(ESTIMATED PUB DATE) SCIENTIFIC AND TECHNICAL INTELLIGENCE REPORT - STATUS AND TRENDS OF THE SOVIET WEATHER AND CLIMATE MODIFICATION PROGRAM

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• Document Number (FOIA) /ESDN (CREST): 00122620
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• Document Page Count: 16
• Document Creation Date: December 28, 2022
• Document Release Date: May 14, 2018
• Case Number: F-2016-00405
• Publication Date: February 1, 1970

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DIRECTORATE OF
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Scientific and Technical
Intelligence Report
Status and Trendr of the Soviet Weather and Climate
Modification Program
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STATUS AND TRENDS OF THE SOVIET WEATHER AND CLIMATE
MODIFICATION PROGRAM
Prefect Officer
OSI-ST1R/70-4 :
Fetivory 1970
CENTRAL INTELLIGENCE AGENCY
DIRECTORATE OF SCIENCE AND TECHNOLOGY
OfRCE Of SCIENTIFIC INTEUJGENCE
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PREFACE
Weather modification is directed toward changing meteorological
phenomena for a short period of time usually over relatively small areas.
Climate modification is directed toward changing meteorological phe-
nomena over a long period of time usually over a large area. Almost
all weather modification techniques can be applied to some type of
military operation. Many have significant economic applications. Suc-
cessful techniques to increase precipitation or to dissipate severe storms
would benefit a country's economy considerably and could also support
military operations. Techniques to dissipate or enhance fog and cloud
could have important military applications, particularly for tactical op-
erations. Even greater military and economic, as well as political, benefit
could be derived from a successful method of modifying the climate.
This report discusses Soviet progress in weather and climate modifi-
cation. �� basic such as cloud �h cs, is also con.
side
This report, which updates an earlier study on weather and climate
modification published in August 1985, has been prepared by the Office
of Scientific Intelligence and coordinated twith the Directorate of Intern-
"�ence� The cutoff date of infomiation used is October 1999.
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CONTENTS
.PREFACE
PROBLEM ,1
CONCLUSIONS 1
SUMMARY 2
DISCUSSION 3
Overall weather modification program 3
Hail suppression � 3
Predpitation augmentation 5
Cloud and fog dissipation
Severe storm modification 8
Related research 10
Climate modification �
UNCLASSIFIED REFERENCES 13
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STATUS AND TRENDS OF THE SOVIET WEATHER AND
CLIMATE MODIFICATION PROGRAM .
PROBLEM
To determine the status and trends of Soviet research and develop-
ment in weather and clinsate modification.
CONCLUSIONS
CONCLUSIONS
L The Soviets have maintained a very large
weather modification R&D program for a number of
years but, despite the size of this program, they have
contributed no significant or unique advances to the
tmdcrstanding of the phenomena Involved. In cer-
tain instances the Soviets have been quicker than
the United States to introduce new weather modifi-
cation trAniques into operational service. Their
climate modification program is still in the con-
ceptual or bask research stage as is the case in
other countries.
2. The Soviet weather modification program is
well organized and apparently has high-level cen-
tralized direction. The Soviets have concentrated
their MD efforts in sublields they fudge to offer
the most premise for military and economic pur-
poses. In the 1950s this concentration was on super-
cooled fog and clood dissipation techniques, which
became operational about 1900. In the 1900s the
Soviets concentrated their R&D effortv on hail sup.
pression techniques.
3. The Soviets have conducted no known field
experiments in climate modification. Conservatism
Is e..*.ztated by their inability to predict what effects
such experiments might have in geographical areas
outside the experimental area. The Soviets are work-
ing on mathematical models of the atmosphere to
assist them in predicting these effects but their
progress has been hindered by the inadequacy of
their computers.
4. The concentrated Soviet effort of the past 10
years in hail suppression has progressed to the semi.
operational stage and the benefit-to-cost ratio ap-
pears to be about 5 to L Some scientific resources
used in this developmental effort probably will now
be diverted to other weather modification subfields.
The most likely subfields for new Soviet R&D ap-
pear to be warm fog and cloud modification and/or
modification of larger weather systems. Some in.
crease in the precipitation augmentation effort also
seems possible.
& Although most of the Soviet weather modifica-
tion program appears to be unclassified, there is
e-.4dence of classified R&D in warm cloud and fog
modification. Such modification techniques could
have Immediate military applications for offensive
and defensive tactical operations.
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SUMMARY
The major Soviet weather modification effort in
the 19503 was on supercooled fog and cloud dis-
sipation. This effort culminated in the development
of a technique for clearing airports of supercooled
fog; a semioperational status was reached in the late
1950s, several years before the Urited States began
a similar operational program.
After the fog dissipation project passed from the
R&D to the operational stage, a large portion of
the Soviet scientific resources was diverted to attack-
ing the problem of suppressing the number of
oecurence. and severity of hailstorms in the USSR.
An experimental research area was established in
a grape-growing section of the Caucasus in the mid-
19503 and experiments began on a large scale about
1900. The motivation behind this program probably
was to a large extent the potential economic bene-
fits to agriculture, but a method for dissipating or
preventing hailstorms could also have military ap-
plications., particularly for protecting vulnerable
equipment such as aircraft and missiles.
The Soviet hail dissipation experiments have pro-
gressed systematically through the past 10 years.
Since the Soviets first established the feasibility for
modifying hailstorms, they have concentrated on
conducting these experiments over different types
of terrain, on developing a means for introducing
reagents into the clouds, and on improving various
related techniques. According to the Soviet theory,
the time and place that t1 reagent is introduced
Into the cloud is criticaL The use of aircraft was
Judged to be inadequate and antiaircraft artillery
shells and rockets were developed for this purpose
The Soviets claim that their hail suppression re-
search program has been ccrmpletey successful. The
official Soviet estimate of the benefits versus cad
ratio is about 5 to 1 and this estimate probebly is
accurate. In 1967 the Soviet government made the
decision to expand these operations to all areas of
the country subject to significant hail damage, and
It now appears that they consider this program to
be at least semioperational and no longer expert-
mentaL
Becanse the Soviets Lave emphasized supercooled
fog and cloud dissipation and hail suppression over
2
the past 15 to 20 years, they have put relatively
less effort into other subEelds of weather modifica-
tion than has the United States. These subEelds in-
dude precipitation augmentation and warm fog
and cloud dissipation, both of which could have
significant economic or military value if techniques
are perfected. The Soviets maintain only one known
sizeable project (in the Ukraine) engaged in pre-
cipitation augmentation, but apparently it has pro-
duced no significant amounts of precipitation. Some
increased activity in other geographical areas has
been noted in the past year.
Based on open sources, it appears that Soviet ex-
perimental research on warm fog and cloud dissipa-
tion is in the initial stage, although there is evidence
that at least one classified project was begun a few
years ago. One unclassified project is an attempt to
prevent fog from forming over the Kola Bay by
covering the bay surface with a monomolecular film
that reduces the rate of evaporation. A recent in-
crease in Soviet basic research on hygroscopic nuclei
may indicate that experimental research on warm
fog and cloud dissipation using such nuclei win
receive greater emphasis.
Soviet experimentation on severe storms and
modification of large weather systems also is in its
beginning stages and the Soviets have no known
projects which compare in size or complexity with
the US STORMFURY project to modify hurricanes.
Current Soviet work on severe storms appears to be
confined to experiments on individual cumulus
ckuds and thunderstorms. Some success has been
reported in -lissipating thunderstorms, but the So-
viets need more data to make a final evaluation of
the results. No information is available on recent
Soviet experiments on large weather systems, but
it appears that such work will be stepped up.
Soviet scientists and engineers have discussed the
possibility of climate modification for many years,
particularly the prospects of melting the Arctic ice.
The well-known proposal by P. M. Borisov to dam
the Bering Strait is directed to this end but Soviet
scientists have warned that melting the Arctic ice
could have harmful effects on the climate in other
areas of the world. The uncertainty of these effects
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probably has kept field experimentation to a mini-
mum. Current basic Soviet research on the develop-
ment of realistic mathematical models of the attnce-
pbere could greatly assist in predicting effects over
the entire Northern Hemisphere. The BESMA
probably the best computer available for testing
these models, is not adequate for performing the
movie: computations frt. olvtd, although even the
most advanced computers are not completely ade-
quate for this job.
The Soviets are actively engaged in research en
the microphysics of clouds and precipitation in sup-
port of weather modification. They are pat uculariy
active in laboratory studies involving cloud chain-
hers. They also have been imaginative in applying
radar to cloud research and precipitation studies.
Soviet administrators of the weather modification
program have stated that there is a need for inten-
sifying these basic studies.
DISCUSSION
OVERALL WEATHER MODIFICATION
PROGRAM
The Soviets have maintained a large weather
modification program for about 20 years. In terms
of numbers of personnel involved, it probably is the
Largest in the world. It appears that the Soviets
maintain a much larger field experimental program
than the United States but that their related basic
research effort is smaller.' Consequently, the Soviets
generally have been quicker to test weather modi-
fication techaiques in the field than has the United
States.
The Soviets appear to have a well-organized pro-
gram.' High-level direction of the program Is In-
dicated by their apparent ability to channel efforts
Into particular subfields. Thus very intense work is
carried out until a technique is perfected to the
point that it can be used operationally or semiopera-
dangly. At that time, scientific resources are di-
verted to another subfield. M an example, a large
Soviet effort in dissipating supercooled fogs and
clouds was apparent in the middle and late 1950s.
When this technique was developed to the point
that tt could be used operationally, the concentra-
tion of effort was shifted to hail suppression, where
It has been since the early 190. The decision as
to which rubfield to concentrate the effort must be
made at high levels and probably is based no a
combination of factors, such as which areas appear
to be the most promising and which have the most
military and economic potential
It is evident from the published literature that
the overall weather modification program in the
USSR underwent a considerable expansion in 1990-
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1984, with a steady but slower growth rate since
then.' However, this expansion may have been more
apparent than real because a general declassifica-
tion of the program in the late 1950s may have re-
sulted in an increase in published articles. Never-
theless, there is no question that the Soviet weather
modification efforts have been increasing and they
probably will continue to do so. Further, high-level
Soviet officials have indicated that the future pro-
gram probably will have a better balance between
theoretical research and field experimentation.'
Ilan suppression
The Soviets have continued to expand their ac-
tivities in hail suppression over the past 5 years.
This effort, which began in 1956 as a rather small
experimental effort in the Caucasus Mountains near
Mt. Elbrus, has now expanded to include areas of
the republics of Georgia, Moldavia, Tadzhikistan,
Ukraine, Armenia and Uzbekistan. Recently a co-
operative hail se:pression project has also been ini-
tiated with Buizar1a.4 The long time period and the
number of r.cperiments conducted probably have
given the bevies more experience in this area of
weather modification than any other country.
The Soviet government made the decision in 1967
to expand the hail suppression operations to include
eventually all areas of the USSR that are subject
to significant ban damage.' This decision leaves little
doubt that Soviet officials are convinced that the
method effectively reduces the amount of damaging
hall which falls, but there appears to be some ques-
tion as to the exact amount that hafi damage is re-
duced. G. X. Sulakvelidre, who leads the hail sup-
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pression effort in the Caucasus and who is one of
the most enthusiastic proponents of the method,
claims a benefit-to-cost ratio of about 17 to 1. The
official Hydrometeorological Service estimate of the
benefit-to-cost ratio appears to be siaout 5 to L'
The more conservative estimate probably is closer
to the true value. Part of the discrepancy between
thete figures probably is due to different methods
of figuring the cost of the program. It is not entirely
clear bow the cost of such items as guns, rockets,
ammunition, and radars are figured into the cost Of
the program since some of this equipment appear.
to be military surplus material" The benefits of
the program are calculated on the basis of insurance
claims ;or the protected areas compared with claims
for adjacent unprotected areas.*
The size of the hail suppression program in the
USSR indicates that it has passed from a strictly
experimental program into at least a semioperational
program It is not likely that the Soviet government
would decide to expand a strictly experimental pro-
gram into all hail-affected areas of the country.
Nevertheless, the fact that a control area is almost
invariably established alongside a protected area
Indicates that the Soviets do not consider the pro-
gram to be entirely operational at present, and they
are still interested in obtaining experimental data.
The principle behind the Soviet hail suppression
efforts is that certain portions of well-developed
convective clouds often have large accumulations
of moisture in a liquid supercooled state. The ice
particles which form as a result of the natural freez-
ing of droplets falling through these areas grow
rapidly and are transformed into hailstones. The
Soviet theory states that by injecting a large num-
ber of artifical crystallizaticm nuclei into the cloud,
the nuclei can convert the region of high, super-
cooled water content into small ice crystals, thereby
eliminating the large supply of supercooled water
which Is necessary for the formation of hailstones.'
According to the Soviet theory, the artificial nuclei
must be injected into the portion of the cloud which
has the high supercooled water content and they
must be placed there before the hailstones can grow
to a large size. Soviet observations and computations
show that large hailstones can be formed in a matter
of 5 to 10 minutes after the hail forming process
begins.'
4
The Soviets rely heavily on radar to determine
where they want to seed the clouds!' Their experi-
ence has shown that the radar reflectivity undergoes
a perceptible change in the area of the cloud where
the hail formation is beginning. Either rockets or
100-mm antiaircraft artillery are used to deliver the
seeding agents to the cloud, and both delivuy sys-
tems are tied into radar control points. Based on the
military precision with which they operate, the gun
crews appear to be either military personnel or
civilians who have had extensive training with the
guns.' The shells normally are loaded with a lead
iodide reagent, and a timing device is used to ex-
plode the shell at a preselected point in the tra-
jectory. The rockets are equipped with two timing
devices: one tp set the time of burning of the
reagent and the other to set the time for parachute
deployment' Possible danger to the local population
from antiaircraft shell fragmenfs or from rockets
landing in a populated area does not seem to con-
cern the Soviets greatly. They claim that the shells
fragment completely and that it is rare to find a
piece as large as 1 grain on the ground.' The danger
from the rockets is minimized by the use of para-
chutes, and the rocket sites are established in rela-
tively unpopulated areas. Rocket firings must be
coordinated with civil and military aircraft author-
ities, who have veto power over rocket firings."
There is a certain degree of rivalry between the
groups using guns and those using rockets, but there
is DO evidence that the Soviet decision makers have
any Intention of adopting only one delivery method.
The rockets used in the program have undergone
continued improvement through the years and the
Soviets presently are using a multiple rocket
launcher capable of firing four rockets simulta-
neously. These rockets are approximately 5 ft long
and have a range of about 8 km. The new larger
Alazani rocket is now in Its final test phase. It has
a launcher capable of simultaneously launching
several rockets in different directions.' �
Each delivery system has certain advantages and
disadvantages. The antiaircraft artillery can deliver
a shell to a particular spot in the eoud.with rela-
tively good accuracy. When the shall explodes, a
large number of nuclei are then released in a rela-
tively small volume. A large storm would require a
large number of firings to seed it completely. In one
operation observed by Western scientists, about 200
rounds were fired to seed one storm.' The rockets
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apparently also achieve good accuracy and they
have the ability to deliver the nuclei over a con-
siderable volume of the cloud. The number of nuclei
delivered per unit volume is not as high as in the
case of the shells, but the rockets are somewhat more
versatile in that they can be set to eject the nuclei
either in a horizontal trajectory through the cloud
or vertically as the rocket descends through the
cloud by parachute
The hail suppression expedition baited near Kor-
meshta in Moldavia appears to be the most sci-
entifically oriented group of its kind in the USSR.
The Moldavian expedition is under the leadership
of I. I. Cayvoronskiy of the Central Aerological Ob-
servatory. Although all the hail suppression groups
study the result their efforts have on crop damage The largest Soviet weather modification effort to
by hail, only the Moldavian expedition apparently increase precipitation is a joint effort between the
has made any study of the effects their operations Ukrainian Hydrometeorological Research Institute'
have had on precipitation In the area of operations. at Kiev and the Main Ceoplrisical Observatory at
Cayvoronskirs statistics, based on 10 years of ob- Leningrad.' This project was established in 1959
servation, tend to show that his operations have had and cloud seeding with dry ice has been carried
little effect on precipitation In the area." out continuously since 1259." The Ukrainian ex-.
periments have been conducted using two IL-14
aircraft for dispensing dry ice into the clouds.
Precipitation augmentation
Precipitation augmentation, a subEeld of weather
modification popularly referred to as rain-making,
has received a large percentage of the total weather
modification budget in the United States. In the
USSR, however, this subEeld has received consid-
erably less effort than that of hall suppression, and
there is some indication that it is not receiving un-
qualified support at the top administrative levels.
One reason may be the belief, expressed by some
Soviet crE6cials, that the increase In precipitation
produced by cloud seeding has not been great
enough to make It economically feasible on a large
The overall Soviet hail suppression program is a
large, Impressive effort which seems to dominate the
entire Soviet weather modification program.' The In setting up this operation, the Soviets estab-
Soviets have developed effective delivery systems lished two areas of equal size (3,750 km2) separated
and have a well-coordinated program. The primary by a distance of 30 km. All the cloud seeding experi-
benefit of hail modification is, as the Soviets have ments have been conducted in the eastern area,
stated, for the protection of crops. However, the and the western area has been used as a control area.
ability to dissipate hall storms could also be used Operating in this manner, the Soviets are able to
by the military to protect personnel and certain avoid contaminating the control area with seeding
valuable equipment. The Soviet use of lead iodide nuclei because of the prevailing westerly winds in
as a seeding agent may be somewhat less efficient the area. The Soviets set ups dense network of rain
than silver iodide, but is not a serious limitation guages In the two areas (one per every 10-12 km2)
to the program. to make fine-scale measurement; of natural precipi-
tation in the control area and of that from cloud
seeding in the operating area. The experimental
area Is also instrumented with two radar installa-
tions to observe areas of precipitation and to track
and control the aircraft doing the seeding."
scale.' Another possible explanation is that the So-
viets may hnve decided to concentrate their re-
sources on hail suppression because the economic
benefits were more dear cut Some Soviet scientific
resources allotted to hall suppression could be di-
verted to other areas of weather modification, such
as precipitation augmentation, as the hail suppres-
sion operations become less experimental and more
operational. In any case, there is little doubt that
the Soviets recognize that even a small increase in
precipitation at the right time and place can have
considerable economic benefits. Military benefits
from precipitation augmentation are less clear cut
but certain tactical operations could derive some
marginal benefits from such a program.
The Soviets have seeded stratus and stratocumulus
air mass clouds as well as frontal-type clouds in the
Ukrainian operaHons. They have reported about a
10 percent increase In precipitation amount: when
operating on winter air mass clouds. However, the
scientists involved do not consider this a very sig-
nificant increase because the total water content of
these clouds Is very small in the first place.' They
claim to have been more successful when operating
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on frontal-typo clouds, with some claiming as much
as a 20 to 25 percent increase while others, only
about 15 percent.' 12 If this magnitude of precipita-
tion augmentation could be achieved for all frontal
cloud situations, it could be quite significant. How-
ever, the Soviets have determined that only about
50 percent of the winter frontal-type clouds are fa-
vorable for seeding."
Since 1960 the Ukrainian expedition has also
systematically seeded summer cumulus clouds. From
1980 to 1966 the Soviets seeded when possible all
clouds which exceed 2.2 km in depth and whose
temperature at cloud top was lower than �5� C.
'These parameters had been established, through
previous Soviet investigations, as being necessary
for favorable seeding conditions. The amount of
precipitation which fell over the operational area
was then compared with the amount which fell
over the control area to determine the effectiveness
of the experiments. The results showed some in-
crease in the seeded area, but the increase was not
large enough to rule out the possibility that it could
have been a chance occurrence."
Because of this uncertainty in the results, the So-
viets changed their approach in 1966 and began the
random selection of the clouds to be seeded. The
evaluation of these randomized experiments involves
the eornparisou of the amount of precipitation from
the seeded clouds with the amount from the un-
seeded clouds. These experiments have not been
under way long enough for them to make a definite
conclusion about the effectiveness of the experi-
ments; however, preliminary results have not been
particularly encouraging." Perhaps the most sig-
nificant aspect of these experiments is that this is
the first time the Soviets have been known to use
this technique. One of the criticisms of the Soviet
weather modification experiments in the past has
been the lack of statistical controls for evaluation
purposes. Randomization is a technique commonly
used by Western scientists to establish such con-
trols, and recent information indicates that the So-
viets will be using it more in the future.".
Scientists involved in the Ukrainian experiments
have subjected their data to analysis to determine
whether or not the cloud seeding operations re-
sulted In any decrease In precipitation downwind
from the operating area." Several specialists In the
field have postulated that such a decrease might
6
occur, but the researchers in the Ukraine turned up
no detectable decrease. However, they have reported
that a secondary maximum in precipitation down-
wind from the operating area seems to be indicated.
This secondary maximum, if real, is quite small and
probably will have little significance on the overall
precipitation pattern producci by the cloud seeding
� operations.
The only other known sizable Soviet effort to
augment precipitation is a project in northern Ka-
zakhstan under the control of the Kazakh Scientific
and Experimental Hydrometeorological Institute."
This effort apparently has been under way since
about 1963, but little else is known about it. The
Wet that practically nothing has been published
concerning this Lffort is unusual; it could indicate
that certain aspects of the project are classified, or
It might indicate that the operations there are being
conducted with little scientific analysis of the re-
sults of the experiments. A recent press report has
mentioned another operation designed to augment
precipitation in the Yakutia ASSR. According to the
report, an experiment was conducted to produce
rain in the area of a forest fire; however, it is not
clear from the report whether this was part of an
established weather modification program or was
carried out on an ad hoc basis."
Cloud and fog dissipation
Much of the early effort by the Soviets in weather
modification apparently was devoted to the dissipa-
tion of supercooled fog and clouds, which has par-
ticular application for military and civil air opera-
tions. This work proved the feasibility of using cloud
seeding techniques. After the feasibility was estab-
lished, the major remaining problem was to develop
reliable and economical techniques for dispersing
the seeding agents. As early as 1959 the Soviets
claimed that they were using dry ice on at least a
semi-operational basis to dissipate supercooled fogs
over airports in the USSR At present the Soviets op-
erationally clear supercooled fogs at 10 to 12 airports
using ground equipment that blows flakes of CO2
to a height of 20 meters. These flakes are produced
from tanks each containing 25 kg of liquid CO3;
four tanks are used to seed at 6.5 kg per minute.' In
the early 1960s the Soviets reported experiments
on clearing large areas (up to 20,000 km*) of super-
cooled clou4s. Successful operataions of this type
could have considerable military potential for tic-
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tical air, land, and sea operations, and are of con-
siderable scientific interest because the energy in-
volved approaches that required to cause a meas-
urable perturbation in atmospheric circulation. No
seevet referervce has been found to any further op-
erations involving large areas, although at a recent
meeting, Ye. K. Fedorov, chief of the Main Ad-
ministration of the Hydrometeorological Service
(CUCMS), stated that more work should be done
on large cloud systems"
Work still continues in the USSR on supercooled
cloud and fog dispersal, but the major effort of
Soviet scientists in this subEeld has been diverted
to the much more perplexing problem of dissipating
warm clouds and fogs.' Warm clouds and fogs are
much more prevalent than supercooled types, and
they are much less susceptible to modiScatiole The
Soviet warm cloud and fog effort is led by the Main
Geophysical Observatory in Leningrad with the
cooperation of the Central Aerological Observatory
In Dolgoprudnaya, the Institute of Experimental
Meteorology in Obninsk, and the Ukrainian Sci-
entific Research Hydrometeorological Institute In
Kiev." Any successful techniques developed in
warm cloud and fog dispersal would have consid-
erable military, civil, and scientific significance.
The Soviet program for modifying warm clouds
and fogs generally has proceeded along lines similar
to those of Western countries that are active in the
field. The major Soviet effort has been devoted to
determining the feasibility of using heat sources
and of seeding with hygroscopic or surfactant ma-
terials.� "The available information indicates that
the Soviets have not yet settled on any one tech-
nique but that they are still searching for a workable
method.� xi
Heat sources have been mei et least since World
War II when the British developed the fog in-
vestigation dispersal operations (FTDO) system
to dissipate warm fogs over runways. The prin-
ciple behind this method is that the addition of
*Hygroscopic materials have the property of increasing
the corldemation of water vapor, and such materials is
NaCi and Caa. are commonly use.] is hygrosce0c seeding
agents. Surfactant materials reduce the surface tension of the
cloud or fog droplets, whkli resuN in a more rapid corks-
cent rate of the droplets. When the droplets wow la.-ge
enough through this room they fan out as rain or mit
and the cloud or Fog should dissipate providedthe efficiency
6 greet encash.
-
beat will result in the evaporation of the fog. The
heat may be applied from below, as with the FIDO
system, or from above. The addition of beat from
above is a commonly observed natural phenomenon
when ground fog is dissipated after the sun rises
in the morning. In principle, this process can be
assisted and speeded up by adding a heat absorb-
ing material, such as carbon black, to the top of
the fog deck thus increasing the absorption of the
solar radiation. The addition of beat to evaporate
a warm fog is a proven technique; however, US
studies to date have determined that it is only
marginally cost effective. Nevertheless, at some lo-
cations where fog is very prevalent this method
may prove to be worthwhile. The French have
made the decision to install Jet aircraft engines
underground alongside the runways at Orly Air-
field to provide the necessary hest dissipate warm
fogs-
There is some evidence that the Soviets currently
consider the heat source technique to be the most
practical, at least for situations where there is a
requirement for rapid fog dissieon as might be
required for aircraft operations Ilayvoronskly of
I' Central Aerological Observatory cites these
fige...z from theoretical calculations: for a warm
fog 50 m thick with a water content of 0.1 gm/ms,
149 cal/ms of heat are required to disperse the
fog in 0.5 minute. To perform the same rate of
clearing with hygroscopic' particles, hundreds of
kilograms of seedi.ng material per second would
be required Ccayvoronslciy further points out that
the beating method contributes little pollution to
the atmosphere, is fast acting, and is not de-
pendent on the varying microphysical characteris-
tics of fogs. He concludes from this that thermal
methods of warm fog dispersal should be given
preference over others."
Although there has been some laboratory work
reported by the Soviets on hygroscopic and sur-
factant materials, there has been surprisingly little
repod in the way of actus1fleldepaimenta.
Mon.
However, one Soviet scientist has stated
that Ms laboratory work in this field which for-
merly was unclassified has now been classified by
the Soviet military." This indicates that the pub-
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bably do
not give a true picture a situation, and
field experimentakon on the dissipation of warm
clouds and fogs very likely is under way in the
USSR.
The reason such R&D has been classified by the
Soviets is not entirely obvious. There is no question
that the development of a successful method to dis-
sipate warm clouds and fog would have important
military implications, but other types of weather
modification, which they do not classify, also have
such implications. Warm cloud and fog dissipation
has the obvious potential for aircraft operations
and many ground and sea battle situations. Other
reasons for the classification could be that the So-
viets have discovered a technique which they be,
lieve to be superior to techniques under develop
"-
merit by other countries or that its potential is
greater than other subfields of weather modification.
In contrast to the general lack of information on
Soviet field experiments on warm cloud and fog
dissipation, one field project to disperse fog over
Kola Bay has been reported rather freely. This
project is under the direction of the Ukranian Scien-
tific Research Hydrometeorological Institute, and
personnel from Kiev State University and the Mur-
mansk Administration of the Hydrometeorological
Service also are involved." These experiments were
started in the winter of 1964-1965 to determine
the feasibility of dispersing warm fogs over the bay
by covering the water surface with a monornolecular
Elm of higher fatty alcohols. In theory, such a film
should reduce the evaporation from the water sur-
face thereby cutting off the moisture supply which
Is responsible for the formation of the fog. Although
the Soviets have claimed some success with this
technique, no spectacular results are apparent"
One interesting result the Soviets have reported
L ow these experiments is that when the winds are
stronger than 7 m/sec (about 15 mph) the film is
destroyed.' Nevertheless, the Soviets have been
successful in ditsipating warm fog using these tech-
niques when the proper conditions have existed.
HOWeVer, they have found that very large quantities
of reagents are needed to clear large areas. Presently
they are using kerosene as a solvent for the fatty
alcohol reagent, and this presents problem when
large quantities are involved. Consequently, the
8
Soviets are stazehing for other solvents which could
be used for spreading an effective film on the
water."
One laboratory experiment has been reported
which has interesting possibilities if it proves to be
successful. it was an attempt to coat the fog droplets
rather than the sea surface with a nsonomolecular
film of higher alcohols." If this technique were suc-
cessful, it should reduce evaporation within the
fog or cloud and thereby prolong rather than reduce
the lifetime of the fog or cloud. The capability to
prolong cloud or fog lifetime could be used in many
tactical military situations, but there are few ob-
vious situations where such a technique would
have an economic application. This experiment was
reported at a 1966 conference in the Soviet Union
and no further information has appeared. This could
indicate that the Soviets have found the technique
to be infeasible under natural conditions as op-
posed to the laboratory conditions under which
it was first tested with some reported success. On
the other hand, it could also indicate that work has
continued but has been classified because of military
Implications.
Severe storm modification
The Soviets have scpthted no experiments to
modify large severe storms comparable with the
US STORMFURY project, which is designed to
study the effects of modification techniques on
hurricanes. However, the Soviets have conducted
numerous experiments on individual cumulus clouds
and some on fully developed thunderstorms. These
experiments in general have been designed to stop
the growth of the cumulus clouds before they reach
the thunderstorm stage or, in the case of the experi-
ments on cumulonimbus clouds, to reduce the effects
after the thunderstorm stage has been reached. In
one set of experiments, the Soviets have attempted
to produce the opposite effect; that is, to induce the
growth of small cumulus clouds into mature cumu-
lonimbus clouds. Such experiments, if successful,
would have application both for military and civil
operations. The ability to prevent severe thunder-
storms would be useful for protecting vulnerable
military equipment such as aircraft or missiles and
for protecting exposed personneL The ability to pro-
duce thunderstorms could be used as an offensive
weapon In tactical situations.
Apii 1995
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A group of scientists under the leadership of
the Central Aerological Observatory is conduct-
ing an experimental field program in the Geor-
gian SSR to dissipate rapidly growing cumulus
and cumulonimbus clouds. This project is designed
to destory the ascending currents within the cloud
and to change them to descending currents. The
downward motion 'tops the vertical growth of the
cloud and, if it continues long enough, will result
eventually in the destruction of the cloud."" In
these experiments the Soviets have seeded the grow-
ing cumulus clouds with insoluabIe particles of 5 to
50 microns. Different seeding agents have been
tested but clay and cement have been the most
commonly used. In some of the later experiments
a CuO powder also has been tested. The seeding
agent is dispensed in fairly large quantities (up to
50 kg have been used) from an IL-29 jet aircraft.
The material is ejected into the cloud where upward
motion is the greatest; tests have been conducted
on clouds of up to 10 Ian in vertical extent." Ac,
cording to recent information, the Soviets have con-
ducted experiments of this type on 500 cumulus
clouds and on 65 cumulonimbus clouds which had
reached the durnderstorm stage." The Soviets claim
that effects from the seeding were observable on 82
of the CZ experiments on cumulonimbus clouds, and
almost all of the cumulus clouds showed an effect."
The first effect usually observed after seeding was
a noticeable darkening of the cloud followed by
lamination and evaporation. Precipitation often was
noted falling from the cloud following the seeding,
but this usually was very light and in many cues
evaporated before reaching the ground. In the
majority of CaSel reported, complete dissipation
of the cumulus cloud occurred In 20 to 30 minutes,
although remnants of middle or high level clouds
often persisted." To minimize the possibilities that
these effects could have occurred naturally, the
Soviets have conducted all the experiments between
1300 and 1000 bra local time when convection
normally is at its greatest They also have observed
the behavirse of untreated clouds in the vicinity of
operations to determine whether any of these dis�
sipated naturally. Visual and instrumented observa-
tions of the results of these experiments have been
carried out from an IL-14 aircraft and by ground-
based radars." Apparently no attempt has been
made up to the present to randomize the expesi-
ments, and it is therefore difficult to judge the true
efficacy of the work. However, the results reported
are rather impressive and indicate that the Soviets
have been able to dissipate at least some cumulus
and cumulonimbus clouds under proper conditions.
Another project, similar in p.inciple but smaller
In magnitude and using different techniques, is
being carried out by personnel from the Institute
of Experimental Meteorology. This project also is
directed toward the dissipation of cumulus clouds
by creating artificial downdrafts, but aircraft jets
are used instead of cloud seeding agents' Jet air-
aaft are flown through the clouds at high pitch
angles, thereby directing their Jet dcwrnvard
through the cloud. Nine experiments of this type
have been reported, and in all cases some effect
was noted. According to the Soviet report, the clouds
eithtx completely dissipated, broke into paxs, or
ceased their vertical growth. The operations were
carried out on cumulus clouds ranging from 5 to
km in vertical extent" Although positive results
were reported from these experiments, the necessity
of flying the aircraft through the clouds probably
will limit the usefulness of this teclmiqae to a
considerable degree.
The same experimenters together with personnel
from the State Scientific Research Institute of Civil
Aviation have tested the feasibility of using jet air-
craft engines on the ground to create artificial up-
drafts in an attempt to stimulate the growth of
cumulus clouds into cumulonimbus clouds. During
dry weather in the summer, cumulus clouds often
will form but will be prevented from developing
Into cumulonimbus clouds by a temperature in-
version at some level in the free atmosphere. In
theory, if an ascending current could be pcnduced
that could penetrate this inversion, the cloud might
continue to grow and eventually to produce rain.
An analysis of several years' data showed that 75
percent of the summer inversions over Moscow
could 'De penetrated in this manner, and in 1967
an experimental apparatus was set up near Borispot
Four jet engines were joined so that their exhaust
jets all fed into one vertically directed vent Twenty
experiments were carried out to test the technique.
In most cases the Soviets reported that small cu-
mulus clouds were formed over the jets. In the
case where natural clouds were already present,
they generally became larger in size. In a few
cases the clouds darkened at the base and occa-
sicmally produced rain. According to Soviet reports,
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they plan to continue these experiments and increase
the number, of jet engines used from four to ten."
These results reported thus far by the Soviets do
not appear to be very significant. The use of ad&
ticnutl engines might produce better results, but the
fuel consumption is likely to make this technique
marginal at best with regard to cost effectiveness.
However, cost may not be a factor for a military
system, and the Soviets might continue MD on this
technique if further testing indicates that it may
be militarily nsefuL �
Related research
Despite the relatively large weather modification
research effort that has been carried out over a
number of years, there are still several questions
relating to the basic physics of clouds and precipita-
tion that are still not completely understood. One
of the unresolved microphysical problems of cloud
and precipitation processes concerns the initial
stages of rain formation through coalescence of
water droplets. A requirement for relatively simple,
reliable Ecld instrumentation for measuring the cou-
centrations of atmospheric ice nuclei still has to
be met. Further, much work needs to be clone on
measuring and zprodudng in mathematical models
the atmospheric motions in and around clouds."
The Soviets have recognized the unsolved prob-
lems in basic cloud and precipitation physics, and
they have conducted an active research program
for many years in these areas. In general, however,
It appears that the Soviets lag the United States
in these theoretical aspects of their research l The
Soviets have acknowledged that they are weaker
In the basic research than in the experimental work,
and Ye. K. Fedorov In stated that one of his ob-
jectives is to strengthen that portion of the program
to increase the understanding of the physics of
what really happens.2
The Soviets have relied heavily on cloud cham-
bers to collect basic data for their microphysical
studies on clouds. The Institute of Experimental
Meteorology at Ohninsk has at Its disposal three
large cloud chambers, two with a volume of 103 ms
and one with a volume of 3,200 mi.1" The latter
chamber is one of the largest in the world, and one
of its advantages is that it *allows larger volumes
of clouds to be studied. The 18-rn height of this
chamber also allows the Soviets to study the effects
10
of seeding nuclei on the water droplets as the nuclei
fall down through the artificial cloud. A distinct
disadvantage of the chamber is that the temperature
can be regulated only between 15' and 20�C, and
the pressure can be regulated only between 3-0
and 1.5 atm." Although these restrictions are not
very serious for the study of low-level clouds, they
are unreal for higher level clouds. This chamber
Is highly instrumented to collect �microphysical
data from the artificial clouds contained in it. One
impressive instrument used on this chamber is a
photoelectric sensor which measures the drop size
distribution in the air that is funneled past the
counter. This instrument can be set to measure
particles in increments of 4-micron steps, the small-
est being 2 microns."
The two smaller cloud chambers at the Institute
of Experimental Meteorology are much more versa-
tile than the larger chamber. These cloud chambers
are designed so that the temperature can be regu-
lated between �50� and 20�C, and the pressure can
be regulated from 0.05 to 2.0 atm." Thus these
chambers provide for a more nearly real atmosphere
than the larger facility and for most research they
may be more useful. The Soviets are building a
200 m2 cloud chamber at the Institute of Geophysics
under the Georgian Academy of Sciences.� This
chamber will have the capability of reaching tem-
peratures as low as �40�C but its pressure capa-
bility is not known. Preseet plans are to instrumer�
this facility with optical lasers and a 1-cm radar to
measure the moisture content of the clouds which
are produced. It appears that this will be an excel-
lent research facility when completed, but ft is
somewhat questionable whether the staff at the
Institute will be capable of utilizing It to its fullest
extentu
The Soviet; have also been actively investigating
the microphysical properties of clouds using instru-
mented aircraft and radar. These types of investiga-
tions are necessary to supplement the cloud chamber
studies because, no matter how sophisticated a cloud
chamber Is, it is impossible to duplicate all the
processes and interactions found In the real at-
mosphere. Instrumented aircraft, which traditionally
have been widely used for collecting microphysical
data, are still used, but modern radars are now
making it possible to collect much of this data
Indirectly. Aircraft measurements suffer from sevetal
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limitations among which are the difficulties in flying
through convective-type clouds and problems in
developing instruments that will make accurate
measurements of the necessary parameters.
Soviet development of radars for these purposes
generally has kept pace with Western developments.
They have done a great deal of work with dual
frequency radars: 3- and 10-cm radars are used
extensively in the hail suppression program to dis-
criminate between hail and nonhail clouds. Informa-
tion from the two radars Is fed into one radar con-
sole, which then directly presents the difference
between the reflectivity of the cloud in the two
wavelengths on both the plan position indicator
and the A-scope.' The Soviets claim that this
differencing technique is very accurate in discrimi-
nating between those clouds which produce ban and
those which do not They also use the dual fre-
quency technique to determine the intensity of pre-
cipitation. In this case they use wavelengths of 0.86
and 3.2 an. By measuring the differences in reflec-
tivity and absorption In these two wavelengths, the
Soviets claim that they are able to overcome the
problems of variable drop sizes in the cloud, which
make such measurements on single frequency radars
difficult." The Soviet capabilities for processing
the dual frequency radar information in real time
are impressive, and it appears that this technique
should be useful for studies of clouds and precipi-
tation." The Soviets also use radar methods for
other microphysical measurements of clouds, and
it appears that their use of radar and radar process-
ing equipment for these studies will be expanded.'
The Soviets also are actively engaged in seeding-
nuclei research. At the present time they seem to
favor the use of lead iodide, probably because it is
readily available to them."" The United States
favors the use of silver iodide over lead iodide be-
cause US techniques for crystallization have not
worked well with lead iodide. However, ft appears
to work satisfactorily with Soviet pyrotechnic
methods.* The Soviets have expressed some concern
about the toxic effects of lead iodide and they have
tested many other substances in the laboratory and
some in the field. They seem to favor copper sulfide
at the present time to replace lead iodide as the
primary seeding nuclei. They claim to have devel-
oped a powdered form of copper sulfide that can
produce about 1011 nuclei per gram, which is very
good. They have also indicated that they have
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enough confidence in copper sulfide as a seeding
nuclei to begin using it in their hail suppression
program.' This could be quite significant if success-
ful because copper sulfide is a much cheaper prod-
uct than silver iodide. Organic materials, hygro-
scopic nuclei, and various insoluble materials are
also being investigated intensively, particularly for
use on nonsupercooled clouds and fogs.
CLIMATE MODIFICATION
The Soviets have shown an interest in climate
modification for many years. This interest probably
Is partly due to the unfavorable climate which pre-
vails over touch of the USSR. In addition a success-
ful climate modification technique could have con-
siderable significance for both tactical and strategic
military operations.. Many schemes have been pro-
posed in the Soviet Union for melting the Arctic ice
and thus moderating the average temperatures of
the northern areas of the country. One of the oldest
and best known proposals is that of P. M. Boriscrn
who has advocated &mining the Bering Strait
Borisov's concept is to pump water from the Arctic
Ocean through a dam into the Pacific Ocean. This,
In 'turn, would draw the warmer water from the
Atlantic Ocean through the Arctic Ocean and even-.
tually melt the ice." Borisov rh;ini that the ice in
the Arctic Ocean would be completely melted in
three years, and that once melted, it would not
return. Borisov, an engineer, claims that this project
Is technically feasible, and scientific studies at the
Main Geophysical Observatory tend to support his
claim that the ice would not re-form once ft was
melted. However, M. L Budylco, director of the
Main Geophysical Observatory, has pointed out
that his studies show that melting the Arctic ice
could have adverse effects on the climate of the
temperatige zone of the USSR." Despite this warn-
ing, Borisov periodically revives his proposal for
damming the Bering Strait.
Although the Soviets have apparently approached
the proposal for large-scale melting of the ice in
the Arctic with caution, they have developed and
uvol other techniques for melting Ice on a smaller
soak. One technique which they have used for
many years is to blacken the surface of the ice
to increase the amount of solar energy absorbed by
the surface. The Soviets *a parently have conclUded
that this technique is feasible, although some tech-
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