qj.49710343805

__________, 1984:  Further theoretical studies of the role of splintering in cumulus glaciation, Quart. J. Roy. Meteorol. Soc., 110, 1121-1141.

         https://doi.org/10.1002/qj.49711046621

Levin, Z., 1992: The role of large aerosols in the precipitation of the eastern Mediterranean. Paper presented at the Workshop on Cloud Microphysics and Applications to Global Change, Toronto. (Available from Dept. Atmos. Sci., University of Tel Aviv).  No doi.

_______, 1994:  The effects of aerosol composition on the development of rain in the eastern Mediterranean.  WMO Workshop on Cloud Microstructure and Applications to Global Change, Toronto, Ontario, Canada, World Meteor. Org., 115-120. No doi.

_______, E. Ganor, and V. Gladstein, 1996: The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean.  J. Appl. Meteor., 35, 1511-1523.

https://doi.org/10.1175/1520-0450(1996)035%3C1511:TEODPC%3E2.0.CO;2

_________., N. Halfon, and P. Alpert, 2010: Reassessment of rain enhancement experiments and operations in Israel including synoptic considerations.  Atmos. Res., 97, 513-525.

                        http://dx.doi.org/10.1016/j.atmosres.2010.06.011

MacCready, P., 1952: Results of cloud seeding in central Arizona, winter 1951.  Bull. Amer. Meteor. Soc., 23, 48-52.

Mason, B. J., 1982:  Personal Reflections on 35 Years of Cloud Seeding.  Contemp. Phys., 23, 311-327.  http://doi-org/10.1080/00107518208237084

Mossop, S. C., 1985: Secondary ice particle production during rime growth: the effect of drop size distribution and rimer velocity. Quart J. Roy. Meteor. Soc., 111, 1113-1124.       http://DOI-org/10.1002/qj.49711147012

National Research Council-National Academy of Sciences, 1973:  Weather and Climate Modification: Progress and Problems, T. F. Malone, Ed., Government Printing Office, Washington, D. C., 258 pp.

Neumann, J., K. R. Gabriel, and A. Gagin, 1967: Cloud seeding and cloud physics in Israel:  results and problems.  Proc. Intern. Conf. on Water for Peace.  Water for Peace, Vol. 2, 375-388.  No doi.

Nirel, R., and D. Rosenfeld, 1995: Estimation of the effect of operational seeding on rain amounts in Israel.  J. Appl. Meteor., 34, 2220-2229.

https://doi.org/10.1175/1520-0450(1995)034%3C2220:EOTEOO%3E2.0.CO;2

Ramanathan, V., P. J. Crutzen, J. T. Kiehl, and D. Rosenfeld, 2001: Aerosols, climate and the hydrological cycle.  Science294, 2119-2124.

         https://doi-org/10.1126/science.1064034

___________, 1979:  A reanalysis of the Wolf Creek Pass cloud seeding experiment.   J. Appl. Meteor., 18, 579–605.

         https://doi.org/10.1175/1520-0450(1979)018%3C0579:AROTWC%3E2.0.CO;2

___________, 1986:  How good are our conceptual models of orographic clouds?  In Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Meteor. Monographs, 43, Amer. Meteor. Soc., 115-124. (An invited paper.)     https://doi.org/10.1175/0065-9401-21.43.115

___________, 1988: Rain from clouds with tops warmer than -10 C in Israel.  Quart J. Roy. Meteor. Soc., 114, 495-513.

     https://doi-org/10.1002/qj.49711448011

__________, 2000:  Comment on “A review of cloud seeding experiments to enhance precipitation and some new prospects.” Bull. Amer. Meteor. Soc., 81, 583-585.  No doi

__________, and P. V. Hobbs, 1980a: Comments on “Randomized seeding in the San Juan mountains of Colorado.”  J. Appl. Meteor., 19, 346-350.

     https://doi.org/10.1175/1520-0450(1980)019%3C0346:COCSIT%3E2.0.CO;2

__________, and _________, 1980b: Comments on “Generalized criteria for seeding winter orographic clouds”.  J. Appl. Meteor., 19, 906-907.

    https://doi.org/10.1175/1520-0450(1980)019%3C0906:COCFSW%3E2.0.CO;2

__________, and _________, 1981: Comments on “Reanalysis of ‘Generalized criteria for seeding winter orographic clouds’”, J. Appl. Meteor., 20, 216.

https://doi.org/10.1175/1520-0450(1981)020%3C0216:COOCFS%3E2.0.CO;2

__________, and _________, 1983: Production of ice particles in clouds due to aircraft penetrations. J. Climate Appl. Meteor., 22, 214-232.

https://doi.org/10.1175/1520-0450(1983)022%3C0214:POIPIC%3E2.0.CO;2

__________, and _________, 1987: A re-evaluation of the Climax cloud seeding experiments using NOAA published data.  J. Climate Appl. Meteor., 26,  757-762.

         https://doi.org/10.1175/1520-0450(1987)026%3C0757:AROTCC%3E2.0.CO;2

__________, and _________, 1988: Criteria for the development of significant concentrations of ice particles in cumulus clouds.  Atmos. Res., 22, 1-13. No doi.

__________, and _________, 1991:  Ice particle concentrations in small, maritime polar cumuliform clouds. Quart J. Roy. Meteorol. Soc., 117, 207-241. https://doi.org/10.1002/qj.49711749710

__________, and _________, 1993: Further analyses of the Climax cloud-seeding experiments.  J. Appl. Meteor., 32, 1837-1847.

         https://doi.org/10.1175/1520-0469(1990)047%3C2710:RDOHIP%3E2.0.CO;2

­­__________, and _________, 1995:  A new look at the Israeli cloud seeding experiments.  J. Appl. Meteor., 34, 1169-1193.

https://doi.org/10.1175/1520-0450(1995)034%3C1169:ANLATI%3E2.0.CO;2

__________, and _________, 1997a: Reply to Rosenfeld.  J. Appl. Meteor., 36, 272-276.

https://doi.org/10.1175/1520-0450(1997)036%3C0272:R%3E2.0.CO;2

__________, and _________, 1997b: Comprehensive Reply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp.  http://carg.atmos.washington.edu/sys/research/archive/1997_comments_seeding.pdf

__________, and _________, 1997c: Reply to Dennis and Orville. J. Appl. Meteor., 36, 279. https://doi.org/10.1175/1520-0450(1997)036%3C0279:R%3E2.0.CO;2

__________, and _________, 1997d: Reply to Ben-Zvi. J. Appl. Meteor., 36, 257-259.

https://doi.org/10.1175/1520-0450(1997)036%3C0257:R%3E2.0.CO;2

__________, and _________, 1997e: Reply to Woodley. J. Appl. Meteor., 36, 253-254.

https://doi.org/10.1175/1520-0450(1997)036%3C0253:R%3E2.0.CO;2

 

___________, ___________, and L. F. Radke, 1977:  Tracer and diffusion and cloud microphysical studies in the American River basin.  Final Report to the Bureau of Reclamation, Final Report to the Division of Atmospheric Water Resources Management, Bureau of Reclamation, Contract 6-07-DR-20140), University of Washington, Seattle, WA, 98195.

(american_river_cloud.pdf

Rosenfeld, D., 1980:  Characteristics of Rain Cloud Systems in Israel Derived from Radar and Satellite Images.  M. S. Thesis, The Hebrew University of Jerusalem, 129pp. (Available from the Department of Meteorology, Hebrew University of Jerusalem, Jerusalem, Israel).

_________, 1989:  The divergent effects of cloud seeding uncer different physical conditions in Israeli 1 and 2 experiments.  Dept. Atmos. Sci., Hebrew University of Jerusalem, May 1989. No doi.

___________, 1998: The third Israeli randomized cloud seeding experiment in the south: evaluation of the results and review of all three experiments. Preprints, 14th Conf. on Planned and Inadvertent Wea. Modif., Everett, Amer. Meteor. Soc. 565-568. No doi.

Rosenfeld, D., and H. Farbstein, 1992: Possible influence of desert dust on seedability of clouds in Israel. J. Appl. Meteor., 31, 722-731.

https://doi.org/10.1175/1520-0450(1992)031%3C0722:PIODDO%3E2.0.CO;2

Schultz, D. M., 2009:  Eloquent Science:  A practical guide to becoming a better writer, speaker, and atmospheric scientist.  Amer. Meteor. Soc.  pp412.

Sharon, D., A. Kessler, A. Cohen, and E. Doveh, 2008:  The history and recent revision of Israel’s cloud seeding program.  Isr. J. Earth Sci., 57, 65-69.     https://DOI.org/10.1560/IJES.57.1.65.

Silverman, B. A., 2001: A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement. Bull. Amer. Meteor. Soc., 82, 903-923.

https://doi.org/10.1175/1520-0477(2001)082%3C0903:ACAOGS%3E2.3.CO;2

Wurtele, Z. S., 1971: Analysis of the Israeli cloud seeding experiment by means of concomitant meteorological variables. J. Appl. Meteor., 10, 1185-1192.

https://doi.org/10.1175/1520-0450(1971)010%3C1185:AOTICS%3E2.0.CO;2

Review of a published assessment of Israeli cloud seeding potential in support of the Israel-4 cloud seeding experiment

After pasting my incredibly LONG review of this article in this space, I realized it was too long for a blog, so will just put a link here where that strange person who would want to read it will find it.  I’m following in the paths of F. A. Gifford and Fred Sanders, of whom it was said their reviews were sometimes LONGER than the manuscripts they were reviewing!

Review of Freud et al 2015 (monograph sized)

Below is my pathetic attempt to put my review into a viable/readable blog that I will be working on to “clean up”, add figures from the original and “other”.  So look for changes as time goes by.  I don’t expect the pdf to change.   The figures are in the pdf above, btw.

A continuing theme of reviews like this is, as in other cases,  I was not asked to review this manuscript in my expertise before publication, even though I was known by the authors as an expert on Israeli clouds, weather, and cloud seeding.  Perhaps the editor of this journal,  who chose the reviewers did not know???   Right now, its “Ready, Fire, Aim” to quote a book title describing the premature publication of this blog.

Oh, that Israel-4 cloud seeding experiment?!    The result of the seven season randomized experiment was published by Benjamini et al. (2023, J. Appl. Meteor.).  The “primary” evaluation found no viable increase in precipitation due to cloud seeding, in agreement with my 2017 review of this cloud seeding potential paper and all my prior work on Israeli clouds (Rangno 1988, Quart J. Roy. Meteor. Soc.) and cloud seeding (Rangno and Hobbs 1995, J. Appl. Meteor.)

Cloud seeding potential was grossly exaggerated by Freud et al. (2015).  I wanted to scream to the Israel National Water Authority, “Don’t do a cloud seeding experiment based on these findings!”  But, it was too late.

==================================================================================================

A comprehensive review of

“Cloud microphysical background for the Israeli-4 cloud seeding experiment”

by Freud, E., H. Koussevitsky,  T. Goren and D. Rosenfeld,

(the article which is reviewed below was published in 2015 by Atmospheric Research)

with a recap of the Hebrew University of Jerusalem’s cloud seeding experiments

as seen by a long-time observer (me)

  1. A. L. Rangno[1]

Opening remarks

“What is scientific knowledge? When is it reliable?”, ask Kenneth Foster and Peter Huber (1997), in “Judging Science:  Scientific Knowledge and the Federal Courts”, MIT Press.  “Scientific knowledge” might be considered anything published in a peer-reviewed journal.  Having passed the peer review “filter” gives, or should give, that which appears in a peer-reviewed journal particular reliability on which our scientific knowledge grows.

Much of this review addresses the second question raised by Foster and Huber, the reliability of published science. Implicitly, this review also addresses the quality of the peer-review “filter” in the cloud seeding domain:  “Has it improved since the 1960s through 1980s when hundreds of pages of faulty cloud seeding claims concerning experiments in Colorado and Israel were published, ones that misled our best scientists?”  In this review of a recently published paper, we must answer, “No.”

In this review[2], we examine the reporting of current and past research by researchers at one of the world’s great universities, the Hebrew University of Jerusalem (HUJ). The researchers at the HUJ in the article to be examined are reporting in a domain of science particularly susceptible to controversy, cloud seeding (e.g., Changnon and Lambright 1990); a field of study afflicted by a quasi-religious “confirmation biases”, and polarization that have corrupted it repeatedly.

Moreover, can the contents in articles published in peer-reviewed journals always be trusted in the polarized domain of cloud seeding with so much at stake for experimenters who report on their own work (jobs, prestige, confirmation of a priori beliefs, etc)?  And, it is experimental work that is unlikely to have attempts at independent replication, our best safeguard against faulty claims, due to the high cost of field experiments.  There may be no more vulnerable field to corruptive influences than cloud seeding due to these factors.

Conversely, pressure arises when you can’t find more rain on your cloud seeding experiment’s seeded days; you may be deemed a failure by others who KNOW that seeding worked.   You may lose funding and your job since you found no response.  This is because the value of a carefully conducted cloud seeding experiment with no viable proof of a seeding effect is undervalued.  These factors converge to produce repeated false “happy” results in cloud seeding publications.

The idea of making it rain or snow on command, as it were, has corrupted many a good scientist since the earliest modern days of this field when Schaeffer dropped dry ice in a layer of Altocumulus clouds in 1946)[3].    The controversy largely results from reports of cloud seeding successes (precipitation increases) by the original experimenters whose findings are subsequently overturned by independent scientists “upon closer inspection” in re-analyses.  This cycle of reverses has gone on since Brier and Enger (1952) right through the era of randomized experiments (e.g., Levin et al. 2010)!   Randomization apparently did not remove experimenter bias.   The Israeli experiments have been subject to this rise and fall cycle.

In Freud et al. (2015)—hereafter, F2015, this rise and fall cycle in the Israeli experiments conducted by the HUJ-CSG is not explained as candidly as it should have been for their Atmospheric Research ( AR) readers and funders, thus prompting this review.  This review scrutinizes all aspects of the F2015 paper which apparently led to additional cloud seeding in Israel.   Because  F2015 was also part of a proposal to the Israel National Water Authority (INWA), it is also reviewed with more rigor for that reason.  Proposals are written by “Party A” to extract monies from “Party B”;  it’s a sales pitch.  When this is done, one might find that Party A has painted a rosier scene for possible accomplishments (his “product”) than is viable for Party B.  In droughty times, it’s always the cloud seeding salesman that wins.  And it’s a win situation for funders who want to show constituents that they are doing something about a drought.

The review of F2015 is organized by topics.   It also contains a “corrective history” of cloud seeding in Israel since Israeli 1.   The history is based on the hope that it will be useful to potential future reviewers of  manuscripts in cloud seeding that might emanate from the HUJ’s “cloud seeding group” (hereafter, “HUJ-CSG”;  referring to those HUJ authors over the decades that have authored or co-authored papers on cloud seeding).  This history may also be of interest to young graduate students within the HUJ science department who may not be informed about it.

Much of this critique of F2015 is due to the authors’ incomplete and misleading descriptions of prior cloud seeding results reported by the HUJ in the abstract and “Introduction” segments.  The former chief editor of Science magazine says it all:

The difficulty is that positive claims are sometimes made against a background of    unrevealed negative results.” 

—————– Donald Kennedy, 2004 Science editorial:  “The Old File Drawer Problem.”

The word “independent” is highlighted in this review due to the remarkable number of times that outside, independent researchers, when examining the findings published by the HUJ-CSG in peer-reviewed journals, beginning with Rangno (1988-hereafter R88), could not substantiate or reversed them.   This may give the HUJ-CSG the unenviable reputation as a frequent producer of published, but “unreliable, irreproducible” results.  The primary reason is that the HUJ-CSG publishes ambiguous results but describes them as though they were “in concrete”, hiding the ambiguities in their findings that others bring out later.  What should be troubling is that there are likely more ambiguities in HUJ-CSG publications hidden in what appear to be solid findings that have not yet been examined by independent researchers.

HUJ are you listening?

“One-sided citing” is often practiced by the HUJ-CSG, and is seen again in F2015.  Those instances are called out in this review.   “One-sided citing” has recently been condemned in the American Meteorological Society book, Eloquent Science, by David Schultz (2009).  Here’s what Schultz had to say about one-sided citing:

“One-sided reviews of the literature that ignore alternative points of view, however, can be easily recognized by the audience, leading to a discrediting of your work as being biased and potentially offending the neglected authors (who might also be your reviewers!).”  (Yep, me!)

Moreover, there is material damage to your fellow scientists when they are not cited when they should be, as by the HUJ-CSG in this and other cloud seeding articles.  The impact in one’s field; promotions, awards, impact and status, is usually determined by an impact metric, such as the number of citations of your work.

Too, there is implicit damage to the reputation of the home department and institution from which one-sided citing emanates.

HUJ, are you listening?   After all, “the Hebrew University of Jerusalem is Israel’s premier academic and research institution,” as the HUJ states on its web page.  Thus, it should be held to a high standard of research reporting.   The HUJ should be appropriately troubled to read what it finds here.

It is strongly recommended that the HUJ-CSG authors read Schultz’ book, and also that a course in scientific writing and ethics be taught at the HUJ.  (Perhaps many research institutions involved in cloud seeding research would benefit from such courses.)

One-sided citing in F2015 also demonstrates a poor AR peer review process prior to publication, perhaps by seeding partisans (“one-sided reviewing”?)  The obvious poor peer review of this article in the manuscript stage is a further reason why I have troubled to spend time doing a “comprehensive” , “no-stone-unturned” review.

———————–Organization of the Review——————

1)  Overall assessment of this paper and its claims about cloud seeding potential in northern Israel.

2) Who should be assessing seeding potential in Israel?  Ans.  Not the HUJ-CSG, as told by their history.

3)  The shifting cloud microstructure reports over the decades from the HUJ-CSG: how did it go so           wrong in the first place?  (Ans.  “We don’t know yet.”)

4)  The wrongful scientific consensus on Israeli cloud seeding:  how did it go so wrong?

Ans.  Inadequate peer-reviews,  insufficient skepticism and too much trust on the part of scientists reviewing manuscripts on cloud seeding.

5)  A mandated list of publically-available data from the F2015 field program described in this paper,       and why (see above remarks).

6)  “Filling in the blanks”:  Correcting F2015’s incomplete descriptions of Israeli 1, 2, and 3, and operational seeding  (in separate, titled “modules.”)

7) If you want to go further:  the remainder of the original article, absent the abstract and Introduction sections follows in black type with “inline” reviewer’s comments following highlighted statements.

8) After the References follows reviewer’s disclaimers, baggage, conflicts of interest, a prior convictions about cloud seeding, and his background that qualifies him for this review, etc., items that should always be mentioned.

Line numbers have been added so that rebuttals or support for this review can be easily accomplished.

I don’t apologize for the length of this review.  After all, reviews are intended to prevent faulty science from reaching the pages of journals, and help authors in explain their work.   It didn’t happen under AR prior to the publication of F2015.

The excessive length?   The HUJ-CSG has “earned it”; it can’t be trusted in the seeding domain under its current leadership IMO.  If this sounds overly provocative, or even outrageous, read on:

“It didn’t come out of a vacuum[4].”

This review is virtually identical to the one I would have done for AR for F2015 and the HUJ-CSG’s accompanying proposal for Israeli-4 to the INWA if I had been asked.  In polarized research environments, reviews of manuscripts by must be especially intense, every sentence checked for accuracy, every claim suspect until clearly proven;  the discovery of omissions of critical data called out and discussed as in this review.  F2015 encapsulates all that is right and wrong with the HUJ-CSG cloud seeding literature.

The decision from here on the manuscript version of this article would have been:

“Accept, but ONLY upon the authors fulfilling the required major revisions, posting mandated data online, and implementing corrections to their partial descriptions of prior work.”

As a proposal to initiate the Israeli-4 randomized experiment?

“Reject.”

There is insufficient evidence to guarantee a successful outcome.  I review F2015 as a proposal that I myself would be asked to pay for (as an Israeli citizen will be doing).

This “review” will contain compliments and condemnations.   Expect to get mad at someone, maybe me.  The language is sometimes blunt, and the question of misconduct is raised[5].

  1. Overall assessment of F2015

 

This article, due to its “Jeckyl-Hyde” properties, presents a unique review challenge; some of the best conscientious scientific writing by the HUJ-CSG is in this very article; the kind of writing marked by caveats and qualifications made in a circumspect manner.

On the positive side, too, it was pleasant and unexpected to read in F2015 that the HUJ-CSG has finally agreed with long standing work, first published by R88, that the Israeli clouds are overall unsuitable for seeding with silver iodide due to their propensity to form precipitation/ice readily.  This finding was re-iterated in Rangno and Hobbs (1995-herafter RH95).   Due to an oversight, or small-mindedness, however, F2015 do not cite the original altruistic work.

In contrast to the positive writing mentioned, there are elements of writing in this paper that cast a dark shadow on the authors, their home institutions, and ultimately, the journal that their article appeared in, AR.   Partial, and therefore, misleading descriptions of the prior Israeli experiments are found in several places, along with omissions of important references to work that was critical of HUJ-CSG findings, thus representing a stunningly “gorgeous” exhibition of “one-sided citing” in F2015, as is often practiced by the HUJ-CSG.

Nonetheless, the HUJ-CSG’s idea that inland clouds reforming over the Golan Heights/Mt. Hermon region might have seeding potential has merit and is worthy of further investigations and corroboration and expansion of the results in this paper by independent groups before any seeding takes place.

Viable seeding potential in the Golan region, however,  is not demonstrated in this paper, as will be shown in subsequent commentaries.

Factors to consider in the extreme northern Israel seeding scenario:  Cloud tops in northern Israel are usually significantly colder than those in the central and southern regions of Israel (Gagin and Neumann 1974, hereafter GN74; RH95).

GN74 reported modal radar tops on rain days in the north target of Israeli 2 near -19°C, whereas in the south target of Israeli 2, they were -16°C.  GN74 (written in 1972) in preliminary analyses, used those temperature differences to explain why seeding was seemingly effective in the north target (more activation of AgI), but not in the south target due to less activation of AgI[6].

Today, however, due to R88, Levin 1992, 1994, and Levin et al 1996, hereafter L929496, and in F2015, we know thatboth cloud top temperatures given in GN74 would be associated with high ice particle concentrations as turrets mature; they would be highly unsuitable for seeding, a situation this reviewer feels would extend into the Golan on many, if not most, storm days.

3)  Who should evaluate cloud seeding potential in the Golan?  Not the HUJ-CSG

Perhaps the most surprising and troubling aspect of F2015  is that the assessment of seeding potential in the Golan is being undertaken by HUJ-CSG; “troubling” due to that organization’s prior reporting history in that domain, i.e., its inability to detect (or hid) the nature of Israel’s clouds for decades with so many tools at its disposal, and the inherent conflict of interest such a new study represents.

Philosopher George Santayana said it: “Those who cannot remember the past are condemned to repeat it.”

Moreover, if the present “background” paper by F2015 is the primary reason why a new randomized cloud seeding experiment, Israeli-4,  was undertaken, then yes, the failed past of the HUJ-CSG’s seeding experiments (Israeli 1, 2 and 3) will be repeated providing that Israeli-4 is evaluated by independent, non-HUJ statisticians and scientists divested of cloud seeding interests!

The evaluation of the clouds in this article in AR is not complete enough to provide confidence that seeding is going to increase rain by an economically worthwhile amount in the Golan.   A new randomized experiment, or operational seeding, both appear to this reviewer to be unwise or at least, premature undertakings in spite of Israel’s urgent water needs.  Cloud seeding “salesmen” are drawn to drought like bees to a jar of spilled honey.  Funders, too, are anxious to open their tills to show their constituents that they are doing something about drought.  It’s a win-win situation for both.  Thankfully, the INWA in a burst of courage, went “randomized” and not into direct operational seeding based on the HUJ-CSG claims.

The sad history of the HUJ-CSG reporting in the cloud seeding domain is reprised for the reader or reviewer who is/was likely unaware of it so that the faults in F2015 can be seen in the context of  “damage control.”   These faults also represent “baggage” carried by the HUJ-CSG and their efforts to recoup the HUJ-CSG’s damaged credibility when they re-write and minimize key elements of that seeding history in F2015.

What “baggage”, you ask?

What if the HUJ-CSG knew for decades that the seeding operations started by the INWA after Israeli 2 in 1975 and  costing millions over the following 30 plus years were actually targeting inappropriate, highly efficiently precipitating clouds rolling in off the Med with little or no seeding effect likely?

What alternative would that group have other than posting one unreliable finding after another that seeding had worked anyway on such clouds?

Is it really possible for the HUJ-CSG to acknowledge error and cover up of that cloud knowledge as likely happened and apologize to the INWA and to the people of Israel?    Absent that apology, the HUJ-CSG group should be terminated IMO.

The appearance of F2015 showed that the HUJ-CSG has yet one more chance (after Israeli 1,2, 3, and in their evaluations of operational seeding) to skew findings to impress an apparently still naïve INWA and their countrymen about  seeding potential in the Golan.

This is the perfect example of the “fox guarding the hen house,” analogous to the Phelps-Dodge Mining Corporation being solely responsible for the environmental impact statement of its next mine.  That Phelps-Dodge assessment could be right; but it would never be trusted as such without outside,  independent confirmation.

Why doesn’t the INWA recognize this inherent, and, obvious to all familiar with the history of seeding in Israel, HUJ-CSG conflict of interest?

Why weren’t outside,  independent groups, such as the University of Wyoming, Stratton Park Engineering Company, NCAR, Droplet Measurement Technologies, Tel Aviv University, etc., brought in by the INWA to make this assessment?  The people of Israel and their media should be asking this question.   The HUJ-CSG forfeited its right to do such an assessment decades ago due to their incompetence in assessing their clouds.

Lastly, because of our experiences with the HUJ-CSG and the unreliability factor in their cloud seeding publications, I URGE that  INWA  have outside, independent groups experienced in airborne work collect data and report on the seeding potential of Israeli clouds in conjunction with critical supporting ground measurements of the nature of ice crystals and precipitation at Mt. Hermon as a next step before experimentation begins. (OK, I’m late to the party, but that’s what I would have recommended to the INWA).

 

  1. The shifting sands of the HUJ-CSG cloud microstructure reports over the decades and their shifting implications on cloud seeding

The essential question that should be asked by all of us is, “Why did it take so long for HUJ-CSG to discover the true nature of their highly efficiently precipitating clouds, given all the tools they’ve had available to them since the later 1970s? The tools at their disposal included multiple radars, including a vertically-pointed 3-cm one (Gagin 1980), aircraft, IMS rawinsondes, and the skill of the IMS forecasters who were well aware of the efficiency (shallowness) of Israeli clouds when they begin to precipitate[7].  And this information was there in plain sight for all of us (e.g., GN74, Fig 13.4, GN76, Figs. 2 and 3, Druyan and Sant 1978).

The inability of the HUJ-CSG to detect the nature of their clouds can be either seen as an example of astounding incompetence or one of investigable misconduct if those within the HUJ-CSG knew that their clouds were not as they described them in journals so many times; but, rather, hid that knowledge from their peers and the INWA to keep their jobs, their seeding programs, and misbegotten prestige intact.

Donald Kennedy (2003), in another Science editorial on research fraud:

In the real instances of research misconduct we know about in biology and physics, the motive appears to have been career enhancement, pure and simple. It is, after all, a competitive world, and the incentive to gain reputation can be powerful. But other motives may appear in those social sciences that bear upon major policy issues.”  (Always was and always will be—reviewer’s comment)

 

You decide.

The reason why the Israeli government is now attempting to once again see if the clouds of Israel can be made to produce economically useful amounts of water via seeding is because none of the prior Israeli experiments produced credible rainfall increases due to seeding.  And that due to the unsuitable clouds for seeding.

5) The false scientific consensus on cloud seeding created by the HUJ-  CSG

 That the HUJ-CSG could not discover the true nature of their clouds until recently, and did not report results of experiments in a timely manner[8], also produced an erroneous “consensus” view in the science community that cloud seeding had been “proven”in Israel (e,g, Tukey et al. 1978, Mason 1980, 1982, Kerr 1982, American Meteorological Society 1984, Dennis 1989, World Meteorological Organization 1992, Young 1993).

So what?

A wrongful consensus damages all of science!   This false “consensus” was published in numerous textbooks, and in countless popular articles along the lines of, “Israelis make it rain in the desert.” Who will retroactively correct those statements?

  1. Mandated publically-available data requirements from the F2015 cloud sampling program

Due to the past history of much-published, but faulty, cloud seeding research by the HUJ-CSG,  this reviewer would have mandated prior to publication of F2015 and before any cloud seeding experimentation took place, that the HUJ-CSG provide the following critical data online so that the wider community of experts could have evaluated the findings in F2015.  These should be provided at this time:

1) A table of flight data with dates and times of flights, linked to synoptic maps and satellite imagery for those flight days, and the ability to access flight videos from this program.

2)  A table detailing some of the microstructural measurements, following Hobbs and Rangno (1985), Table 1:

  1. a) maximum ice particle concentrations found in each sampling zone on each day over widths of                         of 300 m and 1-km,
  2. b) cloud top temperatures and heights of sampled clouds
  3. c)cloud base temperatures and heights of sampled clouds
  4. d)flight level temperature at which sample was obtained,
  5. e) height of the sample below cloud top,
  6. f) widths[9] near cloud top of the clouds that were sampled,
  7. g) average and maximum liquid water content in each “study” cloud,
  8. h) sizes of droplets <13 µm diameter and >23 µm diameter within the H-M temperature zone of                        -2.5° to -8° C  clouds,
  9. i) Large size tail of the FSSP droplet spectrum (“threshold diameter”, after Hobbs and Rangno 1985)
  10. j) average and maximum droplet concentrations in study clouds,
  11. k) estimate of stage that the cloud was in when sampled
  12. l)results of any ground work in the Golan/Mt. Hermon
  13. m) back trajectories for flight sampling times over the Mediterranean Sea, and over the Golan

The mandated data elements for outside researchers to examine may seem like an undue burden to the HUJ-CSG since some of these require care to obtain.  But these requirements have to be put in the perspective of how much the prior erroneous and incomplete reports by the HUJ-CSG cost not only the people of Israel in ineffective cloud seeding but also by neighboring Arab countries that undertook similar ineffective seeding operations, and finally, by the cost of the failed attempted replication of the ersatz Israeli results in Italy (List et al. 1999).

  1. a) The Israeli 1 experiment as described by F2015 and the counter evidence to that description; “filling in the blanks”

F2015 Abstract:  “These clouds were seeded….producing statistically-significant positive effects…”

This partial description of results for the first two experiments in the authors’ abstract should have been removed by the prior reviewers.  Right from the start the HUJ-CSG authors began misleading less-informed AR readers, some of whom will likely not go beyond the abstract.

There are MANY reasons why the Israeli 1 rain increase results are suspect, all known by the authors of F2015.  They deflected the full story about those reasons to, “positive effects.”  We reprise those reasons why no one any longer believes that Israeli 1 nor Israeli 2, have credibility as successes in rain production for AR readers who might have taken the faulty abstract prima facie:

Prior to the appearance of F2015 in ARINDEPENDENT  assessments (this cannot be overstressed) of  the statistical results of seeding in Israel  found them questionable at best  (RH95, Silverman 2001[10], Levin et al 2010, 2011, the latter in reply to Ben-Zvi et al 2011).   Those independent assessments are strongly supported by clouds that we now know are unsuitable for seeding due to the copious natural formation of ice at modest supercoolings.  Indeed, the Israeli clouds have never been suitable for seeding in spite of the numerous published reports by the HUJ-CSG to the contrary.

Conversely, it was those erroneous ultra “ripe-for-seeding” cloud descriptions by the HUJ-CSG in the 1970s and 1980s that gave the statistical results of the Israeli 1 and 2 experiments credibility; that seeding really had increased rain (e.g. Kerr 1982, Mason 1982, Dennis 1989).

Thus, the F2015 authors cannot reasonably believe that actual rainfall increases occurred in Israeli 1 and 2 although they inform the AR reader of “positive effects” in the abstract.  Seeding clouds whose high natural efficiency to form ice is as high as that anywhere in the world, cannot lead to statistically-significant results in a “static-style” cloud seeding experiments, as the Israeli experiments were.

Gagin (1986):

“While it is important to record the effects of seeding on rainfall at the ground, the statistical evaluation of this parameter alone cannot constitute an acceptable result of a successful seeding effect.”   Q. E. D.    End of story.

Turning our attention specifically to Israeli 1 and why the indications of rain increases are no longer credible:

1) The clouds of Israel have been found largely unsuitable for seeding as the HUJ-CSG themselves finally have discovered and now report in F2015, in agreement with several other studies, initially by R88.  If there are no suitable clouds for seeding, then statistical results cannot be due to seeding effects, but rather must be due to “lucky” random draws, or other mischief such as omitting data, post-facto cherry-picking controls, etc.

It is worthwhile to reprise another GN74 statement concerning statistical results without a cloud foundation, a well-known principle within the weather modification community:

“…no statistical evaluation will be of real value unless these results are substantiated by detailed physical considerations.”   

It’s the clouds that drive the credibility of the statistical results, not the other way around.

2) Evidence for a Type I statistical error in Israeli 1 was reported by the Chief Meteorologist of that experiment, Mr. Karl Rosner,  who pointed out to Wurtele (1971) that the region that exhibited the highest statistical significance on Center seeded days,  the “buffer zone” (BZ) between the two targets, could barely have been seeded (“5-10%” of the time).  The HUJ seeding unit did not give this “red flag” enough attention; that is, they did not attempt to reconcile the wind analysis by Shimbursky (in GN74) with their own Chief Forecaster Rosner’s evaluation.   In contrast to their Chief Meteorologist’s view, they considered the BZ inadvertently seeded (GN74).

Let us also quote Neumann et al. (1967) on the BZ issue:

“An acceptable and unbiased way of omitting most unsuitable days was to restrict the analysis to the 327 rainy days, defined as days with some precipitation in the buffer zone by the Mediterranean, a location where rainfall is unlikely ever to have been affected by seeding in either experimental area.”

 

3) The BZ seeding issue was examined independently and in more detail by Rangno and Hobbs (1995-hereafter RH95).  In RH95 was concluded, based on their wind analysis when rain was falling in Israel (when seeding would have been expected to be taking place) that it would take a very bad pilot to have inadvertently seeded the BZ when instructed not to do so.  This conclusion due to the very narrow low-level wind envelope concurrent with rain in Israel.

The Shimbursky wind analysis in GN74, on the other hand,  had only a once-a-day IMS rawin launches, which may or may not have been associated with clouds and rain, and thus, could not address the direction of winds solely coincident with rain falling in Israel at the time of the launch as did RH95.

4) Additional evidence for a Type 1 error in Israeli 1 was presented in RH95 due to more rain on seeded days in the immediate coastal zone of Israel over which the seeding aircraft virtually flew, a conclusion that was reached earlier by Neumann et al 1967, also due to logistical considerations.  Quoting Neumann et al (1967):

“After some 2 1/2 seasons of operational seeding experience, it was noticed that flying was effectively limited in such a way as to affect only the interior parts of the two areas.”

 

Gabriel (1967:

 It was claimed that the seeding plane generally did not fly outside visual contact with the coastline so that there could have been no seeding effect near the coast; hence a 10 km

wide coastal strip must have been unaffected.

 

Gabriel and Baras (1970)

The second modification was suggested in 1963 in view of the actual flight patterns of the seeding plane. It seemed that seeding could only effectively reach the interior parts of the two areas and that analysis should therefore be restricted to these sub-areas.

Rosenfeld (1997) in a series of grand speculations concerning Israeli 1, offered an alternative to RH95 and those by the experimenters:  he argued that some of the airborne-released AgI dispersed downward from the initial releases in the southwesterly or westerly flow, was eventually into in a thin offshore flowing layer near the ground.  That portion of the plume, Rosenfeld conjectured,  then went  offshore, was ingested by seedable clouds (which we know do not exist; never did) at the right distance upwind for the AgI to rise up into the those offshore clouds, nucleate at appropriate levels (usually above 3.5 km ASL),  grow into precipitation-sized particles that fell out just in time on the Israeli coast, thus “explaining” the indications of a bias in storms (more rain on Center seeded days on the Israeli coast).

Whew.  Irving Langmuir comes to mind….

On Rosenfeld’s behalf, there is an occasional offshore flowing shallow layer during less vigorous synoptic rain situations, and one largely confined to early morning hours.  But, Rosenfeld provided no statistics on how often that shallow offshore flow occurred while seeding was taking place in Israeli 1.

5) Too little seeding (an average of but 4 h per day and only about a kilogram of AgI, Gabriel 1967) was carried out and dispersed in Israeli 1.   RH95 demonstrated that the area claimed to have had increased rainfall (under the seeding line, sidewind, downwind, in the target) was not commensurate with the amount of seeding material released in Israeli 1, a conclusdion reinforced by unsuitable-for-seeding clouds (R88, F2015).

6) The line seeding carried out by a single aircraft flying 75 km up and down the Israeli coastline was deemed ineffective by RH95 in having seeded enough clouds to have produced an effect; more rigorously corroborated in later modeling studies by Levin et al. 1997.[1]

 

  1. b)  The Israeli 2 experiment as described in F2015 and the counter evidence to that description; filling in more blanks

In Israeli 2, the HUJ-CSG, realizing the poor seeding strategy it had used in Israeli 1, added a second aircraft, and 42 ground generators in Israeli 2 (NRC-NAS, Panel on Weather Modification, 1975).  In Israeli 1 there had been but a single aircraft, and four ground generators located in the far NE of Israel (GN74).

The authors omit for the AR reader, the fact that the north “positive” effect in Israeli 2 was found to be  the product of an astoundingly one-sided random draw[2] for heavy storms throughout Israel (Gabriel and Rosenfeld 1990[3]), and also one that affected Lebanon, and Jordan (RH95).   The extraordinary random draw saw the home of HUJ-CSG in the south target experience the most rain of all the stations available to RH95 on north target seeded days!

Ignoring the report of extreme rain in the south target on its control days, those when the north target is being seeded,  Rosenfeld and Farbstein (1992) proposed that dust-haze,  when combined with AgI, had caused overseeding of clouds in the south target; that is, rain had actually been decreased while the north target, having fewer “dust-haze” days, experienced rain increases due to seeding.  This assessment gained wide traction for a time (e.g., Simpson 1990, Presidential Address to the Amer. Meteor. Soc., Young 1993), but like so much HUJ-CSG work, it was unreliable.

Let us quote Gabriel and Rosenfeld (1990) on the rain in the south target:

“Otherwise, one would need to explain why there was so much more rain in the south when the north was being seeded; as of now, no explanation is available, especially as the prevailing wind direction is from the southwest[4].”

Ergo, rain in the south was not “decreased” by seeding, but rather, in no way could seeding overcome the astounding random draw for north seeded days[5].  And, as we expect, the finding of extreme rain in the south target on north seeded days is not mentioned by Rosenfeld and Farbstein.  How could they?

The rain throughout Israel on north target seeded days once again points to efficiently precipitating clouds that are doing just fine without seeding with AgI.

Levin et al 2010 examined Israeli 2 in more detail than did RH95.  They attributed the apparent seeding-induced extra rainfall in the interior of the north target as due to a bias in strong synoptic systems on north target seeded days, one that created a misperception of seeding (see also, Levin et al 2011, reply to Ben-Zvi  et al. 2011).

Ironically, the Levin et al. (2010) findings are strengthened in F2015 when they observed that the intrusion of large aerosols inland from the Mediterranean on windy days in the north increased rain efficiency of inland clouds.

The Israeli 2 experiment had several design options (GN74), the first of which was the “crossover” evaluation, the same evaluation mode as was used in Israeli 1.  The true tragedy of Israeli 2, however, was in the omission of numerical results of random seeding in the crossover scheme, and in the south target by the HUJ-CSG after 1974.  It was an omission that kept the scientific community in the dark about how the full Israeli 2 had actually turned out.

While it is true, as GN81 pointed out, that the larger area of seeding done in the south in Israeli 2 reduced the correlation with the north, thus making seeding effects harder to detect in Israeli 2 compared with the Center/North crossover comparisons in Israeli 1.  Nevertheless, a crossover analysis based on the prior Center target gauges could have been presented with whatever caveats the authors wished to add.  The prior Center target gauges were in zones S1 and S3 of Gabriel  and  Rosenfeld (1990).  However, it is clear from the SAR’s of those regions in Gabriel and Rosenfeld (1990) that the crossover result of  Israeli 2 was not going to replicate Israeli 1.  At this point, if GN81 had done what they should have, they would have displayed that null result, and provided some thoughts on why it had happened.

It took 15 years after Israeli 2 ended, and at that,  spurred by a letter writing campaign begun in the winter of 1986 by the Israeli experiments’ own Chief Meteorologist, Mr. Karl Rosner, to “out” both the crossover results (-2%) and the negative SAR (-15 to -20%) for the south target.  And this was ONLY after the lead HUJ-CSG experimenter passed in 1987.

We have to assume that without Mr. Rosner’s public call for the exposition of the crossover and south target results, they would still be hidden from view within the HUJ-CSG.  Why weren’t authors, Gabriel and Rosenfeld, or others at the HUJ, troubled by this omission over the years after Israeli 2 ended in 1975[6]?  (Ans.  We don’t know why.)  Donald Kennedy does:

The difficulty is that positive claims are sometimes made against a background of    unrevealed negative results.” 

Furthermore, the early reports of a “confirmation” of the results of Israeli 1 due to the partial reporting of an Israeli 2 “success,” limited to the north target in a  target-control evaluation, spurred the decision by the INWA to begin an “operational seeding” program in 1975 (GN76), one that produced no viable results for more than 30 years when evaluated by independent scientists.[7]  And, perhaps, those Israeli 2 partial results also convince the INWA to begin Israeli 3 in the south target of Israeli 2.

Did the INWA know about the south target results of Israeli 2 before they began Israeli 3?  We don’t know what inspired Israeli 3.  INWA, F2015:  please tell us.

Where, too, was the outside cloud seeding community, one that failed to raise post-publication questions about the results of random seeding in the south target of Israeli 2 following GN81? ( I count myself in this oversight…and blame.)   Statistician Jerzy Neyman, who closely monitored cloud seeding publications and had a reputation for commenting on them, would surely have caught the Israeli 2 omissions had he not passed in 1980.   There is a lot of blame to go around.

Not reporting the south target results of Israeli 2, one that superficially suggested decreases in rain on seeded days also suppressed the inevitable questions that would have arisen:  “How could there be a suggestion of decreased rain on seeded days with such ultra “ripe-for-seeding” clouds (with warmer tops than in the north) as had been described by the HUJ-CSG over so many years?

Without doubt, the wheels would have come off the HUJ-CSG’s seeding train with full reporting of Israeli 2 in a timely manner.  And the report in Science that there had only been “one success in 35 years” in cloud seeding (Kerr 1982) would never have occurred.

We reprise the speculation of Gabriel and Rosenfeld (1990) near the end of their statistical analyses, one that was to be confirmed 20 years later by Levin et al. in 2010:

“The most plausible explanation (for the statistical results of Israeli 2) is one of random variation, with the north-seeded days being more rainy inland, especially towards the northern and southern edges of the experimental region.”

 

7  c)  The reported, primary effect of seeding in Israeli 2: duration:  where it stands today (it’s not credible).

Virtually the entire supposed seeding effect claimed in the Israeli 2 experiment was due to a greater duration of rain, not greater intensity  (GN81, Gagin and Gabriel 1987, hereafter, “GG87”).  Seeding with AgI, they reported,  caused cold-topped (-15°C to -21°C),  non-precipitating clouds to precipitate exactly like natural clouds, thus extending the duration of rain on seeded days (north target evaluation only).     The increase in that one temperature range was a whopping 46%, all of it due solely to extended duration caused by seeding!

That duration finding no longer makes sense in the face of highly efficiently precipitating Israeli clouds.   It never really did upon close,  independent inspection.

 

 

7 d) The Israeli 3 experiment:  its delayed reporting, and its significance

The first interim report about the progress of Israeli 3 randomized experiment from the HUJ-CSG was in 1992 (Rosenfeld and Farbstein), 17 years after it began[8].  Decreases in rain were suggested in that experiment year after year.  The final result, reported by Rosenfeld (1998) at conference, was that after 19 winter seasons and nearly 1000 random decisions there was an indication of a decrease in rain of 8% on seeded days (non-statistically significant).

In F2015, the authors, following in the footsteps of GN76, cannot divulge for the AR reader the indication of decreased rain on seeded days in Israeli 3.  Instead they cloak that result, as did GN76 for the Israeli 2 south target, with the correct but carefully chosen word, “inconclusive”.  “Inconclusive” could refer to increases or decreases in rain that are merely not statistically-significant; reporting indications of decreases, even if not statistically significant,  would have raised more interest.

The 8% suggested reduction in rainfall on seeded days after 19 winters and nearly 1000 random decisions were important on two accounts: that 1000 random decisions after 19 winter seasons could lead to a result so far from a null one after so many random draws,  assuming there really was no seeding effect as Rosenfeld (1998) asserted.  IF Rosenfeld and Farbstein (1992) are right about “dust-haze” combined with AgI, then the HUJ-CSG in the conduct of Israeli 2 and 3, combined,  have decreased rain for 25 years in the central and southern parts of Israel.

Israeli 3 also demonstrated that the clouds of Israel are unsuitable for glaciogenic cloud seeding.  There is nothing substantially different between the clouds that affect the central and southern regions of Israel from those that affect the north in terms of microstructural behavior except that the clouds in northern Israel are overall generally colder from top to bottom.  In both regions they glaciate effectively.

And, who would undertake a randomized seeding experiment for 19 years knowing you might have a natural draw so far from zero that can’t even be overcome by an actual 10% seeding-induced increase in rain[9]?   (One wonders about the quality of the random draw again…)

7 e)  Operational seeding:  the descriptions in F2015 and the counter evidence to those descriptions; filling in still more blanks

F2015:  “Subsequently operational seeding in the north of Israel was carried out between 1975 and 2013.”

The above quote by the HUJ-CSG authors’, writing in 2015 in AR, shows that they cannot bring themselves to report that the “operational seeding” program in the north of Israel, as it was originally formulated, was terminated in 2007 (Sharon et al 2008[10]).    We quote Sharon et al. 2008 for the AR reader:

 

“3b. A revision and elaboration of possible future seeding activities

In view of Kessler et al.’s initial finding in Section 2a and the ensuing controversy, a joint forum of the

National Water Authority and other professionals involved, met early in 2007. After 50 years of uninterrupted seeding activities, the forum decided to discontinue the program at the end of that rainy season (April 2007) and instead, consider the initiation of a new updated experiment, Israeli IV.”

Why was the original program terminated by the INWA and its panel[11]?

Answer:  The independent panel of experts (Kessler et al 2002, Kessler et al. 2006, distilled by Sharon et al 2008) could find no additional runoff due to seeding into the target, Lake Kinneret (aka, Sea of Galilee) over the 30 plus years of seeding.  They also found that the small increases (6%) reported by Nirel and Rosenfeld (1994); Rosenfeld and Nirel (1996) could not be substantiated when more data from later years were used.   This null finding for the operational program by Kessler et al. was later corroborated by independent scientists at Tel Aviv University (Levin et al. 2010, 2011, the latter in reply to the comments of Ben-Zvi et al 2011).

At this point, one wonders who the reviewers of an article in the respected journal, AR, were?

How could they let such partial statements and an article absent vital references appear?  One must also assume that the reviewers for AR were woefully ignorant of the history of the Israeli experiments to have allowed the F2015 distortions reach the print stage of a major journal.  Truthfulness and a full exposition of events is not part of the HUJ-CSG’s understanding of how to compose a manuscript for a scientific journal.   Their manuscripts and publications, in essence, need to not just be reviewed, but “policed” for accuracy.

F2015:  “Additional statistical analyses showed that the orographic precipitation responded most sensitively to the seeding experiments (Givati and Rosenfeld 2005).”

F2015 claimed in the above publication, that air pollution had decreased precipitation exactly by the amount that seeding was increasing it in the interior of Israel (thus explaining the lack of operational seeding effects reported by the independent panel).  The finding by Givati and Rosenfeld (2005)

could not be substantiated independently by either (Alpert et al 2008, Halfon et al 2009a[12], b) nor by Levin et al. 2010.   The pollution claim by Givati and Rosenfeld (2005) was found to be ambiguous at best.

 

It is useful to quote Thom (1957) on how Givati and Rosenfeld came up with their “pollution” findings (as was demonstrated by Alpert et al 2008 and Halfon et al 2009):

 

“If one takes the liberty of choosing among minimum distance controls, he can often find any result for seeding that suits his purpose, either positive or negative.”

That the results of operational seeding as reported by the HUJ-CSG could not be validated by independentresearchers on four occasions (Kessler et al 2002, Kessler et al. 2006, Halfon et al 2009, and Levin et al. 2010, 2011 (reply to Ben-Zvi et al) is one of the most important aspects of the seeding history in Israel.

For those who know this story, we again see one-sided citing in this discussion; the HUJ-CSG in F2015 cannot bring themselves to cite those publications, damaging those independent workers, themselves, and whether they realize it or not, their own home institutions.

HUJ, are you listening?  Isn’t it best if you policed the HUJ-CSG publications instead of someone like me doing it after they’re out in print?

  1. A critique of the cloud sampling and its effects on the cloud microstructural properties reported: how unbiased are they?

This discussion will make it clear why F2015 must make videos from their research flights publically available; these are crucial to understanding what they did and how they did it.

Median concentrations in “hard”, newly risen turrets over the Mediterranean, as the authors show in Figure 16 from their Mediterranean cloud targets, produces a bias toward low ice particle concentrations and higher liquid water contents compared to values that would be found as those same clouds as they matured minutes later.   The authors know this.  The authors are to be commended for adding the description of the stage that the Mediterranean clouds were in when they were sampled.   This really helps the experienced reader weight those “medians” in the Figure 16.

But did the authors’ sample “hard” but meteorologically inconsequential, slender, “chimney” Cu as well in Figure 16?  These are ones we know produce little ice/precip compared to their wider brethren even if they are at the SAME cloud top temperature (e.g., Schemenauer and Isaac 1984, Rangno and Hobbs 1991).  Cloud top width, in particular, is an extremely important metric and should be listed in an online supplement by F2015.

Some background on the width issue:  the apparent error of penetrating isolated, likely “chimney” Cumulus with “smooth, hard tops” Cumulus clouds instead of the wider complexes that produce appreciable rain in Israel was one that was made in the original cloud reports coming out of the HUJ-CSG in the 1970s and 1980s (e.g., GN74, GN76, Gagin 1975, 1981).

Due to that sampling strategy, it misled those HUJ-CSG scientists on the ice content in their clouds, and ultimately their journal audiences.  In contrast to those early cloud samples, GG87 reported that the average duration of a shower in Israel was 23 minutes.  With just a 10 ms-1 wind carrying that shower along, that rain would have fallen from a cloud system at least about 13 km long; at least 26 km long if it was carried along in a 20 ms-1 wind!

So, what DID F2015 sample that was relevant to Israeli shower clouds?  We don’t know.  But its critical that we do know.

Another source of bias toward low ice concentrations can result if the authors, in fact,  did sample wider, high ice-producing complexes, but only penetrated the very newest, “hard” turrets in them (typically on the upwind side) in which the explosion of ice had not yet occurred.

Lastly, another critical metric for understanding the quality of the HUJ-CSG authors’ measurements in Fig. 16 is the height of sampling below cloud top.  Sampling too close to cloud top, say, tens of meters instead of a few hundred meters, also leads to a low detection of precipitation-sized particles (and also why Re satellite derivations can mislead in newly risen turrets, and in ice-spewing, supercooled water-topped layer clouds common in orographic settings.  This again reinforces the need for videos of the F2015 study.

  1. The HUJ-CSG’s continuing trouble with ice

The HUJ-CSG has carried out several airborne sampling programs with modern droplet and hydrometeor probes over the past 25 years, beginning in the middle 1990s (Rosenfeld and Lensky 1998).  Further airborne studies were conducted by Lahav and Rosenfeld (2000), Rosenfeld et al. 2001), and by F2015.   Maximum ice particle concentrations and the degree of ice multiplication were not divulged by the HUJ-CSG in any of these publications!

In F2015, we finally have ice particle concentrations!   However, what we get are unsatisfactory-for-seeding-potential, “median” concentrations obtained  in “hard” turrets for those clouds in the Mediterranean.   This prevents us from understanding the “ice life cycle” of Israeli clouds.

Ice particle concentrations, and their origin,  has been one of the continuing mysteries of cloud microstructure (e.g., Mossop 1970, 1985);  in particular,  a primary enigma is how secondary ice forms in clouds with top  temperatures warmer than about -15°C, as occurs prolifically in Israel.    AR readers are likely aware of the 2017 Amer. Meteor. Soc. Monograph  (Field et al.[13]) that focused on the origin of secondary ice and the puzzle it still represents.

Israel is in a region of confluence of various aerosols that affect clouds.  Reports of the degree of ice multiplication from Israel would have surely helped fill in some microstructural blanks in our knowledge.  What a shame the HUJ-CSG can’t address this question in their cloud sampling programs!

Too, where are the droplet spectra and graupel concentrations in the Hallett and Mossop secondary ice-producing temperature zone of -2.5° to -8°C?  Nowhere to be found.    More missing pieces to the knowledge required to understand the clouds of Israel.    Why does it feel like I am reading a paper written in 1968?  The authors could have done better with the “black glove” technique, or a foil sampler (Koenig 1963).

From the reviewer’s experiences in 1986, ice multiplication in the clouds of Israel is rampant.  But, remarkably, only L929496, has addressed this issue in Israel been addressed over the past 43 years since Gagin (1975). The study of ice multiplication, a staple of airborne cloud microstructural studies over the past 60 years (e.g., Mossop et al 1972).  T he HUJ-CSG seems to have trouble since the early 1980s of honoring this standard.

This discussion above begs the question about why F2015 didn’t target mature and dissipating portions of Mediterranean clouds after high ice particle concentrations had formed?  Its inexplicable.  The statement by F2015 that mature, heavily precipitating clouds were avoided due to aircraft safety considerations is not credible to us researchers in airborne studies.  Heavy icing, graupel, hail are found in the younger turrets, not in the maturing ones where icing is subdued due to the formation of high ice particle concentrations that consume the liquid water.

Neither can the HUJ-CSG’s median ice concentrations be compared to the concentrations of ice in Israeli clouds reported by L929496 who was somehow able to sample the high ice-containing regions of Israeli clouds that F2015 found so dangerous.

Specific examples of HUJ-CSG reporting from airborne work over the years since Gagin 1975:

Rosenfeld and Lensky (1998) flying on shower days in pursuit of a comparison between satellite and aircraft measurements of Re, wrote that they  did not carry a 2-DC probe for hydrometeors on their aircraft on the two flights with showers (!).

Lahav and Rosenfeld (2000), in a ten flight sampling program having a 2-DC probe, nevertheless refrained from reporting ice or other hydrometeor concentrations, while titling their paper, “Microphysical Characterizations of the Israeli Clouds from Aircraft and Satellites.”    But that’s not what they did, or, at least reported.  They only reported partial results.  Sound familiar?

Rosenfeld et al. 2001 had a 2-DC on their research aircraft, but once again, refrained from reporting  concentrations of hydrometeors in the clouds they sampled.  What they did report was that there was a “large number”, or that they were” increasing” or “decreasing.”  What’s going on here?  How does such reporting like this make it into a prestigious journal like PNAS?

This reviewer’s guess, from his 1986 Israeli field project, is that the HUJ-CSG has found in those several airborne projects mentioned above that they have an “embarrassment of ice particle riches” and wants to keep those concentrations and the degree of ice multiplication away from AR readers and funders who might consider cloud seeding.   Ice multiplication in clouds has always been considered an impediment to successful “static” glaciogenic cloud seeding (e.g., GN74, Dennis 1980).

Is there another motive by the HUJ-CSG for keeping maximum concentrations from us?  Yes, another critical omission of results by the HUJ-CSG.    To repeat:

The difficulty is that positive claims are sometimes made against a background of       unrevealed negative results.” 

This is why, again, that  independent groups are critical in evaluating seeding potential in Israel!

INWA, are you listening?

Gagin (1975), in support of ripe for cloud seeding clouds, claimed that ice particle concentrations do NOT increase with time.  This finding could have been evaluated, too, at many points in the HUJ-CSG airborne studies.

Even more relevant is that those very same ice-filled clouds over the Mediterranean Sea are going to be swept downwind and into the Golan within ~30-40 min during rainy spells, making it doubly important to have reported those maximum concentrations and followed their evolution downstream in route to the Golan.

In sum, yes, you CAN mislead with an aircraft, even one with a full complement of 21st century cloud microstructure instruments via omission and sampling biases.

The points raised in the foregoing section concerning the airborne sampling carried out by F2015 emphasizes all too well why in-flight videos must be made publically available as they are at the University of Washington and also for a number of other projects at NCAR.

To summarize the dark history of the HUJ-CSG:   over a period of several decades: it misled their own people and the world repeatedly about their clouds, withheld statistical results for Israeli 2 for 15 years, results that would have raised so many questions, delayed for 17 years the reporting of results from the Israeli 3 randomized experiment that, too, would have raised numerous questions.   And under its new leadership, that following the passing of Professor Gagin still can’t seem to publish reliable results about their cloud seeding work, either.  Neither can they fully report on their clouds such basic information as the degree of ice multiplication that Israeli clouds exhibit.

Furthermore, and this may the most telling of all, every paper the HUJ-CSG has published and that has been examined by outside, independent investigators, has been found to be unreliable.  Will more unreliable HUJ-CSG claims be turned up in their literature?  It seems inevitable.

One can predict confidently that in the future the HUJ-CSG will, without major changes to its leadership,  and without a more skeptical INWA concerning the claims coming out of that group, “repeat history.”

——–End of “Commentary” on the F2015 Abstract and Introduction

Following the Abstract and Introduction segments, F2015 improves demonstrably; it is written extremely well in places, representing the best in what we think of as scientific writing.  However, there are still a few lapses and reviewer-required “clarifications” that will be addressed as they appear.  The type in black is that from the original article.

The objective of this paper is to present the available knowledge on  the cloud  properties in northern Israel,  which supported the decision to commence with the Israel-4 experiment, as briefly described above. Section 2 describes thetypical synoptic conditions during the rainy  days  and  the dynamics of the  clouds as they  interact with the sea  and  the topography. Section  3 describes the  methodology of the physical experiment,  the  cloud  physics aircraftinstrumentation,  flight  patterns and  methodology of data analysis. The methodology of supporting satellitemicrophysical retrievals is also given  in this section. The results of the measurements with respect to aerosols and theway they determine the microstructure at cloud base are given  in Section  4.1. The subsequent vertical evolution ofcloud microstructure with height above  cloud  base  and  initiation of rain are described in Section 4.2. The mixed-phase processes and availability of super-cooled cloud water are presented in Section 4.3. Finally, a summary ofthe results and a discussion of the suitability of the clouds over  the Golan  Heights to glaciogenic seeding aregiven  in Section 5.

  1. Synoptic, dynamic and macro-physical considerations

2.1. Meteorological conditions

The  synoptic systems that are  responsible for  more than

90% of the annual precipitation in northern Israel occur  with cyclones passing through the  north-eastern part of the Mediterranean Sea, these cyclones are  referred to as Cyprian Cyclones  (Goldreich, 2003). A rain  event typicallystarts with the passage of a cold  front  followed by  a  thermal low  that develops in  the  cold  air-mass behind thefront   due  to  the relatively warm sea and the lee effect of the Turkish  mountains to the north. An upper trough withrelatively cold  air aloft is associated with the  cyclone,  which increases the thermal instability and  favors  thunderstorm  formation over  the  sea. First precipitation over  land  typically starts with the arrival of the cold front, as the air ahead of it is characterized by dry and often dusty air from the Sahara desert. Fig. 2 shows the synoptic conditions on a typical rainy day in Israel, at the time of the cold front  arrival.  As the winds veer from southerly towesterly, the low-level air  becomes moister and  the cloud-base elevation lowers to a typical level of 500-1000 m (allabsolute heights are given  above  sea  level).  The thermal instability reaches its maximum in the thermal low afterthe passage of the cold front. The average wind speeds are often greater than 10 m/s and they contribute to theorographic component of the precipitation. When the low-pressure system moves to the east the instability is graduallyreduced. However, due to the long trajectory of the cool low-level air over the warm sea the instability and moisture supply supports continued rainfall for another day or two.

Minor:  The IMS refers to periods of rain as “rainy spells.”   This is because they often consist of several consecutive days with recurring showers.  In Israeli 1, there was a period of 17 consecutive days with rain.  The F2015 highlighted sentence might be revised to reflect the occurrence of “rainy spells.”

2.2. Cloud dynamics

Fig. 3 illustrates the cloud and  precipitation characteristics on a typical rainy  day in the  air-mass behind the coldfront.  It is a west–east cross-section across northern Israel,  and  it is based on our  observations and  impressionsfrom  the physical experiment. The schematic figure  is intended to illustrate the main features of the cloud  and  precipitation processes that often  take place  as the air-mass travels eastwards across  the land  and  over themountains.

Figure 3 and its caption:  “…clouds in a typical rain day on northern Israel, as a west-east cross section from the Mediterranean Sea to the Golan Heights.  Rain originates in convective clouds over the sea as graupel and hail.  The sea spray from the rough sea seeds the clouds hygroscopically.  Orographic cloud over the Galilee are often seeded by the remnants of convection.  The clouds evaporate into the Jordan Valley and reform over the Golan Heights.”

This figure is over-simplified, perhaps out of necessity due to the many scenarios that would have to be presented to reflect the several stages in Israeli storms as troughs come and go as documented in the comprehensive satelllit studies by Rosenfeld in 1980, 1982, by Gagin 1981, R88, RH95).

F2015 show a higher level stratiform region extending from a line of convection at the Israeli coast in Figure 3.  However,  it is but one snapshot of an incoming storm, not a semi-permanent pattern as the AR reader might infer.  There are many other scenarios that could have been drawn, which could have been as online supplements to fill in the picture of Israeli rainy days more. Figure 3 is really much closer to a depiction of the coastal convergence zone that tends to develop in the later nighttime and morning hours during lesser onshore flow periods (e.g., Neumann 1951, Goldreich 2003).

Satellite imagery reveals that during major events (lines of convection organized by upper level troughs) clusters of Cumulonimbus clouds and stratiform rain areas barge into Israel en masse.  While the roots of the of convection might be lessened when they move inland in wintertime, as F2015 note,  these mesoscale/synoptic scale systems march across Israel with much of the deep, precipitating cloud system intact.  They do not separate completely, as a rule, into an upper layer and lower layer as shown in Figure 3.   Too, some of the rain that falls is due to aggregates in quasi-stratiform debris clouds.

The Stratocumulus over the hill regions in Figure 3 might be accurate for that specific moment of an approaching storm.  However, drizzle, and mist-like rain (due to collisions with coalescence) often falls from such hill-topping overcast low clouds topping out,  as shown in Figure 3,  at about 3 km ASL[1].   It should have been pointed out that such low clouds, “auto-precipitate.” They frequently top out at temperatures where seeding them would not be effective (> -5°C, e.g.,  R88).

In later winter and spring, shallower Stratocumulus clouds tend to lift off the lower hills as temperature rises during the day, and by later afternoon can sprout into small Cumulonimbus clouds (glaciated clouds) under cold trough situations.  Also, due to the local strengthening of the onshore flow during the afternoons, incoming convection can weaken and may disappear altogether in the coastal divergence zone responding to that strengthening flow.

The deepest clouds in springtime are frequently over the inland hill regions rather than offshore as evidenced by an increase in lightning frequency inland during the late winter and spring.

Minor:  Figure 3 also indicates that the bases of the clouds reforming over the Golan are virtually as low as those on the hills of Galilee.  This seems implausible under the loss of precip water and downslope motions in prevailing westerly flow.  Bases should be higher over the Golan, and probably closer to the freezing level?  Or?

As mentioned in  the  previous section, the  lower troposphere during a typical rainy  day  is quite moist and  unstable due to the relatively warm sea (sea  surface temperature never drops below 17 °C) and colder air aloft(typically below + 2 °C at 850 hPa during the rainier days).

The cycle of Mediterranean Sea temperatures from fall to late winter is significant.   It starts out at around 22°C and descends gradually to 17° C.  Cloud base temperatures, hence, water content in clouds and the propensity to form warm rain and copious ice, also are impacted, likely further reducing seeding opportunities in the warmer fall/early winter period.

This favors the formation of fairly  deep convective clouds over  the sea.  This  is also  why hailstorms and  lighting activity are  more probable near the coastline and less common further inland (Altaratz et al., 2003; Goldreich, 2003).

Lightning activity is about equal over the Mediterranean Sea and inland areas in November and March (Altaratz et al. 2003).   This equality likely extends into April as well.

When these convective clouds move inland, they become separated  from   their main sensible heat and moisturesource and  weaken quickly.

To repeat, the roots of convection may weaken, but these major complexes usually don’t separate with a clear zone between upper and lower clouds as shown in Figure 3; its just one of many scenarios.  F2015 do not support their Figure 3 scenario with frequencies of occurrence during the winter.  How does it compare with the frequencies of other storm scenarios?

However, the moist air that is pushed inland by the strong westerly winds is forced upwards  by   the  topographyof  the  western  Galilee,   and therefore an orographic component is added to the weakening convective  clouds.  The  annual precipitation amount in  the upper Galilee peaks at 1000 mm, as compared to the ~ 600 mm at the coast.

When the air continues eastwards it descends about 800-1000 m to the Jordan (Hula) valley, the clouds, unlessthey are synoptically forced,  tend to dissipate and  break up. This leaves the valley   with  an   annual  precipitation  amount  of  only

~ 500  mm.  This is the  area  where often  visual  flight rules  can apply  and  below-cloud aerosol measurements can  be  made safely.

The slopes of the Golan  Heights force  the air to rise  again and  to produce new  orographic clouds with smallerdroplets.

Check+

The crest  of the Golan Heights rises  gradually from  a height of 400  m  in  the south to  1200  m  in  the  north. Further north, Mount Hermon rises  up to an elevation of 2800  m. The Golan Heights  are   45–70  km  away   (shortest  distance) from   the coastline and  the  clouds there are  normally less  convective than the clouds overthe Galilee and over the sea, because much of the instability is consumed upwind.

 “…normally less convective… ”  True,  except maybe for November  and spring when convection over inland regions is apparently more evenly distributed if lightning occurrences are an indicator (Altaratz et al 2003).  What are the seeding implications of enhanced convection in the Golan?  Do the authors know?  Likely less potential if deeper clouds in the Golan glaciate at modest supercoolings.

The  terrain over  the Golan  Heights is also  less  complex than over  the Galilee  and therefore the flight throughthe  clouds over the  Golan Heights is often relatively smooth. The top of the ridge is only about 10-15  km  downwindfrom  the foothills where the  clouds form. This leaves the clouds little time to  convert their water into precipitationbefore they start to dissipate and lose their water content back to the atmosphere.

We reprise Figure 1 from F2015:  Isn’t the target too small and close from seeding release points for seeding to result in a fallout of precip on it?  Where does the water go in the lee of the Golan, to Syria or into Lake Kinneret?   (This diagram should have had a kilometer scale.)

GN74 estimated 30 min for precip fallout from line seeding, as do F2015.   In the HUJ-CSG publications we find various distances from the aircraft line seeding at which the fallout of seeding-induced precipitation may have occurred, possibly due to variations average wind velocities used .  These ranged from 25-35 km downwind (Gagin and Neumann 1976;  35-50 km  (Gagin 1981); 25-45 km (Gagin and Neumann 1980) ; “about 40 km” (in GG87) to “25-35 km” in F2015.

So which is it?

 And what wind speeds were used in F2015?  And why?  What climo did you use?  The estimate contained in Gagin 1981 (35-50 km) appears to be too great a distance for a precip fallout for this project to be successful except in deep southwest flows.

What are the flight levels of the line seeding aircraft?  Why is this information not in F2015?   This is critical information since if those seeding lines are too low, the seeding material will not reach the necessary heights for nucleation and precip fallout in time to help runoff.  (Perhaps this information is contained in the full proposal?)

How can airborne or ground releases target the region north of the dashed line in Figure 3, including the wettest location, Mt. Hermon, when seeding plumes have to climb to between 700 and 500 mb levels to nucleate effectively and when the primary wind flow is westerly?  In winds even a little north of westerly, it does not appear that seeding is going to be viable in the wettest portion of the Golan unless you get help from Lebanon.

And isn’t the downwash into the Hula Valley going to be detrimental to seeding the Golan?

See the wind rose for 850 mb for those times that rain is falling in Israel from RH95.  It would appear that  many periods of precip  in the north part of the Golan, anyway, will not be able to be seeded efficiently.

Lastly, seeding can reduce upslope precipitation by reducing the degree of riming on upslope precipitation.  Riming is reduced as new, tiny AgI ice crystals form reduce or deplete the upslope supercooled LWC.  The trajectories of ice crystal/snow precipitation are less steep, raised since riming accelerates the downward fall of snow and that will be lessened in seeding.  Will it be made up by more ice crystals?

Ground measurements of precipitation should have been incorporated into the proposal to the INWA or mentioned in F2015 in supporting their contentions about seeding potential in the Golan.

In case there are synoptically-forced or mature clouds above, which survived the  descent to the Jordan (Hula)valley (Fig. 1), they often  precipitate through the orographic clouds and  seed  them naturally from  the top.

What is the frequency of occurrence of this scenario?

The  annual precipitation amount  over   the ridge   increases from  600 mm  in the south to more than 1200  mm  over Mount Hermon to the north, mainly depending on the surface elevation (Goldreich, 2003).

2.3. Aerosol dynamics

The trajectory of the air  mass  that is associated with the Cyprian   Cyclone  passes various regions on  its approach to Israel. Each of these regions leaves  its signature on the aerosol properties. One of the  common features of the warm sector of the approaching low-pressure system is the reduced visibility due to increasing loads ofdesert dust in the air. The winds with the southerly component get stronger as the cold-front comes closer,  lift the dustparticles from  the  surrounding deserts and keep  them airborne. The low-level convergence raises the dust particleshigher up,  so they can  travel greater distances. The dust concentrations are normally higher in central and southern Israel  than in  the  northern part.  This  is due  to  a number of reasons: 1) Northern Israel is farther away  from  the main dust sources; 2)  The  south-westerly flow  ahead of the  cold  front travels some distance over  the south-eastern Mediterranean before arriving to northern Israel, and is occasionally associated with pre-frontal rains   that can wash out  some   of  the  dust particles; and 3) The Israeli deserts in the south, where sand and dust  storms are  common, can  also  contribute to the aerosol population in central and  southern Israel.  After the passage of the cold-front with the arrival of the cool air, the visibility tends to quickly  improve.

Dust particles can  act as cloud  condensation nuclei (CCN) and  may  also  serve   as  natural ice  nuclei   (IN). The  seeding potential of the  clouds is therefore expected to depend on the presence and  the concentrations of thedust particles in  the boundary layer   and   in  the free  troposphere. This  was  the reason, according to  Rosenfeldand  Farbstein (1992), to why they found a positive seeding effect both in northern and  in central Israel when theystratified the experimental data  based on dusty and non-dusty days. Consequentially, one can assume that therelease of silver iodide may have the intended effect of accelerating the precipitation formation only when and  where natural IN supplies are limited and ice does  not readily form in the super-cooled clouds.

Another common and  important aerosol type that is quite abundant when strong westerly winds are prevailing is thesea salt aerosols. The breaking waves and  rough seas trap bubbles of air in the sea water. As the bubbles float backand  reach the surface of the water, they burst the thin film of the seawater and release small  drops into  theatmosphere — the sea spray.  The largest drops may quickly fall back to the sea, but those that stay airborne just 5

long enough have  the chance to remain in the air for a much longer time period as they evaporate and get smaller and  more concentrated. The vertical mixing in the  boundary layer  together with the convergence associated withthe low- pressure system assist  in raising these sea salt particles to the cloud  base  level.  These  fairly coarse and hygroscopic particles are the first to act as CCN and  make the largest droplets in the cloud, which serve  as embryosfor subsequent raindrops.

Concerning “sea spray” and large droplet formation in Israeli clouds:

The discussion of sea spray and bubbles strongly resembles that of Woodcock (1953).  These researchers stand upon the shoulders of Woodcock but do not cite him.  This again points to weak reviewing of the pre-publication manuscript.  We quote Woodcock (1953) below:

 “It is suggested that bursting air bubbles in “white caps” on the open sea are a major source of the salt nuclei, and that a greater portion of the sea surface may act as a source of these particles during average winds than might be judged from the relatively small area usually covered by white caps”.

 

We note with interest that Woodcock was likely wrong in his initial 1953 finding (e.g., Woodcock et al. 1971).Woodcock’s finding that large particles are more numerous on “average wind days” rather than days associated with a large number of whitecaps, supports the occurrence of warm rain on more days than just those with numerous whitecaps and stronger winds in Israel.

More work is needed on this finding by F2015, preferably, again, by independent groups.

L929496 should be cited here.  In Levin’s studies it was found that large CCN comprised of sulfate-coated desert particles led to large droplets in Israeli clouds starting at cloud base.  He did not report on sea surface conditions, however.

————————

However, rather than strong winds and “sea spray”, the occurrence of large droplets in clouds are likely to be modulated by cloud base temperatures and low or moderate droplet concentrations in clouds over Israel and the Mediterranean, with relatively weak cloud base updrafts in which only the largest CCN are activated.

 In an R88 case study, clusters of Cumulus congestus clouds moving in from the Mediterranean Sea on a nearly calm day and produced light rain showers with cloud tops only near 0°C.  Cloud base temperatures on that day were above the average quoted range of 5° to 9°C, about 11°C.

Cloud base temperatures vary substantially in Israel, not only changing as the air mass trajectory changes, but also due to the warm to cool cycle of the eastern Mediterranean from fall to late winter and spring where the temperature can start at 22°C at the start of the rain season,  and ends up at 17°C in mid-late winter.

In RH95, it was noted that cloud base temperatures in Israel varied from 12°C to 5°C.  There would be approximately 40% more water available for condensation with the highest cloud base temperatures compared to the coolest ones, given the average cloud base altitude of about 800 m above sea level.    We note that the authors are aware of this effect of cloud base temperatures, but they do not present those temperatures.

Herut et al. (2000) analyzed the chemical composition of nearly 600  samples of rain  water collected all aroundIsrael during five rainy  seasons. They found that the  sea-salt fraction of the  rainwater composition is influencedmainly by the distance from the Mediterranean Sea, with a decrease from 73% of sea salt fraction in the coastalsamples in the north to 55% in the samples from  the Golan  Heights. They also  reported that the contribution of non-sea-salt precursors to the salinity of the rainwater was much greater in the south due to higher input of continentalcomponents and  lower annual precipitation there.

  1. Methodology of the microphysical measurements

3.1. The research aircraft

A twin-engine turboprop Beechcraft King-Air C90 aircraft was instrumented for the  cloud  physics measurementsduring the rainy seasons (November through April) between 2009 and 2013.  At the start of every  season the airplanewas fitted with the aerosol and cloud-microphysics instrumentation as well as the data acquisition and displayinghardware and software. The entire system was  tested on the ground periodically while the airplane was standing-byready for suitable weather to arrive.

3.2. Instrumentation

For measuring the  concentrations and properties of the aerosols we used  a CPC (condensation particle counter), acloud condensation nuclei (CCN) counter and an aerosol spectrometer.

The CPC (TSI model 3781) is a water-based condensation nuclei counter that measures the total concentrationof particles larger than 6 nm  in diameter, at a 1-Hz  temporal resolution  (Hering  et   al.,  2005).  The   simple design,   fast response and  continuous measurement help  detecting variations  in  aerosol concentrations that could  be  related to the atmospheric thermodynamic structure, pollution sources and/ or aerosol nucleation events. It is aninstrument that is fairly easy to handle and  maintain and  is considered reliable.

The  CCN counter that was  purchased from  Droplet Measurement  Technologies (DMT)  for  the  experiment is  a continuous-flow streamwise thermal-gradient counter (Lance et al., 2006). It measures the concentrations of theparticles that were activated into  small  droplets at  a set super-saturation, as well as the sizes of the activateddroplets. The CCN counter can  measure continuously at  a constant super-saturation or alternatively cycle  thoughuser-defined super-saturations for measuring the CCN spectra. The downside of changing super- saturations is that ittakes a couple of minutes for  the temperatures to stabilize and  the actual super-saturation to settle around the  required super-saturation. This also happens when the sample temperature or the pressure changes due to changes in flight altitude. We were therefore flying most of the time with a constant super-saturation (typically 0.5%), exceptduring the dedicated time for measuring the CCN spectrum at a constant flight level below the cloud base (typicallytwo-thirds of the way from  the  surface to the  cloud  base). The effects  of the  sample pressure on  the  actualsuper-saturations as  well  as  the  temperature changes within the  instrument were accounted for during the  data  analysis and quality control.

During   the rainy   season  of  2009–2010  we   had   a  DMT manufactured

aerosol spectrometer (PCASP-X2) onboard (Tan et al., 2010). As opposed to the CPC and the CCN counter, it does not expose the aerosols to  any  super-saturation, but  actually does  the  opposite; it dries  the  air sample for avoidingaerosol swelling due to absorption of water vapor. The PCASP-X2 measures the diameters and concentrations of aerosolsin the range 100 nm to 10 μm. The instrument was  mounted inside the cabin.  The air intake was  isokinetic only  up  toaerosols of about 2  μm, thus truncating the sampling of much larger aerosol than 2 μm.

            Another  DMT instrument on  the   plane was   the Cloud, Aerosol  and  Precipitation Spectrometer (CAPS)(Baumgardner et al., 2000). It consists of two spectrometers (CAS and CIP) and sensors for measuring thetemperature, relative humidity, static and  dynamic pressures as  well  as  a  hot-wire for  measuring cloud  liquid  water content (LWC). The CAS (Cloud and  Aerosol Spectrometer) measures particles and  droplets at the diameter range of 0.5 to 50 μm. The instrument is mounted on a pylon under the wing  and  measures directly the airstreamfrom  the cloud.  The measured aerosol spectrum is therefore sensitive to the  relative humidity. Accounting for thiseffect  is not  possible without knowing the chemical composition of the  aerosols, so we  mainly used  this  probe as asecond cloud  spectrometer for particles larger than 2 μm, as a backup for the main cloud droplet probe (CDP) and forquality control.

The CDP is a DMT-made cloud droplet spectrometer that measures the concentrations and  sizes of the cloud droplets in the  2–50  μm diameter range (Lance et al., 2010). This range is divided into 30 bins, which are muchnarrower than the bins of the CAS (in the cloud droplet size range). Both probes size each droplet that crosses theirsampling volume, based on the amount of light that is scattered forward when the laser  beam hits the droplet.

The DMT-made Cloud  Imaging Probe  (CIP) (Baumgardner et al.,  2000) provides 2-D  images of  precipitationparticles based on their shading pattern on a 62-element array of photo- diodes. The CIP that has been used hadpointy tips, to minimize error due  to shattering of large  particles, and  a resolution of 15  μm so  the  nominal widthof the array  corresponds to a length of 930 μm. The CIP allows identifying the different habits of the ice particles aswell  as distinguishing them from  rain/ drizzle.  It is not possible to directly derive the mass  of the precipitationparticles when ice is present due to their complex form and sensitivity to their orientation. However, the number concentration of the particles (after software partial removal of splinters from shattered particles) along  with particleimages can be useful  for identifying different microphysical phases in the clouds.

Details of the methodology used to remove “splinters from shattered particles” by F2015 is mandatory due to the HUJ-CSG’s prior excess removal of “splinters” from in-cloud measurements that apparently misled them about ice formation in their clouds (e.g., Gagin 1975).  We also note that F2015 used a 2-DC probe with “pointy-tips” as described by F2015 to minimize artifacts in the first place.

So, to re-iterate something that shouldn’t need to mentioned more than once, “Why can’t F2015 report concentrations of ice particles, beyond the medians Figure 16?”

Other parameters that were being   recorded during the flights were the air temperature, the relative humidity andthe navigation data from the  GPS system.

3.3. Flight patterns and execution

During the four rainy seasons of the physical experiment, 27 research flights  were conducted. Each flight lastedtwo and  a half  to three hours on  average.

How different were the synoptic settings?

A table of dates and times of flights is mandatory as are related synoptic maps (surface and 500 mb maps) preferably those embedded with satellite IR imagery.  IMS, aircraft soundings, and, if available, Beirut rawinsonde profiles, should also be made available.   Radar imagery should also be posted online for these flights.

These will help corroborate the authors’ findings; to insure that cherry-picking of a few particular synoptic regimes hasn’t been done to “improve” the overall apparent magnitude of seeding potential.  (One can observe the lack of trust of the HUJ-CSG on the part of the reviewer here in evaluating seeding potential with the baggage they now carry. Sorry, HUJ.)   If they did select only certain flow regimes, because only a few produce targeting possibilities, they should have stated this.

Fig. 4 displays a typical flight track. The black curved line shows the ground path, while the colored line  isprojected and  colored according to the flight altitude. The numbering relates to the geographical locations that arementioned below.

The take-off was  either from  Sade-Dov  airport in Tel Aviv (denoted as point “1a”  in Fig. 4), or from  Ben-GurionInternational airport which is ~ 20 km to the southeast (point “1b”).  The flight typically started with flying out to theMediterranean Sea at low  level  in order to assess the roughness of the  sea and  to safely measure the aerosolsbelow cloud base (point “2” in Fig. 4). This was followed by profiling the deepest clouds in the region from bottom to top,away from local pollution sources over land, while heading north (to point “3”). The profiling was done either at aconstant climbing rate of ~ 500 ft/min in case the cloud layer was  continuous or  by  flying  horizontally through cloudsand climbing stepwise 500–1000 ft in the cloud-free air, in the case of well-defined convective clouds.  After reaching andsampling the tops of the convective clouds over the sea we were normally able to look  eastwards towards the hilly regions of northern Israel, and  identify new  clouds over  the  Galilee. We would then fly to these clouds and profilethem from their tops to the lowest safety flight level (6000 ft) in a spiral  (point “4”).

We note that the sampling height over the Galilee district is about 3500 feet above the bases of the Mediterranean Sea and coastal clouds.

 Sampling “new” clouds might bias ice concentrations to lower values than actually developed a little later. Perhaps the authors don’t mean “new” in the sense of cloud stage?

The next step  was to descend to below the cloud bases over

the Jordan  valley  between the western and  eastern mountain ranges (i.e.,  between the  Upper   Galilee  mountainsand  the Golan  Heights) in order to measure the aerosols inland.

Heights of cloud bases and temperatures should have been given here; preferably listed in a comprehensive table for all flights and different sampling regions.

This was  either done over  the Hula Valley (point “5a”) or over  the Sea of Galilee (“5b”), depending on the  weatherand/or the  air traffic control directions. The CCN counter was set at this point to cycle through three super-saturations(normally 0.3, 0.6 and 0.9%) for approximately 15 min, while we were flying in circles at a constant altitude, and  tryingto avoid  areas with rain. The third cloud  profile  was  done over  the  Golan  Heights, starting with the cloud basesover the eastern edge of the valley and  above  the  slopes (point “6”).  Due to the proximity of the Syrian  border, therest  of the  climb  over  the crest  was  mostly done either in spiral  ascent or in a number of north–south legs, each  approximately 5 min  long,  perpendicular to the  westerly wind direction, until  reaching the cloud top or the heightwhere the  cloud  was  fully glaciated. At that point we typically started heading back south, unless we had a chance tocomplete another profile   or  measurement that we  were not  able  to  complete earlier. Finally we landed at Herzliyaairport (point “7”).

The maneuvering was reasonable in consideration of the realities of the area.  However, as the authors know, sampling on the upslope side of mountains leads to more LWC and less ice than would be found farther downwind.  Again, is radar coverage of the sampling area on the fight days available?  Did the aircraft have recorded radar imagery?  If so, can it be made available for each zone that sampling took place?  Are there ground hourly precip reports?

3.4. Data analysis  and quality control

The main software onboard the research aircraft for real- time data  acquisition was  PADS (Particle Analysis  and  Display System). PADS has been developed and  is maintained by DMT.  This data  was  subsequently processed byour  own  procedures for merging PADS and non-PADS datasets, extending the analysis from   the   research  aircraftmeasurements,  as  shown  in Section  4.2.

Interesting commentary here on what happens to DMT’s PADS processing package.  What exactly is meant here,  “processed by our own procedures”?  What changes, if any, are made from what PADS puts out?  Does DMT agree with this revision to your software’s output?  These may be harmless, but they should be discussed.

  1. Results and discussion

4.1. Aerosols and cloud base microstructure

The research aircraft was not equipped with instruments to study the chemical composition of the cloud  and  rain  water. However,  we  noticed that often  on  windy days,  after flying through a cloud,  there were white streaks ofsalt left on  the windshield of the aircraft after the evaporation of the  cloud water streamers.  Fig. 5  shows what theaircraft windshield looked like after passing through a cloud over the Sea of Galilee on 3 Feb 2010, as an example.This is one of the expressions of high  salinity of  the  cloud/rain water in  Israel,  as  had  been studied by Herut et al. (2000) and  mentioned in Section  2.3.

Nice photo.

Another  and  more quantitative expression of  the  abundance of sea  spray  is achieved by comparing the  aerosol size distributions  (ASD)  that  were measured by  the PCASP-X2 below cloud   bases   (Fig.  6).

Each  curve   shows a  60-second averaged ASD at elevations between 400 and  700 m. The black, blue and greencurves show the ASD measured on 28 Feb 2010, which was  a fairly windy day (mean wind of 10.3 m/s  at Haifa Port during the flight  time). The sea  was  rough and  full with white caps — and hence we would expect an extensivedischarge of sea  spray.

We note again that Woodcock et al (1971), in later studies of the chemical composition of rain, did not find the expected association between salt in rain.  We would like to see independent confirmation, of course.

 It can  be  seen  that these three curves have  the greatest concentration of super-micron aerosols — even  when the  measurement was  made approximately 45 km inland (the green curve) over  the Hula  Valley. These  largestaerosols are normally the first to activate into droplets at cloud base at rather low super-saturations, as they act as giantCCN (GCCN).

There  were probably more GCCN than what is shown in Fig. 6, but the experimental setup and the inlet of thePCASP-X2 caused the truncation of  the  ASD at  aerosol dry  diameters greater than 2  μm,  as  mentioned in Section 3.2.  However, despite the slight undercounting of the super-micron particles, it may still be useful to lookinto the geographical differences in their concentrations.

          Fig. 7 presents the  statistics of the  concentrations of super- micron (diameter N  1 μm)  aerosols in  the  marine boundary layer and at the foothills of the Golan Heights measured during four  different flights.   The dataset comprises the 60-second averaged PCASP-X2  concentrations measured at  a maximum elevation of 1000 m above  the ground. In-cloud and  noisy measurements were filtered out, so each  box in Fig. 7 is based on  5  to  20  one-minute  averaged aerosol distributions.  The green text  above  the boxes  denotes the mean wind speed and direction that were measured at Haifa Port at the  time  of the flights.

One can see that the last flight (12 Apr 2010) stands out in the  sense that this  was the  only flight where the super-micron particle numbers at the foothills of the Golan Heights were not considerably smaller than in  the marineboundary layer.  On the other three flights  the large aerosol concentrations over the sea  were 2–5  times greaterthan ~ 45 km  inland. The smallest difference and  the greatest inland concentrations (excluding the last flight) wereon 28 Feb 2010 — the day with the strongest winds. This implies that relatively little time was  available for the  large  particle to  settle on  their way  inland. The  greatest difference and  lowest inland concentrations was  on  26  Feb2010, with the weakest winds out of the three earlier flights.

Levin et al. 2010 attributed their finding of synoptic bias that explained the north target results of Israeli 2 to to stronger synoptic systems with strong winds that drove the precip max farther inland.  The authors’ finding seems to support the idea that large, Mediterranean Sea-derived aerosols also played a role in creating an ersatz seeding effect in the interior regions of that experiment.

The  wind speed at  the shore is not the only  factor that determines the absolute concentrations of the super-micron particles  and   certainly not  their  rate   of  removal  through cloud  and  precipitation  processes.Furthermore,  there could be additional sources of super-micron particles, other than sea spray,  such  as desert dustand  local  pollution. The PCAPS-X2 does not distinguish between the different particles, this allows only  aqualitative estimation of their relative contribution to the observed values.

The flight notes and pictures from the flight of 12 Apr 2010 indicate hazy conditions over central and northernIsrael, with desert dust being  the  probable main constituent of the super-micron aerosols. That is also the day withthe weakest winds recorded at the shore and  lowest concentrations of large aerosols near the coast, so the seaspray  production may be the lowest on that day, compared to the three others. Low sea spray production and highregional dust loading can  explain the relatively low concentration of large  aerosols over sea, and  the small differences between the marine boundary layer  and  the foothills of Golan Heights, as were observed on that day(Fig. 7).

What were the offshore cloud droplet concentrations for 12 April 2010?

Both desert dust and sea salt have  the  potential of accelerating the  precipitation formation, but  through different microphysical processes. The sea salt is an efficient CCN/GCCN, which can  produce large  cloud  droplets and drizzle particles, and   hence  speed  up  the warm rain   processes.  The  larger droplets are also more likely tofreeze and accelerate the rate of secondary ice splinter production (Mossop and  Hallett, 1974). Desert dust particles,on the other hand, may not be as effective CCN as sea salt, but they tend to be more efficient ice nuclei that mightmake cloud seeding with silver-iodide redundant  on dusty days. This may be something to account for in operational cloud seeding.

The sub-micron particles contribute much more to the aerosol total number concentrations than the super-micron particles. A large  source of small  aerosols is local  pollution, especially when  the  air-mass travels inland over  densely- populated areas,  such  as in central Israel. This is demonstrated by comparing the blue and green curvesin Fig. 6 with the black curve — all from 28 Feb 2010. The first two curves demonstrate the fairly  low  backgroundaerosol concentrations on that day because the green curve,  despite showing an  inland distribution,  is from  the rather sparsely-populated north. The  black curve,  on  the other hand, shows the aerosol size distribution downwindfrom  the heavily-populated Tel Aviv area  where the concentrations of  both   sub-  and  super-micron particles increase. But it is the sub-micron population that dominates the number concentrations, thus being  responsible fordoubling of the PCASP-X2 concentrations from  ~ 350 cm− 3 over  the sea to~700 cm−3  about 10 km downwind ofTel Aviv.

The remaining three curves in Fig. 6 show the  aerosol size distributions on relatively calm days; one with hazyskies — due to dust that was  transported from  SW (12  Apr  2010) with mean winds of 7 m/s  at Haifa Port; and  one  with no haze  (26

Mar 2010) and  mean winds of only 4 m/s.  The ASD of 26 Mar

2010   (in   purple)  shows  the  least   super-micron  particles despite being  sampled only  5

km  inland.  With  weak winds and calm seas the production of sea spray was very limited, but local air pollutionprobably caused the high  concentrations of the sub-micron particles. The  red  ASD in  Fig. 6, which was measureddownwind from  the heavily industrial area  near Haifa, had  the highest total aerosol concentration of all other ASDs. There were about 1000 cm−3 particles in the 0.1 to 2 μm size  range.  These  particles make the largest partof the  CCN population.

Fig. 8  presents a  comparison  of  two CCN spectra from another flight. The blue curve shows the CCN concentrations at three different super-saturations (nominal 0.3, 0.6 and 0.9%), as measured over  the sea  on  2  Jan 2012  at  ~ 600  m.

What were cloud base heights, if any?  What time of day was this measurement made?  Onshore or offshore flow?  The Bet Dagan sounding nearest the time of the flight should be presented so we know this case is not a fair weather day with the aerosols clamped down by stable layers.  Also, over what distances were these data collected?

 The  CCN concentration at 1% super-saturation is estimated at 360 cm− 3, while the total aerosol concentrationmeasured by the CPC was 700–1000 cm-3. The red  curve,  on the other hand, shows the  higher CCNconcentrations ~ 45 km inland. The low-level winds on  that day  had  a  clear  southerly component,  which could have  brought the pollution from  the industrial area  near Haifa to the Hula  Valley. The CPC concentrations below theclouds were 3000–3500 cm-3  while the CCN concentrations at  1% super-saturation were close  to 2000  cm-3. The  actual cloud base super-saturation was probably lower, as the highest cloud droplet concentrations in that area  barely exceeded 1000  cm-3 on that day.

The cloud drop concentration and size distribution at cloud base are determined primarily by the properties of theaerosol population (concentrations,  sizes  and  chemical composition) as well  as the cloud  base  updraft. GreaterCCN concentrations and  stronger updrafts lead  to nucleation of more and  smaller cloud  droplets at  the cloud  base.

     Fig. 9 shows a comparison between the shapes of  the cloud  droplet size  distributions (DSD) slightly above the cloud  base  for a windy, a hazy  and  a calm day — all over the sea. All DSDs have a mode near 10 μm, a totaldroplet concentration of ~ 120  cm-3  and a liquid  water content of ~ 0.04 g/m3. However, the difference that standsout between the DSDs is the “tail” of the largest droplets. While  on the calm  day  of  26  Mar  2010,  the DSD is quite symmetric around the  mode,  it becomes more and  more skewed with increasing concentrations of super-micron aerosol concentrations (see matching colors in Fig. 6). On the windy day of 28 Feb

2010,  the concentration of the ~ 20 μm cloud  droplets is about an order of magnitude greater than on the calm  day,with the concentrations of the hazy day in between.

Would like to see more November – December data, that period when the Mediterranean Sea temperatures are warmer; cloud bases, too!

A comparison of near cloud-base DSDs of more than 20 clouds sampled during 12 different flights  over theMediterranean Sea and the Golan Heights, is presented in Fig. 10.

There is no separation between windy, hazy  or calm  days  because the emphasis here is on the geographicaldifferences. Because  the cloud  droplet initially grow  (in  diameter) rather quickly,  only clouds within a  hundredmeters from  the  cloud  base  were considered —  as  long  as  the mode of the  volume-weighted distribution wasbelow 10 μm and the mean LWC was between 0.01  and  0.1  g m− 3.  These  filters were applied in  order to avoid  including DSDs from  clouds whose bases  could  not  be documented due to safety and air traffic controlrestrictions, as well  as in order to exclude highly  diluted clouds.  In addition, the cloud   base   altitudes had   to be within 300  m  in  both locations on the  same day.  This is to prevent large  variations in cloud  base  temperatures that determine the  amount of condensable water vapor near the  cloud  base.

Superlative considerations, but where are the ACTUAL cloud base temperatures?  Nowhere to be found!  The reader will want to know what they were to compare with “historical” reports of cloud base temperatures.  Also, without care, low LWC’s and small droplets can be found in clouds with bases that are evaporating upward providing a false indication of where an original base was.  Here’s where flight videos would be helpful to outside researchers evaluating these claims.

          The integrated LWC of the mean cloud  base DSD over  the sea and  over  the Golan  Heights, as indicated inFig. 10, is comparable (0.052 vs. 0.045 g m-3, respectively). This facilitates the comparison of the  shapes of the observed distributions  because it suggests that the  differences in the distance of the compared samples from  the  actual cloud  base  and/or different exposures to entrained cloud-free air,  are  probably not the main contributors to  the   non-overlapping DSDs in  Fig. 10. This  leaves  the different mean aerosol properties and  cloud base updrafts as  the probable causes for  the different DSDs. However,  the  greater instability over  the sea  isexpected to produce stronger updrafts that would result in a larger number of CCN to activate there — assuming acommon CCN spectra. This would shift the blue DSD in Fig. 10 to the left, i.e. to smaller sizes.  But the mode of theblue  DSD is actually ~ 4 μm larger than the  red  DSD (9.0  vs. 4.8 μm). So apparently the different mean aerosolproperties and their resulting CCN spectra, as the example in Fig. 8 shows, are  the  main factors in shaping the mean near cloud  base  DSD.

The droplet number concentrations that corresponds to the DSDs in Fig. 10 are 225 and 480 cm-3 over the sea andthe Golan Heights, respectively.

These are very credible concentrations from the author’s experience in Israel, except on some haze and smoke,  afternoon “fair weather” Cu days (Cu mediocris, even Cu congestus) in the Golan  (where the reviewer was briefly in ‘86),  droplet concentrations would likely be higher than 480 cm-3.

The larger number of activated droplets over the western slopes of the  Golan  Heights results in  the smallerdroplet sizes  near the cloud  bases  there, compared to over the sea.

Furthermore, the  proximity of the  Mediterranean clouds to the  source of the sea  spray  tends to result in a tail  oflarger droplets, as the comparison of the mean near cloud base DSDs in Fig. 10 shows. This is due to the activation ofthe giant CCN there (which are much fewer than the rest  of the CCN). The  90th percentile DSDs in  Fig. 10  (filled   circles   above   the curves) indicate that the cloud base DSD over the Golan Heights can also have a considerabletail of large droplet. This is probably caused by  activated sea  spray,   which has  been transported inland withstrong winds, because the  dust particles, as  discussed above,  are  less efficient as CCN.

Here is another finding about large aerosol particles that supports the Levin et al 2010 reanalysis of Israeli 2 and the finding that strong synoptic situations led to the misperception of a seeding effect in the interior of the north target.

 The largest cloud  drops at the tail of the  DSD have  greater fall speeds than the  smaller cloud droplets,  and  therefore they can  collide  with and  collect the small   droplets and   grow   further.  Those  droplets also  have higher probability of freezing in sub-freezing temperatures and hence help  producing precipitation-sized particles moreeffectively. The clouds over the Golan Heights, however, most often have  a smaller tail and  hence convert theircloud  water into precipitation-sized particles by warm processes less efficiently.

4.2. Vertical evolution  of cloud microstructure

The convection that occurs from synoptically or topographically-induced updrafts raise  the cloud  droplets that nucleate at cloud  base  to higher elevations and  colder temperatures.

This is such a common descriptor combination it’s hardly worth pointing out, but a temperature cannot be warm or cold.  Peter Hobbs:  “A cup of coffee can be warm or cold, but not a temperature.”  A temperature refers to an object that is warm or cold.  It itself, a number, cannot be warm or cold, it tells one aspect of the physical state of an object.

The droplet condensational growth is determined by the number of activated CCN and the height above cloud base(Freud et  al.,  2011). The  rate   of  droplet  coalescence is  determined mainly by droplet size and  is related to the 5th power of cloud drop effective radius (re) (Freud and Rosenfeld, 2012). This rate depends also on cloud  dropletspectrum width and  concentrations. When re exceeds 14 μm rain tends to initiate. This process takes normally a  fewtens   of minutes and  requires that the typical convective cloud  in Israel would exceed a vertical extent of 2 to 3 km(Freud and Rosenfeld, 2012).

This process normally takes “tens of minutes”? It’s not is clear what the authors are referring to.  Is “tens” of minutes from the first visible evidence of a cloud?

If not, F2015 need to walk along the beaches of Israel when the skies are boiling with Cumulus to Cumulonimbus transitions as I did.  RH95 show incontrovertible evidence of the rapid glaciation of Israeli clouds, within a few minutes.

But let us assume a Cumulus cloud forms (becomes visible) at 800 m above the Med.  It contains a 5 m sˉ¹ updraft.  From an 800 m it would reach the freezing (typically about 2500 m above sea level on rainy days), in 340 s, and the 700 mb level (3000 m) in 440 s, where the temperature is typically about -5°C.  To reach 4000 m ASL, about 600 mb, would take 640 s since the cloud first appeared above the Med Sea.  The temperatures are now typically-10°C or lower on Israel rain days at 600 mb (4000 m).

      The 700 to 600 mb (4 km ASL) temperatures are typically in the zone where ice is initiated in Israeli clouds (-5°C to -10°C).   At still lower cloud top temperatures, the ice concentrations would increase (in non-chimney clouds).

Ice would be appearing rapidly in such a cloud in just over ten minutes from its initial appearance as a visible cloud, and certainly, if it reached the -12°C to -15°C, would contain hundreds per liter of ice particles from its first appearance, and in just a few minutes after surpassing the freezing level.   Go to your radars and look at the time to first echo.

   But why do we have to go through this simple example?

Please allow me to take your research plane up next winter (with a 2-DC probe that works).  How about if I bring DMT’s Darryl Baumgardner or Duncan Axisa along to insure accurate 2-DC concentrations from the DMT CAPS probe?  I bet that in the first two hours of flight I can find the highest concentration of ice particles that has ever been REPORTED by the HUJ-CSG in 40 years.  I may not find the highest that they have measured; only the highest that they have REPORTED.  (They seem not to want their funders, nor the rest of the science community, to know just how high ice particle concentrations can be in Israeli clouds.  Is there another reason why they don’t report them in airborne study after airborne study?)

The authors, or at least one of them, is well aware of this fast-glaciating behavior of Israeli clouds and has been for at least 30 years (e.g., Rosenfeld 1997; Rangno and Hobbs, 1997.)

Perhaps the phrase, “tens of minutes” was a careless entry in the original ms?

Fig. 11 shows the evolution of the DSD with increasing height in convective clouds over the Mediterranean Sea on 12Jan 2012. The mean DSD of every  cloud  pass is given  as a single  curve  in the plot. The clouds were repeatedlypenetrated close to their tops as they grew,  until  small  precipitation particles (diameter ~100 μm) were detected bythe  CIP at the altitude of 3000 m, on that day.

 How close to cloud top?  Too close to cloud top misses the formation of precip because they lag the smaller droplets at the tippy-top.

These cloud-top “precipitation embryos” become much larger (N 1 mm) as they fall through the cloud and collect othercloud droplets and precipitation particles. On other days, precipitation embryos were detected in the growingconvective  clouds at other altitudes depending on the  specific  conditions (Freud and  Rosenfeld, 2012). However,most of the time that happened when the volume-weighted mode of the DSD exceeded ~ 20 μm.

For comparing the vertical evolution of the DSD for clouds growing in different aerosol environments, it is easier to represent the entire DSD with a single  number,  such  as  the cloud  drop effective radius. This was  derived from  the binned

“EQUATION”

The values of re, the mode of the volume-weighted DSD and the  droplet mean volume radius (rv) are linearlycorrelated as most DSDs have  a generally similar shape (Freud et al., 2008). Freud  and  Rosenfeld (2012)  showed  that  these  relations  are independent of geographical location. They also showed both theoretically and  empiricallythat the  mode of the  DSD and  rv have  values that indicate the  initiation of rain.  This  is  why vertical profiles ofre, derived from satellite retrievals (Rosenfeld and  Lensky,  1998) can  be  used  in  real  time  to  estimate the droplet sizes at cloud  top, as well as their potential for forming precipitation even  before it is detectable by the  precipitation radars. This concept is already in use  in the  operational cloud seeding program in Israel.  An example of the retrieval of the  cloud  microstructure for 10 Dec 2012,  at 10:56 GMT (12:56 LT),  in the form  of re vs. cloud  top  temperature, is presented in Fig. 12.

This retrieval is based on NPP/VIIRS high-resolution data, which allows effective analysis of differences in the  microstructure of clouds developing in rather small user-selective areas (Rosenfeld et al., 2014).

What is the depth of cloud from which these retrievals were derived?  One meter? 10 m? 100 m? 1-km?  This should be stated here for the AR reader.  Ice will certainly fall out of super cooled liquid-topped layers in the Golan; Re will mislead in those instances.  Another reason for ground obs in the Golan.

 There are three T–re  profiles for different regions in this  figure; the  Mediterranean Sea (area 3), the Galilee (2) and  the Golan  Heights (1).  The median re  (the bright-green curve  in each sub-plot) in areas 3 and 2 reached 15 μm at a temperature of about -5 °C. In addition, the  T–re  profiles in these two areas indicate that  cloud   glaciation  has   occasionally occurred  at temperatures as  warm as  -10  °C.

Can F2015 supply numbers to quantify the “occasionally” statement?  Also, isn’t this old news, about 30 years old, about clouds glaciating/raining when their tops are >-10°C?  (See R88; not cited here, as one would expect by the HUJ-CSG).  Also, from the IMS, 1986:  “We get good rains from clouds with tops at -10°C.”  This quote demonstrates how the every day weather forecasters within the IMS could have prevented the early cloud misinformation published by the HUJ-CSG, that clouds had to be much colder–topped before they rained.

Glaciation is  indicated by spikes of high  re  and  by  a red  tone of the cloudy pixels.

In contrast, the median re  of the clouds over  the Golan  Heights (area 1) did  not reach the  precipitation thresholdof 14  μm (Rosenfeld and Gutman, 1994) and did not show any indication of glaciation. The cloud  tops thereappear to contain mostly super-cooled drops despite developing above  the -10  °C isotherm.

To emphasize, in more stratiform clouds, the top of ice-producing clouds is often supercooled droplet clouds, as reported on several occasions (e.g., Cunningham 1957, RH85, Rauber and Tokay 1991).  The Re reported here is likely to be misleading.  Ground confirmation is required for assertions of “non-precipitating clouds” as indicated by an Re value.

Perhaps, since F2015 do not discuss it, they are not aware of the problem in using Re when precipitating clouds have liquid tops from which ice emanates?   Can they supply hourly precipitation data, radar imagery or weather reports for these times in the Golan?

While there may be, indeed, supercooled LWC at cloud top, it is from that liquid top that ice crystals are spawned, grow, and breakup increasing ice particle concentrations below top (Hobbs and Rangno 1985).   In turn these consume water vapor via deposition/riming in ice supersaturated conditions.  Is F2015 sure they want to disrupt this system by seeding a liquid topped ice-producing layer?

While  Fig. 12  presents a  snapshot of a  single  case,  as  an example of how the different re profiles look in cloudsdeveloping in different areas,  it is useful  to use  a statistical approach and examine additional cases.  Fig. 13 showshow  the  cloud  droplet effective radius varies with the cloud top temperature. It is based on all high-resolution satelliteretrievals from the rainy season of 2012–2013 that were suitable for obtaining the  T–re  profiles for  clouds over theMediterranean Sea and over the Golan Heights. In total,  seven retrievals from  days  with seeding potential, according  to  the  criteria of  Israel-4,  contained  clouds with varying tops in  both areas.   The  cloudy pixels   were grouped according to  their 11.8  μm brightness temperature to  clusters with the same temperature ± 1 °C, and then differentpercentiles of re were calculated for each group. Fig. 13 displays the first and third quartiles for each  cluster and area  as dashed lines, and the median re in each  area  as a solid  line. Only clusters containing more than 100  data  points are  displayed for more robust statistics.

All the curves in Fig. 13 show an increasing re with colder cloud  tops,  but  the  change tends to be more substantialover the  sea. The median re over  the  sea (blue solid  curve) crosses the precipitation threshold of 15  μm alreadyat − 3 °C, even before the  silver   iodide can  have   any  effect,  compared to − 12 °C over  the Golan  Heights (redsolid  curve).

I applaud the authors for this information, highlighted above.  It gives one hope that we may not travel down the same path that the HUJ-CSG has traveled so many times before.  We rephrase the authors’ somewhat obtuse description more simply for the reader:

The clouds moving into Israel from the Mediterranean Sea are unsuitable for seeding with silver iodide. 

This is a new finding for the HUJ-CSG, and it should have been given more attention in F2015.  R88 should have been cited here, who concluded virtually the same thing 27 years before F2015 were able to discover it.

By not citing those who went before, it makes F2015 look like the work of small minds, not that of disinterested scientists only interested in truth.  Omitting relevant work is devious, harms conscientious workers, and degrades the HUJ.

Is this really how F2015 want to represent their home institutions?  It would seem so.

This means that on average, the clouds over the  Golan  Heights have  to acquire a greater vertical extent than theclouds over  Sea to  start precipitating. The probable cause for that is the greater aerosol and  CCN concentration(e.g.  Fig. 8) and  less  sea  salt particles further inland (Fig. 7). But the  different characteristic dynamics andthermodynamics of the clouds may contribute to the differences as well.

As  in  Fig.  12,  Fig.  13  also   shows  indications  of  early glaciation over the sea at rather warm temperatures ofaround − 10 °C,  where  the  75th  percentile of  re   is  close   to  the saturation value  of 40  μm. Furthermore,  thecurves indicate that the clouds over  the sea  tend to  have  a greater vertical extent and  reach colder temperatures.

The temperature bugaboo strikes again.

This is probably caused by the stronger convection over  the  sea  that encourages the formation of  deep clouds,  while the clouds over  the  Golan Heights normally have a more orographic nature and a layered structure, accordingto our subjective observations.

In November, and in later winter and spring, thunderstorms are as common at inland hill regions as over the Mediterranean (e.g., Altaratz et al. 2003), so the idea of perpetual stratiform clouds over the Golan as suggested by F2015 is flawed and needs to be revised to draw this out.  Too, clouds may not be ripe for seeding in these deeper convective situations that occur in November and later in the spring.  Further independent airborne work is needed.

This is also supported by the differences in the  patterns of rain  durations and  intensities between the coastal and hilly stations in Israel (Goldreich, 2003), where rainfall at the coastal plain  is much more intense and has a shorterduration.

It is important to keep in mind that the colored curves in the subplots of Fig. 12 can be considered as verticalprofiles in the convective clouds because the cloud  base  temperature do not tend to vary much within the sameconfined area. re also shows little variance in a given area and altitude (Freud et al., 2008) and the  cloud  top  re  at  agiven  temperature does  not  vary  much during the lifetime of a convective cloud (Lensky and Rosenfeld, 2006). Fig.13, however, is based on seven different profiles, not necessarily with the  same cloud  base temperature and probably with varying aerosol properties and atmospheric thermodynamics. This is why the curves in Fig. 13 cannot really bereferred to as vertical profiles that represent the  development of individual deep convective clouds.  They  should be treated as  a  general statistical view of the T–re  relations in the indicated areas.

These are excellent qualifiers, as scientific writing should contain when necessary.

        The  large number of flight  hours and  the penetration of clouds at  various heights and  in differentgeographical areas facilitate a similar statistical analysis to what is presented in Fig. 13 for satellite data,  with thein-situ data.

The flight hours are really not so large at <81.

What is far more important, to repeat, is the synoptic setting in which the flights actually took place.  As a reviewer, I would have mandated a supplemental appendix with synoptic maps and satellite imagery for each flight be supplied by the authors prior to publication.

I am sorry to say that the HUJ-CSG long ago forfeited the right to make general statements without comprehensive backup material that independent researchers can investigate for reliability.  Furthermore, and I repeat for emphasis, videos of flights should be made available on request or made

available online.  Most of us “senior researchers” who know well the trail of the prior reports from the HUJ-CSG, understand why more evidence is required from them in their cloud seeding reports than might be the case for another institution.  “Fool me once, shame on you; fool me twice, shame on me.”

The 1 Hz measurements inside the clouds represent a spatial averaging along a ~ 100  m  long  path.  Thesemeasurements from  15  research flights  that were conducted during the physical experiment were groupedaccording to the measured temperature at the flight  elevation. The percentiles of the CDP-derived  re  were calculated  for  each   group  of  measurements  and   no  other filtering or normalization was applied except thegeographical separation between the clouds over the Mediterranean Sea and the Golan Heights. Fig. 14 shows acomparison between the re values of the clouds sampled over  these areas.  Here  too the apparent trend ofincreasing re with colder temperatures is more pronounced over  the sea  than over  the Golan  Heights, as  in Fig.13.

The  two profiles appear to  separate around the temperature of − 5 °C, where the marine cloud seems to maintain its convective profile,  i.e. increasing re  with colder temperatures. Over the  Golan  Heights, however, the  effects  ofelevated cloud layers   with embedded  convection and/or  secondary droplet nucleation, may  explain the offset  ofthe peak  between re and LWC (see Fig. 17).  This  is  supported by  the statistics of the droplet numberconcentrations around those peaks (not shown here). The differential likelihood of freezing of larger cloud droplets,elevated cloud  layers,  cloud-top entrainment and precipitation, may  all contribute to maintaining a low  median re attemperatures below − 10 °C.

References supporting the freezing of larger drops could have included, for example,  Vali 1971, Pitter and Pruppacer (1973), among many others.  FYI:   HR85 used the large size end tail of the cloud droplet spectrum (the so-called, “threshold diameter”) as measured by a FSSP-100,  in newly risen, low ice containing Cumulus turrets as a predictor of later maximum ice particle concentrations.  It worked pretty well except in short-lived narrow “chimney Cu”.

The  percentile-profiles of  the   satellite-derived re   of  the convective clouds over  the sea  exhibit greatervariance than those of the orographic clouds over the Golan Heights (Figs. 12 and  13). This is partly caused by theso-called 3D effects  — the variable illumination of the cloud  tops by the sun  due  to their inhomogeneous physicalstructure (Marshak et al., 2006). The cloud   top   re  of  cloud   surfaces that  incline away   from   the satellite, i.e. ina direction that increases the sun–cloud–satellite angle,  would be  overestimated (even more in  shaded cloud surfaces). The cloud  surfaces that incline towards the  satellite would have  their re underestimated due to theopposite effect, resulting in a falsely wide  re distribution for clouds with a non- horizontal cloud  top surface. This, ofcourse, does  not apply  for in-situ derivation of re, as in Fig. 14.

Outstanding distinterested writing by the authors describing issues, both above and below!  Here the paper has the feel of real science!  I’m excited.

Furthermore,  the  absolute re  values that were calculated from  the  CDP measurements,  are  typically smaller inFig. 14 than the satellite-derived re shown in Fig. 13. Possible  sources for this apparent discrepancy include

1) Our  focus  was  on  documenting the  evolution of the  cloud DSD as it grew  and  on measuring the formation ofprecipitation embryos and  the  initiation of effective precipitation.

What is “effective precipitation”?

In addition, we tried to avoid  flying higher than ~ 5 km or in heavy precipitation from  mature clouds due  to flight safety  and  performance reasons.

F2015 stated that they had targeted growing, “hard-topped” Cumulus, filled with supercooled liquid water that would cause heavy icing on their twin-engine, turboprop Beechcraft King Air C-90 aircraft.

Icing is one of the great dangers of sampling Cumulus congestus clouds at below freezing temperatures.  When Cumulus congestus transition to those modest Cumulonimbus clouds of the Mediterranean loaded with ice crystals, the supercooled liquid water disappears and they are virtually harmless to aircraft as an icing threat.

F2015 seem to be indicating that they are unaware of the reduction of icing hazard when this transition to the modest Cumulonimbus clouds, the vast majority are not strong enought to produce lightning.  We’re not sure what hazard they could possibly be thinking about.

 High ice particle regions of clouds have, as a rule, little icing in them and less turbulence, and MANY in Israel in those low theta-e air masses will be found with tops less than 5 km ASL.  In this airborne researcher’s experience in similar clouds in the Washington State coastal waters, such clouds have never posed a hazard to our aircraft except via icing because of sampling too many new turrets too quickly.   (Icing buildups can be removed by descending to lower, warmer levels.)

The highlighted sentence is incomprehensible as a reason not to have sampled the maturing and dissipating portions Cumulonimbus clouds in the eastern Med.

This is why  our  sampling strategy did not cover the area uniformly but instead favored clouds in their early  growingstages — unlike the satellite retrieval.  The aging  of the  deep convective clouds allows more time for  the  collision and   coalescence process to produce large  droplets and  increases the  chances for  ice formation.Therefore  the underrepresentation of the  mature clouds in  the  in-situ measurements and  in  Fig. 14 reducesthe re values.

Qualifying one’s measurements doesn’t get any better than this!  Thank you, authors! Just for the record, this reviewer believes that GN74—written in 1972) represented one of the best examples of objective writing within the often murky domain of weather modification/cloud seeding, where “confirmation bias”, monetary considerations so abound that they deflect true science into something else.

But, this outstanding description begs the question, “How were L929496 able to sample mature, full of ice Israeli clouds, and F2015 were not?”  Isn’t the HUJ-CSG more experienced in airborne research? To the cynical, it could look like an excuse not to sample high ice concentrations in even modest Cumulonimbus clouds.  Authors:  please explain why L929496 was, and you weren’t able to do this.

 2)  The CDP measures only  droplets with a diameter smaller than 50 μm. If larger drops or even  small  iceparticles are present at the  cloud  top or slightly below it (or  even  as a thin cloud layer above  it) then thesatellite-derived re might be overestimated Point (1) above also helps explaining why the blue profile in Fig. 13  is  deeper than the   red  profile,   but in  Fig. 14  it  is shallower. We basically stopped climbing when cloud waterwas mostly converted to precipitation or glaciated. This happened on average at a  slightly warmer temperature  over  the sea,  and hence the shallower profile  in Fig. 14. The clouds over  the  sea often reached much higher altitudesthan over the Golan Heights (e.g. Fig. 12) due  to the  more unstable conditions.

To repeat, the situation highlighted  is often reversed early winter, and certainly during the spring in major troughs when thunderstorms are as common inland as over the Sea.  This needs to be revised to reflect this reality.

The satellite retrievals  reflect this,  but the   in-situ measurements  do  not because of the sampling strategy

4.3. Formation of hydrometeors

Supercooled cloud  water tends to be quite abundant in northern Israeli rain clouds.

F2015 do not provide specific data on this “tends to be abundant” claim anywhere in this paper, nor do they seem to realize that supercooled water is often short-lived in Israeli clouds due to the rapidity of ice formation.

Most of the rain that falls in northern Israel during the winter initiates as mixed phase hydrometeors in clouds withtops  that are  well  above  the  0 °C level.

Omit, “well”;   “above the 0°C level” is sufficient for the “initiation” of precip.  Furthermore, in low stratiform clouds that are thickening upward as an upper trough approaches, drizzle and mist-like rain from warm rain processes are initiated (as was observed on several occasions during the reviewer’s 1986 experiences in Jerusalem).  One suspects drizzle will also occur in hill locations in the far north of Israel as well.  It seems strange to tell people who live in Jerusalem about this!

This again speaks to the critical importance of having independent ground obs at Mt. Hermon;  maybe Har Kana’an, as well.

This has been documented with the help  of the  CIP that provided 2D images of the  hydrometeors in  its  sampledvolume of cloud/ air.  Although  the  CIP does  not  allow  distinguishing between spherical super-cooled liquid  dropsand slightly irregular frozen drops at diameters smaller than ~ 100  μm — due  to its 15 μm resolution, riming offrozen drops and  graupel particles can be easily   identified.  These  particles  provide  clear   indication  of ongoingmixed-phase processes in the clouds.  Quantifying the ice  content in  the  cloud  with a  2D imaging probe is  highly uncertain, however we were still able to see and  document the increasing concentrations and  sizes  of the iceparticles as the clouds matured and the  water content decreased.

Here’s what a Droplet Measurement Technologies rep has to say about the “highly uncertain” claim in F2015 concerning its CAPS probe:

I agree with you that the authors could have reported the ice particle concentrations from the CIP if they wanted to. I see CIP images in Fig 15 (of F2015), so the authors should be able to get particle concentrations. The CIP does report particle concentrations and processing software is capable of producing high quality particle concentrations.”

Doesn’t this make the “highly uncertain” claim in F2015 a falsehood?  Its does to this reviewer.  But where were the other reviewers, if any, of this article???

The American Meteorological Society (AMS) has recently issued a Monograph (Field et al 2017) focused on secondary ice particles and the efforts to explain them, authored by our leading scientists.  Most of the observations discussed in that Monograph are due to measurements with a 2-DC probe!

A possible cynical translation of the HUJ-CSJ “highly uncertain” claim about ice content:   “We measured really high ice particle concentrations similar to those of L929496  but we,  F2015, wish not to reveal in an article about cloud seeding potential having such high concentrations of ice as we found.  We therefore have invoked the excuse that the “mature” clouds of Israel were too dangerous for our aircraft to sample where all that ice was.  Its amazing to us that Zev Levin was able to do it!”

2-D artifact reduction:  Since the 1970s, there have been ways in software of reducing 2-DC artifacts caused by, say, shattering on probe tips.  Indeed, in F2015 they inform us that they used 2-DC probes with “pointy tips” to reduce shattering artifacts.  But then they reverse course, and tell us they can’t report what they found with that probe.  This is sad, because it appears to be another omission of important data by the HUJ-CSG.

Maybe we shouldn’t be surprised at such an omission, except that it appears in a peer-reviewed journal.   What ARreviewers, ad nauseum,  allowed an omission of such critical data in an evaluation of cloud seeding potential?

If this type of “editing” of findings in F2015 was what convinced the INWA to proceed with rudimentary operational seeding or “Israeli-4”, then the HUJ-CSG has misled them once again.   It is likely, in such an experiment with an unbiased draw, that no statistically-significant results from seeding will accrue (providing the evaluation is conducted by independent non-HUJ statisticians).

Fig. 15  shows some 2D images of the hydrometeors that were observed at  different altitudes over  the sea  on  12  Jan 2012,  as an example.

The images are quite nice; shows what we can do today.

However, a series of single strips of hydrometeors chosen by F2015 in Figure 15, does not suffice to prove much.  They have omitted (sound familiar?) those images and concentrations of sheaths and needles, those crystal habits that form at temperatures  > -10°C  which would document the prolific operation of a secondary or other ice particle production mechanism that operates in the clouds of Israel.    The aerosol environment of Israel, with its large CCN and often high concentrations of smaller droplets due to pollution in the Hallett-Mossop riming/splintering zone creates the “perfect storm” for ice multiplication in their clouds, as F2015  should know when they cite Mossop (1978).

 Figure 15 is not acceptable to this reviewer without extensive 2-D imagery with “best possible” concentrations available online.

The CIP particle size distributions for the same cloud/area were shown in Fig. 11. According to the combinedCDP/CIP particle size distributions, the mode of the cloud  DSD reached ~ 20  μm at  an  elevation of slightly below3000  m. This is also where the CIP water content of ~ 100  μm particles  became  more  significant. Fig. 15  showsthat these precipitation embryos are  spherical,  i.e. probably still  in  the liquid  phase, although the temperature isclose to − 8 °C.  The LWC at  that elevation reached 1.6  g m-3  and  there was  no indication for ice. Higher  up inthe  cloud  the particles became even  larger and  started having a more irregular shape.  The irregular particles seenat temperatures warmer than − 5 °C are not likely to have frozen at the  observed elevation, but rather have  fallen  from  above   while riming smaller particles. This leads  to another small  mode in  the far  right  of the  CIP size distribution (Fig. 11) rather than a more continuous decline in LWC with increasing particle diameter in the  CIP range.

            Documenting a similar process of cloud droplet growth, the formation of precipitation embryos and theirfreezing over the Golan Heights was much more challenging due to a number of reasons.  It  was  difficult to  follow   the   same cloud   element through

its lifetime due  to the more orographic nature and layered structure of the  clouds.

The authors recover from the omissions discussed previously and write an outstanding couple of qualifying sentences, the type that normally accompany a great science piece!  I’m excited again!

And even  if distinct convective cloud tops were identified, they often quickly drifted eastwards into  Syria, where itwas  not possible flying to. The impression was  that often the clouds there would consist only  of supercooled waterwith no  precipitation, unless having embedded convection or ice particles falling from above.

The above is good, and the use of the word, “impression” makes it even better.  Thank you authors!

Fig.  16  presents the   profile   of  the concentrations of hydrometeors with diameter greater than 100  μm in  clouds over the Sea and the Golan Heights — as measured by the CIP. It is based on the same 15 flights  used  forthe  analysis in Fig. 14 and  both figures have  some common features.  As with the cloud  droplet effective radius,the  concentrations of the large hydrometeors increase with decreasing temperatures  in  the developing convectiveclouds over  the  sea. This is because as the cloud grows and its top becomes colder,  the cloud droplets and  the hydrometeors that do not fall become larger,  and  also because the freezing of the largest droplets, which may  push them over the 100 μm cutoff size used  in Fig. 16, is more likely.

The  statistics of  the hydrometeor concentration over  the Golan  Heights, on the other hand, shows a maximumconcentration between − 5 and  − 10 °C, with median concentrations close  to 10 L-1. The inclusion of cloud  layers with colder bases, smaller droplets and  less  LWC might explain the decreasing hydrometeor concentrations atcolder temperatures over  the Golan Heights. This might not, however, explain the finding that the CIP concentrations inthe − 5 to − 10 °C temperature band are considerably higher over the Golan Heights than over the sea.

This doesn’t make sense.  The reality would be just the opposite if they had been more adventurous with their aircraft sampling in the Med.  The reason for the lower concentrations in the -5° to -10°C temperature range over the Mediterranean where ice multiplication is rampant, compared to those concentrations found in the Golan,  is the sampling by F2015 of young, newly risen,  “hard” turrets before the ice explosion occurs over the Med.

It is worth noting that the temperature of maximum hydrometeor concentration over  the  Golan  Heights coincideswith the activation temperature of the silver-iodide which was released upwind during most of the sampling.

WHY would one sample, at great operating cost, clouds when seeding was underway upwind???  Isn’t that a waste of precious INWA resources?  Was this unintentional?  Are there no data from your flights that were gathered in the Golan without seeding taking place?  Did you measure ice nucleus concentrations, ones that could have alerted you to this problem?  This, unfortunately, raises the issue of incompetence unless there were mitigating circumstances.

It is also close to the temperature of maximum Hallet–Mossop ice multiplication rates, which may be suppressed instrong convection (over the sea) due to relatively short residence time of the graupel in the optimal temperature band for ice splinter production (Hallett and Mossop 1974).

Suppressed H-M process?  This is non-sense.  Gimmee your plane!  These authors need to go outside and watch there incoming Cumulus congestus clouds as they convert to ice (and small Cumulonimbus clouds) within minutes after reaching very much above the -5°C level.  With proper aircraft sampling, the authors would have found a ton of H-M generated (and/or that by other processes) ice crystals (needles and sheaths) in the temperature zone (-3° to -10°C) where H-M-produced ice can reside (as at Mt. Hermon on many occasions).

One wonders why the analysis goes so badly here?  Who was directing the aircraft?  Who wrote this segment?

But this process may  be  enhanced by  the embedded convection that often occurs over  the Golan  Heights.  Thisis because the mixing of the convective cloud  element with the stratiform cloud  with a colder base,  can  result in abroad, or even  bi-modal, droplet size distribution, which is favorable for ice splintering (Mossop, 1978). It is notpossible, however, to quantify the relative contribution of each factor to the observed hydrometeor concentrationswithout a very  detailed case  by case  analysis, because the variation from  cloud  to cloud,  and even  within a cloud  is rather high.

Send me the videos from these flights, your ice and droplet concentrations and spectra, and I promise to help you understand what you did!  Better yet, give me your research aircraft for the month of January and we will find some ice, and some new findings commensurate with those of L929496.

4.4. Availability of supercooled cloud water

The supercooled liquid  water content of the clouds over the Mediterranean Sea and over the Golan Heights, atdifferent temperatures, is presented in Fig. 17. The water content was integrated over the binned CDP data and, ifnecessary, slightly adjusted to match the measured content of the Hot-wire probes. Fig. 17 is based on the samedataset as Figs. 14 and 16. Note that the abscissa in Fig. 17 is in the log-space due  to the large  possible variationin  LWC. At  the initial stages,  as  the clouds develop,  their tops   get cooler   and   the   LWC  values increase bothover  the Mediterranean Sea and  over  the Golan Heights. At − 4 °C, 25% of the  measurements that were taken over the Golan  Heights had  a LWC greater than 0.4  g m− 3, while over  the  Mediterranean Sea that number,  at  thesame temperature, was slightly smaller.

As the authors noted previously, they don’t know what happened to the LWC in the clouds at the upwind side of the Golan because it went over toward Syria.  That should be re-iterated here, lest the AR reader be misled by the F2015 claim that this is unambiguously potential water for seeding purposes.  That potential remains to be seen without more comprehensive measurements, such as ground measurements of ice crystal concentrations, habits, riming characteristics at the top of Mt. Hermon, which is often in the H-M temperature zone during precip events in Israel.

Mt. Hermon crystal data would make a stupendous paper of itself.  But could we trust the HUJ-CSG, with so much seeding baggage, to do it objectively?  I really don’t think so.  What a shame that a “senior” researcher, who is extremely familiar the output of the HUJ-CSG over several decades, feels this way.

Further up the LWC values over the Golan Heights started decreasing, while the LWC over the sea  continued toincrease as  the  cloud   tops developed further.

As mentioned in Sections 3.3 and 4.2, the sampling strategy over  the  Mediterranean Sea and  over  the Golan Heights was often  different because of the different typical cloud  structure/ dynamics as well as flight safetyrestrictions. While over the sea “hard” tops of deep convective clouds were more abundant and favored, over theGolan  Heights the maneuvering was more  restricted and  the  sampling covered the  area  more homogeneously.

Here and below, the authors divulge critical pieces of information about sampling that represents the highest form of objective, scientific writing for their readers!

Preferential sampling of developing cloud  tops  with relatively little history of mixing over  sea,  versus measuring mostly orographic layer  clouds over  the Golan  Heights,  can explain the  greater LWC values over  the sea  and the positive trend all the way up. More than half of the samples over the sea at  a  temperature around − 16  °C had  a  LWC greater than 1 g m− 3.

The quote above about 1 gm m-3 at -16°C concerns liquid water that would be very short-lived,  indeed, as I believe the authors know, or should know.    Would it last at that level even five minutes in a Langrangian sense?  Give me your research plane and we will see!

The  likely   explanation  for  the LWC “bump” only   over the Golan  Heights is the sampling of cloud  layers  withbases at  colder lower temperatures  and   hence reduced LWC. As Fig. 3 illustrates, the  clouds over  the Golan Heights tend to  have  a structure of layers (on the days that we chose to sample on) and  a more homogeneouscoverage of the area  would include sampling of those layer  clouds.  This explanation is supported by Fig. 14, asnew  high  cloud  layers that are separated from the clouds below, are expected not only to have  low values of LWC,but also small re (Fig. 14). The LWC in those elevated cloud  layers  would increase little with height due to the coldlow temperatures, but re might increase rapidly due to the low concentration of CCN and hence also cloud  droplets, even  in the undiluted parts of the clouds.

This doesn’t make any sense to this reader; “re might increase rapidly..”   Where?

Another possible contributor to the changing trend of LWC over   the   Golan   Heights  at  temperatures  below − 8  °C is the conversion of liquid  cloud  water into  ice  (which is not measured by the CDP or by the Hot-wires). Theconcentrations of the  hydrometeors (Fig. 16) are at maximum at that temperature and  that might not be justcoincidence — as discussed in Section 4.3. In order to determine the causes and the effects  of the observedrelations, as well  as the contributions of the  seeding operations versus the  natural processes, other methods arerequired.

Again, why spend so much on research targeting natural clouds when seeding is going on?  Its crazy.

So, within the scope of this study, it is practically impossible to quantify the relative impacts of the explanationsabove  to the observed different trend of LWC versus the temperature over the sea and over the Golan Heights without analyzing a larger dataset and  a more dedicated planning and  filtering.

Yes! Thank you, authors, for this candid assessment.  I would love to take part in those additional studies!  “Call me!”   Furthermore, having a senior researcher as a kind of “Resident Skeptic” would improve the credibility of future HUJ-CSG publications.

However, despite the reduction in LWC with altitude, and  regardless of its true explanation, there are still  non-negligible amounts of  super-cooled LWC over  the Golan   Heights.

The end result of the supercooled water they observed at the upwind side of the Golan is not known.  Caution is advised in what to make of this statement.

As far as  cloud seeding  is  concerned,  the relevant question is  the precipitation efficiency of  the orographiclayer  clouds.  Obviously, this type of cloud  is inexistent over sea.

Fig. 18  provides the probability distribution and  the cumulative distribution function of the  supercooled water content over  the  (upwind side of the) Golan  Heights at temperatures  colder lower than − 8 °C.

You can’t emphasize the sampling bias contained in Figure 18 enough; otherwise it will likely mislead the INWA or other organizations into funding cloud seeding with no real return, as we saw the HUJ-CSG caused the INWA to do in the past at great expense to the people of Israel.

While some of the water might have been converted to ice due  to the  seeding operations, the  remaining liquid  water might mark the  potential of additional precipitation enhancement.  It shows that 55% of the measurements in theclouds had less than 0.2 g m-3 of super-cooled water, but it means that 45% had more. 20% of the data had  morethan 0.5 and  ~ 4% even more than 1.0 g m-3 of liquid  water with a potential to freeze with silver-iodide.

This sentence is lacking the very nice qualifiers you incorporated in this piece at other points.  Were these questionable portions written by only one of the authors?  One wonders.  But, unless the writing is partitioned in a footnote, all of the writers are responsible for a paper’s content.

Since the flight pattern over the Golan Heights was  more or less fixed, this represents the  true areal  fractional coverage of these clouds during the flights there. Therefore, this represents significant amount of super-cooled cloud water and indicates that ice  nuclei may  still  be  a  limiting factor in  the conversion of LWC into ice and further toprecipitation. So there might be room for extending the seeding efforts that target the clouds over  the  Golan  Heights torealize more of their seeding potential.

  1. Summary and conclusions

A key  factor  that determines the seeding potential of the clouds is the quantity of super-cooled water in the clouds,  the time that the water droplets remain in the super-cooled region and  the temperatures at  which supercooled waterpersists.

Add this sentence after, “persists”:  “We were unable to do all the necessary maneuvers to establish these parameters.” ( It doesn’t mean you failed….)

More  super-cooled water, longer time and  colder lower temperatures,  all  lead   to  greater  seeding potential  as  there  is  a possibility to convert more of the super-cooled water into  ice and  precipitation.

After analyzing 27 research flights during four rainy seasons (2009–2013) we  see  that although the  naturalprocesses of converting  cloud   water  into   precipitation  is   often    quite efficient,

Yep.

there  are  still  occasions with good  potential for precipitation augmentation by glaciogenic cloud  seeding.

        Remains to be seen.  “Good” potential was not demonstrated in this paper.  There were too many unanswered questions.  This sentence appears to have been written for funders, not for those of us senior researchers who know the paper trail of the HUJ-CSG literature well.  One wonders how F2015, who wrote so eloquently about the drawbacks of this study, and the questions that remain, could have written this sentence?  Here the questioning and objectivity have disappeared.

One natural seeding process is  the  hygroscopic seeding by  the abundance of sea  salt aerosols in the boundarylayer  close  to the coast due  to the strong winds and  rough seas.  Another natural seeding process is called  the“seeder–feeder” mechanism,   where hydrometeors from   more mature  and   higher clouds fall through the clouds atlower levels and collect or rime their water content.

        In this scenario, there well might be an underlying, shallow orographic Stratocumulus layer that is present before the rainy/icy complex of Cbs arrive.  If precipitation is falling over mesoscale regions, downdrafts can be present that weaken of dissipate the lower Stratocu layer as the complex barges into the hill regions and the Golan.  This is a reviewer speculation; I just don’t think we have enough information to know what exactly happens, how much supercooled water there is when weakening Cb clusters/lines organized by upper troughs arrive in the northern mountains.   Observations at Mt. Hermon, to repeat, are critical in answering this question.

The results of this study have  been already applied for the design of the Israel-4 cloud seeding experiment.

        I find this statement sad, because this study/proposal was not reviewed properly, and those who assembled it have so much cloud seeding baggage, as is demonstrated in this review.  I feel sorry, too, for the Israeli people who paid millions based on prior faulty interpretations of cloud seeding results and seeding potential based on fictitious cloud descriptions.   The HUJ-CSG for too long has prospered on the backs of the Israeli people with their biased, self-serving presentations of clouds and seeding potential.

            Finally, why wasn’t I sent this manuscript in the first place?  One of the authors, DR, knows I am “above ground”, and I do not oppose seeding in proper circumstances.  I do know Israeli clouds pretty well….

This was done by  an  addition of  an  eastern seeding line  for  targeting the clouds developing over  the  Golan  Heights and  by positioning the ground generators accordingly. The main objective of the Israeli rain enhancementprogram is to increase the amount of water that reaches the Sea  of  Galilee,  therefore adding an eastern seedingline  contributes to  fulfilling  this objective in four ways: 1) The Golan Heights contribute most of the water to the Sea  of Galilee;  2)  The  clouds over  the Golan  Heights typically undergo less natural seeding by mature cloudsand sea spray;

There is quite a bit of conjecture in item 2.  This study didn’t quantify how much “less natural seeding by mature clouds” happens in the Golan.  Such a study would take several winters in this reviewer’s opinion, of combined satellite andsurface observations, and many more flights than in this study.   To repeat, such a study shouldn’t be done by the HUJ-CSG for the highest credibility.  They had their chances over so many years to get it right, and couldn’t do it.

Cloud tops are colder in extreme northern Israel and offshore region compared with those areas to the south (GN74; RH95) as noted.  Decreased cloud top temperatures lead to more ice and deeper clouds.  Presumably more Cbs, organized by troughs and by the Cypress low, would move onshore and into the Golan in most rainy day situations.  Whether the underlying orographic forcing would supply enough water for seeding purposes in the context of these mesoscale systems remains unknown.

 3) The clouds over  the Golan Heights occasionally have relatively high  concentrations of supercooled water attemperatures in which silver iodide can serve as efficient ice nuclei;

Add this qualifying sentence:  “Due to flight limitations, it is not known whether this liquid water persists long enough to be a viable seeding target.”

 4) There  is a greater seeding potential for the less convective clouds (King and  Ryan, 1997), such  as thoseclouds over  the Golan Heights.

Who knows?  Don’t count on it, Israel.  Be cautious.

A further indication of citation sloppiness, and a poor manuscript review of this article; “King and Ryan” should be Ryan and King (1997).

This whole article has degraded AR in my opinion.

            The Israel-4 randomized seeding experiment started in November 2013.  The expected duration of theexperiment is about 6 winters, during which the randomized seeding will be done in the  same consistent way, and  further accompanied by the cloud  physics measurements by aircraft and  satellites.

Acknowledgements

This study was funded by  the Israeli  water authority for supporting the rain enhancement project.

Very sad to read that this article, or some other version of it in a proposal, led to INWA to seed operationally or otherwise.     Doesn’t the INWA have any cloud expertise within it, or consultants to rely on?  It doesn’t seem like it.

Nevertheless, the INWA is to be admired and congratulated for having the wisdom to do a randomized experiment even if deemed premature, rather than just initiate another operational seeding project,  while asserting to its public, with little evidence, that rain is being increased.  It doesn’t happen in the US!

REFERENCES

Alpert, P., Halfon, N., and Levin, Z.. 2008:  Does air pollution really suppress precipitation in Israel? J. Appl. Meteor. and Climate, 47, 933-943

Altaratz, O., Levin, Z., Yair, Y., Ziv, B., 2003. Lightning Activity over Land and Sea on the  Eastern Coast of  theMediterranean.  Mon. Weather  Rev.  131, 2060–2070

American Meteorological Society, 1984:  Statement on planned and inadvertent weather modification. Bull. Amer. Meteor. Soc., 65, 1322.

Baumgardner, D., Jonssonc, H., Dawsona, W., O’Connor, D., Newtona, R., 2000.

The cloud, aerosol and precipitation spectrometer: a new instrument for cloud investigations. Atmos. Res.,  59,251–264.

Brier, G. W., and I. Enger, 1952: An analysis of the results of the 1951 cloud seeding operations in central Arizona.  Bull. Amer. Meteor. Soc., 23, 208-210.

Ben-Zvi, A., Rosenfeld, D., Givati, A., 2011 Comment on  “Reassessment of rain experiments and operations in Israel including synoptic considerations” by Zev   Levin,   Noam  Halfon and  Pinhas  Alpert  [Atmos. Res.   97   (2010)513–525]. Atmos. Res. 99, 590–592.

Blyth, A., and Latham, J., 1998:  Comments on cumulus glaciation papers of P. V. Hobbs and A. L. Rangno.  Quart. J. Roy. Meteorol. Soc., 124, 1007-1008.

Cunningham, R. M., 1957:  A discussion of generating cell observations with respect to the existence of freezing or sublimation nuclei.  In Artificial Stimulation of Rain, H. Weickmann, Ed.  Pergamon Press, NY.,  267-270.

Dennis, A. S., 1980:  Weather Modification by Cloud Seeding.  Academic Press, NY, 145.

Dennis, A. S., 1989: Editorial to the A. Gagin Memorial Issue of the J. Appl. Meteor.,  28, 1013.

Druyan, L. M., and Sant, Y., 1978: Objective 12 h forecasts using a single rawinsonde.  Bull. Amer. Meteor. Soc., 59, 1438-1441.

Field, P., Lawson, P., Brown, R. A., Lloyd, G., Westbrook, C., ,e D. Moiseev, D., Miltenberger, A., A. Nenes, A., Blyth, A.,  Choularton, T., Connolly. P., Buehl, J., Crosier, J., Cui, Z., Dearden, C., DeMott, P., Flossmann, A., Heymsfield, A., Huang, Y., Kalesse, H., KANJI, Z. A., Korolev, A., Kirschgaessner, A., Lasher-Trapp, S., T. Leisner, T., McFarquhar, G., , Phillips, V., , J. Stith, J., Sullivan, S., 2017:  Secondary Ice Production: Current State of the Science and Recommendations for the Future.  Amer. Meteorol. Soc.,  Monograph, 58, 7.01 – 7.20. DOI: 10.1175/AMSMONOGRAPHS-D-16-0014.1

Freud, E., Rosenfeld, D., 2012. Linear relation between convective cloud drop number concentration and depth forrain initiation. J. Geophys. Res.  117, D02207. http://dx.doi.org/10.1029/2011JD016457.

Freud,  E., Rosenfeld, D., Andreae,  M.O.,  Costa, A.A., Artaxo, P., 2008.  Robust relations between  CCN  and  the  vertical evolution of  cloud drop  size distribution in deep convective clouds. Atmos. Chem. Phys. 8, 1661–1675.

Freud, E., Rosenfeld, D., Kulkarni, J.R., 2011. Resolving both entrainment-mixing and number of activated CCN in deep convective clouds. Atmos. Chem. Phys. 11, 12887–12900. http://dx.doi.org/10.5194/acp-11-12887-2011.

Freud, E., Koussevitsky, H., Goren, T.,  and Rosenfeld, D., 2015: Cloud microphysical background for the Israeli-4 cloud seeding experiment, Atmos. Res., 158-159, 122-138. doi.org/10.1016/j.atmosres.2015.02.007

Gabriel, K. R., 1967: The Israeli artificial rainfall stimulation experiment: statistical evaluation for the period, 1961–1965.  Proceedings, Fifth Berkeley Symposium on Mathematical Statistics and Probability, Vol. 5, L. M. LeCam and J. Neyman, eds., University of California Press, 91–113

Gabriel, K.R., Rosenfeld, D., 1990. The second Israeli rainfall stimulation experiment:  Analysis of  precipitation onboth targets. J. Appl.  Meteorol. 29, 1055–1067.

Gagin, A., 1975: The ice phase in winter continental cumulus clouds.  J. Atmos. Sci., 32, 1604–1614.

Gagin, A, 1980:  The relationship between the depth of cumuliform clouds and their raindrop characteristics.  J. Res. Atmos., 14, 409-422.

Gagin, A, 1981:  The Israeli rainfall enhancement experiments.  A physical overview.  J. Wea. Modif., 13, 108-120.

Gagin, A, 1986: Evaluation of “static” and “dynamic” seeding concepts through analyses of Israeli II and FACE-2 experiments. In Precipitation Enhancement–A Scientific Challenge, Meteor. Monog., 21, No. 43, Amer. Meteor. Soc., 63-70.

Gagin, A., Neumann, J., 1974. Rain stimulation and cloud physics in Israel. In: Hess, W.N. (Ed.), Weather andClimate Modification. John Wiley and Sons, pp. 454–494

Gagin, A., and J. Neumann, 1976: The second Israeli cloud seeding experiment–the effect of seeding on varying cloud populations. Proc. II WMO Sci. Conf. Weather Modification, Boulder, WMO Geneva, 195-204.

Gagin, A., Neumann, J., 1981. The  second Israeli randomized  cloud seeding experiment: Evaluation of the results.J. Appl.  Meteorol. 20, 1301–1311.

Givati, A., Rosenfeld, D.,  2005. Separation between cloud-seeding and air- pollution effects.  J. Appl.  Meteorol. 44,1298–1314.

Givati, A., Rosenfeld, D., 2009. Comments on “Does air pollution really suppress

precipitation in Israel?”. J. Appl.  Meteorol. Climatol. 48, 1733–1750.

Givati, A., Steinberg, D., Binyamini, Y., Glick, N., Rosenfeld, D., Shamir, U., Ziv, B.,

  1. 2013. The Precipitation Enhancement Project: Israel-4 Experiment (טקיורפ רטמה תרבגה: לארשי יוסינ 4). The WaterAuthority, State of Israel, 55.

Goldreich,  Y.,  2003.   The  climate   of   Israel,  observations,   research  and applications.        Kluwer Academic/Plenum Publ,  New York, NY,  p. 298.

Halfon, N., Z. Levin, P. Alpert, 2009:  Temporal rainfall fluctuations in Israel and their possible link to urban and air pollution effects.  Environ, Res. Lett., 4, 12pp. doi:10.1088/1748-9326/4/2/025001

Hallett, J., and Mossop, S.C., 1974. Production of secondary ice particles during the riming process.  Nature 249, 26–28.

Hering, S.V., Stolzenburg, M.R., Quant, F.R., Oberreit, D.R., Keady, P.B., 2005. A laminar-flow, water-basedcondensation particle counter (WCPC). Aerosol Sci. Technol. 39, 659–672.

Herut, B., Starinsky, A., Katz,  A., Rosenfeld, D., 2000. Relationship between the conditions along a  transition zonebetween large deserts and Mediterranean climate, Israel. Atmos. Environ. 34, 1281–1292.

Hobbs, P. V.,  and Rangno, A. L., 1978: A reanalysis of the Skagit cloud seeding project.  J. Appl. Meteor., 17, 1661–1666.

Hobbs, P. V., and Rangno, A. L., 1985: Ice particle concentrations in clouds. J. Atmos. Sci., 36, 2523-2549.

Hobbs, P. V.,  and Rangno, A. L., 1998:  ‘Reply to “Comments by Alan M. Blyth and John Latham on ‘Cumulus glaciation papers by P. V. Hobbs and A. L. Rangno. Quart. J. Roy. Meteorol. Soc.,         124, 1009-1011.

Hobbs, P. V., Lyons, J. H., Locatelli, J. D., Biswas, K. R., Radke, L. F., Weiss, R. W., Sr., and Rangno, A. L., 1981:  Radar detection of cloud-seeding effects.  Science, 213, 1250-1252.

Kennedy, D., 2003:  Research fraud and public policy.  Science, 300, 393.

Kennedy, D., 2004:  The old file drawer problem.  Science, 305, 451.

Kerr, R. A., 1982: Cloud seeding: one success in 35 years.  Science, 217, 519–522.

Kessler, A., A. Cohen, D. Sharon, 2002:  Interim analysis of the cloud seeding in Northern Israel. A report submitted to the Israel Hydrology Institute and the Israel Water Management of the Ministry of Infrastructure, In Hebrew.

Kessler, A., Cohen, A., Sharon, D., 2006:  Analysis of the cloud seeding in Northern Israel. A report submitted to the Israel Hydrology Institute and the Israel Water Management of the Ministry of Infrastructure, In Hebrew. 117pp.

Lahav, R., Rosenfeld, D., 2000. Microphysics characterization of the Israeli clouds from aircraft and satellites.Proceedings of the 13th International Conference on Clouds and Precipitation, pp. 732–735.

Lance,  S., Nenes, A., Medina, J., Smith, J.N., 2006.  Mapping the operation of the DMT continuous flow CCN counter.  Aerosol Sci. Technol. 40,  242–254.

Lance,  S., Brock,  C.A., Rogers, D., Gordon, J.A., 2010. Water droplet calibration of the Cloud Droplet Probe (CDP) and in-flight performance in liquid, ice and mixed-phase clouds during ARCPAC.  Atmos. Meas. Tech.  3, 1683–1706.

Lensky,  I.M., Rosenfeld, D., 2006.  The  time-space exchangeability of  satellite retrieved relations between cloud toptemperature and particle effective radius. Atmos. Chem. Phys. 6, 2887–2894.

Levi, Y., Rosenfeld, D., 1996. Ice  nuclei,  raiINWAter chemical composition, and static cloud seeding effects in Israel.J. Appl.  Meteorol. 35, 1494–1501.

Levin, Z., 1992: The role of large aerosols in the precipitation of the eastern Mediterranean. Paper presented at the Workshop on Cloud Microphysics and Applications to Global Change, Toronto. (Available from Dept. Atmos. Sci., University of Tel Aviv).

Levin, Z.,  1994:  The effects of aerosol composition on the development of rain in the eastern Mediterranean.  WMO Workshop on Cloud Microstructure and Applications to Global Change, Toronto, Ontario, Canada. World Meteor. Org., 115-120.

Levin, Z., Ganor, E., Gladstein, V., 1996. The effects of desert particles coated with sulfate on rain formation in theeastern Mediterranean. J. Appl.  Meteorol. 35, 1511–1523.

Levin, Z., Kirchak, S. O., and Reisen, T., 1997: Numerical simulation of dispersal of inert seeding material in Israel using a three-dimensional mesoscale model.  J. Appl. Meteor., 36, 474-484.

Levin,  Z., Halfon, N., Alpert, P., 2010. Reassessment of rain enhancement experiments and operations in  Israelincluding synoptic considerations. Atmos. Res. 97, 513–525.

Levin, Z., N. Halfon, and P. Alpert, 2011:  Reply to comments by Ben-Zvi, A., D. Rosenfeld and A. Givati on the paper: Levin, Z., N. Halfon and P. Alpert, “Reassessment of rain experiments and operations in Israel including synoptic considerations.” .  Atmos. Res., 98, 593-596.

List, R., Gabriel, K. R., Silverman, B. A., Levin, Z., Karacostas, T., 1999: The Rain Enhancement Experiment in Puglia, Italy: Statistical Evaluation.  J. Appl. Meteorol., 38, 281-289.

Marshak, A., Platnick, S., Várnai, T., Wen, G., Cahalan, R.F., 2006. Impact of three‐

dimensional radiative effects on satellite retrievals of cloud droplet sizes. J. Geophys. Res. 111, 1984–2012.

Mason, B. J., 1980:  A review of three long-term cloud-seeding experiments.  Meteor. Mag., 109, 335-344.

Mason, B. J.,, 1982:  Personal Reflections on 35 Years of Cloud Seeding.  Contemp. Phys., 23, 311-327.

Mielke, P. W., Jr., 1979: Comment on field experimentation in weather modification. J. Amer. Statist. Assoc., 74, 87-88.

Mossop, S. C., 1970: Concentrations of ice crystals in clouds. Bull. Amer. Meteor. Soc., 51, 474-479.

Mossop, S.C., 1978. The influence of drop size  distribution on the production of secondary ice  particles during graupelgrowth. Q. J. R. Meteorol. Soc. 104, 323–330.

Mossop, S. C., 1985: The origin and concentration of ice crystals in clouds. Bull. Amer. Meteor. Soc., 66, 264-273.

Mossop, S.C., Hallett, J., Hallet, J., and Mossop, S. C., 1974. Ice crystal concentration in cumulus clouds: Influence ofthe drop spectrum. Science 186, 632–634.

National Research Council-National Academy of Sciences, 1973: Weather Modification: Progress and Problems. T. F. Malone, ed., 258 pp. (Available from the National Research Council, Washington, D. C.)

Nirel, R.,, and D. Rosenfeld, 1994: The third Israeli rain enhancement experiment-An intermediate analysis. Proc. Sixth WMO Scientific Conf. on Weather Modification, Paestum, Italy, World Meteor. Org., 569-572.

Neumann, J., 1951:  Land breezes and nocturnal thunderstorms.  J. Meteor., 8, 60-67.

Neumann, J., Gabriel, K. R., and Gagin, A., 1967: Cloud seeding and cloud physics in Israel:  results and problems.  Proc. Intern. Conf. on Water for Peace.  Water for Peace, Vol. 2, 375-388.

Pitter, R. L., and H. R. Pruppacher,1973: A wind tunnel investigation of freezing of small water drops falling at terminal velocity in air. Quart.  J. Roy. Met. Soc., 99, 540-550.

Rangno, A. L., 1979.  A reanalysis of the Wolf Creek Pass cloud seeding experiment.   J. Appl. Meteor., 18, 579–605.

Rangno, A. L., 1988: Rain from clouds with tops warmer than -10 C in Israel. Quart J. Roy. Meteorol. Soc., 114, 495-513.

Rangno, A. L., and Hobbs, P.V.,. 1991: Ice particle concentrations and precipitation development in small polar maritime cumuliform clouds. Quart. J. Roy. Met. Soc., 117, 207-241.

Rangno, A. L., and Hobbs, P.V., 1993: Further analyses of the Climax cloud-seeding experiments.  J. Appl. Meteor., 32, 1837-1847.

Rangno, A.L., Robbs Hobbs, P.V., 1995. A new look at the Israeli cloud seeding experiments. J. Appl. Meteorol. 34,1169–1193.

Rangno, A. L., and Hobbs, P. V., 1997: Comprehensive Reply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp.  (Available at http://carg.atmos.washington.edu/)

Rauber, R. M., and Tokay, A.,  1991:  An explanation of supercooled water at the top of cold clouds.  J. Atmos. Sci., 48, 1005-1023.

Rosenfeld, D., 1980:  Characteristics of Rain Cloud Systems in Israel Derived from Radar and Satellite Images.  M. S. Thesis, The Hebrew University of Jerusalem, 129pp. (Available from the Department of Meteorology, Hebrew University of Jerusalem, Jerusalem, Israel) in Hebrew, no translation yet.

Rosenfeld, D., 1997: Comment on “A new look at the Israeli Cloud Seeding Experiments”, J. Appl. Meteor., 36, 260-271.

Rosenfeld, D., 1998.  The third Israeli randomized cloud seeding experiment in the south: evaluation of the results and review of all three experiments. Preprints, 14th Conf. on Planned and Inadvertent Wea. Modif., Everett, Amer. Meteor. Soc. 565-568.

Rosenfeld,  D.,  Farbstein,  H.,  1992.  Possible  influence  of   desert  dust  on seedability of clouds in Israel. J. Appl. Meteorol. 31, 722–731.

Rosenfeld, D., Givati, A., 2005. Evidence of orographic precipitation suppression by  air  pollution induced aerosols in the western U.S.  J. Appl.  Meteorol. Climatol. 45, 893–911.

Rosenfeld, D., Gutman, G., 1994. Retrieving microphysical properties near the tops of  potential rain clouds by multispectral  analysis of  AVHRR data. Atmos. Res. 34, 259–283.

Rosenfeld, D., Lensky, I.M., 1998. Satellite-based insights into precipitation formation processes in  continental andmaritime convective clouds. Bull. Am. Meteorol. Soc. 79, 2457–2476.

Rosenfeld, D., Nirel, R., 1996. Seeding effectiveness — the interaction of desert

dust and the southern margins of  rain cloud systems in  Israel. J. Appl. Meteorol. 35, 1502–1510.

Rosenfeld, D., Rudich, Y. and Lahav, R., 2001: Desert dust suppressing precipitation:  a possible desertification feedback loop. PNAS, 98, 5975-5980.   doi/ 10.1073/ pnas.101122798

Rosenfeld, D., Liu, G., Yu, X., Zhu, Y., Dai, J., Xu, X., Yue, Z., 2014. High resolution (375 m) cloud microstructure asseen from the NPP/VIIRS Satellite imager. Atmos.  Chem.  Phys.  14,   2479–2496. http://dx.doi.org/10.5194/acp-14-2479-2014.

Ryan, B.F, King,  W.D., 1997. A Critical Review of the Australian Experience in

Cloud Seeding. Bull. Am. Meteorol. Soc. 78, 239–254.

Schaefer, V. A., 1946: The production of ice crystals in a cloud of supercooled water droplets.  Science, 104, 457-459.

Schemenauer, R. S., and Isaac, G. A., 1984:  The importance of cloud top lifetime in the description of natural cloud characteristics.  J. Climate Appl. Meteor., 23, 267-279.

Schultz, D., 2015.  Eloquent Science.  American Meteorol. Soc., 412pp.

Sharon, D., A. Kessler, A. Cohen, and E. Doveh, 2008:  The history and recent revision of Israel’s cloud seeding program.  Isr. J. Earth Sci., 57, 65-69.

Silverman, B. A., 2001. A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement. Bull. Am. Meteor. Soc., 82, 903-924.

Tan,  W.,  Yin,  Y., Chen, K., Chen, J., 2010.  An  experimental study of  aerosol particles using PCASP-X2  andWPS™.  Geoscience and Remote  Sensing (IITA-GRS),   2010 Second IITA International  Conference on  vol.  1.  IEEE, pp. 586–589.

Thom, H. C. S., 1957: An evaluation of a series of orographic cloud seeding operations.  Final Report of the Advisory Committee on Weather Control, Vol. II, Government Printing Office, 25-49.

Tukey, . Brillinger, D. R.,  and  Jones, L. V.,  1978b: Report of the Statistical Task Force to the Weather Modification Advisory Board, Vol. II.  U. S. Government Printing Office,  pE-3.

Vali, G., 1971: Quantitative evaluation of experimental results on the heterogeneous freezing nucleation of supercooled liquids. J. Atmos. Sci., 28, 402-409.

Woodcock, A. H., 1953:  Salt nuclei in marine air as a function of altitude and wind force.  J. Meteor., 10, 362-371.

Woodcock, A. H., Duce, R. A., and Moyers, J. L., 1971. Salt and raindrops in Hawaii.  J. Atmos. Sci., 28. 1252-1257.

Woodley, W. L., and D. Rosenfeld, 2002: Comments on “A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement.” Bull. Amer.Meteor. Soc., 83, 739–740.

World Meteorological Society, 1992: Statement on the Status of Weather Modification.

Wurtele, Z. S., 1971: Analysis of the Israeli cloud seeding experiment by means of concomitant meteorological variables. J. Appl. Meteor., 10, 1185-1192.

Young, K., 1993: Microphysical Processes in Clouds.  Oxford University Press, pp427.

Reviewer “baggage” module: bio, a priori convictions, and a little about the reviewer’s 1986 11-week cloud investigation in Israel

Background:  Chased storms, cloud photographer.

I have worked on both sides of the seeding fence, having participated in operational seeding projects in South Dakota twice, India, Washington State, and in the Sierras of California.  I was a forecaster for the Colorado River Basin Pilot Project (CRBPP), a large, multi-million dollar advanced randomized cloud seeding experiment in Colorado from 1970-1975.  Beginning in 1976,   I worked in airborne studies of clouds and the origin of ice in clouds in the University of Washington’s Cloud and Aerosol Research Group for the 28 years.  I was a “flight scientist” for NCAR during the 2006-07 winter during their Saudi Arabia cloud seeding potential study.

A priori convictions concerning cloud seeding:

Cloud seeding works in limited situations, principally via the seeding of non-precipitating, supercooled clouds (e.g. Hobbs et al 1981, an experiment suggested by the reviewer; “wonderful experimentation”).  Whether there is economically viable return from such seeding, I don’t know.  I begin every talk I give with, “Cloud seeding works!”, and show a couple of examples of effects of seeding (those resembling Schaefer’s dry ice seeding experiments in 1947)

Motivation for this review:

The review of F2015  was motivated by the absence of post-publication comments on F2015 over the past three years.   And it comes from the emotional reaction after I read it recently for the first time: “Someone has to do something about this!”, the very same feeling I had before I went to Israel in 1986 as a skeptic of ripe-for-seeding cloud claims emanating from the HUJ-CSG.  (That same emotional reaction first happened during the CRBPP which led to a “career” of own-time scrutiny of suspect cloud seeding publications (e.g., Rangno 1979).

The 1986 Israel cloud investigation

 At the end of 1985 I resigned my job with the Cloud and Aerosol Research Group over issues of credit, and went to Israel in early January 1986 to investigate their clouds[1].  I was skeptical that those many descriptions of them in the peer-reviewed literature and in conference presentations were correct.   I did not go to Israel without “baggage,” but had done a considerable amount of “homework.”

A note-sized paper asserting that the Israeli clouds were not as they were being described in journal articles and elsewhere, had been rejected in 1983 (B. Silverman, Ed., J. Appl. Meteor.,  personal communication).

That rejection was instrumental in my 1986 trip.

The several reviewers’ negative takes on my 1983 “Comment”, including that of the leader of the HUJ-CSG at that time who lectured me in person at the 1984 Park City weather mod conference about how wrong I was about his clouds,  had no effect whatsoever about what I thought about them.  He had also been a reviewer of that “Comment.”

To repeat, I had done my homework, plotted numerous soundings when rain was falling at launch time or within the hour at Beirut and Bet Dagan, and had scrutinized all of the HUJ-CSG cloud reports in great detail.  Even the daily rainfall in the Israel Meteorological Service (IMS) monthly weather reports indicated something was terribly wrong with clouds that were being described as highly inefficient rain producers.

While in Israel in 1986, that same leader of the HUJ-CSG prevented this writer from visiting the HUJ-CSG-controlled radars to evaluate cloud top heights during rain spells.  I wanted to see what top heights were, and indirectly via IMS rawinsonde soundings, obtain top temperatures.  (The HUJ-CSG leader, “AG,” did allow a brief “show and tell” visit to his Ben Gurion AP radar in February as a storm approached[2] as part of our third and last meeting in February 1986.)

To disallow a bona fide worker in the field of cloud microstructure and weather modification access to data/measurements to test claims about the Israeli clouds was demonstrable scientific misconduct IMO[3].   The clouds of Israel can only be studied in Israel, and as scientists we must be open to cross-checking of our results; having our findings tested.  It’s what we do in science (e.g., see Blyth and Latham’s 1998 criticisms of the glaciation papers of Hobbs and Rangno and our Reply (Hobbs and Rangno 1998) as a great example of open criticism).

But this was not what the leader of the Israeli experiments understood about science.  If he was deluded about his clouds, or was correct about them, I would have been welcomed, I thought.  If he had “contrary knowledge”, I would be blocked.  Q. E. D.

My findings (R88), in lieu of radar data, were based on Israel Meteorological Service’s (IMS) four-times-a-day rawinsondes, and were published in 1988.  They strongly suggested that there was a serious problem with the HUJ-CSG’s ultra “ripe-for-seeding” cloud descriptions.  Rosenfeld and Farbstein (1992) within the HUJ-CSG, belatedly discovered that “dust-haze” when present, apparently produced efficiently raining clouds in Israel, findings that supported R88.   Dust-haze has been around for quite awhile in Israel.

Later independent aircraft reports by Tel Aviv University (Levin 1992, 1994, Levin et al. 1996, hereafter L929496) also supported R88 and further exposed the faults in the HUJ-CSG cloud descriptions.

Today, and at last in F2015, the HUJ-CSG finally acknowledges, implicitly, why the leader of the Israeli experiments refused this visitor access to radars in 1986:   the high precipitating efficiency of Israeli clouds was going to be obvious in radar cloud top imagery.[4]  F2015 offers additional confirmation of those long ago findings in R88.  Lahav and Rosenfeld (2000), and Rosenfeld et al. 2001 had also found unsuitable clouds for seeding, but did not state that as explicitly as did F2015, or only alluded to “some clouds.”

Too, the high precipitation efficiency of Israeli clouds, too, is not limited to “dust-haze”; it never was.  The belief that the Rosenfeld and Farbstein (1992) attribution of “divergent seeding effects” to dust-haze was unreliable was the “acorn” of conviction that led to the “oak” of RH95.[5]

Rather than “dust-haze, that high efficiency is due relatively low droplet concentrations in Mediterranean clouds moving into Israel.    Larger droplets in clouds accelerate the formation of precipitation via several processes.

End of “baggage” module.

[1] Done on “own time, own dime”; not on grant monies.  I went to Israel in 1986 after I became convinced that the cloud reports by the HUJ-CSG were in substantial error and that the people of Israel were likely paying for the seeding of unsuitable clouds: “Someone has to do something about this!”  It was a “do-gooder” thought, and felt I COULD do something about it due to my background in airborne studies in the Cloud and Aerosol Research Group at the U of Washington, as a weather forecaster, as a storm chaser, and as a cloud photographer.  I spent 11 weeks in Israel watching the clouds and storms and working within the IMS.  I lived off my savings ($$$$) the rest of 1986 after I left Israel while preparing the manuscript that became R88.  It was submitted to the QJ in January 1987.  “Quasi-altruistic”?  Yep. I wanted to also demonstrate that I was the BEST at “outing” bogus cloud seeding work that none of my gullible peers suspected, to be completely candid.  Yes, it was a little megalomaniacal…

[2]Marked by a mid-level overcast of Altostratus and some lower Altocumulus with dust.

[3] After being asked to leave the offices of the HUJ-CSJ and not come back at the end of my 2nd meeting with AG in Janaury, I wrote to several scientists around the world about that event. Those I wrote to were: P. V. Hobbs and Lawrence F.  Radke, University of Washington; Gabor Vali, University of Wyoming; Roscoe Braham, Jr., North Carolina State University; and S. C. Mossop, CSIRO, Australia.

[4] Those within the HUJ-SU had about ten years of viewing and recording storms on their Enterprise 5-cm radar by the time of my  1986 visit.  Was no one “minding the store”?

[5] Also done on “own time, own dime”; not on grant monies.  Crackpot alert?

[1] As experienced in this writer’s 11-week stay in 1986, events in which embedded, much taller clouds sprang forth as the upper trough approached.

[1]Not cited by the HUJ-CSU in this paper. We expect studies that offer counter views to F2015 findings not to be cited by them at this point.  Perhaps they are taught that at the HUJ?  HUJ, are you listening?

[2] The reviewer believes that it is critical that the INWA or other organization certify that the list of random decisions provided prior to each season for Israeli 2 by statistician Ehud Shimbursky are, in fact, the ones that were used in Israeli 2.  This reviewer is doubtful, to add yet another layer of darkness to this analysis.  It’s just too tempting for those in the cloud seeding realm to say that, “Yes, we seeded that heavy rainstorm.”

[3]The authors omit the indication of the remarkable biased random draw of Israeli 2 experiment in which the rain in the south target was “statistically significant” in terms of standard error from average amounts on rain days (Gabriel and Rosenfeld 1990).

[4] Also from Gabriel and Rosenfeld (1990):  “The easiest explanation is to ascribe everything to chance, and accept H00 (the null hypothesis) . But the majority of the analyses run counter to this simplistic summary. Most of the evidence favors a positive effect of seeding in the north, and there is more evidence for a negative effect in the south than for a zero effect.”  This interpretation no longer holds water.

[5] The random draw for Israeli 2 was much different than for Israeli 1.  In Israeli 1 (1961-1965 daily randomization period), there were few consecutive draws of the same sign (13%) of the total of draws (Gabriel 1967, Table II).  In Israeli 2, consecutive draws of the SAME sign predominated (58%).  The list of random days for Israeli 2 was provided to Peter Hobbs in 1983 by A. Gagin.  Further investigation will likely find that this is the root cause of the lopsided draw in Israeli 2.

[6] From the Weather Modification Association’s Code of Ethics:  “Falsification: changing or not reporting appropriate data or results (i.e. the purposeful omission of conflicting data or information with the intent to falsify results; deceptive selective reporting). Isn’t that the purpose of “one-sided” citing as well?   Of note:  The American Meteorological Society does not have a Code of Ethics, but rather “suggestions” or “guidelines” for professional conduct.

[7] See the discussion of operational seeding below for details.

[8] Sound familiar? We repeat the WMA Code point for your consideration:  falsification: changing or not reporting appropriate data or results(i.e. the purposeful omission of conflicting data or information with the intent to falsify results; deceptive selective reporting).

[9] We can only imagine how these results would have been spun around if this had been a suggestion of an 8% increase in rain.  How many statistical tests would be tried?  Would the authors really just say, “inconclusive”?

[10] Sharon et al (2008), and the reports that it was distilled from (Kessler et al. 2002, 2006), are nowhere to be seen in the HUJ-SU authors’ paper.  Should we be surprised at this point?  I don’t think so.  This is not science as we know it.  HUJ, are you listening?

[11] While the original INWA program was terminated, some additional experimental-operational seeding did carry on, beginning with the 2007-08 rain season; it was terminated again in 2013 (according to F2015).  The reviewer does not yet know the details to the “supplemental” seeding following the termination in 2007.

[12] Alpert et al 2008 and Halfon et al 2009, and the exchange between Givati and Rosenfeld, also go uncited, strengthening a pattern of deception by the HUJ-SU; such actions by the authors that can no longer be attributed to oversights, but are meant to keep the ARreaders in the dark about the quality of the HUJ-CSG research.

[13] “Cast of thousands!” (except me..)

[1] Retiree, Cloud and Aerosol Research Group, Atmos. Sci. Dept., University of Washington, Seattle, 1976-2006.

[2] I dedicate this review to Jerzy Neyman, whom I greatly admired for his careful and voluminous criticisms of papers in the cloud seeding arena; to K. Ruben Gabriel, who was able to “stay above the fray” as a careful and objective statistician for the Israeli experiments, and lastly to Karl Rosner, Mekoroth’s Chief Meteorologist for Israeli 1 and 2, for his ability to remain objective within the “halls of seeding.”

[3] The great Nobel Laureate, Irving Langmuir, comes to mind, who once bitten by AgI, believed that any rainfall event could be explained by cloud seeding had there been any, no matter how large or far away from the release the event was.

[4] The above provocative conclusion comes from someone who has followed the HUJ-CSG reports over the past 35 years or so; is it me or them?

 

[5] The reviewer is not and has never been a faculty member at a university and therefore can raise such an issue with impunity unlike those with faculty status due to the “live and let live” de facto rules of the “faculty club.”

[6] This was the last mention of a numerical result of seeding in the south target of Israeli 2.

[7] The several IMS forecasters I spoke with when I worked within the Israel Meteorological Service (IMS) in 1986 were well aware of the “efficiency” that Israeli clouds exhibited.  One stated, “We get good rains out of clouds with tops at -10°C.”

 

[8] It had to be done by an outsider.

[9] Width (and implicitly, cloud top lifetime) has a direct bearing on the production of precipitation (e.g., Schemenaur and Isaac 1984; Rangno and Hobbs 1991.

[10]Whom also goes uncited (strangely) since one of the authors of F2015 (DR) commented on his BAMS cloud seeding review.  Small-mindedness here as well?  Or is it the desire by the authors to hide alternative views from their funders and journal readers?

Cloud Seeding and the Journal Barriers to Faulty Claims: Closing the Gaps

This manuscript had a close call in being accepted into the American Meteorological Society’s  Bull. Amer. Meteor. Soc. in 1998-1999.  The key reviewer that I had to satisfy (according to journal Editor  I. Abrams)  insisted that I make it clear that the cloud seeding experimenters in Colorado  and Israel did the “best they could with the tools available at that time”, paraphrasing here.

I couldn’t do it.

I had personal experience with the leaders of both those benchmark experiments; one was intransigent regarding new facts that upset a key claim he repeatedly made about the height of cloud tops in the Rockies during storms, and the other leader denied me access  to his radar to observe cloud top heights (and thus obtain temperatures).  I went to Israel suspecting that his many papers on the clouds of Israel were in major error.  (They were later proved to be in major error  on several occasions over the following 20 years.)

So, how could I agree with the key, “Reviewer B” stating that those experimenters did the best they could?  I might have “got in” by doing that.  Both cloud seeding leaders caused their respective country’s millions of dollars in wasted cloud seeding efforts.

An updated  “Gaps” manuscript was rejected a second time (!) in 2017 or so by the editor of the weather modification/cloud seeding issue of “Advances in Meteorology”, L. Xue, as “not the kind of paper we were looking for.”  Perhaps, though, it’s the kind of article YOU were looking for:

2017 Gaps-revised following comment