FRAGMENTATION of CHARGED ICE PARTICLES
FROSTY SURFACE of
A FROZEN DROP(ICE PELLET)
A NEW MECHANISM of RAPID ICE MULTIPLICATION PROCESS
ELECTRIFICATION in A THUNDER CLOUD
THE PRODUCTION of
ICE CRYSTAL FRAGMENTS
SUBLIMATION AND ELECTRIFICATION
J. SCHAEFER and Roger J. CHENG
of New York, Albany, N.Y... U.S.A
de RECHERES ATMOSPHERIQUES
Observations of ice crystal
fragments ejected from a frost surface during a positive growth
cycle suggest a multiplication process of glaciations in the
atmosphere. Photomicrographic studies reveal that the structures
of ice particles are identical to ‘most samples collected in natural
convective clouds and the mechanism for their breakage is due
to sublimation governed by curvature effect rather than by
simple mechanism is described which may explain the rapid
glaciations which commonly occur in the cold portions
of super cooled convective clouds. The process begins with
the formation of a few ice particles in the cloud. Since they
have no competition for moisture and cloud droplets present,
they grow rapidly by crystal growth and the accretion of cloud
droplets. As they enlarge through dry growth to form graupel
or hail particles, their falling velocity increases so that
they encounter warmer supersaturated air. This causes the graupel
particles to become coated with a very fragile dendritic frost
studies of this mechanism are very spectacular. A simple demonstration
of the basic phenomenon can be observed by placing dry ice in
a polyethylene bag in warm air. Within a few seconds a dust-like
layer of frost will be seen which rapidly grows until dendritic
growths appear. Low power magnification shows a very rapid development
of frostiness, accompanied by great mobility of particles. It
soon becomes obvious that this growth involves electrification
phenomena, the dendritic <TREE> twisting and
turning as they respond to the moisture flow, electrical stress
and growth environment. At times an entire tree will suddenly
shoot off and then disintegrate into myriads of fragments as
they literally explode.
a less intense temperature gradient, the same effects can be
seen but with less rapid changes.
1-a, b and c show the moisture and particle relationships observable
within a 8-minute period in which there was a temperature difference
of 5C degree between simulated graupel particle and its moist
environment. 1-a is the initial flow pattern of super-cooled
droplets around the particle when it is first placed in a moist
environment. 1-b shows the moisture, liquid and ice crystal
particle regime which develops in one minute. 1-c depicts some
of the ice particles ejected from the frosty environment as
the dendritic trees become electrified and are repelled by
the particle. It is possible that electrification develops
due to the Workman-Reynolds effect.
2-a, b and c illustrate the tenuous attachments which bind frost
crystals grown from water vapor and accreted frozen cloud droplets.
these attachments often have diameters of less than 5 microns,
they readily evaporate, even when the larger portions are growing,
because of the difference in vapor pressuren these slender
columnar attachments and the more massive ice structures nearby.
In many instances the ice growths forming the dendritic trees
appear to be held together by nothing but electrical attraction.
Some of the branches of the trees will be seen to rotate with
complete freedom. If a charged object is brought nearby, much
of the structure responds as in a magnetic field and some of
the formations will fly toward the charged object or will
be repelled in an opposite direction at high velocity. At
times these fragments will be seen to disintegrate into many
examination of the ice particles in convective clouds such as
produce thunder, in blizzards and in intense lake-effect snow
storms, show ice particles very much like the nondescript particles
collected from the simulated graupel particle growth regime
described here, and will be found illustrated in a number of
recent papers published in the scientific literature , ,
simple and spectacular demonstration of this phenomenon can
be observed by placing a metal plate, cooled to -10C degree,
1 cm above a water surface and illuminated with daylight or
a beam from a flashlight. In less than a minute after placing
the cold plate above the water surface, a dense miniature snow
storm can be seen in the space between the water and the cold
on the temperature profile existing between an icy precipitation
particle and its warmer environment, the shape of the frost
crystals which form will follow the classical growth pattern
outlined by Nakaya  or modified by environmental gaseous
impurities  Variations we have observed are shown in Figures
8-a, b, e and d. Notice also in these illustrations, especially
in 3-a and 3-d, the very small ice structures which hold the
Odencrantz has suggested a multiplication process of glaciations
is caused by frost growth, the illustrations used by him ,
 are very different from the method we are describing here,
and we find ourselves in agreement with Smith-Johannsen 
that the modified crystalline structures he uses to illustrate
his papers are due to artifacts produced by the replications
basic experiments illustrated in this paper are not new discoveries.
The senior author first encountered the phenomenon in his original
studies of frost crystal replication. The concept of frost shedding,
causing a sort of chain reaction within a super cooled cloud,
was described in his notebook at General Electric on the day
he discovered the dry ice effect on July 13, 1946, and a brief
reference to this work was published  two years later. Electrical
aspects of the phenomena were mentioned in several papers ,
 and most recently in ICCIN .
laboratory experiments have been shown to many persons over
the years. To our knowledge no one has yet pointed out these
should be emphasized that the phenomena described in this paper
are observed only during a strong positive growth cycle
and not during an evaporating phase as discussed by Ruskin ,
Cross  and others, and is rarely of whisker-like structure
but mostly of a nondescript but more < massive
> structure than filamentous.
I (Schaefer) have known of this phenomenon for 24 years, described
it at a public meeting about 20 years ago, and have referred
to it in several papers cited, the present paper resulted directly
from an impetus received during the visit last winter to the
Island of Hokkaido as part of our Japanese-American Scientific
Cooperative Program, NSF Grant GF-280. While stormbound at a
ski hostel in the high mountains near Nisekoxx hot Springs,
I spent part of the demonstrating to Dr. Choji Magono and two
of his associates, the phenomenon described in this paper. Using
a chunk of dry ice held in a polyethylene bag, I was able to
show him the extremely rapid growth of dendritic frost formations,
the high charge which develops on the ice crystals which form,
and the manner in which the dendritic trees suddenly leave the
cold surface and disintegrate into myriads of tiny ice fragments.
Although Dr. Magono is an exceedingly well informed and capable
experimentalist, he had never encountered this phenomenon and
immediately made plans to make some laboratory studies of the
effect which occurs under these conditions.
was an unexpected development which flowed from the National
Science Foundation grant mentioned, and this support is gratefully
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- JOURNAL de
RECHERES ATMOSPHERIQUES (1971)
- "The Production of
Ice Crystal Fragments by Sublimation and Electrification"
- Vol V. No I.-1971
- SCHAEFER and CHENG
CHARGED(-) ICE PARTICLES
from FROST SURFACE of an ICE PELLET(FROZEN DROP)
TYPTS of AEROSOL ARE GENERATED
from the FROZEN DROP(ICE PELLET)
ELECTRICALLY CHARGED ICE PARTICLES (ICE FRAGAMENTS
and RIMED CLOUD DROPS)
REPELLING from ICE
MICRO-DROPLETS fromed by CONDENSATION of VAPOR NEAR
THE ICE SURFACE --FREE
FALL due to NO CHARGES.--THERE IS NO PHYSICAL SEPARATION.
of FROST GROWTH and RIMED CLOUD DROPS on ICE SURFACE
of FROSTINGS. WHICH OCCUR at SEVERAL TEMPERATURE FOLLOWING
NAKAYA'S ICE PATTERN GROWTH.
HEAT RELEASED ON THE ICE SURFACE due to PHASE
CHANGE of WATER to ICE . THE TEMPERATURE on The
ICE SURFACE IS ALWAYS HIGHER THEN the INTERIOR DURING
the STATE of GROWTH.
ICE SURFACE and SUBLIMATIONAL NARROWING STEM
of CRYSTALS due to The CURVATURE EFFECT,---DIFFERENT
VAPOR PRESSURES on ICE SURFACE.
IS FOLLOWING by NATURALLY BREAKUP of ICE
FRAGMENTS (ICE PARTICLES and FROZEN DROP) FROM
THE ICE SURFACE DURING The STATE of GROWTH.
of EJECTED ICE FRAGMENTS(right) from the ICE
SURFACE of A FROZEN DROP(left) DURING the STAGE of
by STROBOSCOPE (3 FLASHS ) REVEALING the ACCELERATION
of EACH EJECTED ICE PARTICLE from ICE SURFACE.
CHARGED ICE PARTICLES****
from FROST SURFACE of an ICE PELLET
C SHOWS AN EXPERIMENTAL HAILSTONE in
A MOIST ENVIRONMENT REPELLING FROST
PARTICLES ELECTRICALLY from ICE SURFACE.
PHOTOGRAPHED by STROBOSCOPE (3 FLASHS
) REVEALING the ACCELERATION
of EACH EJECTED ICE PARTICLE from ICE SURFACE.
NOTE--THE DISTANCE BETWEEN EACH EJECTED
ICE PARTICLE with SAME ELECTRICAL CHARGES
E. .J. and
S. E. Reynolds,
E. .J. and
occurring during the
freezing of dilute aqueous solution and their
possible relationship to
78 254 259 ,I950.
are generated by the freezing of a super cooled
water drop, which is followed by the ejection of
electric charged ice fragments from a frosty surface
of the frozen drop. This observed microscopic phenomenon
of fragmentation of hydrometeors with their accompanying
electrical charges suggests a mechanism of rapid
glaciations of ice multiplication process and electrification
in the atmosphere.