CHAPTER 4: THE TRIP TO ISRAEL TO SEE THE “RIPE FOR CLOUD SEEDING” CLOUDS

The trip to Israel

My self-funded trip to Israel was one of 11 weeks, from January 4th  through March 11th, 1986.  I loved my time in Israel and would go back in a heartbeat any winter to see those beautiful Cumulus and Cumulonimbus clouds rolling in off the Mediterranean again!

Following my return and for the rest of 1986 I lived off my savings in Seattle to write up an analysis and draft of what I had found.  Despite my resignation, Prof. Hobbs and I retained a civil relationship as I also finished grant work that I said would before resigning (which ended up being Rangno and Hobbs 1988, Atmos. Res., “Criteria for the Onset of Significant Ice Concentrations in Cumulus Clouds.” In this short 1988 paper, it was noted that the reports from Israel concerning the onset of ice in clouds was sharply at odds with similar clouds.  I discussed why that might have been in the paper.

Prof. Hobbs also agreed to look over my drafts and figures of the Israeli cloud investigation as I brought them in to the University of Washington from time to time.  Being who he was, Prof. Hobbs greeted me when I first dropped by the University of Washington upon my return from Israel with, “I doubt you’ll get a paper out of your trip.”  However, I knew exactly what I had to do to pass journal muster because of the rejection of that 1983 paper.  It was also evident that no American Meteorological Society journal was likely to accept a paper like the one I was putting together;  too many potential reviewers had heard at conference or read in journal articles on too many occasions how Prof. Gagin had described Israel’s hard to rain natural clouds.

That I got any Israeli data at all to take home and analyze was to the credit and magnanimous view of my outside cloud inquiry by the Israel Meteorological Service (IMS), Director, Y. L. Tokatly, who gave me pretty much a free reign to examine historical balloon soundings and synoptic maps within their Climate Division.  The Climate Division was headed by Sara Rubin, who was also friendly and extremely helpful.  I was even given a little desk space in the climate division!  I went there every day that there wasn’t a storm to experience, clouds to assess with this experienced eyeball and photograph while traveling all over central and northern Israel on their stupendous bus system.  I had also crated my bicycle to Israel for local travel.

Here is the IMS Headquarters building I worked in and the little desk space they gave me, two of the several officemates I had, and a shot of the IMS map and briefing room.

Zohar Moar (?) working next to my little desk space in the Climate Division office of the IMS.

Ronit Ben-Sara and Geulah Siles in the climate division office.

Forecaster Uri Batz in the IMS map room.

Below these is a list of the bus rides I took on ONE storm day, always sitting behind the driver and looking out the front window, recording drop sizes and nature of the rain  on  the  front  window::

In some interesting cases, such as in the hill region and the Golan Heights, I would get out and walk around in the wind and clouds, the latter often topping a hill region such as Jerusalem.   I had my heaviest clothing, but it really wasn’t enough to keep me warm, and I had no gloves. Temperatures during storms were usually in the low 40s in Jerusalem with winds of 20-30 mph and passing showers.  Once, I could not pull the shutter lever on my Rolliecord film camera to take a cloud photo my fingers were so cold.

This weather, too, really put an edge on those Bible stories.  I could not imagine how miserable it really was for people living here in the winters.  It even snows in Jerusalem from time to time as I saw myself in a January 1986 storm pocked with thunder.   I listened to the IMS weather briefings most mornings, too.  I was in heaven.

First Impressions

What was particularly interesting to me was that I encountered more skepticism about Israeli cloud seeding efforts in the IMS than there seemed to be in the entire world outside of it!

My first meeting with Prof. Gagin:   January 10, 1986

It was an extremely cordial meeting in his office at the Rivat Gam branch of the Hebrew University of Jerusalem at the end of a dry week in Israel.  That was followed by a family dinner at his residence where he regaled me with so many interesting stories.  I really thought at that time that he didn’t mind my intrusion into his cloud seeding world, and I began to feel some guilt about it since he was so nice to me!  But I had to persevere in my “task” I thought.

Prof. Gagin took this photo atop the HUJ satellite campus at Rivat Gam during that first meeting. He would not allow me to take his photo.  I also suggested at this time that if I “found something” that perhaps we could co-author a paper.  He deferred.

Not too surprisingly, all the weather forecasters I spoke with in the Israel Meteorological Service in 1986 were well aware that clouds much shallower than Prof. Gagin was describing as seeding targets, that is, those with tops >-10°C rained.  It must have seemed bizarre to them that I had come 7,000 miles to document something they deemed so ordinary!

But where were Tel Aviv University atmospheric scientists in in these matters?  Think how embarrassing it might be to all Israeli scientists to think that a minor foreign science worker had  traveled thousands of miles to inform them about the true nature of their own clouds as they were described in the peer-reviewed literature!

You may have guessed the possible answer to this puzzle about the lack of involvement of other scientists in questioning or overturning Prof. Gagin’s cloud reports.

It turned out that considerable funding from cloud seeding operatives in Israel went to Tel Aviv University (Z. Levin, 1986, private conversation).  He simply could not openly help me, he stated, in our one and only meeting.   He also had trouble believing at that time that my cloud assessment (ice particles onset in Israeli clouds with tops between -5°C and -8°C, and that concentrations of “50-200” per liter were present by the time cloud tops reached -12°C, was correct.  I wrote this same assessment following my 2nd meeting with Prof. Gagin to Professors Roscoe R. Braham, Jr., at North Carolina State University, Gabor Vali, University of Wyoming, Peter V. Hobbs and  Lawrence F. Radke at the University of Washington, and to Dr. S. C. Mossop (of the Hallett-Mossop riming and splintering process).  Why I wrote to them will become clear in the next segment.

January 19, 1986:  My second meeting  with Prof. Gagin

There had been several shower days in Israel when Prof. Gagin and I met for the second time.  He asked me at the very beginning, after handing me a cup of coffee,  “What have you found?”

I unloaded a boatload of findings contrary to his cloud reports.  Suffice it to say, our meeting did not go well after that.  In a sense, I was Professor Gagin’s nightmare; an under-credentialed worker coming to “his house” to expose faulty cloud reports.  But, with his radars and aircraft, how could he possibly not have known that his reports were faulty?

I had also felt true drizzle falling in Jerusalem in the early morning hours during the very first storm.  Drizzle tiny (<500 um in diameter) drops that are close together was something that was not supposed to occur in Israel due to the polluted nature of the clouds reported by Prof. Gagin.   I certainly did not expect to see it, and when I stuck my hand out of my apartment window, I yelled, “drizzle?” to no one in particular.

Then, when I came down from Jerusalem on a bus that morning to the coastal plain, I was amazed by shallow, glaciating clouds (modest Cumulonimbus clouds) rolling in from the Mediterranean Sea.  Namely, in less than three hours of the first storm, I had seen all I needed to know that Prof. Gagin’s clouds reports had described non-existent clouds.

In this 2nd meeting, I had brought with me an IMS sounding from Bet Dagan when rain was falling lightly throughout the hill region of Israel that had a cloud top, marked by a sharp inversion and strong drying,  at -5°C.  Professor Gagin was non-plussed by the sounding, stating that balloon soundings are unreliable for the purpose of assessing cloud top temperatures.

Prof. Gagin Had Heard Enough.

He informed me how offended he was by my visit to check his cloud reports.  He asked me, “Who do you think you are, the Messiah, come to expose the liars?” He immediately then asked, “Did Hobbs send you?”

Peter Hobbs had not sent me5! !

I was reeling at that point in my meeting with Prof. Gagin, almost speechless even though I knew something like this, being bawled out,  might happen.   However, I did cough up an admonition: “Don’t be like Lew Grant,” referring to Grant’s stubbornness in accepting new information.  Prof. Gagin replied, “I don’t appreciate the comparison.”  This is the first time I have mentioned this quote.  Prof. Grant deemed Abe Gagin a good friend and wrote a testimonial on his behalf when Prof. Gagin died.  I would be willing to bet that Prof. Gagin later deeply regretted uttering that about Grant.

Before many more words were spoken, Prof. Gagin was escorting me out of his office and telling me not to come back; “Do your own thing,” he said.  I went back to my apartment and wandered down King David boulevard in Jerusalem in kind of a haze.

For me, to “do your own thing” was continuing to gather historical data at the IMS on fair weather days and travel around eye-balling and photographing clouds and rain on storm days.  I decided I needed to alert my former colleagues at the University of Washington and other scientists in this field about what had happened and what my so-called, “findings” were.  I wrote to five leading scientists of the day, Prof. Peter V. Hobbs and Prof. Larry Radke at the University of Washington, the leaders of my former group, to Professor Roscoe R. Braham, Jr., at North Carolina State University, Professor Gabor Vali, at the University of Wyoming, and to Dr. S. C. Mossop at the Commonwealth Science and Industrial Organization in Australia.  All wrote back except Hobbs and Radke who were on a field project in North Carolina.

All that replied supported what I was doing.  Vali described my investigation as “spectacular,” and Mossop stated that I was a “genius for discovering sometimes unwelcome results.”  Mossop was alluding also to my discovery of that an aircraft can create ice in clouds at temperatures around -10°C (Rangno and Hobbs 1983, J. Appl. Meteor.) a paper that had little credibility until confirmed in trials eight and 18 years later, it was that unexpected.

I  felt an obligation to tell ASAP what had happened with Prof. Gagin to IMS Director, Y. L. Tokatly, in case he might wish to revoke my visitor privileges.  He did not!  He replied that it was just a difference of opinion, and I could continue to visit the IMS and gather data!  How magnanimous was that?

February 3rd, 1986:  My Third and Last Meeting with Prof. Gagin Takes Place at His Ben Gurion AP Radar.

A third meeting was arranged, despite what had happened in our 2nd meeting, after I learned that Prof. Gagin and his cloud seeding group had their own radar located on the outskirts of Ben Gurion AP.   I did not even know that Prof. Gagin had his own radar at that point until informed of the “private radar” by an Israeli air traffic control person when I was looking for pilot reports of cloud tops!  I had to call Prof. Gagin, as hard as that would be, and ask him about visiting it.  A third meeting was arranged.  Prof. Gagin was cooperative.

But what about that radar, located on the outskirts of Ben Gurion Airport?  That radar would surely prove that Prof. Gagin was right and I was wrong; that rawin soundings indicating high cloud top temperatures of precipitating clouds were, indeed, unreliable as Prof. Gagin asserted.

I bicycled from my Riviera Hotel in Tel Aviv to this meeting.  The sky was overcast in deep Altostratus (a mostly ice cloud) underlain by Altocumulus opacus clouds.  A storm was approaching, but it would be hours before rain arrived.  Below, a vertical look at those clouds from the site of the Ben Gurion radar as I was leaving.

The main thing I wanted to ask Prof. Gagin in our third meeting was whether I could go to this radar during storms and see cloud top heights.   He said “no,” giving “airport security” as the reason.  He repeated to me  how (understandably) offended he was by my visit to Israel to check his cloud reports.

But, “airport security?” I had just bicycled to his radar on the outskirts of Ben Gurion; no problem!  Later, a grad student at Tel Aviv U. in Professor Zev Levin’s group,  Graham Feingold, would erupt over the “airport security”  claim as a lie, as it clearly seemed to to be at the time.

Prof. Gagin further assured me in this meeting at his radar that radar top measurements would only confirm his reports (that is, if I could only view those top heights on his radar!)

I also informed Prof. Gagin that due to his behavior in our 2nd meeting that I had asked several scientists around the world to intervene with him on my behalf.  He asked me who I had written to and I told him (those listed earlier).

How crazy was this episode?  

A minor, but well-known cloud seeding critic, as I was at that time, could be easily convinced that he was wrong by examining Prof. Gagin’s  radar top height measurements.  But he was denied the opportunity to be proved wrong!

Learning about private flying in Israel and then getting a pilot to be on “standby” for cloud sampling

Late in February,  I learned that there was a robust private aircraft touring business in Israel.  I had assumed, based on the reports of Professors Mason, Hobbs, and Vali,  that research groups weren’t able to get in, that flying around in Israel to sample clouds couldn’t be done due to security issues.  But then, how could there be a strong tourist flying program?

I then went to one of the aircraft touring sites at Sade Dov Airport near Tel Aviv, and found that I could get a single engine aircraft and pilot, Yoash Kushnir, who would sample the tippy tops of clouds along the coastline of Israel with me along.  He said it would cost $250 an hour and I was willing to spend about $500 to do give it a try.   His aircraft had a ceiling of about 14 kft as I recall,  just “high enough” to sample cloud tops that would average >-10°C.  Tippy tops is not the best place to find much ice.  Higher concentrations of ice are found lower down when ice is developing, as a rule, unless the top has completely glaciated.

The pilot I had on standby, incidentally, was angry that it was believed outside of Israel that you couldn’t fly research in Israel and sample clouds.  It was a presumption I had, too, because the University of Wyoming and the British teams were not able to get in to sample Israeli clouds.  This pilot regularly flew tourists to view ruins at Masada and other historical sites in Israel.

While Prof. Levin felt he could not openly support my efforts due to funding issues, he did provide me with a graduate student, Graham Feingold, who was willing to go along on a flight.  He  would act as a witness to what was found in those “tippy tops.”  I had planned to use the “black glove” technique used decades earlier in sampling clouds for the presence of ice.  You literally stick a black-gloved hand (or a black stick) out of the window of the aircraft and look for what hits.

You can only imagine how crazy these people thought I was!  Years later I learned that I had been described by Graham, who was to become my friend, as, “that cowboy from America.”

No flight ever took place as the weather dried out by the time l learned I could hire an aircraft to sample cloud tops.  Ironically, the only rain after having Yoash Kushnir on standby fell briefly from clouds whose tops were near the freezing level, and likely, if I had flown that morning, no ice would have been found in them!  It was a surprise weather event that produced barely measurable rain.

My Meeting with Israeli experiments’ “Chief Meteorologist,” Mr. Karl Rosner

Late in my 1986 cloud investigation, I met the Israeli cloud seeding experiments’ “Chief Meteorologist,” Mr. Karl Rosner.  It was IMS’ scientist, Alexander Manes, that got me in touch with him.  I learned that the chief meteorologist, too, knew that Israel clouds rained having tops warmer than -10°C!  It then seemed that the only three people in Israel who did not know that rain fell from such clouds were those who studied them in great detail, Prof. Abe Gagin, his frequent co-author, Jehuda Neumann,  and Prof. Gagin’s only graduate student, Daniel Rosenfeld!

But Mr. Rosner had a more important and astounding thing to tell me:  Prof. Gagin had refused to publish the result of the south target random seeding for Israel-2.   Mr. Rosner had launched a campaign to see that it got published.  The results of the “full” Israel-2 experiment were published by Gabriel and Rosenfeld (1990).   Prof. Gagin, his co-author, J. Neumann, had stated in their 1981 journal paper that the seeding of the south target was “non-experimental.” They wrote that this was due to the lack of a suitable coastal control zone like the that they used to evaluate the north target’s random seeding.  Previously, in 1974 these authors had given the result of random seeding in the south target as suggesting a decrease in rain after two rain seasons, and by 1976 at conference, stated the south target results were inconclusive for the full Israel-2 experiment.

So, here I was questioning the cloud reports and then learning from Mr. Rosner that half of the Israel-2 experiment had not been reported!  In Gabriel and Rosenfeld’s 1990, we learned that the “full” result of Israel-2 was a -2% suggested effect on rainfall;  it had not replicated Israel-1 as was previously believed based on the partial reporting of Israel-2.

Some Speculation About Why Prof. Gagin Might  Not Known Have Known About the Natural Precipitating Nature of Israeli Clouds

It may be that Prof. Gagin’s graduate student knew the true cloud/rain situation but did not pass that crucial information along.  It does happen that lab directors and important scientists have staff and students who do all the research, and upper echelon scientists are not close to what’s being done by the lower echelon staff;  the latter might not pass along all the relevant information if it goes against the beliefs of their bosses.

One must conjure up a dizzying amount of incompetence concerning the three principal Israeli cloud seeding researchers (Gagin, Neumann,  and Rosenfeld) who could not identify the most basic aspects of their clouds;  the depth  and cloud top temperatures  at which they started to rain.

But is an “incompetence” hypothesis credible? Or was it that a knowing graduate student did not pass along to Prof. Gagin information that would have eroded his cloud reports?  Read on….

Prof. Gagin and his student had monitored cloud tops with a vertically-pointed radar with tops having been confirmed by aircraft flyovers.  This was done for two rain seasons in the late 1970s (Gagin 1980, Atmos. Res.)  Prof. Gagin made no mention in his article of the shallow raining clouds that violated his cloud reports, ones that had to have passed over his radar during those two rain seasons.

Dr. Rosenfeld studied radar data and satellite cloud patterns in his 1980 master’s thesis and 1982 Ph. D. dissertation2.  Yet, he did not bring to his country’s attention or to the scientific community, those shallow raining clouds with relatively warm tops, either.  Such reports, if outed, would have had a profound effect on the viability of cloud seeding to increase rain in Israel, perhaps saving the country 10s of millions of dollars in wasted seeding efforts, as we now know happened when an independent panel (Kessler et al. 2006) found no via evidence that cloud seeding for 27 rain seasons had increased runoff into Lake Kinneret (Sea of Galilee).

Moreover, these researchers were recording echo top data from their Enterprise 5-cm wavelength radar at Ben Gurion AP after it had been deployed in support of cloud seeding efforts in the late 1970s.  Dr. Rosenfeld cited 1986 recorded radar top data in his 1997 “Comment” on the Rangno and Hobbs 1995 J. Appl. Meteor. paper.  Another enigma.

 A regret about stridency

My last communication to Prof. Gagin following my cloud investigation trip was from Seattle in June 1986.  In that long letter I recapitulated the elements of my cloud investigation.  This letter was copied to Prof. Peter Hobbs, Roscoe R. Braham, Jr.3, at North Carolina State University, and Prof. Gabor Vali at the University of Wyoming.

The one thing I came to regret was how I closed that June 1986 letter.  I closed it with a challenge:  That I, myself, would leave the field of meteorology, all aspects, if my Israeli cloud observations were wrong; that ice was not forming in high concentrations in Israeli clouds with top temperatures >-12°C (eyeballing 50-200 per liter as I wrote in my letters from my experience sampling glaciating clouds at the University of Washington).   I then challenged Professor Gagin himself to leave the field of meteorology instead of me if my observations were later proved correct:

So, there I was, the person who was told to give up meteorology by Joanne Simpson, who believed that “statues will be raised in his honor” challenging that very professor to quit the field.

Joanne likely never remembered who I was, and I had a couple of cordial correspondences with her due to my cloud seeding reanalysis publications that began reaching the literature in the late 1970s and early 1980s.  Later, when it was thought there was  some overarching claims about “global warming,” she sent me her banquet talk given in October 1989 to a statistical conference, shown here to indicate this cordial relationship:

1990 1-22 Simpson, from, about GW and cloud seeding_color version_ocr

I wish I had gotten to know her.

The End

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Joanne Simpson’s homage to Prof. Gagin:

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1This was, and is even today (!),  a sore point for me; that someone might believe this.  Prof. Hobbs was clueless about Israeli cloud anomalies and the Israeli experiments except for those plots and information that I relayed to him while studying those experiments on my own time.  As most professors would do,  he read in the peer-reviewed literature and took it at face value.

2Rosenfeld’s works are in Hebrew and have never been translated into English, but should be.

3The full letter, and others that I wrote to Prof. Roscoe R. Braham, Jr., are in an archive of his professional correspondence at North Carolina State University.

CHAPTER 3: THE REVIEW OF THE ISRAELI CLOUD SEEDING LITERATURE BEGINS

By the end of the 1970s, Prof. Gagin and his work had become of interest to me.  After all, as I learned in Durango, nothing could be taken at face value in the cloud seeding literature unless I had personally validated that literature by scrutinizing every detail of the published claims in it, looking for omissions and exaggerated claims, something reviewers of manuscripts certainly did NOT do.

I had a lot of experience by this time.  I had reanalyzed the previous published reports of cloud seeding successes in the Wolf Creek Pass experiment (Rangno 1979, J. Appl. Meteor.);  the Skagit Project (Hobbs and Rangno 19781, J. Appl. Meteor.), and had authored comments critical of the published foundations of the Climax and Wolf Creek Pass experiments in Colorado (Hobbs and Rangno1 1979, J. Appl. Meteor.) and others.

What was to transpire was that the person Joanne Malkus Simpson suggested to give up meteorology, me, helped eliminate the reasons why anyone, let alone her, would continue to believe that “statues” should be raised to honor Prof. A. Gagin’s contributions to cloud seeding.  Here’s what happened.

The Israel chapter of my cloud seeding life begins

In about 1979, the Director of my group at the University of Washington, Prof. Peter V. Hobbs, challenged me to look into the Israeli cloud seeding experiments:  “if you really want to have an impact, you should look into the Israeli experiments.”  I guess he thought I had a knack seeing through mirages of cloud seeding successes.

I did begin to look at them at that time.  Prof. Hobbs asked me to prepare a list of the questions I had come up with after I started reading the literature about the Israeli experiments.  He wanted to ask questions of Prof. Gagin at the latter’s talk at the 1980 Clermont-Ferrand International Weather Modification conference in France.  Those at the conference said that he did ask Prof. Gagin questions but it wouldn’t have been like Prof. Hobbs, as I began to learn over the years in his group, to have said, “My staff member has some questions for you, Abe.”  Maybe he thought that wasn’t important.

I already knew something of the rain climate of Israel long before reading about the Israeli cloud seeding experiments.  This was due to a climate paper I was working on when I arrived in Durango, CO, as a potential master’s thesis for SJS.  My study was about “decadal” rainfall shifts in central and southern California and I wanted to know if what I observed in California had also been observed in Israel, a country with long term, high quality rainfall records and one having a Mediterranean climate like California.  I received several publications from the Foreign Data Collections group at the National Climatic Center in those days, such as Dove Rosnan’s 1955 publication, “100 years of Rainfall at Jerusalem.”

So, I was not coming into the Israel cloud seeding literature “blind” to its surprisingly copious winter rain climate.  Jerusalem averages about 24 inches of rain between October and May, something akin to San Francisco despite being much farther south than SFO.

My interest in the Israeli cloud seeding experiments, however, ebbed and flowed in a hobby fashion until the summer of 1983 when I decided to plot some balloon soundings when rain was falling, or had fallen within the hour, at Bet Dagan, Israel, and Beirut, Lebanon, balloon launch sites. Anyone could have done this.

The plots were stunning!

Dashed line is the pseudoadiabatic lapse rate; solid line, the adiabatic lapse rate.   The synoptic station data are those at the launch time or within 90 min.  

Rain was clearly falling from clouds with much warmer tops at both sites than was being indicated in the descriptions of the clouds necessary for rain formation in Israel  by Prof. Gagin, descriptions that made them look plump with seeding potential.  His descriptions were of clouds having to be much deeper, 1-2 km,  before they formed rain.   And those descriptions were key in supporting statistical cloud seeding results that gave the first two experiments, referred to as Israel-1 and Israel-2,  so much credibility in the scientific community (Kerr 19821, Science magazine).    The deeper clouds described meant that there was a load of water in the upper parts of the clouds that wasn’t coming out as rain.  

Shallower clouds that were raining meant that there wasn’t going to be so much water in deeper clouds that could be tapped by cloud seeding; much of it would have fallen out as rain before they reached the heights thought to be needed for cloud seeding.

I also scrutinized Prof. Gagin’s airborne Cumulus cloud reports that appeared in the early and mid-1970s.  I found several anomalies in them when compared to other Cumulus cloud studies and our own measurements of Cumulus clouds.  One example:

While the 3rd quartile droplets became larger above cloud base as expected, droplets >24 um diameter were nil until suddenly increasing above the riming-splintering temperature zone of -3° to -8°C.  Those larger drops should have increased in a nearly linearly way as did the 3rd quartile drop diameters. If appreciable concentrations of  >24 um diameter droplets had been reported in this temperature zone, cloud experts would have deemed them ripe for an explosion of natural ice, not for cloud seeding.  So this odd graph left questions.

Too, the temperature at which ice first appeared in Israeli clouds, according to Prof. Gagin’s reports, was much lower than similar clouds as seen by data point 8 in the figure below constructed in 1984 (published  in  1988,  Rangno  and  Hobbs,  Atmos.  Res.)

When I read about how seeding was carried out in the first experiment, Israel-1,  I learned to my astonishment that only about 70 h of seeding was done during whole winter seasons upwind of each of the two targets by a single aircraft.  I concluded that there could not possibly have been a statistically significant effect on rainfall from seeding clouds given the true precipitating nature of Israeli clouds, the number of days with showers,  and the small amount of seeding carried out.  In Israel-2, the experimenters added a second aircraft and 42 ground cloud seeding generators (NAS 1973).  They, too,  must have realized they hadn’t seeded enough in Israel-1, I though.

Another red flag jumped out in the first peer-reviewed paper that evaluated Israel-1 by Wurtele (1971, J. Appl. Meteor.),   She found that the greatest statistical significance in Israel-1 was not in either one of the “cross-over” targets, but in the Buffer Zone (BZ) between them that the seeding aircraft was told to avoid.  This BZ anomaly had occurred on days when southernmost target was being seeded.   In her paper, Wurtele quoted the chief meteorologist of Israel-1, Mr. Karl Rosner, who stated that the high statistical significance in the BZ could hardly have been produced by inadvertent cloud seeding by the single aircraft that flew seeding missions.

The original experimenters, Gagin and Neumann (1974) addressed this statistical anomaly in the BZ  but did attribute it to cloud seeding based on their own wind analysis.

A Hasty 1983 Submission

Armed with all these findings, I decided to see how fast I could write up my findings and submit them to the J. Appl. Meteor.;  I came into the University of Washington on July 4th, 1983, and wrote the entire manuscript that day. I submitted it to the J. Appl. Meteor. the next day.    (Prof. Hobbs was on sabbatical in Europe at this time.)

I was sure it would be accepted, though likely with revisions required.  No reviewer could not see, I thought, that there was a problem with the existing published cloud reports from Israel.

My conclusions were against everything that had been written about those experiments at that time, that the clouds were not ripe for cloud seeding, but the opposite of “ripe” for that purpose.

In retrospect, it wasn’t surprising that I was informed six months later that my manuscript was rejected by three of four reviewers: “Too much contrary evidence.  You can’t be right” was the general tone of the message.

Nevertheless, I was surprised by the rejection, thinking my evidence was too strong for an outright rejection.  I tried to make the best of it in a humorous way to the journal editor, Dr.  Bernard A. Silverman, passed the news along.  I hope you, the reader, if any,  smile when you read this: In 1984 at the Park City, UT, Weather Modification Conference, I had my first personal interaction with Prof. Gagin.   I was giving an invited talk with an assigned title at that conference about the wintertime clouds of the Rockies, “How Good Are Our Conceptual Models of Orographic Cloud Seeding?”

Prof. Gagin  informed me that he had been one of the four reviewers of my 1983 rejected manuscript.  He “lectured” me sternly between conference presentations about how wrong I was about his published descriptions of Israeli clouds that had a hard time raining naturally until they got deep and cold at the top.

Rejection and Lecture Have No Effect

The rejection of my 1983 paper and Prof. Gagin’s “lecture” about how wrong I was about Israeli clouds, however, had no effect whatsoever on what I thought about them. 

I felt I could interpret balloon soundings just fine after the hundreds and hundreds I examined in Durango with the CRBPP while looking out the window to see what those soundings were depicting.  I marveled, instead, that reviewers couldn’t detect the obvious, especially Dr. Bernard A. Silverman, the Editor of the J. Appl. Meteor.

After that rejection that moved on to studies of secondary ice formation in clouds in Peter Hobbs group, published in Hobbs and Rangno 1985, J. Atmos. Sci.), but the thought of going to Israel began to surface.    Someone has to do something!

It was about this time that I read about American physicist, R. W. Wood, going to France to expose what he believed to be the delusion of N-Ray radiation reported by Prosper René Blondlot (Broad and Wade 1982, Betrayers of the Truth).  I thought, “I bet I could do that same kind of thing,” thinking that  Prof. Gagin might well be similarly deluded about his clouds.  

A Resignation Followed by the Cloud Investigation Trip to Israel 

And so, following the historical precedent that R. W. Wood set, I hopped on a plane to Israel at the beginning of January 1986 following my resignation from Prof. Hobbs’ Cloud and Aerosol Research Group.

Resigning from the Job I Loved .

My resignation was in protest over issues of credit here and there that had been building up for nearly a decade in Peter Hobbs group2.  Peter had lost several good researchers over this same issue.  In a late December 1985 meeting with Prof. Hobbs prior to my January 1986 trip,  he described me as “arrogant” for thinking I knew more about the clouds of Israel than those who studied them “in their own backyard.”

“Confident” would have been more appropriate than the word, “arrogant” Prof. Hobbs had used.  I smirked when he said that; I couldn’t help myself.  I had done my homework in the process of writing that short paper in 1983 critical of those cloud reports when Peter was on sabbatical.  In fact, I was so confident about my assessment of Israeli clouds that I told Prof.  Peter Hobbs,  Prof. Robert G. Fleagle (also with the University of Washington) and Roscoe R. Braham, Jr.3,  North Carolina State University, and others, that I was about “80 % sure” of my assessment of Israeli clouds from 7,000 miles away even before I went.

My Agenda

It was true, however, that I wanted to show the world by going to Israel that I was the best at “outing” mistaken or fraudulent cloud and or cloud seeding reports, ones that were considered credible by the  entire scientific community, including Prof. Hobbs4.  However, virtually any low-level forecasting meteorologist could do what I did, especially storm chasing types like me, that was the fun of it.

And, here was a chance to do something that would be considered, “historic,” just like Wood’s trip to France was!

Another intriguing factor contributing to the idea of going to Israel was the statement expressed by Peter Hobbs to me a few years earlier; “No one’s been able to get a plane in there.”  He told me that British meteorologist and cloud physics expert, Sir B. J. Mason, had said the same thing to him.  I wasn’t a plane, but by god, I was going to “get in there.”   The view of Prof. Hobbs and Sir B. J. Mason  was later to be confirmed in a letter to me in Israel by Prof. Gabor Vali, University of Wyoming cloud researcher who wrote of six attempts to do airborne research of Israeli clouds, all denied.

Too, I looked forward to going to Israel and seeing what that country was like, too, with all of its biblical history.

And, if it was a case of delusion, as American physicist, R. W. Wood, encountered with the N-Ray episode, Prof. Gagin would be happy to cooperate with me and let me see radar tops of precipitating clouds. Prosper-René Blondlot had cooperated with Dr. Wood, allowing him to watch an N-Ray experiment.

But if Prof. Gagin didn’t cooperate with me, I could just hop on the next plane back to America.  I would “know” I was right about those clouds without even seeing them!

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

1Corrections to Kerr’s 1982 Science article were published by Prof. Hobbs in Science in October 1982.  In the original article, Prof. Hobbs inadvertently led Kerr to believe that he himself, and not me, had conducted the reanalysis and other work that undermined the Climax cloud seeding experiments.  Prof. Hobbs apologized to me as soon as he saw Kerr’s article. Still…..

2Authorship sequences on publications under Prof. Hobbs’ stewardship sometimes did not represent the progenitor of a work; i.e., that person who should be first author;  the person who originated the research, wrote the drafts describing results,  the person who had done all the analysis that went into it, as in these footnoted cases of authorship where  Prof. Hobbs had placed himself as lead author.    Prof. Hobbs was a wonderful science editor and made great improvements to drafts that he received.   The authorship sequence problem was to mostly go away after I resigned.

3My resignation letter was 27 single spaced pages!

4Prof. Braham kept the letters I wrote to him and they can be found in his archive at North Carolina State University.

5See Prof. Hobbs 1975 “Personal Viewpoint” comment in Sax et al. 1975, J. Appl. Meteor., “Where Are We Now and Where Should We Be Going?” weather modification review.

Chapter 2: A JOB IN DURANGO, COLORADO, THAT EVENTUALLY LED ME TO ISRAEL

This story begins with my first full-time job after graduating from San Jose State College.  I was hired as a weather forecaster by E. G. & G., Inc.,  in Durango, Colorado in support of a massive randomized cloud seeding experiment called the Colorado River Basin Pilot Project (CRBPP).  It was intended to prove that seeding wintertime mountain storms was a viable way of adding water to western rivers over a large area.   I was to work under lead forecaster, J. Owen Rhea, an expert on wintertime mountain storm forecasting.  Paul Willis was the Project Manager.  The project was intended to replicate stunning cloud seeding successes reported in Colorado by Colorado State University (CSU) scientists, but in the CRBPP, over a much larger area than in the CSU experiments.

The Durango job was to change my life forever, and eventually lead me to Israel as a skeptic of reports of cloud seeding successes.  Ironically, that change was to involve North American Weather Consultants,  and it’s president, Mr. Robert D. Elliott, for whom I had worked in 1968 in Goleta, CA,  as a summer hire between semesters at San Jose State, and again when on loan from the CRBPP  in the summer of 1972 in statewide cloud seeding program in South Dakota.

By time the Colorado River Basin Project (CRBPP), the nation’s largest, most costly ever mountain randomized cloud seeding experiment  ended after five winter seasons,   I had become an orographic cloud seeding “apostate. ”

What caused this epiphany?

This metamorphosis from  an idealistic and naive forecaster  coming right out of college happened due to seeing what I think most scientists would term “misconduct” in the journal literature during the CRBPP in 1974 combined with misleading news releases from the BuRec sponsor of the CRBPP.  In the journal article,  the two authors were asserting things they knew weren’t true.  I personally knew that they knew this.  I decided that  I was going to do something about this deplorable situation after the CRBPP ended.

I then had come to believe that the cloud seeding successes reported by CSU researchers couldn’t possibly have been real ones  due to the many seeding impediments that turned up during the CRBPP (clouds not ripe for seeding as had been described, inversions that blocked the seeding material in the wintertime,  cloud tops not at the heights they were supposed to be, etc.)

It was very troubling to me that the many published scientists that were associated with the CRBPP and knew that false claims had been published in the 1974 journal cloud seeding paper  did nothing.  In that 1974 paper, for example, one reads that the temperature at 490 mb in the atmosphere (about 18,000 feet above sea level) above Wolf Creek Pass, a central target of the CRBPP, was representative of cloud top temperatures during storms.   Both authors, due to the hundreds of rawinsondes launched during CRBPP storms, knew this was untrue.  Robert D. Elliott was one of the two authors.

I  waited years for a correction by the authors, or a journal “Comment” by a knowledgeable, published scientist pointing out that at least this one claim in that article was untrue.  The silence on the part of those many scientists I expected to do SOMETHING was deafening.   I, too,  was part of that “silence.”

Talk Sounds of Silence slide:  a pptx that after hours of investigation I am not able to insert, thanks to changes in WP.  It downloads and then you can play the slide.  In the meantime, this poor substitute for the real thing:

The false claim/misconduct I am referring to appeared in one of the most cited cloud seeding articles of all time, entitled, “The Cloud Seeding Temperature Window.”

Robert D. Elliott, one of the two authors of that 1974 paper was intimate with the CRBPP data as the official evaluator of the CRBPP.  That CRBPP data demonstrated that the claim in his paper that cloud top temperatures over Wolf Creek Pass averaged 490 mb  was false.  In his next visit to Durango I asked him,  “How could you write that (claim)?”   He replied that he had, “just sort of gone along with Lew” (Lewis O. Grant) his co-author.

I thought of Shoeless Joe Jackson and the little kid that said to him, “Tell me it ain’t so, Joe!”, that he had cheated in the Black Sox World Series scandal.  I felt just like that little kid must have.  This was the same Bob Elliott that I had worked for in Goleta  and admired so much.

So, that was the epiphany for me.   I then thought that nothing might be true in the cloud seeding literature no matter how highly regarded that literature or experiment was by the scientific community.

I had come into CRBPP a little too naïve and idealistic, and  when the CRBPP ended, that idealism was nearly gone and replaced by suspicion of any orographic cloud seeding success unless I had personally validated it. Over the next two decades, I was to reanalyze six prior cloud seeding successes in the peer-reviewed literature and not ONE was the success it was deemed to be by the experimenters who conducted it.

This ephiphany set the stage for what was to happen a few years later concerning the scientist in Israel whose work in clouds and cloud seeding Prof. Joanne Malkus Simpson admired so much.

After the CRBPP had ended, I was asked to do an interview about it in November 1975 in the local newspaper, the Durango Herald.   In that interview, I stated exactly what I planned to do; reanalyze all the Colorado State University cloud seeding work that had led to the massive funding of the CRBPP since I now deemed that literature highly unreliable.

After living the winter of 1975-76 in Durango, living off my savings while gathering runoff and CRBPP precipitation data, I was hired for a May-August seeding project in South Dakota by Atmospherics, Inc.  I had worked for them in the summer and fall of 1975  as a radar meteorologist in Madras (now Chennai), Tamil Nadu, India.  While mountain cloud seeding was suspect, Joanne Malkus Simpson and co-authors were published results of successful cloud seeding of tropical Cumulus clouds like those in India.  That’s why I had no qualms about taking that job in India in 1975,  Joanne had influenced me again.

Near the end of the 1976 project in SD, I was interviewed for a job at  the University of Washington by Prof. Larry Radke and Prof. Peter V. Hobbs.  I joined Prof. Hobbs, Cloud Physics Group, as it was known then, in September 1976.

After unraveling bogus cloud seeding successes in Washington State (Hobbs and Rangno 19781 and in Colorado (Rangno 1979, Hobbs and Rangno 19791),  Prof. Peter V. Hobbs who saw I had an interest and skill in examining the cloud seeding literature, said to me that “if you really wanted to have an impact, you should look into the Israeli experiments.”  It wasn’t long before I began reading critically about them.

1Authorship sequences in Prof. Hobbs group, as in these cases, do not reflect who initiated the work, carried out the analyses and wrote the drafts that Prof. Hobbs improved with his great editing skills.

 

Chapter 1. JOANNE, ABE, AND ME: MY ONLY MEETING WITH JOANNE

This is a story about Joanne (Malkus) Simpson and our mutual study interest, Prof. Avraham “Abe” Gagin of the Hebrew University of Jerusalem, the leader of the world famed Israeli cloud seeding experiments that took place in the 1960s to 1970s.  This is a story having irony.  For more about Joanne Simpson and her major contributions to meteorology, see J. R. Fleming’s, “First Woman: Joanne Simpson and the Tropical Atmosphere”.  She was a real superstar.

(https://www.amazon.com/First-Woman-Simpson-Tropical-Atmosphere/dp/0198862733).

My own modest claim to fame,  partly for the work reported here:

washington.edu/…/two-uw-researchers-honored-by-un-for-excellence-in-weather-modification

Following the untimely passing of Professor Abe Gagin[1], Joanne Simpson stated that, “statues will be raised in many towns and halls of fame” in his memory due to his contributions to cloud seeding. Her testimonial appeared in the 1988 memorial issue to A. Gagin of the J. Weather Modification and is shown at the end of this account.  The memorial issue of that journal is here:

(https://journalofweathermodification.org/index.php/JWM/issue/view/38/_24)[2]

As a measure of Prof. Gagin’s stature when he passed and why statue building might be considered for him, the October 1989 J. of Appl. Meteor. also issued a memorial volume to Prof. Gagin in due to his work in cloud seeding.  The preface to that memorial issue, written by Arnett S. Dennis, a former co-author of Joanne’s, is also shown at the end of this account.  Hardly any scientists are tributed by memorial issues of journals, much less, two!  Prof. Gagin’s frequent co-author in describing the results of the Israeli cloud seeding experiments, Prof. Jehuda Neumann, was ALSO tributed with a memorial issue of the J. Appl. Meteor. when he passed ten years later.

Prof. Gagin passed in September 1987 at the untimely age of 54, a few months after learning in a letter from Prof. Peter Hobbs that my manuscript, “Rain from clouds with tops warmer than -10°C in Israel,” had been accepted for publication by the Quart. J. Roy. Meteor. Soc.  This paper showed that the clouds of Israel were completely different than the ones Prof. Gagin was repeatedly describing in the literature and at conference.

At the same time of his passing, Prof. Gagin was also being pressured by his own chief meteorologist, Mr. Karl Rosner, to publish the previously omitted data for the south target of Israel-2.  This was the 2nd randomized cloud seeding experiment that was conducted from the 1969/70 through 1974/75 Israeli rain seasons.  The reporting of Israel-2 had been confined to the north target where there was an appearance that cloud there had pretty much replicated what had been reported in ALL of Israel-1.

The testimonials to A. Gagin by many leading scientists in the cloud seeding domain were omitted in the digital version of the 1988 JWM volume when digitizing  was done many years later but can be found at the end of this story.

My one and only in-person interaction with Joanne Malkus Simpson:  “Go into journalism not meteorology.”

I met with Joanne (Malkus) Simpson in January 1963 at UCLA.  She had been brought to my attention when she had been named, Los Angeles Times “Woman of the Year.”  I was meeting with her, a professor of meteorology, to try and convince her that as a 20-year old junior college student, I was worthy of getting into the UCLA meteorology program even though I did not have a high enough grade point average to do so.  UCLA required a minimum of 2.4 and mine was barely above 2.0000x.  And I had to repeat all but one of my calculus and physics classes at Pierce Junior College.  I had spent too much time playing and practicing for intercollegiate baseball, but I also had no natural aptitude for physics and calculus.

UCLA was the only school offering courses for a degree in meteorology in California in 1963, and that’s why I went there to meet with Dr. Malkus, as she was known as then.  It seemed like UCLA offered the only hope of achieving my dream to become a meteorologist.   I thought explaining my fanaticism about weather would do the trick.  For example I had gone to Louisiana and ended up near Galveston, Texas, chasing Hurricane Carla in September 1961, and chased numerous thunderstorms in the Southern California desert during the summers.

Some early background that if told to Joanne, would convince her I was worthy of UCLA’s program

I began collecting weather maps out of the Los Angeles Daily News when I was in the 4th grade.  (Thank you, Mr. Borders and Mr. De la Gega, my 4th and 5th grade teachers, for encouraging my budding interest!).  Below a sample of a real weather map with isobars from the Los Angeles Daily News for December 26, 1951.  How exciting is this?

Too, I was subscribing to the “Daily Weather Map” by the time I was ten years old.   By the time I was 13 years old, I  was subscribing to the Monthly Weather Review and several states’ government, “Climatological Data” from NOAA.   (Well, my mom subscribed for me.)

I crazily thought that telling Joanne about all this would get me in to UCLA sans the grade requirement.

“The Meeting”

The first thing Joanne Malkus asked me when she kindly took a minute out of her busy schedule (I had made no appointment) was how my grades were in math and physics.   I told her I got “Cs” but did not reveal to her that those “Cs” were on the second try!   She then asked me, “How are your grades in the humanities?” “B’s.”   With my answers to but two questions, Prof. Malkus then advised me to give up the thought of becoming a meteorologist, and become, perhaps,, “a journalist and write about weather.”  And that was the end of the meeting; in less than five minutes I was advised to give up a life-long dream.

Yes, I “held myself back,” to repeat courses in math and physics, and in doing so lost my collegiate baseball eligibility.  Who would do this?But.. that stubbornness, to keep at it, not giving up  my dream, turned out to be key to my whole life.  But perhaps it could be seen as a character flaw, too?

Joanne Malkus assessment of my potential as a student in the UCLA meteorology program was, in fact, “spot on.”

Thank you, Joanne (Malkus) Simpson.

Why?

In retrospect, I never could have gotten through the highly theoretical program at UCLA in those days, a program that featured Morton Wurtele, Yale Mintz, Morris Neiburger, Jörgen Holmboe, Zdenek Sekera, James Edinger, and Jacob Bjerknes, the latter who had founded the Department in 1940.  Fjørtoft, a visiting Norwegian professor of meteorology, or possibly Holmboe, was slinging vector equations across a blackboard as I walked down the hall following my meeting with Prof.  Malkus.  At UCLA in those days, one would have walked the halls with giants. A few years earlier I had tried to get the autograph of Prof. Bjerknes at UCLA since meteorologists like him were to me,  like baseball superstars to other, “normal” kids.  Prof. Bjerknes was not in his office that day, but rather there was a sign said he was, “emeritus,” which I took to mean he was especially good as a scientist, not that he was retired.

After my 1963 meeting with Joanne Malkus I was angry and hurt and promptly went to the UCLA bookstore and bought one of the books they were using in their meteorology program, I was that mad.  The book?  “Introduction to Theoretical Meteorology” by Seymour Hess.  I stopped reading it after a day or two.  It had too many equations. 

It took me more than 25 years to realize that Joanne Malkus Simpson had saved me from myself.   I wrote her a note thanking her  for her keen assessment in the early 1990s.   She did not reply.  

Life After “The Meeting”

In  the spring of 1963 I had lucked out and gotten a job as a “research analyst” at Rocketdyne in their H-1 rocket group in the Simi Hills above the San Fernando Valley.  Rocketdyne was a division of North American Aviation.  By mid-1964, I was “suddenly” married and had a son.  Becoming a meteorologist was slowly slipping off the radar, but I loved my job at Rocketdyne (about Rocketdyne)  and the young, great engineers that led my group, like Wayne Littles  who later became the 8th director of the NASA Marshall Space Flight Center in Huntsville.  They set great examples as engineers and leaders.

Rocketdyne’s Simi Hills test division where I worked, had a weather forecast office and I bugged the guys there, Joe Glantz (former State Climatologist for California) and Hank Weiss, virtually EVERY lunch time during the winter rain season.  We talked “progs” such as they were then.

I also started on another path toward being a meteorologist while married, still not giving up on my goal.  I took two correspondence courses in meteorology from Penn State University (graded by A. K. Blackadar and F. B. Stephens).

When my marriage was going on the rocks in the mid -1960s due to my immaturity, I learned that San José State College had started a program in meteorology.  I applied and got accepted even with my crummy grade point average from junior college.  It was an exciting time for me to meet, for the first time in my life, other weather-centric guys like me when I arrived at SJS in the spring of 1967.  One of them, Bill Hall, was to become something of a modeling superstar at the National Center for Atmospheric Research.  Byron Marler, who ended up with PG&E,  became a life long friend.

I also became friends with the chair of the Meteorology Department in those days, Dr. Albert Miller.  He helped me tremendously by hiring me as a student assistant while I was an undergraduate, and later, as a graduate assistant in the synoptic lab.  Dr. Miller was like a 2nd dad to me.  Also key to being able to continue at San Jose State  was my former Rocketdyne supervisor, A. Dan Lucci, who re-hired me as a summer employee at Rocketdyne in 1967 after my first semester at San Jose State.

Another person whom I became good friends with at SJS due to working together, was C. Donald Ahrens, who was to go on and write the most popular meteorology book for 101 college classes in the nation, “Meteorology Today” and several other books.    His wife was to type the first chapter of his Meteorology Today book on my very own Hermes 3000 manual typewriter!

Don and I also worked together on tetroon (constant level balloon) paths in the Bay Area that disclosed where the onshore maritime air was going.  We worked in a corrugated metal building next to the football stadium far from the meteorology department.  To pass the otherwise tedious time, we had KGO-FM’s no commercials, top 40 radio station with DJ “Brother John” blaring.  And, we would break into song!  We really liked the Four Seasons, Western Union, by the Five Americans, and so many others that  we sang to many of them, harmonizing,  while our heads were down plotting tetroon paths.  I still smile thinking of those days.

In the summer of 1968, I worked for non-other than North American Weather Consultants under CEO, Robert D. Elliott.  That  summer Tor Bergeron came to visit!  For those readers who remember NAWC in Goleta, California, here’s the photo I took of the whole gang, Elliott, Bergeron, Keith Brown, Russ and Elona Shaefer, John Walter and others whose names I  can’t bring to the “surface:”

I’ve never had a job I loved as much as that summer one at NAWC, or people I had so much in common with there.   I also had a chance to meet the head of NAWC, the famous Robert D. Elliott, whom I came to admire so much while at NAWC.  My assignment at NAWC was mainly to draw weather maps of frontal systems coming into southern California and “lake effects” for the Great Salt Lake in winter.  I was in heaven.

Back at San Jose State in the fall of 1968, I started a tiny forecast blurb on the front page of the Spartan Daily.  It devolved into political satire at the suggestion of the Daily’s editor after one my forecasts, “…with the stratus, not the campus, burning off by noon.”  There had been some fires set in trash cans by protestors the day before on the San Jose State campus.   The Daily editor said I should do more of that, and off I went into some pretty lame stuff.  Oh, well; “let’s move along now, nothing to see here.”

I also began to write opinion pieces in the San Jose State Daily, mostly due to the encouragement of Prof.  Phil Wander, my speech teacher.  I deem him one of the most important influences in my life. He thought I had something to say, such as this from a talk I gave in his class:

I was also writing articles for the college paper on ending student funding of intercollegiate athletics due to Governor Reagan’s budget cuts, pollution and the effects on minorities (above), suggesting parking costs be based on the number of people in the car, and on the war in Vietnam, the latter as many others were.  My SJS experience is pretty much reprised in the “friendly” article below, miniaturized for the sake of humility, of which, I probably don’t have enough of:

I graduated from modest San José State College, as it was known then, with a Bachelor of Arts degree in meteorology in January 1969.   My grades, for so much effort I put into my meteorology classes with lots of math were,  nevertheless, mostly mediocre except in synoptic classes.  However,  I was a good weather map drawer and getting A’s in synoptic classes really helped raise my grade point average.

Perhaps due to writing topical articles in the SJS Spartan Daily,   I received the Meteorology Department’s Achievement Award when I graduated in January 1969.  Egad.   I was never sure I deserved it with big hitters and great students like future NCAR cloud modeler, Bill Hall, and other top students like Norm Hoffman, Chris Fontana, in my class getting “A’s.”

An example of over valuing my satirical talent that were on display in the Spartan Daily weather forecasts,  in the summer of 1969, I went to KRLA-AM in Los Angeles to suggest that I could be a weather forecaster for them.  KRLA was a top 40 station whose news team suddenly began doing news satire in 1968, and they dared to offend.   What they did was astounding to me and was even noted in Time magazine!

I wondered if I could be their weather forecaster, and maybe chip in to the their comedy team,  later called,  “The Credibility Gap”.  I showed a page of my Spartan Daily forecasts to a young Harry Shearer, a member of the KRLA satirical news team.  He quickly glanced across them and summarized his thoughts on them like this; “They’re not that funny, are they?”  End of interview.

I hung around San Jose State attending graduate classes until the spring of 1970.   At that time I was offered a job as an assistant weather forecaster with the nation’s largest ever randomized mountain cloud seeding experiment headquartered in Durango, CO,.  Funded by the Bureau of Reclamation, it was called the Colorado River Basin Pilot Project (CRBPP).   I was hired after being interviewed by J. Owen Rhea of E. G. & G, Inc.  in San Jose!  E. G. & G., Inc. had just been selected over North American Weather Consultants (NAWC) as the seeding contractor for the CRBPP.  Owen was going to be the lead forecaster under Paul T. Willis, the E. G. & G., Inc., Project Manager.

I really didn’t belong in grad school, either; too many equations.  Nevertheless,  it was hard to leave the excitement of SJS of those days.  SJS track stars, Tommy Smith and John Carlos had just drawn national attention to SJS,  that season’s NCAA track champion,  at the 1968 Olympics in Mexico City with their raised, “black power” fists.

I also received a job offer from NAWC in Goleta, CA, at that time, too.  I did not know until decades later that they were finalists in bidding on the same contract that E. G. & G., Inc. had won from the Bureau of Reclamation for the seeding and forecasting operations for the Colorado River Basin Pilot Project.

But the job in Durango seemed so important and exciting; I was going to be a part of a giant scientific experiment to see if cloud seeding worked and so that’s where I went.  The thought that it was exciting that I would also be living in a new climate after a lifetime in California’s.

1970:  It was now seven years since Joanne had advised me to give up the idea of being a meteorologist.  And now I was going to enter a field that she was a top expert in; weather modification by cloud seeding.

 

JOANNE, ABE, AND ME: THE “LONG AND WINDING” STORYBOARD

(Joanne Malkus/Simpson and Abe Gagin)

A modern-day story with elements similar to that of American physicist R. W. Wood and his exposé of non-existent “N-Ray” radiation in 1904.  R. W. Wood went to France to expose “N-rays” as the product of experimenter delusion at the turn of the century (Broad and Wade 1982); our protagonist1 went to Israel in 1986 to expose faulty cloud reports by possibly deluded scientists.

The underlying message in this life story chapter?

Hold on Tight to Your Dreams“, one of the greatest-ever song messages.  You just might make something out of yourself even when it appears you don’t have the grey matter to do it, as in my case (the “protagonist” in the outline below.)  “EOM”–skip the rest if busy.

Story board

  • A young, “weather centric” student in junior college, the protagonist in this story, meets with Prof. Joanne Malkus, a famous woman scientist and faculty member at UCLA in meteorology in 1963. He is there because her university is the only one in his state of California that offers courses leading to a degree in meteorology.   She has come to his attention because she had just been named, Los Angeles Times “Woman of the Year.”
  • Though he has loved clouds, weather and forecasting since he was a little kid, he tells her he is struggling in junior college with the courses that future meteorologists are required to take, ones heavy in calculus and physics, and doesn’t have the grade point average to get into UCLA from junior college.  He is hoping to convince her he is worthy of a shot in their meteorology program anyway due to his enthusiasm about becoming a meteorologist.
  • Malkus, after hearing about our protagonist’s poor grades in math and physics, suggests it would be best for him to give up his dream of being a meteorologist and to go into something less rigorous, perhaps “go into journalism and write about weather.”
  • Eventually, and holding himself back by repeating courses in math and physics to get “C’s,”  the stubborn young man becomes a meteorologist, anyway, matriculating at San Jose State College, one that starts a meteorology program a few years after his 1963 visit to UCLA.
  • By chance, our protagonist eventually ends up being an expert in the same specialty as Prof. Malkus (now Joanne Simpson) whom he had met with many years earlier;  rainmaking by cloud seeding and Cumulus cloud structure at the University of Washington under Prof. Peter V. Hobbs.
  • Simpson is particularly enamored of the work of a leading rainmaking scientist in Israel, Prof. Abe Gagin. When Prof. Gagin passes in 1987 at the age of 54,  she proclaims that, “…statues will be raised in many towns and halls of fame to his memory.”  Her view about that rainmaker is shared by many others around the world.
  • Through the rigorous execution of two well designed rainmaking experiments in Israel, each with similar increases in rain, in turn supported by repeated descriptions of Cumulus clouds plump with rainmaking potential, the experiments in Israel, by the 1980s, are deemed to be the one true rainmaking success in the world among all those undertaken.

 

  • Our protagonist, who on his own initiative, has exposed mistaken or fraudulent claims of “successes” in the peer-reviewed rainmaking literature since the late 1970s, comes to doubt the validity of the published work of that very same scientist for whom “statues will be raised.”
  • In the late 1970s after exposing ersatz seeding successes in Colorado and Washington State, our protagonist’s lab chief, Prof. Peter V. Hobbs, challenges our protagonist, a mere staff member in his group, to investigate the famous experiments in Israel, advising him, “if he wanted to have a greater impact” in his specialty of unraveling false cloud seeding claims.
  • Our protagonist begins to do so, and supplies a list of questions, at the request of Prof. Hobbs, to ask Prof. Gagin about his experiments when Prof. Gagin reports on them at a 1980 international conference in France.
  • In 1983, while Prof. Hobbs is on sabbatical in Europe, our protagonist submits a paper to a journal that asserts that the clouds in Israel are not ripe for rainmaking, but rather quite the opposite, and that too little seeding was carried out in the Israel-1 cloud seeding experiment was not enough to have affected rainfall.  Israel-1 was the first of the two famous experiments.
  • The paper is rejected by three of four reviewers. One of the “reject” reviewers he later learns, is Prof. Gagin himself.
  • Our protagonist is undaunted by the rejection of his paper, and begins to contemplate going to Israel after he also reads about American physicist, R. W. Woods’ trip to France to expose N-Rays.
  • Our protagonist resigns at the end of 1985 from the job he has loved over credit issues with Prof. Hobbs and goes to Israel on 4 January 1986.
  • Prof. Hobbs is not onboard with our protagonist’s views on the clouds of Israel before he leaves. He describes our protagonist as “arrogant” for thinking he knows more about the clouds in Israel than those “who have studied them in their own backyard.”
  • Our protagonist eventually exposes the famed rainmaker’s faulty work on several fronts beginning with his self-initiated and self-funded cloud investigation to Israel in 1986, a science excursion that resembles the historic trip by R. W. Wood to France. During the first storm in Israel he finds that the cloud descriptions by Prof. Gagin are, indeed, in error.

 

  • Our protagonist is welcomed by the Israel Meteorological Service (IMS) and given a tiny amount of desk space where he collects historical  data concerning Israel’s clouds and rains, data that will be used in a journal paper.

 

  • Not surprisingly, he finds that all the IMS forecasters know that it rains from clouds that are contrary to those described by Prof. Gagin’s descriptions in the journal literature.  They are much shallower than those described as necessary to develop rain by Prof. Gagin, making them appear necessary for seeding to take place to make them rain.

 

  • Following a first cordial meeting at Prof. Gagin’s office following a week of dry weather,  a second meeting occurs after several days with rain. Our protagonist discusses his observations with Prof. Gagin, which are sharply at odds with his journal cloud descriptions of Israeli clouds.  Gagin, understandably at the end of our protagonist’s discussion, asks him to leave and never come back; “do your own thing.”

 

  • Despite what happened in the second meeting, a third and final meeting is arranged with Prof. Gagin on 2 February 1986.    It occurs at the offices of his  rainmaking headquarters on the grounds of Ben Gurion International Airport.  Our protagonist asks if he can visit this headquarters to observe radar cloud top heights during storms.  His request is declined by Prof. Gagin, who insists that his cloud descriptions are correct.

 

  • In  mid-February 1986 our protagonist meets with the “Chief Meteorologist” of the Israeli cloud seeding experiments, Mr. Karl Rosner. He is informed by Mr. Rosner that a large amount of data was omitted in the reporting of the 2nd “confirmatory” rainmaking experiment whose results were published in 1981.  As it was published without that data, Israel-2 appeared to be a strong confirmation of the results of Israel-1 in the eyes of the world. Mr. Rosner, he tells our protagonist,  is now trying to get Prof. Gagin to publish the missing data.

 

  • The weather fails to deliver any more significant storms through 10 March, and our protagonist departs Israel after 11 weeks of cloud studies and data thanks to the IMS.

 

  • In June 1986, in a letter to Prof. Gagin, our protagonist summarizes his cloud findings; his letter is copied to several leading scientists. In this letter, our protagonist vows that he will leave the field of meteorology altogether if his observations concerning the clouds of Israel are wrong; that high concentrations of ice crystals occur in clouds with tops >-12°C. He challenges Prof. Gagin to leave the field if he is right.
  • Gagin, just 54 years old, passes in 1987 a few months after being notified in a letter by Prof. Hobbs that our protagonist’s cloud investigation has been accepted for publication in the Quart J. Roy. Meteor. Soc.
  • Two journals issue separate memorial issues to Prof. Gagin’s memory in 1988 and 1989, an exceptionally rare tribute that testifies to his standing. Joanne Simpson’s testimonial to Abe Gagin is published along with several others in the 1988 issue of the J. Wea. Mod.
  • The results of our protagonist’s cloud investigation are also published in 1988. It concludes that the clouds aren’t plump with cloud seeding potential as they have been repeatedly described by Prof. Gagin, but are quite the opposite of those descriptions, repeating the conclusions in his rejected 1983 journal submission to the J. Appl. Meteor.  The paper questions how cloud seeding could be effective given the actual nature of Israel’s precipitating clouds.
  • Like N-rays, it is eventually it is revealed in multiple reports that the clouds ripe with rainmaking potential that were described by Prof. Gagin do not exist.
  • 1990: the “full” results of the Israel-2 cloud seeding experiment are reported as urged by Mr. Rosner.  It is now found that the “full” Israel-2 experiment, incorporating previously omitted data, had a null result contravening the previous view of Israel-2 as unambiguous rainmaking success.
  • However, it was also hypothesized in the 1990 journal article that there could have been increases and decreases in rain separately in each of the two targets in Israel-2.   Thus, when these differing results were combined as the design of Israel-2 called for, they canceled each other out, thus causing the null result of the whole experiment and leaving an enigma.
  • 1992: Our protagonist’s 1988 cloud reports are first corroborated in airborne measurements by Tel Aviv University scientists unaffiliated with seeding activities. The Israeli clouds, indeed, appear to have little rainmaking potential due to having high concentrations (10s to hundreds per liter) of natural ice crystals in them at cloud top temperatures >-13°C.  These airborne reports are reiterated in separate publications in 1994 and in 1996.  More research supporting our protagonist’s cloud investigation appears over the next 20 years.
  • 1992: a journal paper by the promoters of rainmaking, one a protégé of Prof. Gagin, claim that dust interfered with Israel-2; that actual increases in rain occurred when there was no dust and decreases in rain occurred when there was dust.   Thus, a “dust hypothesis” is put forth to explain possible real increases and decreases in rain that were suggested in the full result of the 2nd experiment in the north and south targets.

 

  • Joanne Simpson, who advised our protagonist to give up the thought of being a meteorologist, finds the “dust hypothesis” highly credible. Our protagonist and Prof.  Simpson are now on a collision course in opinions again.

 

  • Our protagonist finds the 1992 dust claim ludicrous due to his 11-week cloud investigation in Israel in 1986.  He decides that something must be done about the dust claim.  He begins working at home on his own time in 1992 on the daunting task of reanalyzing Israel-1 and Israel-2.
  • Our protagonist’s reanalyses of the two statistical experiments in Israel are published in 1995 in the J. Appl. Meteor.  Prof. Hobbs is a co-author.  The reanalyses conclude that rainmaking activities did not increase rain in either Israel-1 or in Israel-2.  The clouds are also shown to form precipitation rapidly, leaving little opportunity for rainmaking.
  • 1997: Critical commentaries of the 1995 paper are published. The number of pages of criticism of the 1995 paper sets a record for the pages of  “Comments” on a paper ever published in an Amer. Meteor Soc. journal.  An ox has been gored.  In effect, our protagonist and Prof. Hobbs have become the most “criticized” meteorologists in the history of the Amer. Meteor. Soc.
  • However, the 1995 reanalyses and the 1997 journal exchanges trigger the first major independent review of rainmaking in Israel by the Israel National Water Authority (INWA). This organization had previously relied on the reports of the rainmaking promoters and other rainmaking partisans that rainmaking was working to increase runoff into the country’s largest freshwater lake, the Sea of Galilee, aka, Lake Kinneret.

 

  • 1998:  The results of 19 winter seasons of randomized cloud seeding in Israel-3 in the southern part of Israel are reported. There has been no effect on rainfall due to seeding.  The results again indicate that the clouds of Israel are unsuitable for cloud seeding.

 

  • 2006: After several years of study, the independent Israeli review panel reports that they can find no viable evidence that rainfall has been increased in 27 years of rainmaking (1975-2002)  targeting the Sea of Galilee  watersheds.
  • The independent panel’s finding corroborates the conclusions in the 1995 reanalyses by our protagonist and Prof. Hobbs, and supports the findings of our protagonist’s cloud investigation published in 1988: the clouds in Israel are not viable for rainmaking.
  • Once again, this rainmaking story seems to have reached a conclusion when rainmaking  is terminated in 2007 or 2013.      But it is not so.
  • The promoters of rainmaking in Israel argue that air pollution has suddenly canceled increases in rain due to rainmaking activities during the last decade of the program .  They argue that the review panel’s findings of no viable increases in rain are faulty because they do not include air pollution effects.
  • The independent review panel, and several other scientists in Israel find the air pollution argument by the promoters of rainmaking unconvincing and cloud seeding of the Sea of Galilee watersheds does not resume.
  • In 2010  Tel Aviv University scientists find that the supposed rain increases in the Israel-2’s north target days lacking in “dust,” were bogus. The seeding partisans had been misled in their conclusion because stronger storms happened on days when rainmaking took place in the “dust-free” target.
  • Once again, the story seems to have reached a conclusion in 2010 due to the new independent reanalysis described above. But again, it is not so.
  • 2012: The Israel National Water Authority is convinced to try once again to see if rain can be increased by cloud seeding in a new, sophisticated, randomized experiment, Israel-4.  This time the experiment targets the mountainous, northern extremity of Israel.
  • The conduct of a new experiment is supported by airborne reports by the rainmaking partisans who conclude that the clouds have a lot of rainmaking potential in northern Israel.
  • Importantly, instead of being carried out by seeding partisans, the new experiment is carried out by independent Israeli scientists.
  • Israel-4 ends in 2020 after seven winter seasons. There is no indication that a viable amount of rain has been increased by rainmaking.   The official null “primary” result has since been published by Benjamini et al. 2023, J. Appl. Meteor.
  • This result of Israel-4 parallels the several prior conclusions by external skeptics concerning all the rainmaking activities in Israel, including those by our protagonist and Prof. Hobbs concerning Israel-1 and -2.
  • The null results of Israel-4 experiment also reiterate those of our protagonist in 1988 concerning the clouds of Israel; they are not conducive to rainmaking.
  • This time, in 2023, our “story” finally seems to have reached an end.
  • But how can the “story” end?  Think of the courage it would take for those who promoted seeding in Israel for so many decades and who have cost their own country so much in wasted seeding programs to walk away from repeated faulty analyses and descriptions of non-existent, ripe for seeding clouds?  They won’t.  Count on it!

1Art and Prof.  Peter V. Hobbs, the Director of his group,  were honored by the UN partly for the work reported here.  The 2005 monetary prize was adjudicated by the World Meteorological Organization.

If anyone has gotten this far, you can go even deeper in these posts:

Chapter 1: My One and Only Meeting with Joanne Malkus/Simpson

Chapter 2:   A Story About Lost  Idealism Concerning Science that Leads Eventually to Israel

Chapter 3: The Review of the Israeli Cloud Seeding Literature Begins

Chapter 4:  The Trip to Israel to See the Ripe for Cloud Seeding Clouds that I Doubt Exist

Chapter 5, the last:  Got Published!

A Progress Report on Science Doings…and More (updated in August 2023 after a year-long hiatus)

Dear Friends,
 
First,  turned the big Eight-Oh last year.  Truly bad; time running out.  The Grim Reaper can’t be far behind me.  Let us calm down by listening to some content about death from the Swedish band,  Ghost:
 
 
Still doing science as best I can with this ancient brain!  Lots still to do.  Why even right now, a history of the Colorado River Basin Pilot Project, conducted in the early 1970s, still the nation’s largest, most costly randomized mountain cloud seeding experiment, is in review at the J. Appl. Meteor. and Climate.  My co-author is Dave “Eloquent Science” Schultz!  Will it get published?  I dunno.  It’s not the best science story due to major oversights, failed peer-review of the prior work on which it was based, the usual stuff.
 
Some recent “contributions” posted in the past two years at cloud-maven.com:
 
One-Sided Citing in Cloud Seeding
 
 
The above was submitted to the Bull. Amer. Meteor. Soc. (BAMS) as an “essay” but was rejected by J. Rosenfeld, Chief Ed., in 2019.  This version has been rewritten and expanded from the submitted one and the word “misconduct” removed from the original title which asked the question if one-sided citing should be considered so.  I have a low threshold of scientific misconduct…
 
 One sided citing is a plague, not only in science where controversy exists,  but also in the media.  It is a phenomenon that doesn’t tell the full story but misleads readers.  Please read Sharyl Attkisson’s book, “Slanted” for media examples.
 
The Rise and Fall of Cloud Seeding in Israel
 
A special interest of mine began in 1979 or so when Prof. Peter Hobbs, the director of my group, challenged me to look into the Israeli cloud seeding experiments after I had outed faulty cloud seeding work in Colorado and Washington State.  The history alluded to in the title above has been updated after the seven season Israel-4 randomized experiment ended in 2020 with a null result.  Wow.  
 
I had previously published on the clouds of Israel in 1988, and performed extensive reanalyses of the first two Israeli experiments in 1995 with Prof. Hobbs as a co-author/editor.   Both these pubs were on my own initiative, and considerable time and dime.  (My poor wife!)  You can get the “skinny” here though the piece is pretty “fat” being a full history of the Israeli seeding experience:
 
 
A shorter version of the above article, lacking the result of Israel-4,  was rejected in 2019 by BAMS Special Ed, James Rodgers Fleming, a former member of Peter Hobbs’ group (my former group)!  I got two reviews; an anonymous, “accept, important paper, minor revisions”, and a “reject” by a promoter of cloud seeding at the Hebrew University of Jerusalem, Dr. Daniel Rosenfeld, who signed his review.
 
BAMS would not let me respond to the comments of the reviewers (Special Ed. Rodgers kindly asked BAMS “higher ups”) , so I could make those few necessary revisions to my manuscript.   I thought this refusal was unheard of, especially due to the disingenuous comments of the seeding partisan.  
 
When I queried BAMS last year after the Israel-4 null result became known, BAMS officials indicated that they were not interested in this history.   Amazing.
 
I think the long and winding road of the Israeli cloud seeding experience is a science story that every organization from states to local water districts that have paid for cloud seeding should read. You probably aren’t getting what you think IMO, as the Israeli’s found out when they got independent evaluations of their seeding efforts.
 
The Israeli story is pretty incredible because as much as $100 million in 2022 dollars was wasted on ineffectual cloud seeding due to seeding partisans who missed faults in their evaluations in reporting statistical seeding successes (or omitted data to make them look that way) and described imaginary, “ripe-for-seeding” clouds that buttressed those ersatz statistical results.   I am hoping to get a science medal from Israel for all my volunteer work.  :), sort of.
 
If you want the “big kahuna,” a full book length autobio about how a young, idealistic weather forecaster saw his idealism about science dissipated and then got into questioning the most highly regarded cloud seeding successes after he entered the murky domain of cloud seeding, its all here, in fact, too much.  But “hey” there are embedded slide shows!
 
 
 
LIFE STORIES
 
Also am assembling “life stories,”  a kind of “memoirs,” if you will,  a writing task that was inspired by those of my neighbors, Big Bill Cotton, and Big Roger Pielke, Sr. , both former faculty at Colorado State University, who have written their own fascinating stories.    Prof. Pielke had his own Amer.  Meteor. Soc. Symposium Day last January!  Prof. Cotton  got a medal given out only once every four years last year from the International Committee on Cloud Physics.  Wow.  While I am a pop gun compared to these science howitzers, I do think I have some interesting tales to tell.
 
Here are some chapter titles:
 
“Joanne, Abe, and Me
(Malkus/Simpson, Gagin)” 
 
Contains irony.  
 
Joanne, then at UCLA, advised me to give up the idea of being a meteorologist in 1963, and with good reason; my poor grades in math and physics.   But I became an expert in her field of cloud seeding and cloud microstructure and ended up on opposite sides on the cloud seeding reports of success emanating from Israel.  Irony+.  I was eventually proved correct in doubting those reports.  But Joanne was right in one sense; I could have never have made it through the highly theoretical UCLA program and, instead, matriculated at San Jose State, in a meteorology program that emphasized weather and forecasting along with the “hard stuff.”  I only wanted to be a weather forecaster.  Period.
 
“Peter Hobbs and Me:  Conflict Followed by Reconciliation.”
 
I went from seeing misconduct in a journal while working in Colorado in the early 1970s to another kind of science conflict when arriving at the University of Washington; the misappropriation of credit that had embittered some members of the group I had just joined in 1976.  I got sensitized to this issue immediately by professors and staff members.  I eventually resigned from a job I loved in December 1985 in protest over this issue submitting a 27 page tome to Peter about it.    But, by December 1987, I was rehired by Peter Hobbs!  There were no further credit issues!  What a story.  I’m still amazed!  I could not have done what I did without him.
 
“The Nightmare Before Banff”
A Science ‘Coming Out  Party’ for a Cloud Seeding Activist Who Had Never Before Presented at a Conference.”  
 
I saw months in advance  in the Bull. Amer. Meteor. Soc. program for Banff that it was going to be reviewed by the seeding experimenters whose work I had reanalyzed before I gave it! “WTF.”  I had months of palpitations concerning my upcoming and sure humiliation at Banff.  But the evening before my presentation, the lead professor of the experiment I showed was due to a natural storm bias he told me they weren’t going to talk about my paper.  
 
“The Trials and Travesties of a Seattle Mariners Batting Practice Pitcher.”  
 
Yeah, I did that for a couple of years inn the Kingdome in the early 1980s before I was fired for throwing balls that had  “movement” (cutting the ball) a backup catcher said.  Maybe, too, for beaning Joe Simpson in the knee, the Mariners’ center fielder…
 
And maybe one entire life chapter about that 1960 baseball game in which I got my third hit, a walk off single in the 10th inning to defeat the hated L. A. Dodger Rookies. The Rookies was a premier baseball team that no one on my White Front Redlegs team was good enough to make.   Let us review that historic game here as I do everyday:
 
 
Brain now empty,
 
“Octo” Art

The Rise and Fall of Cloud Seeding in Israel (updated in August 2023)

Once having  proved to the world that cloud seeding works, Israel no longer seeds to add water to the Sea of Galilee, its primary source of fresh water.  This is a scientific story that has taken almost 60 years to play out.

Arthur L. Rangno, retiree,  Research Scientist IV, Cloud and Aerosol Research Group, University of Washington, Seattle.  Recipient in 2005 with Prof. Peter V. Hobbs of a small monetary award adjudicated by the World Meteorological Organization for studies in weather modification/cloud seeding.

 

ABSTRACT

 The Israeli seeding program is traced from its modern inception in 1961 to the pinnacle of success it achieved after the statistically-significant results of the first two randomized experiments, Israel-1 and Israel-2,  had been reported and how the early “ripe for-seeding” cloud reports laid the foundation for the virtually unanimous view that those experiments had provided proof that cloud seeding had significantly increased rainfall.

The peak was followed by an erosion of status that began with a cloud reports at variance with those of the experimenters in 1988 followed by the full reporting of Israel-2 crossover result in 1990 which revealed a null result.  It had not repeated the apparent crossover success of the Israel-1 experiment.  Moreover, reports for a third, 20 year long randomized experiment, Israel-3, in the early1990s suggested rain had been decreased due to seeding by 9%.   This fall in status was accelerated when independent re-analyses of Israel-1 and 2 appeared in 1995 and a second independent reanalysis for the north target of Israel-2 in 2010 all of which found strong evidence of null results in these experiments.

Two independent evaluations of the operational seeding program that began for Lake Kinneret (Sea of Galilee)  in 1975, found no indications that runoff had been  increased by seeding.   The program was terminated as a new randomized experiment, Israel-4 began.

The null results reported in these experiments and the operational seeding are supported by cloud studies over the past 30 years indicating that the clouds of Israel are generally unsuitable for seeding due to their high precipitating efficiency and the high temperatures (>-10°C) at which ice onsets in them.

A final seven season randomized experiment, Israel-4, conducted in the mountainous regions of the Golan Heights, ended in 2020 with a null result; no viable increase in rainfall had occurred on seeded days.

————————————————————————————

  1.  The impact of the first two Israeli randomized cloud seeding experiments:  cloud seeding proved.

            “Almost every review of the status of weather modification published since 1970 has described the Israeli experiments as providing the most convincing evidence available anywhere that cloud seeding can, in fact, increase average rainfall over an area. The credibility of the reported rainfall increases from Israel I and Israel II is due to impressive compilations of statistics and to Dr. Gagin ‘s cloud physics studies, which provided a plausible explanationfor the rainfall increases suggested by the statistical analyses.”                                ————–A. S. Dennis (1989), part of his preface to the                                                                                             Memorial Issue of the J. Appl. Meteor.

 No experiments in the history of cloud seeding have had more impact on the world of cloud seeding than the first two long-term randomized experiments conducted in Israel between 1961 and 1975 by scientists at the Hebrew University of Jerusalem (HUJ).  The apparently successful results of these experiments, Israel-1 and Israel-2[1], were cited in numerous meteorology textbooks as singular successes in cloud seeding from introductory ones (e.g., Neiburger et al. 1982; Moran et al. 1991; Lutgens and Tarbuck 1995) to those at graduate levels (e.g., Wallace and Hobbs 1977; Dennis 1980; Young 1993).  Moreover, it led to attempts at transferring the Israeli results to Spain (Vali 1988) and Italy (List et al. 1999) and influenced nearby Arab countries to try cloud seeding.

These two experiments were also hailed in reviews by expert scientific panels, organizations and by leading individual scientists in the field as cloud seeding successes (e.g., Sax et al. 1975; Tukey et al. 1978a; b; Simpson 1979; Grant and Cotton 1979; List 1980; Mason 1980; 1982; Amer. Meteor Soc. 1984; Silverman 1986; Cotton (1986); World Meteorological Organization 1986; 1988; 1992; Dennis 1989, Cotton and Pielke 1995).  Typical of media reports was a summary of cloud seeding by Kerr (1982), who described the first two Israeli experiments in this way: “Cloud Seeding: One Success in 35 years[2].”

But should they have been that “one success”?  Could all the glowing statistical results from the first two experiments, supported by seemingly solid cloud microstructure studies, in fact, be “scientific mirages”, as Foster and Huber (1997) termed faulty literature? And, as faulty literature, could it still be published in our peer-reviewed journals and be accepted as valid by our best scientists, national and international panels?

The answer to this question is, “yes.”     

The story told here is one of the most compelling chapters in the field of cloud seeding, one that has taken almost 60 years to play out.  And, as many findings are within the domain of cloud seeding (e.g., Changnon and Lambright 1990), it has been steeped in controversy until recently when the “dust” seems to have settled due to the recent null outcome of a fourth long term randomized experiment.  In this case, the controversy has been between those from the institution from which the reports of seeding successes and cloud descriptions originated and the external skeptics who investigated those claims and found them lacking.  

However, as of Freud et al. 2015, there is general agreement that the clouds of Israel exhibit a high precipitation efficiency with the onset of precipitation in clouds with tops between -3°C and -5°C, making them generally unsuitable for glaciogenic seeding.  A hoped-for exception to this  was in the mountainous Golan Heights of Israel where “Israel-4″ was carried out with disappointing results after seven seasons of randomized seeding.

I am well-acquainted with these experiments.  As a skeptic of the experimenters’ many cloud descriptions, I traveled to Israel for an 11-week cloud investigation[3], from January through mid-March 1986.  The results were published in Rangno 1988 (hereafter, R88).   I also carried out re-analyses of the Israel-1 and 2 experiments (Rangno and Hobbs 1995a, hereafter, RH95a), the latter subject to numerous “Comments[4]” (Rosenfeld 1997; Dennis and Orville 1997; Woodley 1997; Ben-Zvi 1997 and “Replies” (Rangno and Hobbs 1997a, b, c, d, e).

This review begins with descriptions of the first two experiments, their initial convincing results followed by the associated “ripe-for-seeding” cloud descriptions. Overall, this review supports the views of Bruintjes (1999) and Silverman’s (2001) that the confidence that the Israel-1 and Israel-2 experiments had proven cloud seeding has waned due to later published work.  Most of the material here was not included in Bruintjes (1999) or Silverman’s (2001) reviews these experiments which included cursory reviews of several other experiments[5].

 

  1. The rain season climate of Israel

 

The rain season in Israel runs from about mid-October through April and consists of about 50-70 days, the greater number in the north (Goldreich 2003).  Showers form in cumuliform clouds as cold polar air masses exiting the European Continent move onto the warm waters of the Mediterranean Sea, enhanced into clusters or bands by traveling upper air troughs in the westerlies but are more scattered in coverage behind troughs as subsidence occurs.  These events produce about 120 hours of measurable rainfall at each site (Goldreich 2003).

The air masses that move onto the Mediterranean from Europe contain considerable aerosol content as the pass over the Mediterranean Sea.  However, as the clouds gain in stature much like lake-effect Cumulus clouds do, the increased mixing depth downstream helps reduce the impact of European aerosols; the initial high aerosol concentrations are dispersed over greater depths.  In addition, these clouds also take up marine aerosols (Levin et al. 1996, Freud et al. 2015).

  1. Descriptions of Israel-1 and 2 randomized cloud seeding experiments.

       a)  About  Israel-1

This first of three two daily[6]randomized cloud seeding experiments, begun in the late winter of 1961 had two targets, one of which was designated in advance to be seeded each day during the rain season of mid-October through April. The Israel-1 experiment of six and a half rain seasons was a “crossover” experiment in which the results of seeding are combined from the two target areas (e.g., Neumann et al. 1967; Gabriel 1967a; b).  In a crossover experiment, one of the two targets is seeded every day; experimental data builds twice as fast compared to single target experiments (e.g., Neumann and Shimbursky 1972; Gabriel 1999).  

 The two seeding targets in Israel-1 were called, “north” and “center”, and were separated by a small “buffer zone” (BZ) that was left unseeded (Figure 1).

Figure 1.  Map of Israel showing the north and center target areas (shaded) and the buffer zone for Israel-1. (after Gabriel 1967a). Thewind rose shows the percentage of the time that the 850-hPa wind was from a particular direction when rain was falling at the time of or within 90 min of, the rawinsonde launch time and at, or within 60 km of, the rawinsonde launch site.

Due to the proximity of the targets, significant correlation (~0.8) in rainfall existed between each one as established in historical comparisons (e.g., Gabriel 1967a).  It is also assumed in crossover experiments that the natural cloud microstructure in the two targets is virtually identical and will respond to seeding in the same way.  

The seeding in Israel-1 was carried out by a single DC-3 aircraft flying at about 50 m s-1parallel to and within about 10 km of the coastline releasing silver iodide (AgI) at or just below cloud bases.  Cloud bases average about 700-800 m above sea level (Gabriel 1967a, Gagin and Neumann 1974, hereafter GN74a). 

The line-seeding legs conducted upwind of each target at cloud base were 65-75 km each way.  This required about 20-25 min to complete one roundtrip seeding cycle[7].  AgI released by the aircraft was expected to be ingested in updrafts to form the ice crystals needed to initiate precipitation by the Wegener-Bergeron-Findeisen (WBF) mechanism. In the WBF mechanism, ice particles grow in clouds containing supercooled liquid water or they grow where ice supersaturation exists even without the liquid phase.  It was generally believed in the 1960s that within the cloud top temperature range of -10° C to -20° C, that there would be few if any ice crystals along with abundant supercooled liquid water in such clouds (e. g., Fletcher 1962; Mason 1971).  The lower part of this temperature range is where AgI that was used in both Israeli experiments was highly active in forming ice crystals.  Cloud tops during storms in the temperature range above were reported to be common from radar data accumulated in Israel-2 (e.g, Gagin and Neumann 1976, hereafter GN76).

Aircraft line-seeding was carried out for an average of 4 h per rain day for a total of about 70 h upwind of each target per entire rain season in Israel-1  (Gabriel 1967a, Table I).  Of these hours, an average of 42 h was carried out in the daytime and 28 h at night (Gabriel and Neumann 1978)[8]

Seeding was conducted when a “cloud seeding officer” (Gabriel 1967a) determined that cloud tops were colder than -5°C, generally above 3 km MSL in Israel. At night, it was assumed cloud tops were colder than -5°C if rain was observed.

 Israel-1 ended with the 1966-67 rain season with 378[9]experimental days (e.g., Wurtele 1971). The days culled were those that had measurable rain in the BZ in an effort to minimize the number of completely dry days in the targets[10].

      b)  Results of Israel-1

 Interim results from Israel-1 were first reported by Gabriel (1967a, b; Neumann et al. 1967), followed by a report of the full experiment in a non-peer-reviewed, Final Report by Gabriel and Baras (1970).  The complete Israel-1 experiment description first appeared in the peer-reviewed literature by Wurtele (1971).  These reports indicated that a 15% increase in rainfall had been produced by seeding when the rainfall data from both the “north” and “center” targets were combined as the design specified.  Larger rainfall increases on seeded days were noted in the center target compared to the north target (e.g., Gabriel 1967a), and the suggested increases in rain due to seeding were larger farther inland from the aircraft seeding line (e.g., Gabriel and Baras 1970; Wurtele 1971, Gagin and Neumann 1974a, and Gagin and Neumann 1974b, hereafter, GN74a and GN74b).  This latter finding was compatible with seeding logistics and the time of formation of rain once the AgI reached the low cloud temperatures (<-10° C) required for appreciable activation, that level generally above 4 km ASL.

However, a discrepancy arose in the analysis by Wurtele (1971) that had not been noted in the analyses prior to 1970:  the greatest of all the apparent increases in rainfall due to seeding was in BZ between the two targets on center seeded days.  This discovery was later inferred by the experimenters as an unintended effect of seeding of the BZ on center seeded days (e.g., Gabriel and Baras 1970; GN74a).  Wurtele (1971), however, had quoted the Chief Meteorologist of Israel-1, who stated that seeding could only have affected the BZ, “5-10% of the time” and “most likely less than 5%” of the hours that the center had been seeded. 

In the meantime, Brier et al. 1974, in an independent re-analysis, expanded the apparent increases in rainfall due to seeding into Lebanon and Jordan, while Sharon (1978) in a study comparing the size of rain systems on seeded days in Israel-1, concluded that they were 10 km larger in area than on non-seeded days.

Except for the discrepancy in the BZ, Israel-1 was a very convincing outcome for a well-designed experiment.  However, at this time, little was known about the clouds of Israel.  This was to change during Israel-2 when descriptions of Israeli clouds began to appear in the literature, ones highly supportive of potential for seeding (e.g., Patrich and Gagin, 1970; Gagin 1971, Gagin and Steinhorn 1974, Gagin and Neumann 1974).

       c) About Israel 2

Israel-2 was carried out from 1969-70 through 1974-75 rain seasons. It was also designed as a crossover experiment patterned after Israel-1 in which random seeding took place in two target areas, this time called “north” and “south” (e.g., GN74a, Silverman 2001).  The north target was shifted inland from Israel-1, as was the aircraft line seeding path to improve targeting of the Sea of Galilee (a.k.a., Lake Kinneret) watershed, Israel’s primary natural fresh water source.  The south target area included the area of the “center” target of Israel-1 as well as a large area to the south of the former “center” target (e.g., GN74a).   The same BZ as in Israel-1 was used in Israel-2 (Figure 2).

Figure 2.  Map of Israel showing the two target areas and the buffer zone for Israel-2. The solid. lines with arrows denote the flight tracks along which artificial seeding was carried out. The circles show locations of IMS rain gauges. The triangle shows the location of the IMS 3-cm radar and rawinsonde launch site at Bet Dagan. The light shading shows terrain between 300 and 600 m MSL, and the darker shading terrain above 600 m MSL. The wind rose shows the per-centage of the time that the 850-hPa wind was from a particular direction when rain was falling at the time, or within 90 min, of the rawinsonde launch time and at, or within 60 km, of the rawinsonde launch site.

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A narrow coastal region located upwind of the north target area, one that exhibited a high correlation (r≈0.9) in historical rainfall with the north target, was designated as a control area at least as early as 1972, adding another evaluation dimension for that target in addition to the primary crossover one (GN74a[11]).  

The amount of seeding was significantly increased from Israel-1 to Israel-2.  A second line-seeding aircraft was added, and a network of 42 generators was installed (National Academy of Sciences 1973, Appendix).   The ground generators were added for more effective seeding of the inland hill regions of Israel than had been the case in Israel-1 where only four ground generators were used, and those were in the far northeast corner of the country (GN74a). 

The Israel-2 experiment had several design/evaluation elements from which statistical results could be derived: a crossover design using the combined data from both targets; a target/control design for the north target; single area evaluations for each target using the rainfall on their respective seeded and unseeded days;  and one using the alternate target’s rainfall on a target’s seeded day as the control rainfall.  One of the key advantages of the crossover method, as was described in GN74a, is to reduce storm bias on experimental days when the alternate target’s non-seeded rainfall is used as a control.

The experimenters also had radar coverage during Israel-2 from the Israeli Meteorological Service’s (IMS) 3-cm wavelength radar from which to examine the echo tops of showers.  The radar data were to prove critical in illuminating results of seeding on various categories of modal echo top temperatures in conjunction with IMS rawinsonde data.

      d) The results of Israel-2

 Preliminary results were reported for Israel-2 by GN74a and GN74b.  GN74a reported that the target/control evaluation of the first two years had produced statistically-significant indications of rain increases in the north target of about 20% (single area ratio of 1.2) in the north target while in the south target using the same statistic was “less than 1,” suggesting rain had been decreased (GN74a).  GN74a noted that cloud tops were appreciably lower and warmer by an average of about 4°C in the south target than in the north target, and that seeding was likely going to be less effective there due to those higher cloud top temperatures.  

GN74b[12]reported the results of Israel-2 after three and four seasons, respectively.  They reported results for the north target only, noting that rainfall in the south target was highly variable, and that it would take longer to determine any seeding results.  The results of seeding in the north target remained virtually the same from season three to season four, with indicated rainfall increases of 13 and 14 %, respectively. 

The greatest effect of seeding (statistically-significant) found by GN74b, was concentrated in the radar echo top temperature range of -15°C to -20°C,  where prior calculations had suggested the greatest seeding effect should be contained given the belief that such clouds would be deficient in natural ice (e.g., Gagin and Steinhorn 1974).

The results of the completed Israel-2 experiment were first reported by GN76, and later by Gagin and Neumann (1981, hereafter, GN81); and in a series of reports by Gagin 1981; Gagin 1986, hereafter, G81 and G86 respectively), and also by Gagin and Gabriel 1987, hereafter GG87).  All these reports that suggested a 13% increase in rainfall due to seeding were confined to the north target using only the target/control evaluation method.  Larger increases were noted farther downwind from the cloud-base seeding line.  The results of seeding using the other evaluation methodologies were not reported.

Radar top height measurements combined with rawinsonde data reinforced the earlier GN74b findings that the peak increase in rainfall on seeded days (46%) in the north target occurred when modal radar tops were between -16° and -21°C.  Much smaller increases were indicated when modal tops were between -12°C and -16°C.  No increases in rain were found for those tops outside of the -12° to -21°C partition.  Radar top temperatures with seeding results were not reported for the south target. 

Benjamini and Harpaz (1986) found evidence that the daily randomized experiment had increased runoff in streams and from springs over entire rain seasons.   However, none were statistically significant. Ben-Zvi et al. (1987); Ben-Zvi (1988); and Ben-Zvi and Fanar (1996) followed with evaluations that found more robust indications of runoff and spring flow increases, some of which were statistically significant.  Sharon (1990) combined the results of the studies mentioned above by grouping them all together and found still more statistically-significant runoff or flow increases from springs over whole rain seasons that he attributed to seeding. The increased spring emissions when compared to historical data (15 years prior to Israel-2) was about 10% and confined to a central target zone northeast of the aircraft line seeding path.

The results reported for Israel-2 north target appeared to offer an unambiguous confirmation of the rain increases due to seeding reported in Israel-1 for a wide scientific audience and as a stand-alone experiment (e.g., Tukey et al. 1978). 

The first two Israeli experiments, as they had been reported, constituted formidable statistical evidence for a cloud seeding success in well-designed experiments having an exploratory phase followed by a confirmatory one.  Now, with reports of rain increases confined to modal echo top temperatures that ranged from -12° to -21°C, the experiments seemed complete as an unambiguous testimony to the positive effect of random seeding with AgI.   

4.   The experimenters’ cloud microstructure reports

 “The body of inferred physical evidence appears to support the claims of physical plausibility for-the positive statistical results of the replicated Israeli experiments I and·II (Gagin and Neumann, 1981) and helps to explain, in retrospect why these experiments were so successful, and others were not (Tukey et al., 1978; Kerr, 1982).” 

                                                                                    ——B. A. Silverman (1986)

A key ingredient buttressing the virtually unanimous acceptance of the statistical results of the Israeli experiments as proof of seeding efficacy were reports that the clouds of Israel were filled with great cloud seeding potential.

Why did the clouds of Israel appear so ripe for cloud seeding?

The experimenters reported on many occasions that ice crystal concentrations were quite low in Israeli clouds until their tops became colder than -21° C (e.g., Patrich and Gagin 1970; Gagin 1971;  GN74a, b; Gagin 1975, hereafter G75, Gagin 1980, G81, G86.  These reports meant that most of the cumuliform clouds rolled into Israel from the Mediterranean Sea with bases averaging 8°C-9°C, were 3-5 km deep with tops >-21°C produced little or no rain; that is, until they were seeded. According to these reports it took deeper, colder-topped natural clouds than these to produce significantnatural rain (e.g., G75; GN76; GG87).  The lower part of this temperature range, from -16° to -21°C was also where the AgI used in Israel-2 was highly active in nucleating activity, another point adding credibility to the statistical results.

The wintertime cumuliform clouds of Israel were being described by the experimenters’ as mirror images of the microstructure that had been reported for the wintertime stratiform clouds in Colorado.  In both locales it was reported that there was a relative dearth of ice crystals until cloud tops were colder than -21°C  (e.g., Grant 1968; G75).   Moreover, the reports from Colorado and Israel were also in agreement with summary reports like those of Fletcher (1962), Grant and Elliott (1974) and Cotton (1986) the latter two articles in particular purporting that a cloud top seeding “window” of opportunity existed for clouds with tops between -10°C and -25°C due to the belief that such supercooled clouds would be lacking in natural ice crystals.  Thus, the Israeli experimenters’ reports of very low ice concentrations in clouds with tops >-21°C, and no ice in clouds with tops >-12°C to -14°C, fit the existing paradigm of ice in clouds and were widely accepted (e.g., Mossop 1985).

It was also reported by the experimenters, as it had been in Colorado, that the cloud seeding scourge of “ice multiplication” (Hobbs 1969, Dennis 1980) did not occur in Israeli clouds (e.g., G75; G81: G86; Figure 1]3, black dots).

Figure 3.  

Figure 3.  Ice crystal concentrations vs. cloud top temperature (dots), including the least squares regression (dashed line) for these data (after Gagin 1975).  In the original equation shown, the letter “C” denotes ice crystal concentration and the letter “T”, the cloud top temperature.   The solid line with the open triangles denotes average ice nucleus spectrum.  The “X’s” are ice crystal concentrations measured by Levin et al. (1996); the squares are one-half those values reported by Levin et al. (1996) to take in possible shattering artifacts.  The upper dashed line represents a criteria suggested by Hobbs (1969) above which the observed concentrations of ice crystals qualify as a case of “ice multiplication.”

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“Ice multiplication” is where 100’s to 1000’s more ice crystals are found in clouds than can be accounted for by standard ice nuclei concentrations as summarized by Fletcher (1962) from world studies.  Ice multiplication is thought to severely reduce or eliminate cloud seeding potential in the kind of cloud seeding experiments carried out in Israel where small amounts of AgI are released (e.g., Dennis 1980).  

In both the exact temperature range in which seeding appeared to have produced the greatest results, and in the magnitude of the response to seeding (about 50% increases in precipitation), Israel-2 was also a mirror image of the results of cloud seeding that had been reported by Colorado scientists (e.g., Mielke et al. 1970; 1971; 1981).  It was a remarkable confluence of reports considering the different types of cloud systems seeded (cold stratiform vs. cumuliform).

Further parallels in these sets of experiments in Colorado and Israel-2 which added to the credibility of both, were that no viable seeding effects occurred at “cloud top” temperatures above -12° C or below -21°C.   The high temperature cutoff was attributed to the low nucleating activity of the silver iodide nuclei used to seed their respective clouds, low crystal growth rates, and the shallowness of clouds having those warmer tops.  The low temperature cutoff of seeding effects was thought to be due to the high natural concentrations of ice believed to exist at cloud top temperatures <-21°C where AgI would have little impact (amplifying the importance of not having ice multiplication occur).

The final parallel reported between the experiments in Colorado and Israel, and one that was also critical to the credibility of the statistical results, was that the effect of seeding had been to create more hours of precipitation; it had not increased its intensity (e.g., Chappell et al. 1971, in Colorado; G86; GG87 in Israel-2)[1].  The duration finding was again compatible with the kind of seeding carried out in each experiment, termed, “static seeding”, where relatively low concentrations of AgI are released into the clouds to initiate precipitation that otherwise would not have occurred (Dennis 1980; National Academy of Sciences 2003).  

Thus, in every way, despite the differences in the clouds seeded, the reports from the experiments in Colorado and in Israel “cross pollinated” one another, helping to increase their mutual credibility. 

5.   The Fall

a.  The erosion of the experimenters’ cloud reports, and ultimately, the foundation for the belief that cloud seeding had increased rainfall

Reversals of the descriptions of the “ripe-for-seeding” Israeli clouds began to appear in 1988 when it was reported that rain fell from clouds with tops >-10°C (R88), contrary to the experimenters’ many cloud reports.  In six flights on shower days a few years later by Levin (1992; 1994; Levin et al 1996, Table 4),  high concentrations (10’s to 100’s per liter) of ice particles were encountered near the tops of clouds ranging from just -6°C to -13°C (Figure 3, crosses).  The values reported by Levin et al. (1996) indicated that ice multiplication is rampant in Israeli clouds and supported the conclusions in R88.[2]  Radar observations by Rosenfeld and Gagin (1989) showed that rain initiates in Israeli cumuliform clouds between -5°C and -10°C when temperatures, estimated by using pseudo-adiabatic lapse rates, are added to their Figure 1.  This is precisely what was reported in a similar figure using the IMS radar by GN74 but went unnoticed.

Ramanathan et al. (2001) using satellite-derived effective radius measurements confirmed the above results that precipitation onset in Israeli clouds with tops between -5°C and -8°C, typically when cloud depth is between 2.5 and 3.5 km.  Ramanthan et al. however, attributed their finding to the presence of dust aerosols rather than reporting that it was a general characteristic of Israeli clouds.   That was to be found later.

Freud et al. 2015, however, attributed the early formation of precipitation in Israeli clouds that they observed in tops ascending through -3°C to -5°C, to a “sea spray cleansing” of pollution aerosols from clouds by the Mediterranean Sea.  This “cleansing” they asserted, allowed large droplets to form in clouds as they moved over the Mediterranean Sea toward and into Israel.  The presence of large droplets made them conducive to early precipitation formation (and ice multiplication), “even before AgI can take effect,” Freud et al. wrote.

The early idea Israeli clouds are solelycontinental in character as had been reported by the original experimenters, that is, that they are characterized by very high droplet concentrations (500-1500 cm-3) and a narrow droplet spectrum throughout, has been revised due to these later reports.  Cloud droplet concentrations in Israeli clouds are only moderately high, from 200-500 cm-3, or “semi-continental,” with exceptions that concern shallow boundary layer clouds in light winds in polluted conditions, almost always on non-storm days.

When these new reports of ice and precipitation onset in Israeli clouds are integrated into the nomogram of Rangno and Hobbs (1988, Figure 3[3]), the clouds of Israel are compatible in the onset of ice to similar clouds having similar base temperatures. They no longer standout as having to be significantly colder than similar clouds as had been indicated in the early cloud studies by the experimenters (e.g., G75).  Moreover, with the lower droplet concentrations (e.g., Levin et al. 1996) and with cloud base temperatures averaging 8°C to 9°C, (GN74, G75), the Israeli clouds now also fall where Mossop’s (1978) nomogram predicts that ice multiplication will occur.

As with other clouds, dust is not required for enhanced ice concentrations; rather, just a broad droplet spectrum is required for Cumulus cloud tops that ascend to below freezing temperatures.  With their relatively warm cloud bases, ranging from 5°C to 12°C (RH95a), modest droplet concentrations and a broad droplet spectrum, the clouds of Israel are indeed, “ripe”, but not for cloud seeding, but rather for ice multiplication and high ice particle concentrations, conditions that make them unsuitable for cloud seeding.[4]

b.   The effectiveness of airborne line cloud seeding in Israel-1 and Israel-2

 

The line-seeding by a single aircraft used in Israel-1 was evaluated in RH95a.  They concluded that the line-seeding method only could have affected a small fraction of all those that produce rain in Israel.  It should be emphasized that the aircraft did not “orbit” in updrafts under promising cloud bases, but merely flew in a line under clouds and showers, whatever their stages (growing or dissipating), and in the clear spaces between them, releasing AgI nuclei all the while.  The long seeding path resulted in untreated clouds going by before the seeding aircraft could return to its starting point.

Levin et al. (1997) also evaluated the aircraft line-seeding method, but for Israel-2, using the Colorado State University RAMS model with a 0.5 km mesh.  They concluded, using rawinsonde profiles on typical shower days in Israel to initialize the model, that the aircraft line-seeding method could only have affected a very few clouds under which the aircraft flew.   Their conclusion, using much more sophisticated calculations than in RH95a, was virtually identical to it.

c.   The erosion of the statistical results of the first two Israeli cloud seeding experiments.

 “Experiments with ‘unsuccessful’ results in the first season or two may often not be reported at all. As a result the experiments whose results are published would be those with initial ‘successes’ which are usually followed, sooner or later, by less ‘successful’ seasons.”                                 —–K. R. Gabriel (1967a),  quoting a personal communication  from fellow statistician, W. Kruskal.

      1. Israel-1

Re-analyses of both Israel-1 and Israel-2 were carried out by RH95a.  Considerable evidence was found for Type I statistical errors or “lucky draws” in each experiment[5]. Ironically, the RH95a findings for Israel-1 and Israel-2 replicated what had happened in the Climax I and II experiments where each of those experiments was found to have suffered from “lucky draws” (Mielke 1979), thus continuing a theme of these experiments mirroring each other’s experimental sequence of events in an unexpected way.   

For Israel-1, Brier et al. (1974) had earlier interpreted regional cloud seeding statistics in Lebanon and Jordan as evidence of massive downwind and side wind seeding effects on center and north target seeded days. RH95a, on the other hand, saw the Brier et al. plots and statistics, in view of how little seeding that was carried out in Israel-1 in largely unsuitable-for-seeding clouds, as equally massive counter evidence of a bias in the random draws.    RH95a also calculated that it was untenable that the small amount of AgI released in Israel-1 created the amount of rain over the vast area that Brier et al. had concluded that rain had been increased. 

Sharon’s (1978) study that indicated that rainfall areas were larger on seeded days than on control days can be seen as compatible with a Type I statistical error or a “lucky draw.”   Stronger storms on seeded days, rather than seeding effects, are more likely to have produced the larger areas of rain that Sharon (1978) attributed to seeding.   

Another “red flag” in Israel-1 indicating something was likely amiss was that the little seeded BZ between the “center” and the “north” targets exhibited the greatest statistical significance of either north or center targets (e.g., Wurtele 1971; GN74a).  As noted, the Chief Meteorologist of the Israeli experiments, (quoted by Wurtele 1971) in his own wind analysis, concluded that the BZ could only have been inadvertently seeded a miniscule amount of the time that seeding took place.

RH95a in their own low-level wind analysis reached a conclusion similar to that of the “Chief Meteorologist” quoted by Wurtele. RH95a focused on those times when rain was falling in Israel at within 90 min of the time of the Bet Dagan, Israel, rawinsonde launch, replicating those times when seeding would have been expected to be taking place.  The very narrow wind direction envelope with rain falling (see wind rose in Figure 1) suggests that it would have taken a fairly negligent pilot to have inadvertently seeded the BZ on center-seeded days if he had been instructed not to seed it. 

Adding to this picture of an uneven draw that favored heavier natural rain in the BZ on center seeded days was greater rainfall on those same days at coastline locations too close to have been affected by a fallout of rain from cloud base seeding (RH95a).  This same conclusion about the coastal zone having been unaffected by seeding had been reached earlier on several occasions by the experimenters (Neumann et al. 1967 N[6]; Gabriel 1967a; Gabriel and Baras 1970 N; Gabriel 1979). 

                  Thus, the totality of evidence above for Israel-1 best supports the “lucky draw” hypothesis (Type I statistical error) that created the misperception of increased rainfall due to seeding.  This conclusion is compatible with too little seeding in Israel-1 and one also compatible with today’s knowledge that the clouds of Israel are unreceptive to producing significant rain through glaciogenic seeding with AgI (e.g., R88, Levin et al. 1996). 

Moreover, the findings of Freud et al. (2015) have undercut the multi-faceted hypothesis of Rosenfeld (1997) who tried to the explain the high seed/no seed ratios in the immediate coastal zone of Israel-1 as due to a “blowback” of cloud seeding material released by the seeding aircraft.  Rosenfeld posited that a portion of the seeding material released in westerly or southwesterly flow at cloud base offshore eventually dispersed downward, got caught in low-level, offshore-flowing easterlies near the surface as the AgI diffused downward and eastward into Israel.   At that point a portion of the seeding plume reversed course and headed to the west or northwest.  It not only went offshore,  he surmised, but offshore far enough that it got ingested into the bases of ripe-for-seeding clouds at locations far enough upwind so that when the AgI rose up the several km required to where the errant AgI could activate, it then triggered ice crystals that grew and fell out as rain on the coastal zone.    These many-linked conjectures “explained” the high seed/no seed ratios on seeded days along the coast according to Rosenfeld (1997). 

The ripe-for-seeding clouds hypothesized by Rosenfeld (1997), ones awaiting the errant seeding plume moving westward and offshore, however, have been shown to be mirages in the many cloud-related citations above, among other unrealistic aspects of this hypothesis critical of  the RH95a reanalysis.  Rosenfeld’s long 1997 commentary was comprehensively addressed in RH97b.

 

      1. Israel-2

 

 The convincing results for the north target of Israel-2 with so many supporting arguments, were compromised when the full results of the experiment were reported (Gabriel and Rosenfeld 1990).  Gabriel and Rosenfeld found that the mandated crossover analysis of Israel-2 resulted in no apparent seeding effect (-2%), reversing the former “optimistic results” of seeding, they wrote.   

The major culprit?   

Unusually heavy rain on north target seeded days also fell in the unseeded south target, the north’s control area in the crossover design. How heavy were those rains in the south target on north target seeded days? 

Quoting Gabriel and Rosenfeld (1990) on their extraordinary discovery in this regard:  the south target rainfall was “several standard errors above the normal daily amount” and it was “clearly statistically significant[7].”  Any real seeding effect in the north may have been canceled out in a crossover type of evaluation.   Gabriel and Rosenfeld (1990) were not able to clarify whether there had been real increases in rain the north target area (13%) and decreases in the south (-15% or more), as their results suggested, or whether there had been no seeding effects at all in both targets.   

However, the statistically significant results using one of the several evaluation methods, the target/control scheme, held out hope that cloud seeding had nevertheless increased rainfall.

Rosenfeld and Farbstein (1992, hereafter, RF92) capitalized on the possibility of actual “divergent” effects due to seeding suggested by Gabriel and Rosenfeld (1990).  They hypothesized that the increases and decreases suggested in rainfall due to seeding in the two targets were real and were were due to the presence or absence of  dust.  Surface weather observations for the presence of dust or haze were examined by RF92 and those days where one or more Israeli surface stations reported “dust-haze” were separated from days without dust-haze and the results of seeding re-evaluated.  The elimination of numerous “dust-haze” days led to improved seeding results in the north target (RF92). 

There were several assumptions in the dust-haze hypothesis of RF92:  1) a report of dust-haze at the ground meant that the clouds aloft  had been seriously impacted by dust-haze, 2) the kind of dust that the clouds ingested led to large cloud droplets,  3) the large cloud droplets led to both the formation of rain through an all liquid process (collisions of droplets with coalescence), and,  if cool enough at cloud top, to high ice particle concentrations. 

They further hypothesized that when seeded, such clouds affected by dust-haze developed too many natural ice crystals for effective rain at the ground.  The more numerous, smaller ice crystals in clouds due to seeding with dust in them resulted in less rain at the ground because the smaller, more numerous ice crystals evaporated on the way down before they could become raindrops. 

In this “divergent effects” hypothesis by RF92, it was recognized that most of the clouds of Israel have naturally high ice particle concentrations, but solely due to dust-haze, except for a portion of those clouds which, by inference, RF92 still deemed as “ripe-for-seeding” when dust-haze was not affecting them.   RF92’s findings also meant that the clouds of Israel generally did not contain modest droplet concentrations with a broad droplet spectrum without dust.  The latter combination would stillmake such clouds ready to produce high ice particle concentrations at slight to modest supercooled cloud top temperatures and unsuitable for producing appreciable results from cloud seeding.  There were no in-cloud measurements to support the RF92 hypothesis concerning the effect of dust beyond ground ice nuclei measurements (Gagin 1965) and soil particles in rainwater (Levi and Rosenfeld 1996).

RH95a, inspired by the RF92 re-analysis of Israel-2 and the “dust-haze” hypothesis, carried out another, but wider re-analysis of Israel-2, one that incorporated data from Lebanon[8] and Jordan.  RH95a concluded that a Type 1 statistical error (lucky draw) had occurred in Israel-2 north target seeded days and that it had produced the misperceptions of increased rain in the north target area (Type I statistical error, or “lucky draw”) and one of decreased rain in the south target area (Type II statistical error, or “unlucky draw”.)   Namely, there were no “divergent” effects of seeding, as hypothesized by RF92.  The RH95a conclusion was reached because not only did the south target experience unusually heavy rain on north target seeded days (the south’s control day for the single area seed/no seed ratio), but sites in Lebanon and Jordan also experienced heavier rain on north target seeded days. Thus, rain wasn’t decreased on south target seeded days as hypothesized by RF92, but rather excessive rain on the south’s control days produced an appearance of decreases due to seeding when only average rain fell on its seeded days. 

            Furthermore, since cloud tops are warmer and lower as a rule in the South target in Israel than in northern Israel (GN74a; RH95a) it is difficult to accept the proposition by RF92, and later by Rosenfeld and Nirel (1996), that clouds in southern Israel could have been “overseeded” due to dust combined with AgI.

It was also observed in the wider analysis by RH95a that the rain gauges used by the experimenters in the small coastal control zone as a control for the north target constituted an anomaly in the regional pattern of heavier rainfall on the north target’s seeded days.  The narrow coastal control zone did not reflect the regionally wide heavier rainfall.  This enigma was not resolved by RH95a but was resolved later by Levin et al. (2010).

            Levin et al. (2010) addressed the question of synoptic bias in Israel-2 and found that synoptic factors had, indeed, compromised Israel-2.   Stronger upper low centers were in the eastern Mediterranean accompanied by stronger low-level winds on the north target’s seeded days.  These stronger storms “drove” the Israel-2 statistical results when the coastal control zone was used.  The stronger lower level winds created a pseudo-seeding effect by intensifying the maximum rainfall from the coastal control zone toward the hilly regions of the target, the rain amplified by orographic effects.   Under stronger onshore winds, the coastal convergence zone that leads to heavy coastal rains is not active.

The re-analyses by Levin et al. (2010) of the Israel-2 north target and of operational seeding, as did that of RH95a, drew vigorous commentary from seeding partisans (Ben-Zvi et al. 2011), with a comprehensive “Reply” by Levin et al. (2011).   The INWA was not inspired to resume operational seeding based on the arguments of Ben-Zvi et al. 2011.  Instead, the INWA moved on to a new experiment, Israel-4, to test whether cloud seeding can increase rainfall in Israel.  The results of this experiment are discussed later.

             3.  The Israel-3 randomized experiment; the longest, least known cloud seeding experiment ever carried out.

             While operational seeding began in northern Israel in 1975[9]triggered by reports of rain increases due to seeding in Israel-2 for its north target (GN76), a new daily randomized seeding experiment, called Israel-3, began in an expanded region of the former south target of Israel-2.  This larger target required a longer line-seeding path by the aircraft.    Changes in the ground seeding network in Israel-3 from Israel-2, if any, have not been reported. 

The results of this experiment began to appear in the literature in 1992, 17 years after it began in RF92[10]. RF92 reported that there was a non-statistically significant indication that rain had been decreased by about 8% due to cloud seeding.  A similar interim report was presented by Nirel and Rosenfeld (1994).  The final result of cloud seeding in Israeli 3 was reported at conference by Rosenfeld (1998).   After 20 winter seasons and 936 daily random decisions, there was an indication of a 9% decreasein rainfall (non-statistically significant) due to seeding.   Several exploratory analyses were put forward by Rosenfeld (1998), however, that suggested might have been increased in some situations.

The suggestion of appreciable decreases in rain on seeded days in Israel-3 constituted a discouraging blow to the daily randomization of cloud seeding experiments as did Israel-2.  It would not be expected in an experiment of so many daily randomizations over 20 winter seasons, with no effect on rainfall due to seeding (as concluded by Rosenfeld 1998), that a statistical result could drift as far as -9% from an expected null result.   An unbiased random draw of rain days would have been expected to have produced a result near zero indicated effect.

There are four major conclusions that can be drawn from Israel-3: 1) the result corroborates the lack of increased rain due to seeding in Israel-1 and Israel-2; 2) the results of all of these experiments, en toto, might be ascribed to a poor seeding methodology that led to ineffective coverage and cloud treatment; 3) dailyrandomization has not proved to be the panacea leading to unbiased natural storm distributions in cloud seeding experiments that it was hoped to be; 4) and probably the most important factor impacting all of these results;  the clouds of Israel are, overall, unreceptive for the production of meaningful increases in rain through AgI seeding due to their naturally high precipitating efficiency and readiness for early natural ice formation at slightly supercooled temperatures.

6.  Evaluations of operational cloud seeding, 1975-2002.

Due to the RH95 re-analyses of the Israeli cloud seeding experiments, the ensuing exhaustive commentaries and replies in 1997, and Levin et al.’s 1997 modeling study that indicated airborne seeding at cloud base was ineffective, the Israel National Water Authority (INWA) formed an independent panel of experts to evaluate the results of operational seeding to increase runoff into Lake Kinneret (the Sea of Galilee).  The final evaluation by Kessler et al. (2006, in Hebrew with an English abstract), distilled by Sharon et al. (2008), did not find evidence that cloud seeding had been increasing runoff (Figure 4). 

Figure 4.  The results of the independent evaluation of operational cloud seeding on rainfall in the Sea of Galilee watershed by Kessler et al. (2006) are shown by the rightmost three columns for the periods shown.  The Hebrew University of Jerusalem evaluation published by Nirel and Rosenfeld (1995) is the leftmost column.

Kessler et al’s result was contrary to seeding expectations based on many earlier reports suggesting runoff increases in streams and springs over whole seeding seasons (Benjamini and Harpaz 1986; Ben-Zvi et al. 1987; 1988; Ben-Zvi and Fanhar (1996); Sharon 1990; and in an updated report on operational seeding results through 1990 by Nirel and Rosenfeld (1995).   A second independent analysis of the operational seeding program by Levin et al. 2010 corroborated the findings of Kessler et al (2006) and Sharon et al. (2008).

Due to the findings in Kessler (2006), operational seeding, in Israel was terminated at the end of the 2007 winter season (Sharon et al. 2008).   These results meant that millions of dollars might have been wasted on operational cloud seeding in Israel for over 30 years, findings that weighed heavily on the HUJ experimenters whose work the operational seeding had begun under.  This was not to go unchallenged.

The first HUJ response to interim findings of Kessler et al (2002) of no seeding results was by Givati and Rosenfeld (2005). While agreeing that no additional runoff due to seeding was occurring in the operational seeding program after 1990, they argued that air pollution was masking seeding increases in rain.  In fact, they claimed, it was decreasing rain exactly as much seeding was increasing it, leading to a null seeding result in rainfall. 

The air pollution claims, while superficially credible except for their sudden hypothesized appearance, were evaluated by several independent groups and scientists besides Kessler et al. (2006) who did not find them credible:  Alpert et al. (2008); Halfon et al. (2009); Levin 2009; and addressed in a review by Ayers and Levin (2009).  All these independent re-analyses and reviews of the hypothesized effect of air pollution on rainfall found the argument that air pollution had canceled seeding-induced increases in rain unconvincing.

Givati and Rosenfeld (2009) contested the findings of Alpert et al. 2008 and submitted a wider analysis that used more gauges than they had previously.  Alpert et al. (2009) responded to the new data presented by Givati and Rosenfeld (2009) showing that the new data of Givati and Rosenfeld (2009) had inadvertently strengthened the original Alpert et al. (2008) conclusions.  

The bottom line was that rain gauges could be found that could support either a pollution effect or a no effect of pollution claim, thus it was not a robust claim having much veracity.  Thom (1957) first noted that virtually any result can be found via cherry-picking of control gauges amid many candidates to prove a seeding effect. There are more than 500 standard gauges and 82 recording gauges in Israel from which to extract seeding effects (A. Vardi, Deputy Director, the IMS, 1987, private correspondence).

More than any words here can demonstrate, it was the INWA’s decision to terminate and not resume operational seeding of the Sea of Galilee catchment that was the final arbiter in settling which of the above arguments were the most convincing to them, the funder of cloud seeding activities.

7.  About Israel-4

The INWA began a new, long-term randomized cloud seeding experiment in the 2012-2013 rain season in the Golan Heights, termed Israel-4.  The experiment was based on the findings of 27 research flights carried out by the HUJ in the search for the best location in Israel to have the best chance of proving that cloud seeding can add measurably to Israel’s water needs.   The results of these flights, summarized by Freud et al. 2015, was that the region of the Golan Heights would make the best site for a new cloud seeding experiment based on airborne observations of “abundant” supercooled water.  The experiment concluded after seven seasons of random seeding in 2020 with a null result, a suggested non-viable 1.8% increase in rain (Benjamini et al. 2023).   So far, the INWA has decided not to pursue further cloud seeding based on this result. 

It is noteworthy that Israel-4 was not conducted by the HUJ scientists, but rather by a collection of other independent Israeli scientists, statisticians, and hydrologists.  Whether this result will be challenged by HUJ scientists has yet to be determined, but one would expect a challenged based on the past.

  1. Summary

The reader may wonder at this point how so many flawed cloud reports and only the partial statistical results of a major, benchmark cloud seeding experiment could be cleared for the peer-reviewed literature, literature that led to a scientific consensus that cloud seeding had been proved in Israel–a consensus that affected a wide range of stakeholders, including Israel’s own government? 

There is a multi-pronged answer to this question: 1) the cloak of daily randomization likely misled experimenters who expected a neutral random draw, considering the length of the Israeli experiments and dismissed the possibilities of natural bias; 2) inadequate and/or conflicted (“friendly”) peer reviews of manuscripts that, in retrospect, demanded too little of the experimenters; 3) a lack of full reporting of experimental results by the experimenters (i. e., all of Israel-2 when it was concluded, and those from Israel-3 in a “timely manner” as suggested by the AMS in its “Guidelines” for Professional Conduct[11]). 

But perhaps the most important element of all, was the experimenters’ failure to discern the natural character of their efficiently precipitating clouds which ultimately cost them and the Israeli people so much.    Moreover, the original experimenters rebuffed independent airborne research efforts to measure the interesting properties of their clouds over the years (G. Vali, personal communication, 30 January 1986)[12].

Why? 

It’s clear that outside researchers would have quickly discovered the true nature of Israeli clouds and informed the world and the HUJ experimenters about them. 

And why did it take the HUJ experimenters 35 years after they monitored their clouds with two radars, one that was vertically pointed and over flown by their aircraft to validate cloud tops (G80, Rosenfeld 1980) to discover that the clouds entering Israel had been “sea spray cleansed” and formed precipitation at modest cloud top heights and temperatures as was finally reported by Freud et al. 2015?

Too, the absence of efforts by the original experimenters to examine the natural weather patterns, uneven storm draws, leaving it to outsiders, speaks volumes to entrenched confirmation and desirability biases.

8.  Reflections on the rise and fall of Israeli cloud seeding.

Given this account, one cannot help but ask if the full results of Israel-2 had been reported in a timely manner, as well as those from Israel-3, as it proceeded, and if the experimenters had gotten the Israeli cloud microstructure correct from the outset, would the Israeli government have pursued operational seeding of the Sea of Galilee watershed with no viable result at a cost of $20 million or more over the 32 years following the conclusion of Israel-2?   

 It is also evident that it is unwise to have the same scientists who carried out a seeding experiment, or personnel within their home institutions, evaluate its results or report on the potential of clouds for seeding purposes.   Independent evaluations by those not having vested interests (operational or otherwise) in cloud seeding should have beenmandatory.  The Israeli’s showed us the way with the INWA’s brave move to have an independent panel of experts evaluate their long-term operational cloud seeding effort.

        Moreover, the HUJ cloud seeding experimenters have been stymied for more than 25 years in their airborne most recent efforts to measure a critical parameter necessary to fully evaluate the seeding potential of their clouds: ice particle concentrations and the rapidity of their development.

        It is urgent for the people of Israel and the INWA that extensive, independent airborne measurements of Israeli clouds carried out soon by groups not relying on cloud seeding funding, and whose aircraft instrumentation can measure ice particle concentrations reliably in Israeli clouds.


Acknowledgements.  Thanks to Prof. Bart Geerts for his many suggestions on an early draft.  I also thank environmental writer, Maria Mudd Ruth, for an encouraging assessment of an early draft.  I thank Prof. David Schultz for a late, highly valuable review.  I also thank the two official reviewers, Dr. Daniel Rosenfeld (the “reject” reviewer) and the anonymous Reviewer 2 (“important paper, accept, minor revisions”) for their many insights that resulted in some corrections.   Figures 1-3 were  improved from original versions by Tully Graphics.

Author disclosure:   I have no funding sources but my own.  I have worked on both sides of the seeding “fence”; in operational seeding programs in South Dakota (twice), in the Sierras, in Washington State, and in India. I have participated in seeding research at the University of Washington and with the National Center for Atmospheric Research in Saudi Arabia.  I was the Assistant Project Forecaster with the Colorado River Basin Pilot Project, a large randomized orographic cloud seeding experiment, 1970-1975.

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___________., and ___________, 1997e: Reply to Woodley. J. Appl. Meteor., 36, 253. https://doi.org/10.1175/1520-0450(1997)036%3C0253:R%3E2.0.CO;2

Rosenfeld, D., 1980: Characteristics of rain cloud systems in Israel as derived from radar data and satellite images. Ms. Thesis, Hebrew University of Jerusalem (in Hebrew) 129pp.

__________, 1997: Comment on “Reanalysis of the Israeli Cloud Seeding Experiments”, J. Appl. Meteor., 36, 260-271.https://doi.org/10.1175/1520-0450(1997)036%3C0260:COANLA%3E2.0.CO;2

___________, 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.

___________., 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

___________ and A. Gagin, 1989: Factors governing the total rainfall yield from continental convective clouds. J. Appl. Meteor., 28, 1015-1030.https://doi.org/10.1175/1520-0450(1989)028%3C1015:FGTTRY%3E2.0.CO;2

____________, and R. Nirel, 1996: Seeding effectiveness—the interaction of desert dust and the southern margins of rain cloud systems in Israel. J. Appl. Meteor., 35, 1502-1510. https://doi.org/10.1175/1520-0450(1996)035%3C1502:SEIODD%3E2.0.CO;2

Sax, R. I., S. A. Changnon, L. O. Grant, W. F. Hitchfield, P. V. Hobbs, A. M. Kahan, and J. Simpson, 1975: Weather modification: Where are we now and where are we going? An editorial overview. J. Appl. Meteor., 14, 652-672.  https://doi.org/10.1175/1520-0450(1975)014%3C0652:WMWAWN%3E2.0.CO;2

Sharon, D., 1978:  Rainfall fields in Israel and Jordan and the effect of cloud seeding on them. J. Appl. Meteor., 17, 40-48. https://doi.org/10.1175/1520-0450(1978)017%3C0040:RFIIAJ%3E2.0.CO;2

_________, 1990:  Meta-analytic reappraisal of statistical results in the environmental sciences:  the case of a hydrological effect of cloud seeding.  J. Appl. Meteor., 29, 390-395. https://doi.org/10.1175/1520-0450(1990)029%3C0390:MAROSR%3E2.0.CO;2

_________, 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. https://doi.org/10.1175/0065-9401-21.43.7

_____________, 2001. A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement. Bull. Amer. Meteor. Soc.,82, 903-924. https://doi.org/10.1175/1520-0477(2001)082%3C0903:ACAOGS%3E2.3.CO;2

Simpson, J. S., 1979: Comment on “Field experimentation in weather modification.” J. Amer. Statist. Assoc., 74, 95-97.  https://doi.org/10.2307/2286732

Tukey, J. W., Jones, L. V., and D. R. Brillinger, 1978a: The Management of Weather Resources, Vol. I, Proposals for a National Policy and Program.  Report of the Statistical Task Force to the Weather Modification Advisory Board, Government Printing Office. 118pp. No doi.

__________., 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. No doi.

Vali, G., L. R. Koenig, and T. C. Yoksas, 1988: Estimate of Precipitation Enhancement Potential for the Duero Basin of Spain.  J. Appl. Meteor.,  27, 829-850. https://doi.org/10.1175/1520-0450(1988)027%3C0829:EOPEPF%3E2.0.CO;2

Wallace, J. M., and P. V. Hobbs, 1977: Atmospheric Science: An Introductory Survey. Academic Press, 467 pp. No doi. 

Woodley, W., 1997: Comments on “A new look at the Israeli Randomized cloud seeding experiments.” J. Appl. Meteor., 36, 250-252. https://doi.org/10.1175/1520-0450(1997)036%3C0250:COANLA%3E2.0.CO;2

World Meteorological Organization, 1986:  Statement on weather modification. Bull. W. M. O.,35, 45-46.  No doi.

___________________________, 1988:  Statement on weather modification.  Bull. W. M. O., 37, 140-144. No doi.

___________________________, 1992: Statement on planned and inadvertent weather modification. WMO, Geneva. Approved July 1992. No doi.

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

Young, K. C., 1993: Microphysical Processes in Clouds. Oxford University Press, 200 Madison Avenue, New York, New York 10016, 427pp. No doi.

———————————————————————————Endnotes

1Ben-Zvi and Fanar (1996) contradicted the results of Gagin and Gabriel (1987) reporting that rainfall intensities had been increased on seeded days in Israel-2, contrary to expectations due to kind of seeding (termed, “static”) that had been conducted.

[2]Due to the likely contribution of probe shattering artifacts in the Levin measurements, values half those reported by Levin are also plotted in Figure 3, an overestimate of artifact contributions.

[3]Updated in RH95a, Figure 12.

[4]The HUJ experimenters have conducted many flights into Israeli clouds since 1990 to determine their microstructural nature and cloud seeding potential but, in spite of their critical importance for cloud seeding,  have not been able to report ice particle concentrations or the rapidity at which they develop due to carrying imaging probes on their aircraft that are not capable of measuring them accurately (Freud et al. 2015;  D. Rosenfeld, 2019, private communication in his review of this manuscript).

[5]The HUJ experimenters changed evaluation techniques from Israel-1 to Israel-2 in reporting a second seeding success and did not pursue the several methods of evaluation outlined in GN74 and here.

[6]Aftersome 2 ½ seasons of operational seeding (i. e.,“randomized”—author’s insertion for clarity)experience, it was noticed that flying was effectively limited in such a way as to affect only the interior parts of the two areas.”  This was repeated by Gabriel (1979).

[7]The random draw sequence for Israel-2 was markedly different from than the one for Israel-1. In Israel-2 long strings of the same random decision occurred whereas in Israel-1 they did not.

[8]In 1969 the Israel Rain Committee, formed by Mekorot, Israel’s national water company, was responsible for overseeing the design of the Israel-2 experiment.  They recommended that rainfall data from Lebanon be incorporated in the evaluations of Israel-2 when it was completed. This did not take place in the experimenters’ many published evaluations; such data may not have been available to them.

[9]Goldreich (2003) reported that operational seeding took place during the 1968-69 rain season that fell between Israel-1 and 2.

[10]The lack of timely reporting of indications of decreased rain on seeded days in Israel-3 made Gabriel’s (1967a) statement appear as “prophesy” for his own experiments; that negative seeding  results may not be reported at all.

[11]In 1988 the AMS dropped its “Code of Ethics” that described the requirements and attributes of professional conduct as a member, downgrading those elements to, “guidelines”, a word synonymous with “suggestions.”

[12]G. Vali, 1986; Mason, Sir B. J., 1997, personal communications, available on request or go here:  https://cloud-maven.com/my-life-in-cloud-seeding-1970-2020/ 

A quantitative study of journal citing practices in a conflicted domain: cloud seeding

Arthur L. Rangno[1]

Catalina, Arizona 85739

[1]Retiree, Research Scientist IV, Cloud and Aerosol Research Group, University of Washington, Seattle (1976-2006). Co-winner in 2005 with the late Prof. Peter V. Hobbs of a monetary prize adjudicated by the World Meteorological Organization concerning our work in cloud seeding/weather modification.

Target journal: Research Integrity and Peer Review (?)

ABSTRACT

This study surveys the citing practices in the literature of cloud seeding experiments. In particular, 90 peer-reviewed journal articles that cite experiments in Colorado and Israel are of particular interest because both went through almost identical rise and fall cycles.  Both sets of these experiments were once deemed by our highest scientific organizations and many individual scientists as ones that had proved “cloud seeding works” (e.g., National Research Council-National Academy of Sciences 1973 for the Colorado orographic experiments; Kerr (1982, Dennis 1989) and in numerous places for the first two experiments in Israel. 

But what happens in the journal peer-reviewed literature when such esteemed sets of experiments are shown to be ersatz “successes,” as happened later to each set of these experiments?  It will be shown in this review of those 90 peer-reviewed publications in several journals that there is an appreciable fraction of researchers who continue to cite only the successful phases of these experiments, thus demonstrating, “one-sided” citing that misled their readers.  These instances, first and foremost, represent failures in the peer-review process.

It is recommended that explicit wording that condemns one-sided citing be placed in our AMS professional “guidelines[1]”  The Weather Modification Association, too, should add a similar explicit wording that condemns one-sided citing in its still extant, “Code of Ethics.”  (The AMS eliminated its “Code of Ethics” many years ago in favor of less stringent, “Guidelines.”)

  1. Introduction.

The purpose of citing in journal articles is to give the reader an accurate, balanced, and up to date background on the area of science being discussed, and to support various assertions in articles so that the reader can see that what is being stated has been shown to have support or needs further research.  Our science ideals mandate that we do this as best we can.  Selective or “one-sided citing” is defined as when an author or authors cite only one side of an issue that is multifaceted; only part of the “story” is revealed to the journal reader, the side that the authors, and by inference, the reviewers of such manuscripts, only wish them to know about.

However, in controversial domains where strong differences of opinion, vested (funding) interests and a priori beliefs (confirmation and desirability bias) abound, we may fall short of this ideal.  But by how much, if any?

We answer this question by examining citations in articles that concern two sets of once highly regarded cloud seeding experiments, those conducted by Colorado State University scientists at Climax and Wolf Creek Pass, Colorado, and those conducted in Israel by scientists at the Hebrew University of Jerusalem.  This test of evenhandedness in our science literature comes by examining the citations in the peer-reviewed literature one-year or more (final accepted date is used) after significant flaws were reported for these experiments to see if the reports that compromised them were also cited, presumably for the purpose of alerting the reader to the discovery of problems.

We used the “advanced search” option of the American Meteorological Society (AMS) journal web site using author names to find the articles that have been associated with these experiments.  The author names used were those associated with the original reports of cloud seeding successes. 

Citations in the 1986 AMS Monograph, 43, No. 21, “Precipitation Enhancement—A Scientific Challenge” were also inspected and were included if they met the search criteria. 

Peer-reviewed articles in the J. Wea. Mod., published annually by the Weather Modification Association (WMA) were also examined.  The non-peer reviewed articles within that journal were ignored. 

The Isr. J. of Earth Sci.was also examined from 1980 through 2011 when the journal discontinued publishing.  Two articles were found that met the citing criteria.

Search year initializations for the experiments:  For the Climax and Wolf Creek Pass experiments in Colorado, compromising literature began to appear with Meltesen et al. (1978), Rangno (1979a, b) Hobbs and Rangno (1979a, b), and Mielke (1979).  Therefore, our scrutiny of citing practices in peer-reviewed cloud seeding articles for these experiments begins in 1980. 

For the Israeli experiments, the first flaw casting doubt on seeding efficacy was reported in January 1988 (Rangno) concerning the clouds of Israel, and was followed by Gabriel and Rosenfeld (1990) who reported a null statistical result for the “full” Israel-2 crossover experiment.  The a priori designed crossover result of this experiment (Silverman 2001), completed in 1975, had not been previously reported. The scrutiny of the citations regarding these two experiments, Israel-1 and 2, therefore begins in 1989.   

In essence, the null hypothesis of this survey based on the ideals of science is that there will be no differences in citation practices following the appearance of the compromising literature; i. e., both the flaws in these sets of experiments and the successful phases will be reported in the articles that cite them after the starting dates above to give the reader a full view of what happened to them.

If only the “success” phase of the Colorado and/or Israeli experiments have been cited in a journal article after the dates that compromising literature appeared, that publication is deemed as having exhibited, “selective” or “one-sided” citing (Schultz 2009).  

Conference preprints or “grey” literature, such as “Final Reports,” are included in this study if they provided key information that was not published elsewhere, such as ice particle concentrations vs. cloud top temperature (e.g., Grant 1968, Vardiman and Hartzell 1976, Grant et al. 1982).  These types of literature appear in a blue font with a gray background in the references.  They often revealed problems in these experiments that did not reach the peer-reviewed literature. Many “grey literature” reports that were cited in journal publications were not available for this purpose.

This survey, in effect, also answers the question, “How exactly does the scientific community react to those who tear down established scientific consensuses rather than building them up?”  “Are they welcomed or shunned?” despite our ideals that mandate us to tell the ‘full story’ to journal readers.

2. Defining contrary or compromising literature 

In one type of literature that can be regarded as “contrary” or “adverse” to a cloud seeding success are cloud reports that go counter to the reports of the experimenters who often reported lower ice particle concentrations in the natural clouds. That is, they described clouds that were ripe for seeding that explained a result where seeding had appeared to increase precipitation. When literature appears that contradicts the “ripe for seeding” cloud reports, that in fact, the clouds that were targeted had much higher natural ice particle concentrations, these later findings are considered “adverse” or “contrary” literature.  Findings like the latter cast doubt that a claimed statistically significant success due to seeding actually happened.   Assertions by the experimenters that cloud top temperatures indexed ice particle concentrations are also assayed and if found unreliable in later research, the later findings are also considered “adverse” to the original reports. 

Both the Colorado and Israeli experiments suffered from these kinds of “adverse” published cloud seeding literature where the true nature of the clouds in each locale does not support the idea that significant increases in precipitation could have been produced by cloud seeding.

The most obvious “contrary” literature is that where a reanalysis of the original experiments has taken place that demonstrates that a natural distribution of storms (“storm types”) on seeded days created the misperception of seeding effects or a Type I statistical error (e. g., Neyman 1977).   For maximum credibility, however, re-analyses should not be wide searches through many variables (i.e, “fishing expeditions”) but far simpler; those, for example, that only expand the original reports to regional views using the same data and experimental dates as did the experimenters.   This type of analysis is one that should have been conducted by the original experimenters in the first place, but is often overlooked as they focused on small target areas, as in the Climax and Wolf Creek Pass experiments in Colorado  (e.g., Mielke et al. 1970, Morel-Seytoux and Saheli 1973).

  1. Results.

Ninety peer-reviewed cloud seeding articles referenced the two benchmark sets of experiments after the dates that compromising literature began to appear in journals or in “grey” literature. Of the 90 peer-reviewed articles examined, 38, or 42% did not cite literature that compromised the successful phase of the experiments in Colorado or Israel; they only cited the successful phase for the reader.  These 38 articles are deemed to have exhibited “one-sided” or “selective” citing.

Twenty-six of 76 articles, or 34%, that exhibited one-sided citing were in American Meteorological Society publications. Twelve of 13 articles in the peer-reviewed segment of the J. Wea. Mod.   exhibited “one-sided” citing, or 92%, of those articles that cited the Israeli or Colorado experiments only cited the successful phase.

The three peer-reviewed articles not under the AMS “tent” or in the JWMA, one in Atmos. Res., and two in the journal, Israel J. Earth Sci., did not exhibit one-sided citing but gave the reader a second view.

The NRC-NAS 2003 volume, “Critical Issues in Weather Modification,” was also reviewed for citing balance, and was found to be skewed toward leaving out important references to publications that compromised those experiments that they had deemed successful in their prior review in 1973. The NRC-NAS 2003 review does not compare in depth to that of the 1973 review. A total of 18 relevant cloud seeding reports or peer-reviewed publications went uncited in this volume (see Appendix 3 for the extant adverse literature that went uncited in the NRC-NAS volume: Fur67, AVM69, VGr72a, b, V74, VH76, V78, R79, HR79, Rh83, R86, RoG89, L92, L94, LGG96, LKR97, RH97a, b, ROS98. Abbreviations are explained in Table 3.

For those few wishing to go farther, a comprehensive review of the NRC-NAS 2003 document by the present writer can be found here.

https://cloud-maven.com/wp-content/uploads/2018/09/2003-Critical-issues-in-weather-modificatio_latest-version.pdf

The articles examined for citing tendencies are listed in Tables 1-3 below the reference section. Table 1 is for AMS publications, including the AMS monograph on cloud seeding, and other journals, including a list of citations within NRC-NAS,  “Critical Issues in Weather Modification Research.”    Table 2 is for those articles in the J. Wea. Mod.    A key to the many abbreviations of relevant literature cited in each article that met the search criteria is found in Table 3.

The table linked to below is a list of those authors that led or participated in one-sided citing and their institutions. In cases where the author name appears once, it was probably a “peccadillo” due to careless citing or possibly ignorance of the full literature on the experiments in Colorado and Israel. Where an author’s name appears repeatedly, it can be surmised that there was an agenda that meant included not informing readers of the full story, thus misleading them.

https://cloud-maven.com/wp-content/uploads/2022/01/One-sided-authors.pdf

  1. Two examples of omitted literature.

Breed et al. (2014) in the context of the National Center for Atmospheric Research’s (NCAR) involvement in cloud seeding in Wyoming, mention the Climax randomized experiments by only citing a single publication, Mielke et al. (1981).  In Mielke et al. (1981), the journal reader will find the story of a robust cloud seeding success.   Breed et al. (2014) deflected the reader from the voluminous contrary journal trail that preceded and followed Mielke et al. (1981), a trail that began with Meltesen et al. (1978), Hobbs and Rangno (1979), Mielke 1979, Rhea (1983) and several more re-analyses and commentaries (Rangno and Hobbs 1987; 1993; 1995, Rangno (2000).  

Hobbs and Rangno (1979a, b) found that the underlying physical foundations for a seeding success at Climax, the stratifications of experimental days by 500 mb temperatures, claimed to have had cloud microstructure implications, was unreliable, as did several other researchers, including Mielke (1979), Cooper and Saunders (1980).

This contrary literature goes uncited by Breed et al. (2014).  Why?  Was it because the authors wished their journal readers to view only one side of the Climax literature to convince readers that a cloud seeding success had been attained in the Rockies? This as the State of Wyoming inexplicably considers cloud seeding after the sophisticated Wyoming randomized orographic cloud seeding experiment, designed and evaluated by the National Center for Atmospheric Research, “failed to deliver” (they got a null result after six seasons of winter seeding).

In fact, the Climax experiments have no remaining credibility as having produced reliable evidence of increases in snowfall due to seeding, as a read of the abundant contrary literature listed above will show.  Thus, the single citation to Mielke et al (1981) by Breed et al. was tantamount to solely citing Fleishmann and Pons (1989) as evidence of “cold fusion.”

Another example of omitted contrary literature was seen in in Freud et al. (2015—hereafter, F15) study of Israeli clouds.  F15 discovered the high precipitating efficiency of Israeli clouds 27 years after Rangno (1988) and Levin (1992, 1994) deduced the same ready formation of precipitation in Israeli clouds.  But F15 does not cite that 1988 breakthrough paper.  

F15 also cite Givati and Rosenfeld (2005) who asserted that Israeli operational seeding-induced increases in rain were completely masked by air pollution.  But F15 did not cite those articles by Kessler et al. (2006), Alpert et al 2008; Halfon et al. 2009; Levin (2009); Ayers and Levin (2009), all of whom reviewed the Givati and Rosenfeld claims and found them unconvincing. 

The final arbiter for this dispute was the Israeli National Water Authority that also found the pollution claims of Givati and Rosenfeld unconvincing after weighing all the evidence.  Operational seeding of the Lake Kinneret (Sea of Galilee) watershed was therefore terminated in 2007 (Sharon et al. 2008). There is some question whether the programs was terminated then or in 2013. Nevertheless, it was terminated.

Instead of operationally seeding all storms, instead the Israeli government undertook a new randomized cloud seeding experiment in the hilly north of Israel. The results of this new experiment, called Israel-4, has just been published by Benjamini et al. 2023. The result of randomized seeding was a null result on rainfall. Benjamini et al. 2023 also performed “one-sided” citing by only citing the success phase of the first two Israeli experiments and did not cite the considerable contrary literature that followed the success phase. These authors should have cited Rangno (1988), and Rangno and Hobbs (1995), the latter a reanalysis of those experiments that showed convincingly that they were the product of favorable draws on randomly chosen seeded days. This would have given the readers a “heads up” that Israel-1 and Israel-2 were straight forward successes as Benjamini et al. (2023) claim in multiple places.

Moreover, Levin et al. (2010), which was cited, corroborated Rangno and Hobbs (1995) concluding that Israel-2 was compromised due to natural storms that favored the misperception of a cloud seeding effect. Both publications, that by Rangno and Hobbs (1995) and that by Levin et al. (2010) were subject to considerable comments mostly by those who carried out the experiments.

5. Discussion.

One-sided, or selective citing in our journal literature has been demonstrated as a frequently occurring phenomenon in the cloud seeding literature.  From a standpoint of our ideals of science, it should never occur.  Readers should never be misled. One-sided citing can be seen as having been encompassed by the Federal Trade Commission’s statement on consumer fraud, adjusted below for the science reader:

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

To mislead, to truncate truth, as one-sided citing is, by any reasonable definition, a form of “scientific misconduct.”  It is, alternately, to use the phrasing of the NRC-NAS (e.g., 1995, 2009), “cooking and trimming” the truth.  One-sided citing, to this author, is the same as eliminating a data point.  

The issue of one-sided citing has been called out by Schultz (2009): “One-sided reviews of the literature that ignore alternative points of view, however, can be easily recognized by the audience, leading to discrediting of your work as being biased and offending neglected authors…”

Not surprisingly, selective citing has been noted in other science domains (Urlings et al. 2019). 

The damage caused by one-sided citing is not just to authors who are seen as biased, it also causes material  damage to authors whose work goes inappropriately uncited; they may lose ground in promotions, awards, and without doubt, in the perceived impact that his/her work has had on his/her field since impact is measured by citation metrics.  From the Council of Science Editors:

“Most metrics of scholarly performance, including the Journal Impact Factor (JIF), are based on citations to published articles.” 

The less you are cited, the less impact you are perceived to have had in your field. 

The question for us then becomes, “Is it OK to have even just a single one-sided reference to one side of the ‘coin’ in our journal articles?” 

We think not.

It was also clear that even though there was an abundance of contrary literature, the successful phase citations to cloud seeding experiments far outweighed the citations to contrary literature.  It was also observed that some (unnamed) authors never refer to compromising literature suggesting personal agendas.

5. The institutional and co-author ramifications of one-sided citing

It can be argued that authors who practice one-sided citing damage their own institutions.  Authors who have performed “one-sided citing” have been associated with such highly regarded institutions such as the National Center for Atmospheric Research, and the Hebrew University of Jerusalem. Those authors have shown little regard for the implicit damage done to their home institutions by “easily recognized” one-sided citing.  Moreover, responsibility for such acts is shared among of all the co-authors who are co-authors of publications that contain this act.

  1. What one-sided citing says about peer-review.

One-sided citing is also an “LED signpost” of inadequate peer-review of manuscripts.  Reviews by knowledgeable, objectivereviewers would never allow one-sided citing to take place in manuscripts destined for publication.  This could only happen if journal editors assigned reviews to those ignorant of the full body of literature that a manuscript addresses, or to seeding partisans that allow one-sided citing to reach journals.  The J. Wea. Mod. results are particularly suggestive of editor/reviewer bias. 

Inadequate or partisan reviews have cost the public and our science cloud community much pain over the entire history of weather modification as long-time observers know. The nation’s most costly randomized orographic experiment, the Colorado River Basin Pilot Project, 1970-75, was based on prior, published  cloud seeding “successes” that never happened in the first place. But those ersatz reports of successes got into our peer-reviewed literature anyway and convinced our best scientists that they were successes due to weak reviews of manuscripts.

The sad aspect of these one-sided journal articles is that a single sentence or even a footnote following the report of the original “success” stating, “These results have been questioned or overturned”, followed by a reference or two, would have made this survey unnecessary. The recent review of orographic cloud seeding by Rauber et al. (2019) fulfills this simple requirement.

  1. What to do about one-sided citing?

Explicit wording that condemns one-sided citing is required in our AMS professional “guidelines[1]” The Weather Modification Association, too, should add a similar explicit wording that condemns one-sided citing in its still extant, “Code of Ethics.”  

Integrating the language of the FTC quoted above at the beginning of this essay (with the applicable word changes) into our AMS “Code of Ethics” would be the responsible course to follow to stop what could be seen as fraudulent acts (no matter how minor they might seem) that mislead readers to false conclusions and harms uncited researchers.  Moreover, such acts denigrate the institutions from which “one-sided citing” emanates.

[1]Also, restore the original AMS label for our professional responsibilities, our stronger label, “Code of Ethics” from the current, mere, “Guidelines” label.

  1. Conclusions.

We have shown that there is a credibility “inertia” that is not easily reversed;  that the authors of numerous cloud seeding papers ignored contrary evidence concerning the successful phase of cloud seeding experiments they cited; nearly all of these adverse reports  were in the same journal that  they themselves had published one-sided articles in.

 One can also posit a strong argument that “one-sided” or “selective” citing that gives only one side of the “coin” should never appear in a peer-reviewed journal. But authors who are not aware of the full body of literature, or have agendas can’t be completely blamed; the reviewers of those 38 articles exhibiting one-sided citing were also unfit to review the articles that they did, or also had agendas in allowing only one side of the story to be told.

While the reasons that authors frequently snub publications that overturn prior work may not be exactly known, it is has been shown that “one-sided citing” exists (some might say is “rampant”) in the cloud seeding literature.

REFERENCES CONTAINED IN THE ABOVE SECTIONS

Thereferences below are limited to those in the preceding discussions. References in a blue font and a gray background are those in preprint volumes or other “grey literature” that did not undergo peer review. In this survey we have tried to avoid those citations since many are also hard to find.  We only use them when critical information has been reported that did not make it into the formal literature.  The survey literature references are found in Tables 1 and 2.  The key to the abbreviations used at the end of each reference in Tables 1 and 2 are found in Table 3.

Alpert, P., N. Halfon, and Z. Levin, 2008: Does air pollution really suppress precipitation in Israel?  J. Appl. Meteor. Climatology, 47, 943-948.  https://doi.org/10.1175/2007JAMC1803.1

Ayers, G., and Z. Levin, 2009:  Air pollution and precipitation.  In Clouds in the Perturbed Climate System.  Their Relationship to Energy Balance, Atmospheric Dynamics, and Precipitation.J. Heintzenberg and R. J. Charlson, Eds.  MIT Press, 369-399.

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. Climate62, 317-327.  https://doi.org/10.1175/JAMC-D-22-0077.1

Breed, D., R. Rasmussen, C. Weeks, B. Boe., T. Deshler, 2014: Evaluating winter orographic cloud seeding:  design of the Wyoming weather modification pilot project (WWMPP).  J. Appl. Meteor. Climate, 53, 282-299.

Cooper, W. A., and C. P. R. Saunders, 1980:  Winter storms over the San Juan mountains.  Part II:  Microphysical processes.  J. Appl. Meteor., 19, 927-941.

Dennis, A. S., 1980:  Weather Modification by Cloud Seeding.  Academic Press, NY, 145.

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

Elliott, R. D., Shaffer, R. W., Court, A., and J. F. Hannaford, 1978:  Randomized cloud seeding in the San Juan mountains, Colorado.  J. Climate Appl. Meteor., 17, 1298-1318. https://doi.org/10.1175/1520-0450(1978)017%3C1298:RCSITS%3E2.0.CO;2

Fleischmann, M., and S. Pons, 1989: Electrochemically induced nuclear fusion of 1262deuterium.  J. Electroanalytical Chem., 261, 301-308.   No doi.

Freud, E., H. Koussevitsky, T. Goren and D. Rosenfeld, 2015:  Cloud microphysical background for the Israeli-4 cloud seeding experiment.  Atmos. Res., 158-159, 122-138.

Gabriel, K. R., and Rosenfeld, D., 1990: The second Israeli rainfall stimulation experiment: analysis of precipitation on both targets. J. Appl. Meteor., 29, 1055-1067. Givati, A., and D. Rosenfeld, 2005:Separation between cloud-seeding and air-pollution effects.  Appl. Meteor., 44, 1298-1314.

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

Grant, L. O., 1968: The role of ice nuclei in the formation of precipitation.   Proc. Intern. Conf. Cloud Phys.,Toronto, Amer. Meteor. Soc., 305-310.

________, DeMott, P. J., and R. M. Rauber, 1982:  An inventory of ice crystal concentrations in a series of stable orographic storms.  Preprints, Conf. Cloud Phys., Chicago, Amer. Meteor. Soc. Boston, MA. 584-587.  No doi.

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

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

_____________, and _______________, 1979b:  A reevaluation of the physical hypotheses for the Climax, Wolf Creek Pass, and Colorado River Basin Pilot Project cloud seeding experiments. Preprints, Seventh Conference on Planned and Inadvertent Weather Modification, Banff, Alberta, Canada.

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

Kerr, R. A., 1982: Cloud seeding: one success in 35 years.  Science,217, 519–522. No doi.

Kessler, A., A. Cohen, D. Sharon, 2006: Analysis of the cloud seeding in northern Israel. Areport 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 available.

Levin, Z., 2009:  On the State of Cloud Seeding for Rain Enhancement.  Report to the Energy, Environment and Water Research Center, The Cyprus Institute, Nicosia, Cyprus. 18pp. No doi available.

Meltesen, G. T., J. O. Rhea, G. J. Mulvey, and L. O. Grant, 1978: Certain problems in post hoc analysis of samples from heterogeneous populations and skewed distributions.  Preprints.,9th National Conf. on Wea. Mod., Amer. Meteor. Soc., 388-391. No doi.

Mielke, P. W., Jr., 1979:  Comment on field experimentation in weather modification. J. Amer. Statist. Assoc., 74, 87-88. https://doi.org/10.2307/2286729

_____________, L. O. Grant, and C. F. Chappell, 1970: Elevation and spatial variation effects of wintertime orographic cloud seeding.  J.  Appl. Meteor., 9,476-488.  Corrigenda, 10, 842, 15,801.

Mielke, P. W., Jr., Brier, G. W., Grant, L. O., Mulvey, G. J., and P. N. Rosenweig, 1981 (February 1981):  A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments.  J. Appl. Meteor.,20, 643-659.

Morel-Seytoux, H. J., and F. Saheli, 1973: Test of runoff increase due to precipitation management for the Colorado River Basin Pilot Project.  J. Appl. Meteor., 12, 322-337.

National Academy of Sciences-National Research Council, Committee on Planned and Inadvertent Weather Modification, 1973:  Weather and Climate Modification: Progress and Problems, T. F. Malone, Ed., available from the National Research Council, Washington, D. C, 258 pp.

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Neyman, J., 1977:  Experimentation in weather control and statistical problems generated by it. In Applications of Statistics, north-Holland Publishing Co., 1-25.  No doi.

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

https://doi.org/10.1175/15200450(1979)018%3C0579:AROTWC%3E2.0.CO;2

_____________, 1979b:  A reanalysis of the Wolf Creek Pass experiment.  Preprints, Seventh Conference on Planned and Inadvertent Weather Modification, Banff, Alberta, Canada,  3.1 to 3.2.

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

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___________, and _________, 1995b:  Reply to Gabriel and Mielke.  J. Appl. Meteor., 34, 1233-1238.   https://doi.org/10.1175/1520-0450(1995)034%3C1233:R%3E2.0.CO;2

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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, 903-924.https://doi.org/10.1175/1520-0477(2001)082%3C0903:ACAOGS%3E2.3.CO;2

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__________, 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. No doi.

Supplemental Material

APPENDIX 1. PEER-REVIEWED PUBLICATIONS IN JOURNALS UNDER THE AUSPICES OF THE AMERICAN METEOROLOGICAL SOCIETY, IN THE JOURNALS ATMOSPHERIC RESEARCH (ELSEVIER), AND THE ISRAEL JOURNAL OF EARTH SCIENCES THAT WERE EXAMINED IN THIS CITATION SURVEY . 

The list of the peer-reviewed cloud seeding papers examined for “one-sided” citing concerning experiments in Colorado and Israel. The papers are confined to those that cited the cloud seeding experiments that were accepted for publication at least one year afterthe appearance of adverse literature had appeared. A reference in a red font indicates a paper that only cited the successful phase of these experiments and ignored the adverse literature (namely, the authors practiced one-sided citing).            At the end of each article that met these referencing criteria, the papers cited in them that indicated a cloud seeding success are abbreviated in red.  Articles that cited both the successful phase and adverse literature of these experiments are in a black font.  Adverse literature also includes cloud reports at odds with those by the experimenters that provided a foundation for beliefs that cloud seeding had been successful.   These supporting early cloud reports by the original experimenters generally indicated lower than actual ice particle concentrations in the seeded clouds compared to later independent measurements.                                                                                                                  

 Appendix 2 lists those 13 peer-reviewed publications from the J. Wea. Mod.  that were examined. 

Appendix 3 is a key to the abbreviations used at the end of each journal article in Appendices 1 and 2 for the seeding success and adverse literature that was contained in them, if any.

———————————————————————————-

  1. Alpert, P, N. Halfon, and Z. Levin, 2009:Reply to Givati and Rosenfeld.  Appl. Meteor. Climatology, 48, 1751-1754.  Cited cloud seeding success literature:  GivR09.  Adverse cloud seeding literature cited:  AHL08.      https://doi.org/10.1175/2009JAMC1943.1
  1. Blumenstein, R. R., Rauber, R. M., Grant, L. O., W. G. Finnegan, 1987: Application of ice nucleation kinetics in orographic clouds.  Climate Appl. Meteor., 26, 1363-1376. Cited cloud seeding success literature:  Metal81.  Extant adverse cloud seeding literature that went uncited: AVM69, VGr72a, b, V74, V78, Melt78, M79, HR79, R79 VH76,GrDR82, Rh83, MAR80, CS80, CV81.
  1. Braham, R. R., Jr., 1981: Designing cloud seeding experiments for physical understanding. Amer. Meteor. Soc., 62, 55-62. Cited cloud seeding success literature:GaN74, Ga75, Tukey et al. 1978, GrE74. Extant adverse cloud seedingliterature that went uncited: Fur67, AVM69, , VGr72a, b, V74,  Hobal75, VH76, V78, Melt78, M79, R79, HR79.  (This article was based on his October 1979 presentation at the Banff 7thConference on Weather Modification.  It is presumed that all of the literature in 1979 was available to him when he framed this article for the Bull. Amer. Meteor. Soc.)
  1. Braham, R. R., Jr., 1986: Precipitation enhancement–a scientific challenge. In Precipitation Enhancement–A Scientific Challenge, R. Braham, ed., Meteor. Monog. 21, No. 43, 1-5. Cloud seeding success literature cited:  GaN74, GaN81, NAS73, Tuk I and II.
  1. Breed, D., R. Rasmussen, C. Weeks, B. Boe., T. Deshler, 2014: Evaluating winter orographic cloud seeding: design of the Wyoming weather modification pilot project (WWMPP).  Appl. Meteor. Climate, 53, 282-299. Cited cloud seeding success literature:  Metal81, MBM82, G86, Rn88.  Adverse cloud seedingliterature that went uncited: AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, GrDR82, Rh83, RH87, RH93, RH95a.

https://doi.org/10.1175/JAMC-D-13-0128.1

  1. Bruintjes, R. T, 1999: A review of cloud seeding experiments to enhance precipitation and some new prospects. Amer. Meteor. Soc., 80, 805-820. Cited cloud seeding success literature: GrM67, MGC71, NAS73, GaN74, Brahm79, Metal81, GaN81, Cot86, ELL86, Ga86, Rn88, BZ97, DO97, ROS97, RF92, Sil86, Wood97. Adverse cloud seeding literature cited: Brahm86, R86, RH87, L92, RH93, RH95b, Gb95.  Additional adverse cloud seeding literature that went uncited:  Fur67, AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, Gretal79, Hill80a, Ro_retra80, GrDR82, Rh83, R88,RoG89, LGG96, RH97a, b, LTR97, ROS98.
  1. Chu, B. Geerts, L. Xue, and R. Rasmussen, 2015: Large-Eddy Simulations of the Impact of Ground-Based Glaciogenic Seeding on Shallow Orographic Convection: A Case Study. Appl. Meteor. Climate, 56, 69-84.  Cited cloud seeding literature:  GaN81. Adverse cloud seedingliterature that went uncited:  R88, RoGa89, GbR90, RH95, RH97a, b,SKCD08, LHA2010.
  1. Cotton, W. R., 1986: Testing, implementation, and evolution of seeding concepts–a review. In Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Monographs, 43, Amer. Meteor. Soc., 139-149. Cited cloud seeding success literature:  Fur67, GrM67, CHAP70, MGC71, Metal81, GrE74, GrK74, C-MAR80, GaN74, Ga81, GN81.  Adverse cloud seeding literature cited:  Hobal75, HR79, CS80.  Additional adverse cloud seedingliterature that went uncited:  Fur67, AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80, CV81, GrDR82, Rh83.
  2. Elliott, R. D., 1986: Review of wintertime orographic cloud seeding. Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Monogr., 43, 87-103. Successful cloud seeding literature cited: GrM67, Gretal69, MGC70, MGC71, C71, Mor-Sey73, GrE74, ELL78, TukII, VM78, ELL80, CM80, RVM81, Metal81, MBM82, MM83, Gretal83, ELL84.   Adverse cloud seeding literature cited: R79 HR79,Melt77(sic), Gretal79, Rot_retra80, MAR80, CS80, Hill80a, RH80a, b, RH81, Rh83. Additional adverse cloud seedingliterature that went uncited:  AVM69, VGr72a,b, V74, V78, M79, Hobal75, Hill80a, C-MAR80, CV81,GrDR82.
  3. Elliott, R. D., Shaffer, R. W., Court, A., and J. F. Hannaford, 1980: Reply to Rangno and Hobbs. Appl. Meteor., 19, 350-355.  Cited cloud seeding success literature:  Gr_etal69, Gr_etal74,Tuk78, ELL76, ELL78.   Adverse cloud seeding literature cited:  Ho_etal75, HR78, R79.  Additional adverse cloud seedingliterature that went uncited:   R79, was published withinthe year that this Reply appeared: M79, RH79, Fur67, VGr72a,b, V74, VH76, V78.
  4. Cotton, W. R., 1986: Testing, implementation, and evolution of seeding concepts–a review. In Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Monographs, 43, Amer. Meteor. Soc., 139-149. Cited cloud seeding success literature:  Fur67, GrM67, CHAP70, MGC71, Metal81, GrE74, GrK74, C-MAR80, GaN74, Ga81, GN81.  Adverse cloud seeding literature cited:  Hobal75, HR79, CS80.  Additional adverse cloud seedingliterature that went uncited:  Fur67, AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80, CV81, GrDR82, Rh83.
  5. Reynolds, D. W., and A. S. Dennis, 1986: A review of the Sierra cooperative pilot project. Amer. Meteor. Soc., 513-523.  Cited cloud seeding success literature:  MGC70, NAS73. 
  6. Farley, R. D., Price, P. E., Orville, H. D., and J. H. Hirsch, 1989:  On the numerical simulation of graupel/hail initiation via the riming of snow in bulk water microphysical cloud models.  Appl. Meteor., 28,1128-1131.  Cited cloud seeding success literature: Ga81.  Adverse cloud seedingliterature that went uncited: R88.
  7. Flueck, J. A., W. L. Woodley, A. G. Barnston, and T. J. Brown, 1986:  A further assessment of treatment effects in the Florida Area Cumulus Experiment through guided linear modeling.  Climate Appl. Meteor., 25, 546-564. Cited cloud seeding success literature: Metal81.  Adverse cloud seedingliterature that went uncited: AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80, CV81, GrDR82, Rh83.
  8. Flueck, J. A., 1986: Principles and prescriptions for improved experimentation in precipitation augmentation research. Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Monographs, 43, No. 21, Amer. Meteor. Soc., Boston, 02108, 155-171. Cited cloud seeding success literature: CHAP70, NAS73, TukII78, MM83, MGC70, MGC71, Metal81. Extant adverse literature that went uncited:AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80, CV81, GrDR82, Rh83.
  9. Freud, E., H. Koussevitsky, T. Goren and D. Rosenfeld, 2015: Cloud microphysical background for the Israeli-4 cloud seeding experiment.  Res., 158-159, 122-138.  Cited cloud seeding success literature:  GaN74, GaN81, RF92, RoN96, GivD05, GivD09, BZ11, RoG11. Cited adverse cloud seeding literature:  GbR90, RH95b, LGG96, LHA2010.    Additional adverse cloud seeding literature that went uncited:  R88.  http://dx.doi.org/10.1016/j.atmosres.2015.02.007
  10. Gabriel, K. R., 1981: On the roles of physicists and statisticians in weather modification experimentation.   Bull. Amer. Meteor. Soc., 62, 62-69. Cited cloud seeding success literature: Gb67a,b, GbB70, W71, GrE74, Tuk78, GbNu78. Cited adverse to cloud seeding literature:HR78, M79. Additional extant adverse cloud seeding literature that went uncited: AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80.   (KRG misconstrued the HR78 3-day effort as more than that which unraveled the Skagit Project as one due to extensive searching.  KRG had mistaken it with the extensive search by the original experimenters through 29 variables.)
  11. Gabriel, K. R., 2000: Parallels between statistical issues in medical and meteorological experimentation.J. Appl. Meteor., 39, 1822–1236. Cited cloud seeding success literature: Gb67, GbB70,M95, RoN96, ROS97.  Adverse cloud seeding literature cited:  Gb95, GbR90, RH93, RH95a, List99.  Additional extant adverse cloud seeding literature that went uncited:AVM69, VGr72a,b, V74, V78, Melt78, R79, HR79, M79, MAR80, CS80, CV81, GrDR82, Rh83, RH87, R88, L92, L94, RH95b, RH97a, b, LGG96, ROS98, Br99.
  12. Gabriel, K. R., 2002: Confidence regions and pooling—some statistics for weather experimentation.  Appl. Meteor., 41, 505-518. Cited cloud seeding success literature: GbB70, GaN81,RF92, RoNi96.  Adverse cloud seeding literature cited:  GbR90. Extant adverse cloud seeding literature that went uncited:  R88, RoG89, L92, L94, RH95b, LGG96,  RH97a, b, LKR97, ROS98.
  13. Gabriel, K. R., and Rosenfeld, D., 1990: The second Israeli rainfall stimulation experiment: analysis of precipitation on both targets. Appl. Meteor., 29, 1055-1067. Cited cloud seeding success literature: Gb67, GbB70, GaN74, GaN81, GaA85, GaGb87, ROS89.  Extant adverse cloud seeding literature that went uncited:  R88, RH88, RoG89.https://doi.org/10.1175/1520-0450(1990)029%3C1055:TSIRSE%3E2.0.CO;
  14. Gagin, A., 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. Appl. Meteor., 26, 913-926. Cloud seeding success literature cited: Gb67, NuGbGa67, GbB70, Ga70, MGC70, CGM71, GaS74, GaN74, Ga75, GaN81, Metal81, , ,  , , GbF69, , , TukII78, Ga81, GaN81.  Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, CV81, GrDR82, Rh83. (Colo only)
  15. Givati, A., and D. Rosenfeld, 2005:Separation between cloud-seeding and air-pollution effects.  Appl. Meteor., 44, 1298-1314.  Cited cloud seeding success literature: G67, GaN74, GaN81, ROS97.  Cited adverse cloud seeding literature:  GbR90, RH95b, Sil2001.  Additional extant adverse cloud seeding literature that went uncited:  R88, L92, L94, LGG96, RH97a, b,LKT97, Br99.             https://doi.org/10.1175/JAM2276.1
  16. Grant, L. O., 1986: Hypotheses for the Climax wintertime orographic cloud seeding experiments.  InPrecipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Meteor. Monographs, 43, Amer. Meteor. Soc., 105-108. Cited cloud seeding success literature: CHAP67, CHAP70, GrM67, MGC70, MGC71, Metal81.  Extant adverse cloud seeding literature that went uncited:  Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, CV81, GrDR82, Rh83.
  17. Heimbach, J. B., Jr., A. B. Super, 1996: Simulating the influence of type II error on the outcome of past statistical experiments. Appl. Meteor., 35, 1551-1567.  Cited cloud seeding success literature: M95, MM83, Metal81.  Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, CV81, GrDR82, Rh83. RH87, RH93, RH95a.
  18. Hill, G. E., 1980a: Reexamination of cloud-top temperatures used as criteria of cloud seeding effects in experiments on winter orographic clouds (July 1980).  Climate Appl. Meteor., 19, 1167-1175. Cited cloud seeding success literature cited: GM67, CHAP70, MGC71, GE74, VM78.  Adverse cloud seeding literature cited: R79, HR79.   Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79.
  19. Hill, G. E., 1980b:Seeding-opportunity recognition in winter orographic clouds.  Climate Appl. Meteor., 22, 1371-1381.  Cited cloud seeding success literature: GrM67, MGC70, MGC71, CGM71, GrE74, ELL78, VM78. Adverse cloud seeding literature cited:  R79, HR79.  Additional extant adverse literature that went uncited:Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79.
  20. Hill, G. E., 1986:Seedability of winter orographic clouds.  Monogr., 43, No. 21, 127-137.  Cited cloud seeding success literature: GrM67, GrE74, MGC70, MGC71, VM78, Hill80b.  Adverse cloud seeding literature that was cited: Rotal75, Hobal75,  CS80, MAR80,  Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, RH80b, RH81, CV81, GrDR82, Rh83.
  21. Jing, X., and B. Geerts, 2015: Dual-Polarization Radar Data Analysis of the Impact of Ground-Based Glaciogenic Seeding on Winter Orographic Clouds. Part II: Convective Clouds. Appl. Meteor. Climate, 54, 2099-2117.  Cited cloud seeding success literature: GaN81, GrE74, Br99, Fetal15, Gb99.  Adverse cloud seeding literature cited: RH95b.Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81, GrDR82, Rh83. RH87, RH93, RH95a, R88, RH88, RF92, L92, L94, LGG96,ROS98, LHA2010.
  22. Levi, Y., and D. Rosenfeld, 1996: Ice nuclei, rainwater chemical composition, and static cloud seeding effects in Israel. Appl. Meteor., 35, 1494-1501.  Cited cloud seeding success literature: Ga75, NiRo95, RF92, RoNi96. Extant adverse cloud seeding literature that went uncited:  R88, RH88, RoG89, L92,94,RH95b.https://doi.org/10.1175/1520-0450(1996)035%3C1494:INRCCA%3E2.0.CO;2
  23. Levin, Z., E. Ganor, and V. Gladstein, 1996 (June 1995): The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean. Appl. Meteor., 35, 1511-1523.  Cited cloud seeding success literature: GaN74, GaN81, Ga75.  Adverse cloud seeding literature cited:  R88.  Extant adverse literature to that went uncited: L92, L94, RH88, GbR90, RF92.
  24. Levin, Z., S 0. Kirchak, and T. Reisen, 1997 (September 1996): Numerical simulation of dispersal of inert seeding material in Israel using a three-dimensional mesoscale model. Appl. Meteor., 36, 474-484. Cited cloud seeding success literature: GaN74, GaN81, GaA85.  Adverse cloud seeding literature cited:  GbR90, L94.    Additionalextant adverse cloud seeding literature that went uncited: R88, RoG89, RH88, RH95b. https://doi.org/10.1175/15200450(1997)036%3C0474:NSODOI%3E2.0.CO;2
  25. List, R., 2004 (August 2003):  Weather modification—a scenario for the future.  Amer. Meteor. Soc.,85, 51-63.  Cited cloud seeding success literature:  Gb67   Adverse cloud seeding literature cited:  GbR90. Additional adverse cloud seeding literature that went uncited: R88, RH88, RoG89, L92, L94, RH95b, MGG96, RH97a, b, LKR97, ROS98, Br99, Sil2001, NAS03.
  26. Manton, M. J., L. Warren, S. L. Kenyon, A. D. Peace, S. D. Bilish, and K. Kemsley, 2011: A Confirmatory Snowfall Enhancement Project in the Snowy Mountains of Australia. Part I: Project Design and Response Variables. Appl. Meteor. Climate, 50, 1432-1447. Cited cloud seeding success literature: MBM82, Br99, Cot_Piel92, NAS03.  Extant adverse cloud seeding literature that went uncited:   Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, CV81, GrDR82, Rh83, RH87, RH93, RH95a M95, Gb95.
  27. Marwitz, J., 1980 (January 1980): Winter storms over the San Juan mountains.  Part I.  Dynamical processes (January 1980).  Appl. Meteor., 19, 913-926.  Cited cloud seeding success literature: GrM67.   Adverse cloud seeding literature cited:  Hobal1975.  Several cited conference preprints were not available.  Extant adverse cloud seeding literature that went uncited:  Fur67, AVM69,VGr72a, b,  V74, VH76,Melt78, V78.
  28. Mather, G., M. J. Dixon, J. M. de Jager, 1996 (June 1995):Assessing the Potential for Rain Augmentation-The Nelspruit Randomized Convective Cloud Seeding Experiment.   Appl. Meteor., 35, 1465-1482. Cited cloud seeding success literature: GaN81, Brillinger et al. 1978.  Extant adverse cloud seeding literature that went uncited:  R88, RoG89, GbR90, RF92, L92, L94, RH95b. https://doi.org/10.1175/1520-0450(1996)035%3C1511:TEODPC%3E2.0.CO;2
  29. Mielke, P. W., Jr., 1985: Geometric concerns pertaining to applications of statistical tests in the atmospheric sciences. Atmos, Sci., 42,1209-1212.  Cited cloud seeding success literature: Metal81, MGC71, MBM82. Extant adverse cloud seeding literature that went uncited:  Fur67, AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81, GrDR82, Rh83.
  30. Mielke, P. W., Jr., and J. G. Medina, 1983: A new covariate procedure for estimating treatment differences with application to Climax I and II experiments. Climate Appl. Meteor., 22,1290-1295.  Cited cloud seeding success literature: MGC71, Metal81, MBM82.  Extant adverse cloud seeding literature that went uncited:  AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81, GrDR82.
  31. Mielke, P. W., Jr., Berry, K., and J. G. Medina, 1982:Climax I and Climax II: distortion resistant residuals.  Climate and Appl. Meteor., 21, 788-792. Cited cloud seeding success literature cited: MGC70, MGC71, Metal81. Adverse cloud seeding literature cited:  M79.  Extant adverse literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81.
  32. Mielke, P. W. Jr., K. J. Berry, A. S. Dennis, P. L. Smith, J. R. Miller, Jr., B. A. Silverman, 1984: HIPLEX-1: Statistical Evaluation (October 1983). Clim. Appl. Meteor., 23, 513-522. Cited cloud seeding success literature:MBM82, MM83. Extant adverse cloud seeding literature that went uncited:Fur67, AVM69, VGr72a, b, V74, VH76,V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81, GrDR82, Rh83.
  33. Mielke, P. W., Jr., Brier, G. W., Grant, L. O., Mulvey, G. J., and P. N. Rosenweig, 1981 (February 1981): A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments.  Appl. Meteor.,20, 643-659. Cited cloud seeding success literature cited: Gretal69, Chap70, MGC70, MGC71, Tukey et al. 1978.  Adverse cloud seeding literature cited:  M79.  Additional adverse cloud seeding literature that went uncited: Fur67,AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80.
  34. Morrison, A. E., S. J. Siems, and M. J. Manton, 2013: On a natural environment for glaciogenic cloud seeding. Appl. Meteor. Climate,52, 1097-1104.Cited cloud seeding success literature: Metal81. Extant adverse cloud seeding literature that went uncited:AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, RH80b, Ro_retra80, RH81, CV81, GrDR82, Rh83. RH87, RH93, RH95a, Gb95, NAS03.
  35. National Research Council-National Academy of Sciences, 2003:Critical issues in weather modification research.  Garstang, Ed., 123pp.  Cloud seeding success literature cited:  GrM67, Metal81, Gb67, GaN74, GaN81, RF92, RoNi96.   Adverse cloud seeding literature cited:  RH87, GbR90, RH93, RH95b, Sil01. Extant adverse literature that went uncited:  Fur67, AVM69, VGr72a,b, V74, VH76, V78, , R79, HR79, Rh83, R86, RoG89, L92, L94, LGG96, LKR97, RH97a, b, ROS98.
  36. Nirel, R., and D. Rosenfeld, 1995: Estimation of the effect of operational seeding on rain amounts in Israel. Appl. Meteor., 34, 2220-2229.  Cited cloud seeding success literature: Gb67, GbB70, Tukey et al. 1978, GaN81.  Cited adverse cloud seeding literature:  GbR90. Additional extant adverse cloud seeding literature:  R88, L92, L94, RF92. https://doi.org/10.1175/1520-0450(1995)034%3C2220:EOTEOO%3E2.0.CO;2
  37. Parkin, D. A., W. D. King, and D. E. Shaw, 1982: An automatic recording raingage network for a cloud-seeding experiment. Appl. Meteor., 21, 227-236.  Cited cloud seeding success literature: GrM67, Gb67, C-Mar80. Extant adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a, b, V74, VH76, V78, Melt78, Gretal79, M79, R79, HR79, MAR80, CS80, Ro_retra80, RH80b, RH81, CV81.
  38. Rangno, A. L., 1986: How good are our conceptual models of orographic clouds? InPrecipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Monographs, 43, Amer. Meteor. Soc., 115-124. Cited cloud seeding success literature: RDW69,CGM71, ELL76, ELL78, Gr68, Gretal69, Metal81.  Cited adverse cloud seeding literature:  AVM69,MedR73, Hobal75, VH76, MCS76, V78, R79, Hill80a, Hill80b, CS80, MAR80, CV81, GrDR82.
  39. Rangno, A. L., and P. V. Hobbs, 1980a: Comments on “Randomized seeding in the San Juan mountains of Colorado.” Appl. Meteor., 19, 346-350. Cited cloud seeding success literature: GrM67, RDW69, MGC70, MGC71, CGM71, ELL76, MWW77, ELL78.  Cited adverse cloud seeding literature:  AVM69, VGr72a, b, Hobal75, MCS76,HR78, HR79, R79.  Additional adverse cloud seeding literature that went uncited: Fur67, V74, VH76, V78,Melt78, M79, Gretal79. https://doi.org/10.1175/1520-0450(1980)019%3C0346:COCSIT%3E2.0.CO;2
  40. Rangno, A. L., and P. V. Hobbs, 1980b (February 1980): Comments on “Generalized criteria for seeding winter orographic clouds”. Appl. Meteor., 19, 906-907.  Cited cloud seeding success literature:  GrM67, MCG71, VM78.  Cited adverse cloud seeding literature:  VH76, M79.  Additional extant adverse cloud seeding literature that went uncited:  Fur67, AVM69, VGr72a, b, V74, Melt78, V78, M79, Gretal79. https://doi.org/10.1175/1520-0450(1980)019%3C0906:COCFSW%3E2.0.CO;2
  41. Rangno, A. L., and P. V. Hobbs, 1981: Comments on “Reanalysis of ‘Generalized criteria for seeding winter orographic clouds,’” Appl. Meteor., 20, 216.Cited cloud seeding success literature: VM78Cited adverse cloud seeding literature: RH80, Ro_retrac80. Additional adverse cloud seeding literature that went uncited: Fur67, AVM69, VGr72a,b, V74, VH76, MCH76, Melt78, R79, HR79, Hill80a, CS80, MAR80.
  42. Rangno, A. L., and P. V. Hobbs, 1993: Further analyses of the Climax cloud-seeding experiments. Appl. Meteor., 32, 1837-1847. Cited cloud seeding success literature:  GrM67, CHAP67, G68, RDW69, Gretal69, CHAP70, CGM71, M-SS73, NAS73,Gretal74, ELL76,ELL78, Metal81, MBM82, G86, GrE74,HILL86, Rn88.  Cited adverse cloud seeding literature:  Fur67,AVM69, Hobal75, VH76, Melt78, HR79, R79, Maret80, Hill80a, MAR80, RH80a, CV81, Rh83, R86, RH87. https://doi.org/10.1175/1520-0450(1993)032%3C1837:FAOTCC%3E2.0.CO;2
  43. Rangno, A. L., and P. V. Hobbs, 1995a: Reply to Gabriel and Mielke. Appl. Meteor., 34, 1233-1238.  Cited cloud seeding success literature:  CHAP67, GrM67, Gr68, Gretal69, CHAP70, MGC70, MGC71, CGM71, Gretal71, GK74, Metal81, Gr86, Rn88.  Cited adverse cloud seeding literature: VH76, MCS76, Gretal79, M79, HR79, C-MAR80, Hob80,Rh83, RH87, RH93. https://doi.org/10.1175/1520-0450(1995)034%3C1233:R%3E2.0.CO;2
  44. Rangno, A. L., and P. V. Hobbs, 1995b: A new look at the Israeli cloud seeding experiments.  Appl. Meteor., 34, 1169-1193. Cited cloud seeding success literature:Gb67a, Gb67b, GbB70, Ga71, W71, Bret73, GS73, GaN74, Ga75, GaN76, GbN78, Ga80, Ga81, Kerr82, Ga86, Sil86, GGb87, B-Z88, RF92, Y93.  Adverse cloud seeding literature cited:  HR78, R79, BHarp86, R88, RH88, RoG89, GbR90, L92. https://doi.org/10.1175/1520-0450(1995)034%3C1169:ANLATI%3E2.0.CO;2
  45. Rangno, A. L., and P. V. Hobbs, 1997a: Reply to Rosenfeld (July 1996).  Appl. Meteor., 36, 272-276.  Cited cloud seeding success literature:  W71, Ga71, Ga75, Ga80, Ga81, GaN74, GaN76, GaN81, Ga86, GaG87, B-Z88, RF92, Y93, ROS97.  Adverse cloud seeding literature cited:  HR79, R88, GbR90, L94, RH93, RH95a, b, RH97a, b. https://doi.org/10.1175/1520-0450(1997)036%3C0272:R%3E2.0.CO;2
  46. Rangno, A. L., and P. V. Hobbs, 1997c: Reply to Ben-Zvi. Appl. Meteor., 36, 257-259. Cloud seeding success literature cited: GaN76, D80, Ga80, Ga81, GaN81, Ga86, GaG87, B-Z88,Sh90, RF92.  Adverse cloud seeding literature cited:  B-Harp86, RoG89, GbR90, L92, L94, R88, RH95b.https://doi.org/10.1175/1520-0450(1997)036%3C0257:R%3E2.0.CO;2
  47. Rangno, A. L., and P. V. Hobbs, 1997d: Reply to Dennis and Orville. Appl. Meteor., 36, 279.  Cloud seeding success literature cited:  D89.  Adverse cloud seeding literature cited:  DO97, RH95b. Additional extant adverse cloud seeding literature that went uncited: R88, GbR90, L92, L94, LGGC96.https://doi.org/10.1175/1520-0450(1997)036%3C0279:R%3E2.0.CO;2
  48. Rangno, A. L., and P. V. Hobbs, 1997e: Reply to Woodley. Appl. Meteor., 36, 253. Cloud seeding success literature cited: Ga75, Ga81, Ga86.    Adverse cloud seeding literature cited: RH88, RH95.  Additional extant adverse cloud seeding literature that went uncited: R88, GbR90, L92, L94, LGGC96. https://doi.org/10.1175/1520-0450(1997)036%3C0253:R%3E2.0.CO;2
  49. Rangno, A. L., and P. V. Hobbs, 1987: A re-evaluation of the Climax cloud seeding experiments using NOAA published data. Climate Appl. Meteor., 26,757-762. Cited cloud seeding success literature:  GrM67,Gretal69, MGC70, MGC71, Gretal74, Metal81, MM83, MBM82, NAS73.  Adverse cloud seeding literature cited:  R79, HR79, M79.  Additional extant adverse cloud seeding literature that went uncited:  Fur67, AVM69, VGr72a, b, V74, VH76, Melt78, V78, Gretal79, MAR80, CS80, CV81, Rh83. https://doi.org/10.1175/1520-0450(1987)026%3C0757:AROTCC%3E2.0.CO;2
  50. Reisen, T, Z. Levin, S. Tzivion, 1996: Rain production in convective clouds as simulated in an axisymmetric model with detailed microphysics. Part II: Effects of varying drops and ice Initiation. J Atmos. Sci., 53, 1815-1837. Cited cloud seeding success literature: Ga75.  Adverse cloud seeding literature cited: L94,   Extant adverse cloud seeding literature that went uncited: R88, RH88, RoG89, RF92, RH95b.
  51. Reisen, T, Z. Levin, S. Tzivion, 1996: Seeding convective clouds with ice nuclei or hygroscopic particles: A numerical study using a model with detailed microphysics.  Appl. Meteor., 35, 1416-1434. Cited cloud seeding success literature: Ga75, GaN81, Sil86.  Adverse cloud seeding literature cited: L94.  Extant adverse cloud seeding literature that went uncited:  R88, RoG89,RF92.
  52. Reynolds, D. W., 1988: A report on winter snowpack-augmentation. Bull Amer. Meteor. Soc., 69, 1290-1300.  Cited cloud seeding success literature: W71, CGM71, GrK74, Metal81, ELL86Su.  Adverse cloud seeding literature cited:   R86, RH87. Additional extant adverse literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79,Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83
  53. Reynolds, D. W., and A. S. Dennis, 1986: A review of the Sierra Cooperative Project.  Bull Amer. Meteor. Soc., 67, 513-523.  Cited cloud seeding success literature: MGC70, NAS73. Extant adverse cloud seeding literature that went uncited:Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83
  54. Rhea, J. O., 1983: “Comments on ‘A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments.'”  Climate Appl. Meteor.,22, 1475-1481.  Cited cloud seeding success literature: GrM67, MGC70, Metal81, MBM82.  Adverse cloud seeding literature cited:  Gretal79.  Additional extant adverse cloud seeding literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81.
  55. Rosenfeld, D., 1997 (July 1996): Comment on “Reanalysis of the Israeli Cloud Seeding Experiments” Appl. Meteor., 36, 260-271. Cited cloud seeding success literature: W71, Bret73, Gb66(sic), GbB70, Ga75, GaN74, GaN81, GaA85, RF92, NiRo95, LevRo96, TukII, Wood97. Adverse cloud seeding literature cited:  R88, RH88, GbR90 L92, RH95b, Ro89.  Extant adverse cloud seeding literature that went uncited:  RH97b.https://doi.org/10.1175/15200450(1997)036%3C0260:COANLA%3E2.0.CO;2
  56. 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 on Planned and Inadvertent Wea. Modif.,Everett, Amer. Meteor. Soc. 565-568. Cited cloud seeding success literature: W71, GaN74, GaN81, Ga81, RF92, RoNi96, LevRo96. Adverse cloud seeding literature cited: GbR90, LGG96.  Additional extant adverse cloud seeding literature that went uncited:  R88, RH88, L92, L94, RH95b, RH97a, b, LKR97.
  57. Rosenfeld, D., and H. Farbstein, 1992: Possible influence of desert dust on seedability of clouds in Israel. Appl. Meteor., 31, 722-731. Cited cloud seeding success literature: NuGbGa67, GbB70, GaN74, GaS74, Ga75, GaN81, GaA85.  Adverse cloud seeding literature cited: GbR90.  Additionalextant adverse cloud seeding literature that went uncited: R88 (appears in references but is not discussed in the text).https://doi.org/10.1175/1520-0450(1992)031%3C0722:PIODDO%3E2.0.CO;2
  58. Rosenfeld, D., and R. Nirel, 1996: Seeding effectiveness—the interaction of desert dust and the southern margins of rain cloud systems in Israel. Appl. Meteor., 35, 1502-1510.  Cited cloud seeding success literature cited: NuGbGa67, GbB70, GaN74, Ga75, GaN81, RF92, NiRo95. Adverse cloud seeding literature cited: GbR90.  Additional extant adverse cloud seeding literature that went uncited: R88, RH88, RoG89,L92, L94, NiRo94, RH95b. https://doi.org/10.1175/1520-0450(1996)035%3C1502:SEIODD%3E2.0.CO;2
  59. Ryan, B. F., 1996: On the Global Variation of Precipitating Layer Clouds.  Amer. Meteor. Soc., 77, 53-70. Cited cloud seeding success literature: Ga75, GaN74, Ga81, GaN81.   Adverse extant literature that went uncited: R88, RH88,RoG89, GbR90, L92, L94, RH95b,
  60. Ryan, B. F., and King, W. D., 1997 (August 1996): A critical review of the Australian experience in cloud seeding.  Amer. Meteor. Soc., 78, 239-254. Cited cloud seeding success literature:  GrM67,MGC71, CGM71, GaN74, GaN81, Cot86, CotP92, RF92, Sil86.  Adverse cloud seeding literature cited:  RH93, L94, RH95b.  Additional adverse literature that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH87, R88. RH88, L92.
  61. Sharon, D., A. Kessler, A. Cohen, and E. Doveh, 2008: The history and recent revision of Israel’s cloud seeding program.  J. Earth Sci., 57, 65-69. Cited cloud seeding success literature:  GaN74, GaN81, GivRo04, GivRo05, NR95.  Adverse cloud seeding literature cited:  GbR90, AHL08.  Additional extant adverse cloud seeding literature that went uncited:  R88, RoG89,RF92, L92, L94, RH95b, LGG96, RH97a,b, LKR97, Br99, Sil01. https://DOI.org/10.1560/IJES.57.1.65.
  62. Silverman, B. A., 2001 (21 Nov 2000). A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement. Bull. Amer. Meteor. Soc., 82, 903-924. Cited cloud seeding success literature: W71, NAS73, GaN74, Ga75, Tuk78 I and II, Ga81, GaN81, Ga86, Cot86, Sil86, RF92, LevRo96, RoNi96, Wood97, Br99.  Adverse cloud seeding literature cited: GbR90, L92, NiRo94, RH95b, LGG96, LKR97, RH97a, ROS98,L99  Additional extant adverse cloud seeding literature that went uncited: R88, RH88, RoG89,L94, RH97b. https://doi.org/10.1175/15200477(2001)082%3C0903:ACAOGS%3E2.3.CO;2
  63. Smith, P. L., A. S. Dennis, B. A. Silverman, A. Super, E. W. Holroyd, III, W. A. Cooper, P. W. Mielke, Jr., K. J. Berry, H. D. Orville, and J. A. Miller, Jr., 1984:HIPLEX-1: Experimental design and response variables. Climate Appl. Meteor.,23, 497-512.  Cited cloud seeding success literature: Metal81.  Extant adverse cloud seeding literature that went uncited:   Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83.

72. Smith, P. L., L. R. Johnson, D. L. Priegnitz, B. A. Boe, P. W. Mielke, Jr., 1997: An Exploratory Analysis of Crop Hail Insurance Data for Evidence of Cloud Seeding Effects in North Dakota. Appl. Meteor., 36, 463-473.  Cited cloud seeding success literature: MBM82.  Extant adverse literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH87, RH93, RH95a.

73. Super, A. B., and J. A. Heimbach, Jr., 1983: Evaluation of the Bridger Range winter cloud seeding experiment using control gages. Appl. Meteor., 22, 1989–2011. Cited cloud seeding success literature: CHAP67, Chap70, GrM67, Gretal69, MGC70, MGC71, HolJ71, GrE74, Rot75, Hill80b, Hill82, Metal81, MBM82. Adverse cloud seeding literature cited:  M79, HR79, CS80.  Additional extant adverse literature to that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, Gretal79, R79, Hill80a, MAR80, CV81. (The authors cited numerous preprints and grey, “Final Report” type literature that were not available for inspection.)

74. Super, A. B., B. A. Boe, and E. W. Hindman, III, 1988 (March 1988): Microphysical effects of wintertime cloud seeding with silver iodide over the Rocky Mountains. Part 1: experimental design and instrumentation.  Appl. Meteor., 27, 1145-1151.  Cited cloud seeding success literature: Metal81. Extant adverse literature that went uncited:Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH87.

75. Tzivion, S., T. Reisen, and Z. Levin, 1994: Numerical simulation of hygroscopic seeding in a convective cloud.   Appl. Meteor., 33, 252-267. Cited cloud seeding success literature: Ga75.  Extant adverse cloud seeding literature that went uncited: R88, RoG89, L92, RF92.

76. Xue, L., X. Chu, R. Rasmussen, D. Breed and B. Geerts, 2016: A Case Study of Radar Observations and WRF LES Simulations of the Impact of Ground-Based Glaciogenic Seeding on Orographic Clouds and Precipitation. Part II: AgI Dispersion and Seeding Signals Simulated by WRF.  Appl. Meteor. Climate, 55, 445-464.  Cited cloud seeding success literature: MGC70, CGM71, Metal81, ELL78, VM78, M95.  Adverse cloud seeding literature cited:  Ro_retra80, Gb95.  Additional extant adverse cloud seeding literature that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH80a, b, RH81, RH87, RH93, RH95a.

——————————————————————————————APPENDIX 2.  THE PEER-REVIEWED ARTICLES EXAMINED IN THE JOURNAL OF THE WEATHER MODIFICATION ASSOCIATION FOR CITATIONS IN THIS SURVEY.

77. R. R., W. E. Finnegan, and L. O. Grant, 1983: Ice nucleation by silver iodide-sodium iodide: a reevaluation.  J. Wea. Mod., 15, 11-15. Cited cloud seeding success literature: GaN74, GaN81, GaM67, Metal81.  Extant adverse cloud seeding literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79,Gretal79, R79, HR79, MAR80, CS80, CV81.

78. Boe, B. A., and A. B. Super, 1986: Wintertime characteristics of supercooled water over the Grand Mesa of western Colorado. Wea. Mod.,18, 102-107. Cited cloud seeding success literature: GrM67. Extant adverse cloud seeding literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79,Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83.

79. Elliott, R. D., 1984: Seeding effects on convective clouds in the Colorado River Basin Pilot Project. Wea. Mod., 16, 30-33. Cited cloud seeding success literature: ELL78, VM78.  Extant adverse cloud seeding literature that went uncited:Fur67, AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh3.

80. Grant, L. O., and R. M. Rauber, 1988: Radar observations of wintertime clouds over the Colorado and Utah.  Wea. Mod.,20, 37-43. Cited cloud seeding success literature: Fur67, Gr87 (sic), Metal81. Extant adverse literature that went uncitedFur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, Hill80a, MAR80, CS80, CV81, Rh83, RH87.

81. Griffith, D. A., 1984: Selected analyses of the Utah/NOAA cooperative research program conducted in Utah during the 82-83 winter season. Wea. Mod., 16, 34-39. Cited cloud seeding literature: GrM67.  Extant adverse cloud seeding literature that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83.

83. Griffith, D. A., and J. R. Thompson, 1991: A winter cloud seeding program in Utah. Wea. Mod., 22, 27-34.  Cited cloud seeding success literature: VM78.  Extant adverse cloud seeding literature that went uncited: HR79, RH80b, Rot_retra80, RVM81, HR81.

84. Long, A. B., 2001: Review of downwind extra-area effects of precipitation enhancement.  Wea. Mod., 33, 24-45. Cited cloud seeding success literature: ELL78, Bret74.  Extant adverse cloud seeding literature that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH95a, b, RH97a, b, Br99.

85. Shaffer, R. W., 1983: Seeding agent threshold activation temperature height, an important criterion for ground-based seeding.  Wea. Mod., 15, 16-20.  Cited cloud seeding success literature: ELL78, VM78.  Adverse cloud seeding literature  cited:  H80a, b, Ro_retra80.  Extant cloud seeding literature that went uncited:  RH80a, b, Rot_retra80, RVM81, RH81.

86. Silverman, B. A., 2009: An independent statistical evaluation of the Vail operational cloud seeding program. Wea. Mod., 41, 7-14. ELL78, GrE74, Metal81.Extant adverse literature that went uncited:  Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, R86, RH87, RH93, RH95a, Gb95, Gb00, Sil01.

87. Solak, M. E., R. B. Allan, T. J. Henderson, 1988: Ground-based supercooled liquid water measurements in winter orographic clouds.  Wea. Mod., 20, 9-18.  Cited cloud seeding success literature: GrE74. Extant adverse literature that went uncited: Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83, RH87.

88. Super, A. B., 1990: Winter orographic cloud seeding status in the intermountain West.  Wea. Mod., 22, 106-116.  Cited cloud seeding success literature: GrE74.  Extant adverse cloud seeding literature that went uncited:Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, R83, R86, RH87.

89.  Todd, C., and W. E. Howell, 1980: General and special hypotheses for winter orographic cloud seeding.    Wea. Mod., 12, 1-15. Cited cloud seeding success literature: MGC71, VM78. Extant adverse cloud seeding literature that went uncited:Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79.

90.  Todd, C. J., and W. E. Howell, 1985: Repeatability of strong responses in in precipitation management.  Wea. Mod., 17, 1-6.  Cited: Cited cloud seeding success literature: ELL84, ELL78, GaN81, GrE74, M63 (sic), VM78.  Extant adverse cloud seeding literature that went uncited:Fur67,AVM69, VGr72a, b, V74, Hobal75, VH76, Melt78, V78, M79, Gretal79, R79, HR79, MAR80, CS80, CV81, Rh83.

_______________________________________________________________________

APPENDIX 3.  Key to abbreviations used in Appendices 1 and 2.  

_______________________________________________________________________

AHL08:  Alpert, P., N. Halfon, and Z. Levin, 2008: Does air pollution really suppress precipitation in Israel?  J. Appl. Meteor. Climatology47, 943-948.  https://doi.org/10.1175/2007JAMC1803.1

AVM69: Auer, A. H., D. L. Veal, and J. D. Marwitz, 1969: Observations of ice crystals and ice nuclei observations in stable cap clouds.  J. Atmos. Sci.26, 1342-1343.

BZ88: Ben-Zvi, A., 1988: Enhancement of runoff from a small watershed by cloud seeding. J. Hydro!.101,291-303. No doi.

BHarp86: Benjamini, Y., and Y. Harpaz, 1986: Observational rainfall-runoff analysis for estimating effects of cloud seeding on water resources in northern Israel.  J. Hydrol., 83, 299-306.Doi not available.

BZetal10: Ben-Zvi, A, Rosenfeld, D., A. Givati, 2010. Comments on “Reassessment of rain experiments and operations in Israel including synoptic considerations” by. Levin, N. Halfon and P. Alpert (Atmos. Res., 97, 513-525.

https://doi.org/10.1016/j.atmosres.2010.06.011

BGM73: Brier, G. W., L. O. Grant, and P. W. Mielke, Jr., 1973: An evaluation of extended area effects from attempts to modify local clouds and cloud systems.  Proc., WMO/IAMAP Scien. Conf. on Weather Modification, Tashkent, World Meteor. Org., 439-447.

Br99:  Bruintjes, R. T, 1999: A review of cloud seeding experiments to enhance precipitation and some new prospects. Bull. Amer. Meteor. Soc.80,805-820.

CHAP67: Chappell, C. F., 1967:  Cloud seeding opportunity recognition. Atmos. Sci. Paper 118, Dept. of Atmos. Sci., Colorado State University, 87pp.

CHAP70: Chappell, C. F., 1970: Modification of cold orographic clouds. Ph.D. Dissertation, Dept. of Atmos. Sci., Colorado State University, 196 pp.

CGM71:  Chappell, C. F., L. O. Grant, and P. W. Mielke, Jr., 1971: Cloud seeding effects on precipitation intensity and duration of wintertime orographic clouds. J. Appl. Meteor., 10, 1006-1010.

CMAR80: 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.

CS80:  Cooper, W. A., and C. P. R. Saunders, 1980: Winter storms over the San Juan mountains.     Part II: Microphysical processes.  J. Appl. Meteor., 19, 927-941.

CV81:  Cooper, W. A., and G. Vali, 1981:  The origin of ice in mountain cap clouds.  J. Atmos. Sci., 38, 1244-1259.

DO97:  Dennis, A. R, and H. D. Orville, 1997: Comments on “A new look at the Israeli cloud seeding experiments.” J. Appl. Meteor., 36, 277-278. 

https://doi.org/10.1175/1520-0450(1997)036%3C0277:COANLA%3E2.0.CO;2

ELL76: Elliott, R. D., R. W. Shaffer, A. Court and J. F. Hannaford, 1976: Colorado River Basin Pilot Project Comprehensive Evaluation Report.  Final Report to the Bureau of Reclamation, Aerometric Research,Inc., Goleta, CA, 641 pp.

ELL78:  Elliott, R. D., Shaffer, R. W., Court, A., and J. F. Hannaford, 1978:  Randomized cloud seeding in the San Juan mountains, Colorado.  J. Climate Appl. Meteor.17, 1298-1318.

ELL80:  Elliott, R. D., Shaffer, R. W., Court, A., and J. F. Hannaford, 1980:  Reply to Rangno and Hobbs.  J. Appl. Meteor.19, 350-355.

Fretal15:  Freud, E., H. Koussevitsky, T. Goren and D. Rosenfeld, 2015:  Cloud microphysical background for the Israeli-4 cloud seeding experiment.  Atmos. Res.158-159, 122-138.  

Fur67: Furman, R. W., 1967:  Radar characteristics of wintertime storms in the Colorado Rockies.  M. S. thesis, Colorado State University, 40pp

Gb67a: 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.

Gb67b:  Gabriel, K. R., 1967b:  Recent results of the Israeli artificial rainfall stimulation experiment.  J. Appl. Meteor., 6, 437-438.                          

https://doi.org/10.1175/15200450(1967)006%3C0437:RROTIA%3E2.0.CO;2

Gb81: Gabriel, K. R., 1981: On the Roles of Physicists and Statisticians in Weather Modification Experimentation.   Bull. Amer. Meteor. Soc.62,

Gb02:  Gabriel, K. R., 2002:  Confidence regions and pooling—some statistics for weather experimentation.  J. Appl. Meteor., 41, 505-518. 

https://doi.org/10.1175/1520-0450(1978)017%3C0552:ANOEOT%3E2.0.CO;2

GbBar70: Gabriel, K. R.., and M. Baras, 1970: The Israeli rainmaking experiment 1961-1967 Final statistical tables and evaluation. Tech. Rep., Hebrew University, Jerusalem, 47pp. No doi.

GbNu78:  ___________., and J. Neumann, 1978:  A note of explanation on the 1961–67 Israeli rainfall stimulation experiment.  J. Appl. Meteor., 17, 552–556.

GbR90:  Gabriel, K. R., and Rosenfeld, D., 1990: The second Israeli rainfall stimulation experiment: analysis of precipitation on both targets. J. Appl. Meteor., 29, 1055-1067

Ga71:  Gagin, A., 1971: Studies of the factors governing the colloidal stability of continental clouds. Proc., Intern. Conf. on Weather Modification, Canberra, Amer. Meteor. Soc., 5-11.

Ga75: Gagin, A. 1975: The ice phase in winter continental cumulus clouds. J. Atmos. Sci., 32, 1602-1614.

Ga80:  _______., 1980: The relationship between depth of cumuliform clouds and their raindrop characteristics. J. Rech. Atmos., 14, 409-422.   Doi not available.

Ga81: _______., 1981: The Israeli rainfall enhancement experiments. A physical overview. J. Wea. Mod., 13, 108-122.  Doi not available.

Ga86: _______., 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

GaA85:  Gagin, A., and M. Arroyo, 1985: Quantitative diffusion estimates of cloud seeding nuclei released from airborne generators. J. Wea. Mod., 17, 59-70.

GaGb87:  Gagin, A., 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

GaN74:  Gagin, A., and J. Neumann, 1974: Rain stimulation and cloud physics in Israel.Weatherand Climate Modification, W. N. Hess, Ed., Wiley and Sons, New York, 454-494.

GaN76: _______., and _________, 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.

GaN81:  Gagin, A., and J. Neumann, 1981: The second Israeli randomized cloud seeding experiment: evaluation of results. J. Appl. Meteor., 20, 1301-1311.

GaS73:  Gagin, A., and I. Steinhorn, 1973:  The role of solid precipitation elements in natural and artificial production of rain in Israel.  Preprints, Intern. Conf. on Cloud Physics, Tashkent,  216–228. (Available from the American Meteorological  Society, Boston, MA 02108.)

Gr68: Grant, L. O., 1968: The role of ice nuclei in the formation of precipitation.   Proc. Intern. Conf. Cloud Phys.,Toronto, Amer. Meteor. Soc., 305-310.

Gr86:  Grant, L. O., 1986:  Hypotheses for the Climax wintertime orographic cloud seeding experiments.  Precipitation Enhancement–A Scientific Challenge, R. R. Braham, Jr., Ed., Meteor. Monographs, 43, No. 21, Amer. Meteor. Soc., 105-108.

GrE74:  Grant, L. O., and R. D. Elliott, 1974: The cloud seeding temperature window.  J. Appl. Meteor.13, 355-363.

GrM67: Grant, L. O., and P. W. Mielke, Jr., 1967: A randomized cloud seeding experiment at Climax, Colorado 1960-1965.  Proc. Fifth Berkeley Symposium on Mathematical Statistics and Probability, Vol. 5,University of California Press, 115-131.

GrDR82:  Grant, L. O., DeMott, P. J., and R. M. Rauber, 1982:  An inventory of ice crystal concentrations in a series of stable orographic storms.  Preprints, Conf. Cloud Phys., Chicago, Amer. Meteor. Soc. Boston, MA. 584-587.

Gretal79:  Grant, L. O., J. O. Rhea, G. T. Meltesen, G. J. Mulvey, and P. W. Mielke, Jr., 1979: Continuing analysis of the Climax weather modification experiments.  Seventh Conf. On Planned and Inadvertent Weather Modification,Banff, The Amer. Meteor. Soc., J43-J45.

Gretal74:  Grant, L. O., Chappell, C. F., Crow, L. W., Fritsch, J. M., and Mielke, P. W. Jr., 1974: Weather modification: a pilot project. Final Report to the Bureau of Reclamation, Contract 14-06-D-6467, Colorado State University, 98pp plus appendices.

Gretal69:  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. (Available from the Bureau of Reclamation, Library, Federal Building, Denver, Colorado 80302)

GivR05:  Givati, A., and D. Rosenfeld, 2005:  Separation between cloud-seeding and air-pollution effects. J. Appl. Meteor., 44, 1298-1314.

 GivR09: ________, and D. Rosenfeld, 2009: Comment on “Does air pollution really suppress rain in Israel?”.  J. Climate Appl. Meteor.,48, 1733-1750.  https://doi.org/10.1175/2009JAMC1902.1

Hill80a:  Hill, G. E., 1980a:  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.

Hill80b: Hill, G. E., 1980b:  Seeding-opportunity recognition in winter orographic clouds.  J. Climate Appl. Meteor., 22, 1371-1381.

Hill86: Hill, G. E., 1986:  Seedability of winter orographic clouds.  Met. Monogr.,43, No. 21, 127-137. 

HR78:  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

HR79:  Hobbs, P. V., and A. L. Rangno, 1979: Comments on the Climax randomized cloud seeding experiments.   J. Appl. Meteor.18,1233-1237.

Hobal75: Hobbs, P. V., L. F. Radke, J. R. Fleming, and D. G. Atkinson, 1975: Airborne ice nucleus and cloud microstructure measurements in naturally and artificially seeded situations over the San Juan mountains in Colorado.  Research Report X, Cloud Physics Group, Atmos. Sci. Dept., University of Washington, Seattle, 98195-1640. No doi. (Available at http://carg.atmos.washington.edu/sys/research/archive/colorado_seeding.pdf

LRo96:  Levi, Y., and D. Rosenfeld, 1996: Ice nuclei, rainwater chemical composition, and static cloud seeding effects in Israel. J. Appl.Meteor.,35,1494-1501.

L92: 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, 115-120. (Available from Dept. Atmos. Sci., University of Tel Aviv).

L94:  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.

LGG96: Levin, Z., E. Ganor, and V. Gladstein, 1996 (June 1995): The effects of desert particles coated with sulfate on rain formation in the eastern Mediterranean.  J. Appl. Meteor.35, 1511-1523.

LHA2010:  Levin, Z.., 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

LKR97:  Levin, Z., S. O. Krichak, and T. Reisin, 1997 (September 1996): Numerical simulation of dispersal of inert seeding material in Israel using a three-dimensional mesoscale model. J. Appl. Meteor., 36, 474–484.

M79:  Mielke, P. W., Jr., 1979:  Comment on field experimentation in weather modification. J. Amer. Statist. Assoc.74, 87-88.

M95: P. W., Jr., 1995: Comments on the Climax I and II experiments including replies to Rangno and Hobbs.  J. Appl. Meteor., 34, 1228-1232.

MM83:  Mielke, P. W., Jr., and J. G. Medina, 1983:  A new covariate procedure for estimating treatment differences with applications to Climax I and II experiments.  J. Climate and Appl. Meteor., 22, 1290-1295.

MBM82:  Mielke, P. W., Jr., Berry, K., and J. G. Medina, 1982:  Climax I and Climax II:  distortion resistant residuals.  J. Climate and Appl. Meteor.,21, 788-792.

MGC70:  Mielke, P. W., Jr, L. O. Grant, and C. F. Chappell, 1970: Elevation and spatial variation effects of wintertime orographic cloud seeding.  J.  Appl. Meteor., 9,476-488.  Corrigenda,10, 842, 15,801.

MGC71:  Mielke, P. W., Jr, L. O. Grant, and C. F. Chappell, 1971: An independent replication of the Climax wintertime orographic cloud seeding experiment.  J. Appl. Meteor.10, 1198-1212.

Metal81:  Mielke, P. W., Jr., Brier, G. W., Grant, L. O., Mulvey, G. J., and P. N. Rosenweig, 1981:  A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments.  J. Appl. Meteor., 20,643-659.

MAR80:  Marwitz, J., 1980 (January 1980):  Winter storms over the San Juan mountains.  Part I.  Dynamical processes.  J. Appl. Meteor.19, 913-926.

MCS76:  Marwitz, J.,W. A. Cooper and C. P. R. Saunders, 1976: StructureandSeedability ofSanJuanStorms.Final Report to the Bureau of Reclamation,University of Wyoming, 324 pp.•

MedR73:  Medenwaldt, R. A., and A. L. Rangno, 1973: Colorado River Basin Pilot Project Comprehensive Atmospheric Data Report, 1972-1973 Season.Report to the Bureau of Reclamation, E. G. & G., Inc., Durango,CO. 376 pp.

Melt78:  Meltesen, G. T., J. O. Rhea, G. J. Mulvey, and L. O. Grant, 1978: Certain problems in post hoc analysis of samples from heterogeneous populations and skewed distributions.  Preprints., 9th National Conf. on Wea. Mod., Amer. Meteor. Soc., 388-391.

M-SS:  Morel-Seytoux, H. J., and F. Saheli, 1973: Test of runoff increase due to precipitation management for the Colorado River Basin Pilot Project.  J. Appl. Meteor.12, 322-337.

NAS73: National Academy of Sciences-National Research Council, Committee on Planned and Inadvertent Weather Modification, 1973:  Weather and Climate Modification: Progress and Problems, T. F. Malone, Ed., Government Printing Office, Washington, D. C., 258 pp.

NGbGa67:  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 available

NiRo94:  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.  No doi available.

NiRo95:  Nirel, R., and D. Rosenfeld, 1995: Estimation of the effect of operational seeding on rain amounts in Israel.  J. Appl. Meteor., 34, 2220-2229.

R79:  Rangno, A. L., 1979:  A reanalysis of the Wolf Creek Pass cloud seeding experiment.   J. Appl. Meteor.18, 579–605Rh83:  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.

R88:  Rangno, A. L., 1988: Rain from clouds with tops warmer than -10 C in Israel. Quart J. Roy. Meteorol. Soc., 114, 495-513.

RH80a: Rangno, A. L., and P. V. Hobbs, 1980a: Comments on “Randomized seeding in the San Juan mountains of Colorado.”  J. Appl. Meteor.19, 346-350.

RH80b: Rangno, A. L., and P. V. Hobbs, 1980b: Comments on “Generalized criteria for seeding winter orographic clouds”. J. Appl. Meteor.19, 906-907.

RH81:  Rangno, A. L., and P. V. Hobbs, 1981: Comments on “Reanalysis of ‘Generalized criteria for seeding winter orographic clouds’”, J. Appl. Meteor., 20, 216.

RH87: Rangno, A. L., and P. V. Hobbs, 1987: A re-evaluation of the Climax cloud seeding experiments using NOAA published data.  J. Climate Appl. Meteor.26,757-762.

RH88:  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.  No doi available.

RH93: Rangno, A. L., and P. V. Hobbs, 1993: Further analyses of the Climax cloud-seeding experiments.  J. Appl. Meteor.32, 1837-1847.

RH95a: Rangno, A. L., and P. V. Hobbs, 1995b: Reply to Gabriel and Mielke.  J. Appl. Meteor., 34, 1233-1238.

RH95b:  Rangno, A. L., and P. V. Hobbs, 1995:  A new look at the Israeli cloud seeding experiments.  J. Appl. Meteor., 34, 1169-1193.

RH97a: Rangno, A. L., and P. V. Hobbs, 1997a: Reply to Rosenfeld.  J. Appl. Meteor.36, 272-276.

RH97b: Rangno, A. L., and P. V. Hobbs, 1997b: ComprehensiveReply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp. Cloud seeding success literature cited:  Gb67, GbB70, W71, Bret73, GaN73, GaN74, Saxet75,GaN76, GbN78, Ga80, GaN81, Ga81, Kerr82, GaA85, Ga86, Sil86, GaG87, B-Z88, RoG89, D89, RF92, NiRo95, RoN96, ROS97.   Adverse cloud seeding literature cited:  HR78, Gretal79,M79, R79, Hob80, Ros80, B-Harp86, R88, RH88, RoG89, GbR90, L94, RH95b. LGG96 (http://carg.atmos.washington.edu/sys/research/archive/1997_comments_seeding.pdf)RH97b: Rangno, A. L., and P. V. Hobbs, 1997b: ComprehensiveReply to Rosenfeld, Cloud and Aerosol Research Group, Department of Atmospheric Sciences, University of Washington, 25pp.

Rn88:  Reynolds, D. W., 1988: A report on winter snowpack-augmentation.  Bull Amer. Meteor. Soc.,69, 1290-1300.

RD86: Reynolds, D. W., and A. S. Dennis, 1986: A review of the Sierra Cooperative Project.  Bull Amer. Meteor. Soc., 67, 513-523. 

Rh83:  Rhea, J. O., 1983: “Comments on ‘A statistical reanalysis of the replicated Climax I and II wintertime orographic cloud seeding experiments.'”  Climate Appl. Meteor.,22, 1475-1481. 

RDW69:  Rhea, J. 0., L. G. Davis and P. T. Willis, 1969: The Park Range Project. Final Report to the Bureau of Reclamation, E. G. & G., Inc.,Steamboat Springs, CO. 288 pp.

ROS97:  Rosenfeld, D., Comments on “A new look at the Israeli cloud seeding experiments.” J. Appl. Meteor.36, 260-271.

RF92:  Rosenfeld, D., and H. Farbstein, 1992: Possible influence of desert dust on seedability of clouds in Israel. J. Appl. Meteor., 31, 722-731. 

RoGa89:  Rosenfeld, D., and A. Gagin, 1989: Factors governing the total rainfall yield from continental convective clouds. J. Appl. Meteor., 28, 1015-1030.

RN96: Rosenfeld, D., and R. Nirel, 1996: Seeding effectiveness—the interaction of desert dust and the southern margins of rain cloud systems in Israel.  J. Appl. Meteor.35, 1502-1510. 

RVM81:  Rottner, D., L. Vardiman, and J. A. Moore, 1981: Reply to Rangno and Hobbs, J. Appl. Meteor.20, 217.

Saxet75: Sax, R. I., S. A. Changnon, L. O. Grant, W. F. Hitchfield, P. V. Hobbs, A. M. Kahan, and J. Simpson, 1975: Weather modification: Where are we now and where are we going? An editorial overview. J. Appl. Meteor., 14, 652-672.

https://doi.org/10.1175/1520-0450(1975)014%3C0652:WMWAWN%3E2.0.CO;2

Sh90:  Sharon, D., 1990:  Meta-analytic reappraisal of statistical results in the environmental sciences: the case of a hydrological effect of cloud seeding.  J. Appl. Meteor.29, 390-395.

https://doi.org/10.1175/1520-0450(1990)029%3C0390:MAROSR%3E2.0.CO;2

ShKCD08:  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.

Sil86:   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.

Sil01:  Silverman, B. A., 2001. A critical assessment of glaciogenic seeding of convective clouds for rainfall enhancement. Bull. Amer. Meteor. Soc.,82, 903-924.

S09:  Silverman, B. A., 2009: An independent statistical evaluation of the Vail operational cloud seeding program.  J. Wea. Mod., 41, 7-14.

V78:   Vardiman, L., 1978: The generation of secondary ice particles in clouds by crystal-crystal collisions. J. Atmos. Sci., 35, 2168-2180.

VG72a:  Vardiman, L., and L. O. Grant, 1972a: A case study of ice crystal multiplication by mechanical fracturing. Abstracts, Intern. Cloud Physics Conference, London, Amer. Meteor. Soc., 22-23.

VG72b:  Vardiman, L., and L. O. Grant, 1972b: A study of ice  crystal concentrations in convective elements of winter orographic clouds.  Preprints, Third Conference on Weather Modification, Amer. Meteor. Soc., 113-118.

VH76: 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.

VM78: Vardiman, L., and J. A. Moore, 1978: Generalized criteria for seeding winter orographic clouds.  J. Appl. Meteor.17, 1769-1777.

Wo97: Woodley, W., 1997:  Comments on “A new look at the Israeli Randomized cloud seeding experiments.” J. Appl. Meteor.,36, 250-252.

https://doi.org/10.1175/1520-0450(1997)036%3C0250:COANLA%3E2.0.CO;2

W71:  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

Y93: Young, K. C., 1993: Microphysical Processes in Clouds. Oxford University Press, 200 Madison Avenue, New York, New York 10016, 427pp.

 

Should “one-sided citing” in journals be considered a form of scientific misconduct?

 

An essay proposed and rejected by the Bull. Amer. Meteor. Soc. in 2019

 

Rejectee and author,  

Arthur L. Rangno

Retiree, Research Scientist IV,

Cloud and Aerosol Research Group, University of Washington, Seattle.

Abstract

 

Peer-reviewed and other publications that lack the full “story” via author omissions of relevant literature having opposing viewpoints are said to exhibit, “one-sided citing.” This is especially frequent phenomenon in journal articles in the domain of weather modification in which the author has worked. 

One-sided citing is particularly pernicious to journal readers who are deliberately misled; to authors that go uncited and lose ground in citation metrics, and are, therefore, perceived to have less standing in their field than they should.   Implicitly, one-sided citing also damages the institutions whose authors practice it. Raising the bar to “scientific misconduct” on such activity will stop it.

That one-sided citing regularly reaches the peer-review literature in controversial arenas is testimony that the peer-review system is broken and needs to be repaired.

Examples of one-sided citing are discussed.


Below are items that must be filled out in support of your submission to BAMS.

  • Category: Essay/opinion piece on “one-sided citing.”

 

  • Purpose: 1) Bring attention to a serious problem in some peer-reviewed publications that will likely lead to future remediation; 2) open a dialogue for others, who, like this author, have had their modest careers diminished by “one-sided-citing.” 

 

  • Importance: alerts journal readers to the phenomenon of “one-sided-citing” in a medium they otherwise trust and perhaps imbue them with a “caveat emptor” attitude when reading articles in controversial arenas. 

 

  • Length: 1770 words

 

  • Illustrations:none

 

  • Scientific context/interpretation of one-sided citing:

 

One-sided citing is a deliberate act by authors to mislead journal readers by “cooking and trimming” truth.  It inflicts material harm on researchers whose work should be cited but isn’t since one’s standing in his/her field, awards, promotions are often evaluated via citation metrics.   Besides in the cloud seeding domain, it has also been observed in the climate literature.

It arises because of poor, or “one-sided” peer-reviews of manuscripts, which in turn, might well be traced to the practice of authors suggesting reviewers to journal editors, which, not surprisingly, leads to fault-ridden, peer-reviewed articles. 

It is recommended that the AMS adopt wording analogous to that of the FTC regarding consumer fraud and label such acts as “scientific misconduct” to put an end to this practice. 

Examples of one-sided citing are provided in the essay.

 

  • There will be no electronic supplements.

——————————————————————————————

Response to the letter of rejection for this

essay/opinion piece from the 

Bull. of the Amer. Meteor. Soc.

Thank you, Jeff R., if I may, for taking your valuable time to respond with an assessment of my provocative proposal.  

I knew this would be a pot boiler, but I reasoned that forming a question about the lamentable practice of one-sided citing in the title that it would fly right in for peer-review!  I have 40 years of experience with this kind of activity. 

So why BAMS (again)?

Here’s what I saw about what BAMS says it publishes from the BAMS web page on “article types for BAMS.”  I hope these words remain and do not disappear.

  • “Essays: Up to 5,000 words (average length is about 3,500 words). Based on experience, opinion, and qualitative or quantitative analysis. These peer-reviewed contributions are designated as a “Forum” within the Articles section.”

Certainly, with 40 years of experience with journal literature, the observation of one-sided citing in it, which I quantify by examples,  falls within the criteria stated by BAMS.

We’ve got that.

Can one determine “one-sided citing?  Of course, IF one knows the literature!  You can’t know what’s being omitted if you don’t know the literature!

The inspiration for this essay?  The AMS recommended book, Eloquent Science (Schulz).  Here’s what Schultz had to say about this phenomenon, which I suspect you have not seen:

One-sided reviews of the literature that ignore alternative points of view, however, can be easily recognized by the audience, leading to discrediting of your work as being biased and offending neglected authors…”. 

For emphasis, please observe that Schultz believes, as we who have been subject to one-sided citing do, that it is “easily recognized.”   

You are of the opposite opinion concerning recognition, which I did not expect.  

But then no single editor such as yourself can possibly know enough about any segment of the literature his journal covers to recognize omissions; one-sided citing.

I discuss an example of one-sided citing that appeared in JAMC, the lead author of that article from a respected institution who knows my work in the weather mod domain well.  He had co-authored one or more articles with the beloved leader of the experiments that were brought down by my work; those at Climax, Colorado.   In his article the discredited Climax randomized cloud seeding experiments are cited once,  Mielke et al. (1981).  End of story.  

The long journal paper trail of reanalyses, beginning with Rhea (1983) that showed those Climax results and the hypotheses behind it were ersatz were ignored.  The journal reader, in examining the single reference to Mielke et al. 1981 will learn of a robust cloud seeding success in a randomized experiment!  End of story#2. 

This is misconduct in MY OPINION—the discussion of which is allowed in BAMS essays/opinion pieces.    Others, of course might disagree, not realizing that the lead author was well aware of the unraveling of the Climax experiments. 

Why should it be formally considered “scientific misconduct”?

Many are harmed:   

  1. the journal reader who expects to find truth in a highly acclaimed journal, 
  2. the authors who exposed faulty claims whose work is not cited (impacting citation metrics), 
  3. the journal it appears in can be deemed, in fact, unreliable for “truth”, 
  4. the institutions from which one-sided citing emanates are harmed implicitly by being seen as houses of bias.  

Why is this not obvious?

Again, I can tell you positively that the lead author of that JAMC publication knew of that journal paper trail regarding his home institution’s (Colorado State University) experiments.  

But let’s write him, with you cc-ed, and ask if he “deliberately” omitted contrary findings?  He can’t say he didn’t know about them.  What other answer is then left?  Q. E. D.

The problem for me, as senior members of the community I represent pass (e.g., Roland List, Bernie Silverman, et al), is that younger researchers will no longer “easily recognize” the abuses of one-sided-citing in this domain.  I myself have been deemed, in two recent e-mails, “the last of a dying breed” and “the best of a dying breed.”  It was use of the word “dying” that made the most impact…and resurrected thoughts of the bucket list.  Jeff Rosenfeld is on the receiving end of that list I’m afraid, thoughts left on the table…

The motivation  to address the one-sided citing problem (after discovering it was still occurring, and represents a blatant sign of inadequate reviews in weather mod.  Those are likely due to the regrettable practice of authors suggesting reviewers to editors (who are out of their element and cannot possibly know all the resources they should be commanding for the breadth of topics of their journal).  

I was not, of course, asked to review those publications.

I will pass my take on to David Schultz, and see what his take is on it, and whether he thinks BAMS is a good place or?  PNAS?

To use the NRC-NAS phrase in their publication on science ethics, one-sided citing can be described as, “cooking and trimming” the truth.  We should all be against such practices in the strongest way and openly condemn them.  That’s why I recommend that the AMS, first, resurrect their abandoned “Code of Ethics” and incorporate wording of the FTC, adjusted for science, concerning consumer fraud.

Sorry to be such a pain in the butt, Jeff, but, as the song says, “I gotta be me.”

art

PS: My goal was to ignite a Society-wide discussion of this problem with a splash in the BAMS opinion/essay domain.  “One-sided citing” is easily proved.  Examples are discussed in detail in my essay/opinion piece, and briefly here.

———————————-

I have posted what became a full journal manuscript, well-beyond a mere essay about one-sided citing here:

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

It has not yet been submitted to a journal, but it damn well won’t be an Amer. Meteor. Soc. one!

Art

Review and Enhancement of Chapter 7 of AMS Monograph 58 ON 2NDARY ICE :

“Secondary Ice Production:  Current State of the Science and Future Recommendations”

by P. R. Field,a,b
R. P. Lawson,c P. R. A. Brown,a G. Lloyd,d C. Westbrook,e D. Moiseev,f
A. Miltenberger,b A. Nenes,g A. Blyth,b T. Choularton,d P. Connolly,d J. Buehl,h J. Crossier,d
Z. Cui,b C. Dearden,d P. DeMott,i A. Flossman,j A. Heymsfield,k Y. Huang,b H. Kalesse,h
Z. A. Kanji,l A. Korolev,m A. Kirchgaessner,n S. Lasher-Trapp,o T. Leisner, G. McFarquhar,o V. Phillips, p
J. Stith,q and A. Sullivan. l

Note to reader: the many superscripts refer to the institutions that the 29 authors belong to. They are not reported in this review.

The entire unadulterated article with its many illustrious co-authors can be found here:

https://journals.ametsoc.org/view/journals/amsm/58/1/amsmonographs-d-16-0014.1.xml

REVIEWER COMMENT on my submission:

“Reviewer #1: I believe the comments made by Art Rangno up through his section 3 should be included as an Appendix to the Monograph as he adds a number of points and references not included in the original monograph that may be of interest to future monograph readers.  I felt that the authors of the monograph adequately responded to the comments made by Art through his section 3.  However, the monograph authors have completely ignored as far as I can tell Rangno’s more specific comments in section 4 of his review.  I would like to see the Monograph authors address these more specific comments in the main body of the Monograph text and would like a response to each comment as in a normal journal paper response to reviewers comments.”
———-
There were no other reviewers. (AR)

Reviewed by (Mr.) Arthur L. Rangno[1]
Retiree, Staff Research Scientist III,
Cloud and Aerosol Group, Atmos. Sci. Dept.,
University of Washington, Seattle.
Currently: Catalina, Arizona 85739

The many authors’ polite response to my novella-sized review is found below. They were very nice considering I was not in a good mood when I reviewed their chapter. Since some of the senior authors of Chapter 7 are friends, I am placing their response before the review and “enhancement” of Chapter 7, American Meteorological Society Monograph 58, that I submitted here:

There are two minor editions additions to my review that have been added concerning a research flight by the Cloud and Aerosol Group that adds more information to the problem of “secondary ice” and a further reference to drop freezing experiments by Duncan Blanchard (1957).

About the journal “Reply” to the
“Review and Enhancement” by the 29 authors of Chapter 7

Monograph Editor, G. McFarquhar, had this to say to me and the 29 co-authors of that chapter about my submission:

All:

First, I would like to give some information on the comment/reply process from my perspective as Chief Editor of the AMS Monographs.  It is true that there has never been a comment/reply published on an AMS Monograph article before.“  

Editor McFarquhar went on to mention the “strange” organization of my “review and enhancement.”  (Hah. Hardly surprising).

So, I inadvertently broke some ground in submitting a “review of a review.”  Why I was overlooked as a reviewer of this chapter is still perplexing. The most gratifying thing about this submission was that one of the 29 co-authors of Chapter 7 wrote and said, “I knew it was you who did the heavy lifting for Peter Hobbs.”  Indeed, and was the case for the other outstanding researchers that passed through his group.  But perhaps because it was in doubt that I could contribute, as a mere staff member in Peter’s group, was the reason why I was not asked to review Chapter 7 before it was published.   I coulda helped.

I have attached the current “status quo” situation, if interested in the topic of secondary ice formation in clouds. You will see in my review that the original Chapter 7 had some amusing errors, such as the Beaufort Sea apparently being in the Washington coastal waters.  I think the illustrious co-authors of Chapter 7 were in a hurry…. Also, in a grotesque error, the co-authors referred to me as, “Dr. Rangno,” while my real name is Mr. Art:

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

Some background on why I decided to review Chapter 7

I discovered the 2017 American Meteorological Society Monograph Number 58 and its Chapter 7 in early 2018.  I had worked on the problem of secondary ice in clouds discussed in this volume for more than 20 years with Professor Peter V. Hobbs, Director of the Cloud and Aerosol Research Group.  I know and consider a number of the senior authors friends.  

Our published work while sampling clouds in different venues and over many years repeatedly concluded that the leading theory to explain “secondary ice” in clouds, came up short.  That mechanism, discovered in careful lab experiments by Hallett and Mossop (1974: Mossop and Hallett 1984),  showed that when graupel (represented by a rod in a cloud chamber) intercepted larger (>23 um diameter) supercooled cloud droplets, some ice splinters were cast off.  However, it was limited to in-cloud conditions when the temperature was between -2.5° and -8°C.  The peak splinter production occurs at a temperature of -4.5°C.  From that peak, the rate of splinter production drops off quickly.

There is no doubt that this process occurs in clouds.  But, is that all there is?

The problem that we encountered was that high ice particle concentrations developed too rapidly in clouds with tops >-10°C to be explained by the Hallett-Mossop riming-splintering mechanism alone,  as it was described in the original lab experiments  and those that followed  (e.g., Mossop 1985).  

We also found high ice particle concentrations in clouds in which the components of this leading theory were not met, or barely so (Rangno and Hobbs 1994).  The discrepancies that we encountered, and those in other publications that reported discrepancies but were not cited in the Chapter 7,  will also be a theme.  It will also give me a chance to present an overview of our extensive findings, especially those that were not cited (Rangno and Hobbs 1991; 1994), and where there were drawbacks in our earlier work on this subject (i.e., Hobbs and Rangno 1985).

Abstract and organization of:

“Review and Enhancement of Chapter 7, AMS Monograph 58

Sections 1-3 below was reviewed and commented by the authors of Chapter 7, but I had not seen those comments as of 19 March 2021. They were not relayed to me by the journal Editor, which is normally done so that errors and misunderstandings in papers can be taken care of behind the scenes before publication. That’s a pretty normal practice, but it hadn’t happened by that date, so read Sections 1-3 with caution since revisions are likely and the authors’ criticisms except as they appeared above.

You can easily skip to the line-by-line critique resembling a “normal” manuscript review that comprise Sections 4 and 5 via “jump” links.

————————————————————————————–The review of Chapter 7 consists of several elements: 1) an introduction section, 2) a review of the Hallett-Mossop process and why it cannot explain, of itself, high ice particle concentrations in Cumulus clouds with slightly supercooled tops; 3) relevant literature that went uncited in Chapter 7 that might have altered, and in some cases, enhanced some of the authors’ conclusions; 4) selected quotes from Chapter 7 followed by my commentary, similar to a formal manuscript review; 5) lesser, picayunish corrections , some involving citation etiquette, all of which should have been caught before Chapter 7 went to press.

Field et al. (2017, hereafter, F2017) have done a remarkable job of summarizing a vast amount of work on the continuing enigma of the origin of ice-in-clouds.  Not surprisingly, considering the abundance of publications in various journals relevant to this mystery, some publications were overlooked that might have helped the reader, and altered some of the conclusions wrought in F2017.  This review is meant to “fill in” those blanks; to be an enhancement of Chapter 7 rather than a series of criticisms.   It is restricted to the cloud microphysical portions of Chapter 7 concerned with ice multiplication in Cumulus clouds, the writer’s specialty.

1. Introduction

The “embarrassment of citation riches” to much of our prior University of Washington work[2], is much appreciated.  Nevertheless, since it is not possible to be cited too many times, only too few, we dredge up even more of our work relevant to the question of secondary ice that went uncited.  The comments contained in this review will range from picayunish errors in F2017 (left until the end) to more significant commentary concerning the workings of the H-M process at the beginning of this review.  This is followed by quotes in F2017 followed by my comments, a style mimicking that of a pre-publication review.

We start with a summary of the Hallett-Mossop riming-splintering process (Hallett and Mossop 1974; Mossop and Hallett 1974, hereafter “H-M”) and why the H-M process cannot, of itself, account for the “rapid” development of ice in clouds that F2017 mentions in their abstract.  In reading Field et al. it was felt that this distinction between clouds that produce ice rapidly and the inability of the H-M process alone to do that in slightly supercooled Cumulus clouds, beginning with primary ice nuclei (IN) was not made clear.

Relevant literature that was not cited or possibly not known about by F2017 is indicated by an “u” after the citation in this review, for “uncited.”   The relevant citations are found at the end of this piece.  (Jump/anchor links will be added when I remember how to do them.)                        ‘

  1. Review of the Hallett-Mossop riming-splintering process

The rapid development of precipitation in Cumulus clouds transitioning to Cumulonimbus clouds, has been noted for many decades via radar (e.g., Battan 1953; Saunders 1965, Zeng et al. 2001) and by aircraft (e.g., Koenig 1963).   A process that can explain such rapid transitions in clouds whose tops reach much above the freezing level must act very quickly (<10min) to enhance concentrations of ice particles in such clouds.  The H-M process is one that is usually cited in conjunction with this rapid formation of ice.  However, of itself, even when the broad droplet spectra is satisfied in a Cumulus turret with a top at -8°C with only primary ice nuclei (IN) as ice initiators, such a cloud can never attain the 10s to 100s of ice particles per liter associated with “ice multiplication”, those in modest Cumulonimbus clouds.   

Why can’t the H-M process alone produce significant ice in Cumulus clouds when its criteria are satisfied? 

The lifetime of Cumulus turrets is too short, <20 min (e.g., Workman and Reynolds 1949u, Braham 1964u, Saunders 1965u). Its too short for several cycles of splinters to develop, those having to reach fast-falling graupel sizes to be significant splinter producers, starting with ice particles from the very few primary ice nuclei (IN) at -8°C.  Even the H-M droplet spectra itself is doomed within a few minutes in the lives of ordinary Cumulus turrets as they fall back and evaporate[3].  Mason’s (1996) calculations, using reasonable assumptions, required 1 h for ice particle concentrations to reach 100 l-1after starting from primary IN, which Mossop noted was untenable for a Cumulus turret.   Chisnell and Latham (1976) understood this: “Firstly there are some reported multiplication rates, 10 in 8 min (Mossop et al. 1970), 500 in 5 ~ min (Koenig 1973-sic), which are inexplicable in terms of a ‘riming only’ model, but which are consistent with a model containing rain drops.”

Absent larger (>30 µm diameter)  droplets and/or precipitation-sized drops (>100 µm diameter), tens of minutes to an hour or more is required to raise ice particle concentrations from from primary IN concentrations to 100 l-1(e.g., Chisnell and Latham 1976, “Model A”, Mossop 1985a,u, Mason 1996), times that are not tenable considering the short lifetimes of Cumulus turrets.

Moreover, air translates through Cumulus clouds analogous to lenticular clouds though at a far slower pace (e.g., Malkus 1952u, Asplinden et al 1978u).  Thus, while a Cumulus cloud can appear to exist for tens of minutes, its individual turrets cannot.   Any splinters that might be formed by a round of very sparse graupel due to primary IN, should an ice crystal have time to become a graupel particle, will go out the side or evaporate as the top declines and evaporates toward the downwind side as illustrated in Byers (1965u, Figure 7.3).  One of the lessons learned in the HIPLEX seeding experiments when dry ice, dropped like graupel into supercooled Cumulus turrets, was that it produced ice crystals that drifted out the side of decaying cloud portions (Cooper and Lawson 1984u).

Mossop (1985a,u) himself had trouble explaining the rapidity of ice development in his own Cumulus clouds in the Australian Pacific.  Using his measured concentrations of frozen drizzle drops as an accelerator of ice formation, Mossop calculated that it would take about 47 minutes to go from initial ice concentrations due to primary IN (0.01 per liter) at -10°C to 100 ice particles per liter. Mossop knew that this amount of time was untenable for a Cumulus turret.  He then reasoned that IN must be about 10 times higher at -10°C to explain that discrepancy, or about 0.1 per liter, to bring the glaciation time he observed down to about 20 minutes (calculating that the concentrations of ice particles increased 10 fold each 10 min beginning with 0.1 IN per liter active at -10°C).   The concentration of IN surmised by Mossop (1985a, u) is now close to that in updated concentrations of IN by DeMott et al. 2010 of about 0.3 per liter active at -10°C[4]

However, IN need to be about 10-100 times higher than Mossop’s estimate of 0.1 per liter to bring down the time of glaciation to that observed in clouds like his own Australian clouds, namely, ones containing copious droplets >30 um diameter and some precipitation-sized drops.  This was demonstrated by Crawford et al. 2012’s case of 100 times the DeMott et al. primary IN with a model cloud top at -10°C, a case study that best mimicked the near-spontaneous glaciation of real clouds having modestly supercooled tops and containing drops >30 µm diameter (often with drizzle or raindrops). 

In sum, if the droplet spectra does not broaden considerably farther so that droplets larger than 30-40 µm in diameter are in plentiful concentrations (past the Hocking and Jonas 1971; Jonas 1972) thresholds for collisions with coalescence to begin,  there will be no “rapid” glaciation in slightly to modestly supercooled clouds that only meet the H-M droplet spectra criteria.  

  1. Discussion of ice multiplication in literature that went uncited by F2017

Our follow up studies of ice development in Cumulus and small Cumulonimbus clouds after HR85 and HR90 went uncited in F2017. Those were Rangno and Hobbs 1991u and 1994u, hereafter RH91u and RH94u.  We offer a brief summary of our findings before moving on to other relevant uncited findings.  We believe that these uncited papers, en toto, cast additional light the nature of the problem posed by ice multiplication.Discussion of RH91u with some background on HR85

In our prior study of ice-in-clouds, HR85, only a 6 s time resolution was available for data during most of the sampling period  (1978-1984). Therefore, we sampled rather wide cloud complexes to get meaningful statistics.   In addition, our 2-DC probe was only operated sporadically, not continuously in cloud.  

In RH91u data resolution was 1 s or less, and there was continuous 2-DC coverage of cloud penetrations.   Moreover, we carried a vertically-pointable (up or down), mm-wavelength radar, perhaps the first cloud research aircraft to do so. 

We often sampled much smaller clouds than in HR85 and we found that maritime, short-lived (<1 km wide) “chimney” Cumulus clouds whose tops fell back into warmer air and evaporated, did not produce much detectableice even if they reached close to -10°C.  This was true even as their wider, nearby brethren with the same cloud top temperature produced “anvils of ice”, replicating the findings in HR85 (see RH91u, Figure 1). The low ice concentrations found in chimney Cumulus clouds could also have been due to not being able to sample very small ice crystals, those below about 100 µm in maximum dimension.  It forced us to reconsider the role of evaporation that we posited was important in the production of ice in HR85.

The finding in RH91u that wider clouds had considerably more ice corroborated Mossop et al.’s 1970 and Schemenauer and Isaac’s (1984u) earlier findings that cloud width had a profound effect on the development of ice in clouds.  These findings implicitly address the importance of the duration of cloud and precipitation-sized drops, if any of the latter, at lower temperatures. 

Of note  is that the maritime Cumulus clouds in Washington State coastal waters during onshore flow are virtually identical to those studied by Mossop and his colleagues in the Australian Pacific in terms of cloud base temperatures, droplet concentrations, ice particle concentrations and in the minimum cloud top temperatures at which most sampling took place  (e.g., Mossop et al 1968u, Mossop and Ono 1969u).   Our studies were, thus, an attempt at replicating the findings of Mossop and his colleagues without going to Australia.  

In RH91u, we found again, as noted in F2017, that Mossop’s (1985a, u) report that ice concentrations required 20 min to rise from 0.1 per liter to 100 per liter, was still too great an amount of time to account for the rapidity of the glaciation that we observed in our Washington clouds.  Lawson et al. (2015) have arrived at a similar conclusion recently though in a different way.

 In RH91u we also compared the explosive formation of ice in our maritime Cumulus to our prior dry ice cloud seeding experiments (Hobbs 1981u) and again in RH94u. The imagery is remarkably similar as a demonstration of the rapidity, the virtually spontaneous formation of ice[5].  We thought that an important comparison.

We also investigated the ocean’s influence on ice formation by sampling small to medium Cumulus clouds that developed out of clear air in an extremely cold[6], offshore flowing air mass over the Washington State coastal waters. Cloud bases were -18°C and cloud tops of the deepest Cumulus, -26°C.   The sea surface was roiled by estimated 25-40 kt winds with widespread whitecaps. Mixing from the sea surface, about 13°C, to cloud bases was extreme, as marked by the heavy turbulence on that flight and vomting.  We sampled those cumuliform clouds as they deepened downwind as far as 100 km offshore that day. 

That day stood out in our studies.  We measured the lowest ice particle concentrations in all our sampling of cumuliform clouds with top temperatures -24°C to -26°C by measuring maximum concentration of only 7 l-1in clouds up to about 1 km in depth.  This day forced us to conclude that the coastal waters of Washington State, anyway, were not a source of high temperature ice nuclei, counter to some more recent work (DeMott et al. 2016).  However, we did not measure concentrations of ice particles that were < 100 µm in maximum dimension.

The droplet spectra in those offshore flowing clouds was narrow, as would be expected with such low base temperatures, and again the idea that droplet sizes control ice formation was once again realized by these low concentrations of ice.

In sum, from our attempts at replicating Mossop’s results in clouds identical to his over many years, we found several departures in ice formation from the operation of the H-M process as it was being described.  These discrepancies are somewhat different than those quoted for our research in F2017, hence we reprise them here: 

The focus of RH94u was to remove the effects of the H-M process by studying ice development continental and semi-continental clouds found mostly east of the Cascade Mountains of Washington State, clouds that did not meet the H-M criteria. We believed that this was an important next step.  The clouds we sampled almost always had base temperatures of 0°C or lower.  Droplet concentrations were semi-continental to “continental” ranging from 300 cm-3to 1500 cm-3, many times higher than droplet concentrations in the Washington coastal waters in onshore flow that averaged but ~50 cm-3.    Thus, the droplet spectra in the eastern Washington and other cold clouds we sampled were considerably narrower than in our coastal clouds, and due to those cold bases, contained few if any drops meeting the large droplet size (>23 µm) in the H-M temperature zone.  We again carried our vertically-pointable, mm-radar to help elucidate cloud structures below or above the aircraft.

Our findings for the eastern Washington State clouds, simply explained, were that the higher the cloud base temperature, the greater the ice at in a Cumulus cloud, holding cloud top temperature constant. Thus, a cloud with a base of -15°C and a top of -20°C had far lessice than a cloud with a base of 0°C and a top at -20°C with no contribution from H-M.  This finding spoke to, as we believed then and continue to believe, the largest droplet sizes of the spectra as being a critical parameter in the production of ice.   We continued to find that a measure of the broadness of the FSSP-100-measured droplet spectrum (our “threshold diameter”, or large end “tail” of the droplet spectrum, e.g., HR85) in newly risen turrets lacking much ice (<1 l-1) continued to be strongly predictive of later maximum ice particle concentrations.

We also found that for very cold based clouds (<-8°C) that Fletcher’s (1962u) summary ice nucleus curve predicted ice concentrations associated with a range of cloud top temperatures extremely well (r=0.89).  This probably indicated that we had little contribution from probe shattering artifacts after accounting for them (see RH91u).   The crystal types in those clouds were almost all delicate stellar and dendritic forms where shattering artifacts would be expected to be rampant[9]

Too, ice formation in the eastern Washington State clouds, as it was in our maritime clouds, was extremely rapid, explosive, in turrets with larger droplets (>~25 µm in diameter) as they reached their peak heights with no contribution from H-M.  As with our maritime clouds, the scenario of a few much larger particles (graupel) appeared to be coincident with wholesale formation of high ice concentrations. 

This did not happen, however, in very cold-based (<-8°C), shallow clouds with small (~<20 µm diameter) droplets and tops down to -27°C where ice appeared to form from a “trickle” process likely due to ambient IN concentrations rather than aided by other factors.  

  • The formation of ice was far more rapid in clouds with tops between -5°C and -12°C than could be accounted for by H-M, requiring <10 min, as judged from the small size of the ice particles in high concentrations, ones that had not yet had time to begin forming aggregates; moreover, they were usually coincident with relatively high LWC that had not had time to be depleted (e.g., HR90, RH91u). Newly risen turrets full of LWC could be seen to transition to an icy, fraying, soft, cotton-candy appearance in less than 10 min.   What cloud observer hasn’t seen this behavior?
  • Our maritime clouds had very low concentrations of small (<13 µm diameter) droplets once appreciably above cloud base and into the H-M temperature zone. Low concentrations of small droplets were once thought to be an impediment to riming and splintering (e.g., Mossop 1978u; Hallett et al. 1980u), though later studies deemed them to have only a “secondary role” (Mossop 1985b).
  • Measured graupel concentrations, despite our “optimizations” (using high concentrations over a few meters rather than turret-averaged) to try to make H-M work in RH91u were still not high enough to account for the high concentrations of ice particles that developed so quickly.
  • Our fast-glaciating, modest Cumulus and Cumulonimbus clouds with tops between -5°C >-12°C did not contain mm-sized raindrops, thought to be critical for rapid glaciation as asserted by F2017. However, copious large droplets (>30 µm diameter) and drizzle-sized drops up to about 500 µm diameter were always found, though the latter in relatively low concentrations[7],[8].  Drop sizes between 30 µm and 60 µm diameter, deemed an important player in ice multiplication by Ono (1972u), were always copious.

  • Discussion of Rangno and Hobbs (1994u)

Too, our evaluation of the H-M process could not explain the ice multiplication that occurred in those few eastern Washington clouds that did meet the H-M criteria.  In our calculations we used a “relaxed” FSSP-100 spectra (as lately invoked by Crawford et al. 2012) that resulted in more >23 µm diameter droplets than were actually observed in our calculations to no avail in an attempt to “break” our conclusions (as good scientists do).                 

Two very short but illuminating papers were published in 1998 that discussed two viewpoints concerning the H-M process.  Blyth and Latham (1998u) “Commented” on the University of Washington findings2as completely explicable due to the H-M process, counter to the conclusions stated in our papers in which we felt that H-M might be playing a lesser role.   We defended our findings in our reply (Hobbs and Rangno 1998u)[10]

Following Mossop’s (1978) nomogram for ice development and ice multiplication boundaries given cloud base temperatures[11], we evaluated the onset of ice based on cloud depth and temperature of the onset of ice in Cumulus clouds using cloud base temperatures for continental clouds in Rangno and Hobbs (1988u), updated with many more data points from various locations around the world in Rangno and Hobbs 1995u (Figure 12). These data, for non-severe convection, point to a critical role of droplet sizes as proxied by cloud depth for the onset of ice in clouds (as Ludlam 1952) first noted), and, thus when ice multiplication can be expected.

  • Other uncited findings that impact F2017

Perhaps the most remarkable instance of “secondary” ice formation was left out of the field studies described by F2017:  that of Stith et al 2004u in clean tropical updrafts.  Stith et al. reported tens of thousands per liter of spherical ice particles in tropical updrafts that led to nearly complete glaciation by -12°C and total glaciation by -17°C.   As Stith et al.  pointed out, and was obvious, there is no mechanism presently known that can explain those observations.  The remarkable findings of Stith et al. should have been “front and center” in F2017. (Or, it should have been called out as bogus in a footnote.)

Another finding, one that resembles the findings of Stith et al. 2004u, and is also inexplicable by H-M, is that of Paluch and Breed (1984u).   High ice particle concentrations (100 l-1) formed in a Cumulus cloud updraft at a moderate supercooling.

Other examples of H-M “exceptionalism” that went uncited in F2017: Cooper and Saunders 1980u, Cooper and Vali 1981u, Gayet and Soulage 1982u, Waldvogel et al 1987u.

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

  1. A tedious line-by-line critique of F2017, analogous to a pre-publication manuscript review, one that should have taken place before publication.

P7.1:  F2017, their introduction:  “Airborne observations of ice crystal concentrations are often found to exceed the concentration of ice nucleating particles (INPs) by many orders of magnitude (see, e.g., Mossop 1985; Hobbs and Rangno 1985; Beard 1992; Pruppacher and Klett 1997; Hobbs and Rangno 1998; Cantrell and Heymsfield 2005; DeMott et al. 2016). In the 1970s (Mossop et al. 1970; Hallett and Mossop 1974) the discrepancy between expected ice particle concentrations formedthrough primary ice nucleation and observed ice particle concentration motivated the search for mechanisms thatcould amplify primary nucleation pathways.”

Comment:  While it was gratifying to have our work cited in the Introduction of F2017, the observations of unexpectedly high ice particle concentrations at slight supercoolings (>-10°C), goes no farther back than Mossop et al. 1970. One wishes some the earlier workers who reported ice at unexpectedly high cloud top temperatures would have been cited in this first grouping[12], such as Coons and Gunn 1951u; Ludlam 1955u; Murgatroyd and Garrod 1960u; Borovikov et al. 1961u; Koenig 1963; Hobbs 1969u; Auer et al 1969u.

P 7.2, Section 2, F2017:  “The consensus is that H-M occurs within a temperature range of approximately -3°C to -8°C, in the presence of liquid cloud droplets smaller than ~13µm and liquid drops larger than ~25µm in diameter that can freeze when they are collected by large ice particles (rimed aggregates, graupel, or large frozen drops).”

Comment:  It is now believed that the small droplets play a far less important role than once envisioned.  Goldsmith et al. (1976), later confirmed by Mossop (1978) appeared to find strong evidence that droplets <13µm diameter played a critical role in ice multiplication.  In fact, it was thought for a time that very low concentrations of those small drops would lead to clouds absent in ice multiplication in clean locations (e.g., Hallett et al. 1980u).   However, Mossop 1985a, u himself, in later laboratory experiments determined that small drops played a much-reduced role in H-M.   Cloud studies in pristine environments where ice multiplication was rampant (RH91u in the Washington State coastal waters in onshore flow, HR98 in the Arctic, Rangno and Hobbs (2005) in the Marshall Islands, and Connolly et al. (2006a) in England, would seem to have confirmed the minor role of droplets <13 µm diameter in riming and splintering in clean conditions.

Section 2, p7.3-7.4:  The F2017 Table 1 and the discussion of laboratory and field observations of secondary ice particles.

Comment:  While Section 2 was remarkably thorough, some important findings were not cited, or listed in Table 7.1 of the many studies of secondary ice particles.  Ono (1971u, 1972u) should have been included in Table 7-1 and in the accompanying F2017 discussions; he appears to have preceded Hallett and Mossop (1974) concerning the importance of larger cloud droplets coincident with graupel in ice multiplication[13].  Two elucidating quotes from Ono: 

Ono (1971u), his abstract:

“(Ice crystal) sizes, concentrations and microphysical conditions of occurrence support the hypothesis that they were formed when ice fragments were thrown off from water drops freezing after accreting on ice crystals.”

Ono (1972u):

“However, from our present observations, it has been found that in the clouds where moderately large drops of 30 to 60 µm in diameter and graupel-like rimed ice particles occurred simultaneously, we have a high concentration of secondary ice crystals. The presence of drops with some hundreds of microns in diameter is not a crucial factor for crystal multiplication.”

Moreover, Ono’s (1972u) findings above would appear to square better with our own findings (e.g., HR90, RH91u) for maritime clouds in the Washington coastal waters concerning high ice particle concentrations since our cumuliform clouds in onshore flow always had plenty of supercooled droplets >30 µm diameter in their middle and upper portions, sizes that Ono implicated in ice multiplication.  Also, our Washington maritime clouds have virtually no mm-sized drops as F2017 erroneously conclude are necessary for the “rapid” ice formation.

At the top of p 7.4: “…and observations are compromised by the potential of ice to break on contact with the aircraft or instruments (e.g., Field et al. 2006).”

Comment:  A single reference to Field et al (2006) regarding probe-related ice artifacts could lead the reader to believe that shattering on probe tips was a very recently discovered problem.   Shattering on probe tips has been a well-known problem and was obvious in the imagery as soon as 2D probes began to be used in the late 1970s.   Those of us in airborne research have been addressing this problem for more than 30 years to minimize the contribution of artifacts to ice particle concentrations (e.g., Harris-Hobbs and Cooper 1987). 

Many of reports of ice multiplication have originated at ground sites (e.g., Hobbs 1969u, Auer 1969u, Burrows and Robertson 1969u, Ono 1971u, 1972u, Vardiman 1978).  Citing these reports and emphasizing that they were ground sites would have made it clear to the reader that airborne artifacts have not reduced this enigma very much.

In fact, in view of the complexity of aircraft measurements of ice particles, MORE ground observations are critical, particularly at sites where the H-M process should be frequently active in clouds at the ground as in the Cascade Mountains of Washington State (e.g., Paradise Ranger Station).  Such ground measurements are vitally needed as well in the Middle East at sites where there has been a dearth of ice-in-cloud measurements[14].  Some authors now claiming that even modern outfitted research cannot derive accurate concentrations of ice particles (i.e., Freud et al. 2015).   Hence, the need for more ground work if, in fact, the assertion in Freud et al. 2015 is true..

Section 2, last paragraph on p7.4: “Splinter production following the freezing of a large millimeter size droplet that subsequently shatters (droplet shattering; e.g., Mason and Maybank 1960..”

Comment:   The authors in citing Mason and Maybank (1960) several times are apparently unaware that Mason and Maybank’s results were compromised by CO2, as discovered by Dye and Hobbs 1966u.  CO2is a gas that promoted the shattering of drops that Mason and Maybank observed. Later, however, Hobbs and Alkesweeny 1968u, did find that a fewsplinters were shed by drops that rotated in free fall as they froze, far fewer than reported by Mason and Maybank.  Hobbs and Alkesweeny’s work should have been cited along with that of Brownscombe and Thorndike (1968).                                                                                                                                            

P7.2, Section 2, laboratory evidence for secondary ice formation:

Comment:  The role of water supersaturation in ice formation was ignored as a possible source of secondary ice.  Gagin and Nozyce 1984u reported the appearance of ice crystals in the environment of freezing mm-sized drops in lab experiments.  They attributed the formation of the new ice crystals to a pulse of high supersaturation with respect to water as the freezing drop warmed to 0°C in their chamber.  This could be an important secondary ice-forming mechanism, similar in effect to that used by Chisnell and Latham (1976), who incorporated splinters derived from freezing drops.   This process might explain the simultaneous appearance of ice splinters that appear so quickly, side-by-side, with frozen precipitation-sized drops.

P7.4, Section 3.  In situ observations of SIP and the discussion of the role of IN.

Comment:  The work of Rosinski (1991u) goes uncited.  Rosinski did a lot of work on maritime IN, ones that he claimed were active at slightly supercooled temperatures in concentrations of tens per liter.  His work should have been mentioned, even if it’s only to state that his measurements are not generally accepted.  However, if he was even partially correct, his findings would go a long way to explaining the rapidity of ice development in maritime clouds.

P7.5, “In addition, the measurements may be affected by the possibility that ice particles generated by the passage of the aircraft through the cloud (Woodley et al. 2003) from previous cloud passes could have mixed into the measured samples.” 

Comment:  The authors only cite Woodley et al. (2003) regarding aircraft-produced ice due to the passage of an aircraft.  This unexpected phenomenon was first reported 20 years prior to Woodley et al.  by Rangno and Hobbs (1983u, 1984u)[15].  Scientific etiquette requires that those who went first be cited.  Not citing benchmark papers that roiled the airborne research community due to the temperatures at which ice was produced (>-10°C) is remarkable. John Hallett (2008) termed this finding, “an embarrassment to the airborne research community.”

Too, not being cited when you should be inflicts material damage since one’s impact in one’s field, likelihood of promotions, awards, etc, is measured by citation metrics.

P7.6 “Lawson et al. (2015) suggest that the rapid glaciation in these strong updraft cores (~10ms-1) occurs at temperatures too cold and a rate too fast to be attributable to the H-M process.

Comment:  Citing the report of Stith et al. (2004u) would have been perfect here, as would have been Paluch and Breed (1984u).

P7.7, discussion of Heymsfield and Willis (2014):  “Heymsfield and Willis (2014)found that SIP evidenced by observations of needles–columns throughout the range -3°C to -14°C was observed predominantly where the vertical velocities were in the range from -1 to +1 ms-1.   The LWCs in the regions where SIP are observed are dominantly below 0.10 gm-3.  Median LWCs in these regions were only about 0.03 gm-3 with no obvious dependence on the temperature.”

Comment:  The Heymsfield and Willis (2014) finding is not only counter to most of the Washington experience but also that of other workers (e.g., Mossop et al. 1968u, Figure 4[16]; Mossop et al. (1972u. Figure 2; Mossop 1985u, Figure 1), Paluch and Breed 1984u; Lawson et al 2015’s “first ice”).  Why?   The initiation and observation of small ice particles in high concentrations usually occurs in the higher (short-lived) LWC zones (>0.5 g m-3).   These contrary findings are not mentioned by F2017, ones that would have presented a different picture of the origin of the high concentrations of ice.  Perhaps Heymsfield and Willis (2014) encountered their high ice particles in cloud “death throes”; evaporating anvil shelving, rather having encountered them close to where they formed? 

P7.7, discussion of Taylor et al. (2016):  “Taylor et al. (2016)analyzed aircraft measurements in maritime cumulus with colder (11°C) cloud-base temperatures that formed over the southwest peninsula of the United Kingdom. They found that almost all of the initial ice particles were frozen drizzle drops [;(0.5–1) mm], whereas vapor-grown ice crystals were dominant in the later stages. Their observations indicate that the freezing of drizzle–raindrops is an important process that dominates the formation of large ice in the intermediate stages of cloud development. In the more mature stage of cloud development the study found high concentrations of small ice within the H-M temperature range.”

Comment:  Virtually identical findings to Taylor et al.’s was reported for even cooler based clouds a quarter of a century earlier by RH91u which should have been cited along with Taylor et al.’s.

P7.7, 2nd: “It has been speculated that graupel does not need to play the rimer role. In situ observations from frontal cloud systems suggest that riming snowflakes may be able to mediate the SIP (Crosier et al. 2011; Hogan et al. 2002.).

Comment:  The 2002 and 2011 references to non-graupel ice particles shedding splinters seem out of place since this was considered so many years prior to these references.  For example, riming by other than graupel particles was part of the “potential” H-M scheme of Harris-Hobbs and Cooper in 1987, in Mason 1998, and by Mossop 1985b.

We should cite those who tread the ground before we did.

P7.8. last three lines:   “Finally, it should be noted that conditions where cloud tops are -12ºC and drizzle-sized supercooled droplets are present do not always result in the production of large numbers of ice crystals. Bernstein et al. (2007) and Rasmussen et al. (1995)identified these conditions as long-lived clouds and hazardous for aircraft.” 

Some elaboration on the interesting and important findings of Bernstein et al. (2007) and Rasmussen et al. (1995):

The University of Washington aircraft observed drizzle drops aloft in orographic clouds in the Oregon Cascade Mountains during IMPROVE 2 (Stoelinga et al. 2003); we had not observed them in the more aerosol-impacted clouds of the Washington Cascades in many years of sampling them, though we did not fly in the kind of strong synoptic situations encountered in IMPROVE 2. 

However, those Oregon drizzle drops that we encountered in IMPROVE 2, as usually happens, didn’t make it to the ground as liquid drops.   IMPROVE 2 had ground measurements in support of airborne work; no freezing rain or drizzle events were reported, a finding compatible with long term records in the Sierras, and Cascades with precipitation at below freezing temperatures under westerly flow situations and when the temperature decreases with height (unpublished data).   There is a duration-below-freezing-temperature factor, as well as the temperature itself, that together control the freezing of precipitation-sized drops.  The deeper the sub-freezing layer at temperatures below about -4°C, the more likely drops will freeze on the way down becoming sleet/ice pellets.

Supercooled layered cloud tops, sometimes colder than -30°C, are common and persistent, and they have been known about since 1957 (Cunningham 1957u, Hall 1957u; this situation is shown in Byers 1965u), and were described later by HR85, HR98, and explained by Rauber and Tokay 1991u. Supercooled tops, usually ones having a broad droplet spectrum if they are shedding ice (RH85), persist because the ice that forms within them falls out, as do precipitation-sized drops, if any, and those drops freeze on the way down.  Altocumulus clouds sporting virga is a common example of this phenomenon.  In this “upside down” storm situation, ice particle concentrations have been observed to increase downward (e.g., HR85; Rasmussen et al. 1995) likely due to the breakup of fragile crystals.  This phenomenon can mislead researchers solely using satellite data to infer the phase of entire cloud systems below those tops.

p7.15, Section 6, discussion and conclusions section, second bulleted item:  “The onset of the rapid glaciation of convective clouds is observed to occur shortly after millimeter-size drops freeze.”

Comment:  If Ono’s 1972u findings are correct the glaciation process is also triggered by drops smaller than even drizzle drops (0.2 to 0.5 mm diameter).  In our cool-based, modest-sized Washington State maritime clouds (bases rarely >6°C) with mm-sized drops were rarely encountered; nevertheless, ice formation was usually rapid and prolific. 

P7.15, Section 6, 2ndparagraph, last sentence: “It has been suggested by, for example, Koenig (1963)and Lawson et al. (2015)that supercooled raindrops play an important role in the initiation of the glaciation process and there is evidence that this can occur at temperatures greater than -10°C.”

Comment:  The phrasing that “there is evidence”, which was likely unintentional, makes it sound like the appearance of ice in clouds with tops >-10°C is a rare phenomenon which the authors know is hardly rare!  It happens globally over the oceans in clean conditions, and in continental convective clouds with warm bases.

  1. Minor comments and corrections

P7.6 “Figure 7-6shows aircraft observations taken within a few hundred meters of cloud top by repeatedly penetrating a rapidly growing convective plume”    

Comment:  Can the authors rule out aircraft production of ice?

P7.7: “They found that almost all of the initial ice particles were frozen drizzle drops ~ (0.5–1) mm], whereas vapor-grown ice crystals were dominant in the later stages.”

Comment: Drizzle drops are defined by the AMS and WMO as close togetherdrops between 0.2 mm and 0.5 mm diameter.  They virtually float in the air. The 0.5 to 1 mm diameter drops that F2017 refer to are raindrops, not drizzle ones.

P7.2, Section 2, Laboratory Studies:

Comment:  Amid citations of laboratory experiments that “have produced secondary ice”, we point out that Choularton et al (1980) only produced protuberances and spicules, not actual ice particles.  Later, F2017 again cite Choularton et al. a bit incorrectly by suggesting the drop sizes for spicule production he studied was “>~25 µm”.  Choularton et al. reported the main increase in protuberances was for droplets >20 µm diameter.

P 7.4, Section 3, In Situ Cloud Studies, first paragraph, 2ndline:  “Ice particles are often observed in abundance in convective clouds that are colder than 0°C but with cloud-top temperatures warmer than about -12°C…”

Comment:   Slightly more accurately: “… clouds whose tops have ascended past -4°C but have not been colder than about -12°C…”

P7.5, Section 3, last paragraph:   “Hobbs and Rangno (1985, 1990, 1998), in a series of aircraft investigations of maritime cumulus off the coast of Washington…” 

Comment:  F2017 indicates that HR98 concerned Washington State coastal clouds.  It concerned Arctic stratiform clouds.  This seems like a remarkable error for 29 authors to make.  Moreover, in HR98 we discussed ice multiplication in pristine, slightly supercooled Arctic Stratus clouds with extremely low (<20 cm-3) droplet concentrations.  We found little correlation between droplets <13µm diameter droplets and small (<300 diameter) ice particles as some have reported (Harris-Hobbs and Cooper 1987) in support of their importance in riming and splintering process.  Yet ice was plentiful (10s per liter) regardless of the concentrations of those small droplets in boundary-layer Stratocumulus clouds with tops of just -4° to -6° C.

P7.5, Section 3, the discussion of Harris-Hobbs and Cooper 1987:  “Harris-Hobbs and Cooper (1987)used airborne observations from cumulus clouds in three different geographic regions to estimate secondary ice production rates.” 

Comment:  The California clouds that HHC87 examined were not Cumulus but were long stretches of orographic stratiform, banded cloud systems rather than Cumulus clouds.

Editorial note concerning the popular phrasing, “warm or “cold” temperatures in numerous places.

A quote from Peter Hobbs on this common error; “A cup of coffee can be warm or cold, but not a temperature.”  A temperature is a number and can have no physical state itself, but rather refers to the state of a tangible object.

Acknowledgements:  This review is dedicated to the memory of Peter V. Hobbs, Director of the Cloud and Aerosol Research Group, Atmospheric Sciences Department, University of Washington, Seattle.  He allowed me to become the most I could be in my field.  This is also dedicated to our “can do” pilots;  the many members of our flight crews; and our software engineers, whose dedication to their jobs over the years in the adverse conditions that we often flew in, made our findings possible.

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FOOTNOTES

[1]Retiree, Cloud and Aerosol Research Group, Atmos. Sci. Dept., University of Washington, Seattle.

[2]Hobbs and Rangno 1985, 1990, and 1998, hereafter HR85, HR90, and HR98, and Rangno and Hobbs 2001 and 2005, hereafter RH2001 and RH2005.

[3]Exceptions might be those situations where fresh turrets rise up through remains of turrets in calm or nearly calm situations.

[4]It is interesting to note that aufm Kampe and Weickmann (1951) produced virtually the same ice nuclei activity graph as found in DeMott et al. 2010. Blanchard (1957) froze freely suspended giant drops at -5° to -8°C using out door air, as did aufm Kampe and Weickmann.

[5]We also found it difficult to arrive at that moment of “explosive” ice development with our aircraft.

[6]The Quillayute, WA, rawinsonde 500 mb temperature was -45°C the morning of our flight!

[7]We note that in the cloud studied by Mossop (1985u) a drop of 1.5 mm diameter was encountered.

[8]If Ono (1972u) was correct about the importance of drops between 30 µm and 60 µm diameter, then we may have been barking up the wrong “ice tree” by concentrating on drizzle and raindrop sizes.

[9]While tedious, we inspected all our 2-D imagery in our Cumulus studies for artifact problems; we didn’t just crunch numbers without looking at every 2-D strip!

[10]This colloquy also emphasized an extremely important point in science; we should speak out on findings that we question instead of remaining on the sidelines.  We admired Blyth and Latham for questioning our work. After all, we could be wrong!

[11]Isaac and Schemenauer (1979), however, criticized Mossop’s 1978 nomogram; Mossop (1979) responded politely with more supportive data.

[12]It has been said that references to ground breaking early work is disappearing in publications due to the presence of younger authors.

[13]Ono worked with Mossop (e.g., Mossop and Ono 1969u), perhaps there was some “cross-pollination” of ideas…

[14]Sites to consider might be at Mt. Hermon, Israel, or at ski resorts in Lebanon. In-cloud situations with snow and graupel precipitation would be common at these sites.

[15]Our first two submitted manuscripts, ones that preceded RH83u, were rejected. The editor wrote, concerning the 2ndmanuscript, “The reviewers are still unconvinced by these controversial claims”, B. Silverman, Ed., personal correspondence.

[16]Mossop et al. 1968u also found columnar ice particles in dissipating, anvil-like regions as well as in high LWC zones.