15 O 04 Phenomenological theory of (ICE) nucleation on mixed aerosol particles

0021-8502/93 $6.00 + 0.00 Pergamon Press Ltd

J. Aerosol Sci., Vol. 24, Suppl. 1, pp. S105-S106, 1993 Printed in Great Britain.

15004 PHENOMENOLOGICAL THEORY OF ( I C E ) NUCLEATION ON MIXED AEROSOL PARTICLES

V.Smorodin

Physics

Dept.,

Moscow S t a t e

Moscow,

119899,

University,

Russia

KEYWORDS ice

nucleation,

condensation,

solubility,

freezing,

aerosols, weather modification,

bioaerosols

The c l a s s i c a l

has been d e v e l o p e d

nucleation

describing

ice

freezing, in For

nucleation

aerosol

clouds

particles,

our

nucleation

Fukuta-Schaller mechanism

fogs

is

very

and

General

cloud

of

(modified

(I)

aerosols,

One

of

the

(2)

the

~qew t h e o r e t i c a l

microphysics:

of

on

mixed

condensation-freezing

effective

criteria

artificial

of

capability

of

which

in

crystallization temperature

are

enables

of

agents

gain of

MAP

the m o d i f i c a t i o n

ice-generating

particles

for

range

the

soluble

based

on m i x e d

theory.

(MAP)

there

ice-forming

high

aerosols

crystallyzing

with

an

is

activity

silver

iodide)

evaluate

the

mixed

have been established.

Optimization

maximum

solution

weakly

on

for

particles

1990,1991,1992,1993). were

expanded

condensation-

aerosol

(Smorodin,

formula

important

1992).

natural

estimates

a

solubility

(Smorodin, aerosols

(3)

mixed

investigations

theory,

as an a p p r o a c h

(deposition,

mechanism

probability

and

optimal of

or

on

condensation-freezing

classical

results

processes

adsorption-freezing)

supercooled the

theory

mixed

in

the

in

weather

of

the

from

S105

effective method.

optimum modified

Fldtcher -10 °

developing

to

the

critical -30°C

maximum

make q u a n t i t a t i v e

modification

(compared with

with

interval

value

aerosol

yield

to

t e c h n i q u e and t o

practical

nuclei

AgI

us

case

AgI-based of

radius)

reaches

The

uniform in

the

5~I02.

T~e

SI06

V SMORODIN

optimal m o d i f i c a t i o n of weakly s o l u b l e aerosol p a r t i c l e s wit;~ Ag:I (when the

c o n d e n s a t i o n - f r e e z i n g mechanism i s

effected)

permits

increases to a maximum gain in the y i e l d of a c t i v a t e d ice ~ c l e i 9! to the upper limit o f o r d e r t0 ° p e r 1 kg of A g I .

These chamber

theoretical

eYperiments

Our a p p r o a c h temperature

calculations

with

NH4I-AgI

yields

a logical

activation

crystallizing

mechanisms

empirical

constants

Na=Noexp(#&T), A long

by

surface sites the

of

two ice

!yophobic in

of

in

clouds.

Therefore,

the

concerning up.

factors: and

(B)

are

ones

(A)

the

ice

with

ones

in

The

surface

properties

with

all

AgI

ice of

formula,

ice-forming is

unite

The

of

unite

activity.

The

both

lyophilic

condensate

"hetrophobic

instable

cannot of

crystal

"centers";

when the

the

the

explained

AgI

(adsorption)

"centers"

minimization

crystals

viewpoint

the

thermodynamic

ice-forming a

of

action

both

~tage contrary

isomorphism ice

(a

nucleation

heterophiticity

and

factors.

effective

ice-forming

same

provides

criteria

hypothesis

to meaning

aerosol

process

1993).

The

artificial

the

heterogeneity.

nucleation

(Smorodin,

a high

AgI

condensation

the

isomorphism

<:loud

empirical

activation

isomorphism

energetic

acting

are

of

reaching

The

and

mechanism o f

after

energy.

the

From a p h e n o m e n o l o g i c a l

activity

contact

misfit)

by

relationship

Fletcher

wetting",

slight

natural their

summed

of surface

comes

explaining

reveals

of

discussion

with

model

and

ice-crystallyzing acting

veri~ied

has been c l a r i f i e d .

o f A g I has been high

well

aerosols.

spectra

nuclei

generation

are

(A)

and

ice-forming concerning

bacteria

is

REFERENCES Smorodin, V.Ye.(1990), Vol.21, 249-253. Smorodin, V.Ye.(1991)

(B),

we

supposed,

aerosol the

particles.

crystallization

to

be universal On

this

for

basis,

mechanism

a of

advanced.

Journal

of

Aerosol

Report

Series

in

Science,

Suppl.1,

Aerosol

Science,