SCIENTIFIC ABSTRACT BIBILASHVILI, N. S. - BIBINOVA, L. S.

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R000205220012-7
• Release Decision: RIF
• Original Classification: S
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• Document Creation Date: November 2, 2016
• Document Release Date: June 8, 2000
• Sequence Number: 12
• Publication Date: December 31, 1967
• Content Type: SCIENCEAB

30) BOV/20-128-3-24/58
AUTHORS: Bibilashvili, ff. Sh., Zaytseva, A. M., Lapcheva,
V. F.,
-___Ord_zh-on_ ~idz~~,A, Sulakvelidze, G. K.
TITLE: On the influence Exerted by a Variation of the
Vertical
Wind Component on the Formation of Shower Precipitations and
Rail
PERIODICAL: Doklady Akadem'i nauk SSSR, 1959, Vol 128$ Nr 3s
PP 521-524
(USSR)
ABSTRACT: Observations made in Transcauoasia and the
Caucasus in 1956-
1958 on stratocumuli, cumuli, and massy cumuli showed the
following: 1) The vertical component of the velocity of cur-
rents, determined by radar methods, amounts to 0.1 - 0-3
m/sec
for stratocumuli, 5 m/sec.for cumuli, and 10-15 M/sec for I
massy cumuli. Several wind gusts attain velocities of 25
m/sec.
The velocity W of vertical currents within the cloud
increases
with rising altitude up to a maximum, W , in the upper part
m
of the cloud, and then decreases rapidly. 2) The temperature.
of the cumulus during its formation is higher by 0.5-1.0 0
than
the temperature of the surrounding medium at the same
altitude.
Card 1/4 During stabilization and decomposition of the
cumultis in the

SOV/20-128-3-24/58
On the Influence Exerted by a Variation of the Vertical Wind
Component on
the Formation of Shower Precipitations and Rail
upper part, the cloud temperature is lower by 0.5-1.0 U t1"an
it is in the surrounding medium- 3) In the part before the
peak, the cumulus becomes rapidly aqueous. Yet in the low6r
and medium part, the water content and the spectrum of
water of the water drops vary but little. The size of the
drops is given. On the basis of these data, the increasing
size of the drops contained in cumuli and massy cumuli-,
nhion
is due to gravitational coagulation was calculated by a
method
devised by E. Bowen (Ref 4) and B. V. Kiryukhin. At high
velocities of the vertical currents, the drops almost do
not increase on the ascending branch of the trajectory.
Por7:311as
for the dependence of radius R of the drop on altitude z are
written down. The drops are retained in the upper part-of the
cloud, where velocities are low. The principal increase in
the drop or the hailstone occurs in the cloud range near the
peak. It the upper part of the cumulus has a temperature
higher than that of natural crystallization, then the cloud
remains droplike liquid. However, hail occurs, if the
tempera-
ture of the cloud peak is below that of natural crystalliza-
Card 2/4 tion. The increasing size of the hailstones up to R
- 2-4 cm

SOV/2o-128-3-24/58
On the Influence Exerted by a Variation of the Vertical
Wind Component on
the Formation of Shower Preoipitatiors and Hail
at Wm from 10 to 20 m/sec, primarily occurs in the cloud
part
near the peak, i.e. at the origin of the descading branch of
the hailstone trajectory . The authors write down a
correspond-
ing formula for the size of the hailstone. The time required
for an increase in the hailstone largely depends on T m, and
varies between 20 and 70 min. The definite size of the hail-
stones depends but little on the vertical thickness Of the
cloud. Completely now results are obtained if the variations
in the vertical component of the velocity of air currents
with the altitude are taken into account. This permits,
among
other thi*o,the following conclusions: 1) A large amount
of droplike water and hail is piled up in the cloud part
near
the peak. 2) The influence exerted by surface-active and
hygroscopic substances on the upper part of the forming
uassy
cumulus does not offer any positive effect at W m> V k.
Vk denotes the critical velocity. 3) By complete
crystalliza-
Card 3/4 tion of the droplike liquid, undercooled fraction
which enters

SOV/20-128-3-24/56
On the Influence Exerted by a Variation of the Vertical
Wind Component on
the Formation of Shower Precipitations and Hail
'he cloud, hail may be prevented or at least reduced 'thus
;reventiftg a gravitation-dependent increase in the
hallst:~ries).
If place and time of the center formation were known, hail
could be prevenied with 4 to 10 kg of silver iodide. Since
these quantities are unknown, an amount of silver iodide
larger by two or three orders is required for hail
preveztion.
There are 3 figures, I table, and 4 references, 3 of which
are Soviet.
ASSOCIATION; Ellbrusakaya sh3peditsiya Institute.
prikladnoy geofiziki
Akademii nauk SSSR
(Elbrus Expedition of the Institute of Applied Geophysics cf
the Academy of Scienoes, USSR)
PRESENTED: May 25, 1959, by I. ff. Vskua, Academician
SUBMITTED: April 26, 1959
Card 4/4

82704
s,/o49/6o/ooo/oo4/oo9/oi8
z- 0 0 ID E032/F,514
AUTHORS: Lapcheva. V.F., Ordzhoniki�&e. A.A.
and Sulakvelidze, G.K.
TITLE. Characteristics of Coagulational Growth 0:~
Hailstones,
Associated with Changes in the Velocity of Vertical
Streams with Altitude
PERIODICAL: Izvestiya Akademii nauk SSSR, Seriya
geofizicheskaya,
ig6o, No.4, PP-585-593
TEXT: Existing theories of precipitation from thick cumulus
clouds lead to certain results which are not confirmed by
observa-
tion. Thus, for example, in order to obtain hailstones
having a
radius of 2 to 3 cm, cloud thicknesses of 10 to 15 km are
required
(Ref.1) with constant upward current velocities of the order
of
20 to 25 m/sec. The amount of precipitation from hail and
shower
clouds exceeds the store of moisture in these clouds by a
factor of
5-10. These and other results are not confirmed in practice.
Studies of cumulus and thick cumulus clouds carried out by
the
present authors have led to the following results: a) in
cumulus
and thick cumulus clouds one observes an increase in the
velocity
of the upward currents with altitude until a certain maximum
value
Card 1/4

82704
s/o49/6o/ooo/oo4/oo9/oi8
E032/E514
Characteristics of Coagulational Growth of Hailstones
Associated
with Changes in the Velocity of Vertical Streams with Altitude
is reached, Thereafter the velocity begins to decrease. The
maximum
value of the upward current velocity in developing thick
cumulus and
storm clouds does no'. exceed 27 m/sec according to the data
obtained
in eighteen experiments. The mean maximum velocity is of the
order
of 7-8 m/sec (Fig.1). A similar distribution of upward current
velocities with altitude is also observed in cumulus clouds.
The
magnitude of the average maximum velocity in cumulus clouds
was
found to be 3-4 m1sec (average of 40 experiments).
Measurements
showed that the mean level of maximum velocities for the above
types of clouds over the Alazanskaya plane and in the region
of
Ellbrus is at 2500-3500 m above the Earth's surface, i.e. in
the
middle or upper parts of the cloud. b) Microphysical studies
showed
that in the lower part of a cloud, most of the droplets have
radii
of 6-10 -~L, and the number of particles per cubic centimeter
lies
between 209 and 1500. The mean liquid water content does not
exceed 10-0 g/cM3. Large droplets having a radius of 40-60 Ii
are
also found in the lower part of a cloud. In the middle and the
upper parts of a thick cumulus cloud located above the zone of
Card 2/4

8270b
s/o49/6o/ooo/oo4/oo9/ol8
E032/E514
Characteristics of Coagulational Growth of Hailstones Associated
with Changes in the Velocity of Vertical Streams with Altitude
maximum vertical velocities, the dimensions of isolated droplet 3
reach 400 - 600 ~ and the liquid water content about 2 x 10---' &;cM
(data from ten experiments). The accuracy of these measurements was
estimated to be about 20 - 30%- c) Radar studies of hail and shower
precipitation showed that the precipitation can continue to appear
from a single focus for 10 to 20 minutes. Thus, the formation and
precipitation of showers and hail is not a prolonged and continuous
process. These results are used in the present paper to set up a
theory of coagulational growth of cloud droplets forming showers and
hailstones. It is shown that the accumulation of large amounts of
water In a cloud takes place as a result of a reduction in the
velocity of upward currents towards the upper part of a cloud. Thus,
favourable conditions are produced for the droplets to come to rest
and increase their size. These droplets then grow by coagulation
with the smaller drops coming up with the upward stream and thus
increase the liquid water content of the upper part of the cloud.
Using this scheme it is possible to predict the appearance of hail,
the finite dimensions of hailstones and the amount of precipitation.
Card 3/4

82704
s/o4q/6o/ooo/oo4/ooq/ol8
E032/E514
Characteristics of Coagulational Growth of Hailstones Associated
with Changes in the Velocity of Vertical Streams with Altitude
The most effective weapon in the fight against hail at the
present
time is the continuous crystallization of the supercooled part
of
the cloud. It is, therefore, important to develop studies of
microscopic parameters of thick cumulus clouds so that hail
centres
can be discovered and neutralized. There are 5 figures, 3 tables
nd 3 references: 1 Soviet, I a Russian translation from English
nd 1 English.
:
ASSOCIATION: Akademiya nauk SSSR Ellbrusskaya ekspeditsiya IPG
(Academy of Sciences USSR, Ellbrus ExDedition of the
Institute of Applied Geophysics
SUBMITTED: February 25, 1959
Card 4/4

s/16g/62/000/008/052/090
E202/E192
AUTHORS: Bibilashvili, N.Azh - 7-ytseva, A.M., Kuzlmin, Ye-A.,
pcheva, V.F., Ordzhonikidze, A.M., and
Sulakvelidze, G.K.
TITLE. Theory of the formation of large drop fractions in
the heavy radial cumulo-nimbus clouds, and factors
affecting these processes
PERIODICAL: Referativnyy zhurnal, Geofii;ika, no.8, 1962, 80,
abstract 8 B 550- (In the collection: "Issled.
oblakov, osadkov i grozovogo elektriches+vall ('Studies
of clouds, precipitations and thunderstorm electricity')
M., AN SSSR, 1961, 3'6).
TEXT: Using observational data from the strato-cumulus,
cumulus and heavy cumulus clouds in the years' 1956-1958 in
Trans- L//
Caucasus and Caucasus, the growth of clouds' droplets was 1-e
calculated according to the method of Bouen and Kiryukhin, in
terms of the gravitational coagulation, assuming linear increase
of the anabatic velocity w, with respect to the height z.
Card 1/4

Theory of the formation of large
s/169/62/000/008/052-/090
E202/E192
As a result of these calculations it was established that with
the
greater velocities of the vertical streams the drop does almost
cease to grow during the anabatic branch of the trajectory. The
droplets are retained in the upper part of the cloud, where the
velocities are small and the principal growth of the droplets or
hailstones occurs prior to reaching the upper portion'of the
cloud.
With the aqueous exchange of 10-6 g/cm31 and the coefficient of
catchment of 0.85, the position of the apex of the trajectory
depends principally on the height zit at which w = w max and
the degree of decrease of w with height at which z -1 zl.
With the velocity of the anabatic stream w max greater than the
velocity attained by the failing droplet with a radius of 2.5 mm
of the v cr, a chain reaction is started which leads to the
accumulation of a large quantity of moisture in the upper part
of
the cloud and to the appearance of intensive showers. A cloud
with w max .:!-_v cr gives only a very short-duration and weak
shower.
Card 2/4

Theory (W the formation of ... s/16g/62/000/008/052/090
E202/E192
In the case when the temperatuee of the cloud's top is lower than
the temperature of natural crystallisation, hail is formed-in the
cloud and the size of the falling hail particles is determined by
the relation: 2 1f
max e-(t) V (0)
where Q(z) and Q(O) are air densities at levels z and y of
the Earth's surface. The growth 'of hail to the size ROI-'2.4 cm
at wmax ;ZZIO - 20 m1sec occurs substantially above the level
wmax* at the beginning of the katabatic branch of hail
trajectory. The time necessary.for the growth qf hailstones to V/
the above dimensions dep?nds chiefly on t-he value of wmax and
varies within the interval"Of 20 - 70 min. The terminal
dimensions of hailstones deperid very little on the vertical
thickness of the cloud, and arc determined chiefly by the
moisture
content of the air masses entering.the cloud, the height of the
zero isotherm, the value and the stability of w max' and also by
the velocity gradient of the vertical streams along their height.
Card 3/4

Theory of the formation of large ... S/169/62/000/008/052/090
E202/E192
Taking into consideration in the calculations the last
mentioned,
leads to*a conclusion that the accumulation of large amounts of
droplet water and hail takes place in the zone before the top
of
the cloud, which explains the high intensity and short
duration of
the showery precipitates and hail. The pressure of the large
droplet fraction in the upper part of the cloud lowers the
value
of the anabatic velocity of the stream down to vcr' and the
corresponding quantity of water holding may be calculated from
the formula: q = m (W2 - V2
2gz max cr
where m - the mass of air in a unit volume. The action on the
upper part of the growing heavy cumulus with w max > vcr' with
surface active or hygroscopic agents does not give a positive
effect. Prevention or even weakening the effect of a hail is
possible only by full crystallisation of the supercooled
fraction
of the liquid droplets entering the upper part of the cloud.
4-10 kg of reagent are required to destroy the hail centre.
Card 4/4 7Abstractor's note: Complete translation$j

3 7 3 2'.
S/1 069/62/000/004/028/103
0
D228/D;,02
S11., 7
J,2 I
-:O-U: Bartishvili, G. S., Biblashvili, N. aytseva,
I __H' -1. A. and
MI., Lapcheva, V. 1 -6 -
I cr2li n i4dze,
Sulakvelidze, G. K.
TITLE: The, ~,rowth of drops and hailstones in thick- cumalus
4641d with allowance for the change in the velocity
of vertical currents with height ana ine physical ba-
ses of the effect on hail processes
P_~IJDICAL: Referativnyy zhurnal, Geofizika, no. .41, 1-962, 19,
ab-
stract 4B134 (V sb. Piz. oblakov i osadkov, v. 2 (5),
H., AN SSSR, 1961, 146-148)
TEX'11: 'In the article a method is given for calculating
-U',.:e groUrth
of cloud drops and hail particles at the expense of coagulation
Vy
processes, and the influence of the character of t'-e change in
the
velocity of ascending currents on the growth of cloud particles
is
investigated. The question of calculating the xater content of
-thick cubulus cloud and the amount of precipitation is
cons-Odered;
Card 1/ 4

3/1 69/62/000/3jl+/0231/103
The growth of drops D2_98/D302
LI>
the oh-,,si-al bases of the effects on hail Drocesses are also illu-
X.
minated. ~he res,,,Its, accumulated during the study of mass convec-
t-ive clouds on the _7111brus and the AlaZanil expeditions of
ID54-1959
4i U
are used as the original experimental matE~rial. in concl,_~sion 'he
deductions are J,'*ormulated: The accumulat`on o-~, -,arc-e %.:a-
7 C) L ;. - C~ - W
.er reserves in a cloud in liouid or solid phases occurs a-, a -e-
sult of th-e decreasin'.- velocity of ascending currents alti-
Uude. This creates favorable conditions for the coagulazion rowth
of' 'U.,-.e lar-rest drops or of soft hail at the expense of the
fine-
droD liquid fraction, enterinal from below. A llloc'~,_ing-layerl' in
which a chain reaction in the watery cloud, or a cons-Ld,_:r,-,b._Ie
growth of hail particles, occurs, is formed in the zone o---'
mum vertical-current velocity. On the whole th~_~ hails:;-Dne
ai,-.~c-_,fons
depend on the presence in the clDud's middle parT. of
,)rolo-kred (not less than 30 - 90 min) vertical currc-2-lul;
0 25 m/s-ec, as well as on the hei-ht o--:' t~_e zeri
and not on the thickness and the water content oi~
part. If the zero iso,.-herm is situated at the level of :nI-xf..'um
ve-r-
..tical velocities, or below this level, the hailstonu s-Lzes ~_,re
Card 2/4

S/169/62/000/A4/028/103
The growth of drops ... D228/D302
C~
largely governed by the vertical flow magnitude. if the zero
iso-,
tilerm is located well above the maximum velocity level, the
hail-
zuo,ne dimensions are determined by the velocity magnitude ~It`
the
zero iso-uherm level. The radius of a fallin's hail~;-tone
satisfies
the followin- disparity, which is one of the criteria for the
likelihood of hail fall:
2w2 PZ
R( 0
PO
where W0 is the astejcending current velocity, P. is the air
density
at a standard Dressure, and pZ is the air density at a set
hei,-,'at.
PL,Ihe ascending current velocity also determines the water
content
of a, cloud's upper part, which may reach 20 g/m3 at the
beginnino"
of precipitation. The amount of precipitation from intra-mass
cu-
mulus clouds depends, too, on the ascending current velocity.
Fail
_processes cannot be averted by the episodic effect of
hygro;scopic
Card 3/4

S/1 69/62/0A/004/0203/1 03
The growth of drops D228/D302
or othe-- substances, which accelerate the 6~~?avi-.ational
Coa-u-a-
T,ion. of drops, upon the upper Dart of a thicl"-L cumulus
,,;a-uer-drop
cloud. However, the continuous action on the cloud's lower part.
may be an effective means of combating hail in consequence o`L'
4-1-1 e
"washing out" of -Uhe lower part and the coarsening of the nuclei
at its summit. The episodic effect of crystallizing substances on
the supercooled part of thick cumulus cloud car. lead to the
airtifi-
cial development of hail. In the authors' opinion the most effec-
tive way of preventing hail is the full crystallizatio-li of the
cloud's supercooled Part. Questions of the study of the
-iicrostruc-
tural cloud parameters that are necessary for the advanced
detection
o--:' hail foci are most pressing at the present time. Questions
of
the method of introducing active matter into a cloud and of the
search for new reagents are also important. /_Abstracter-s note:
Complete 'Uransiation.-7
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