WMOD00298

• Title: Quantifying Ice Nucleation by Silver Iodide Aerosols
• Date: 5/1/1990
• State: CO
• Weather Modification - Doc Type: Report

6.40

7.1

7.2

7.3

7.4

7.5

7.6

A1

A2

Comparison of cumulative ice fractions nucleated in cumulus
seeding simulations with AgI-AgCl versus AgI-AgCl-4NaCl
aerosols. Cases of seeding below 50C cloud base (a) and
into cloud at -50C (b) are shown.

Adiabatic cloud model profiles of cloud and thermodynamic
quantities in the simulation of the 22 June case. Vertical
velocity replaces the supersaturation profile shown in
previous figures of this type. A few observations from the
real cloud are overlain in repective plots (~).

Time histories of temperature (a) and ice formation (b).
-1
Ice is given both as the concentration L and as a
fraction of initial aerosol concentrations injected. In
(b), observed data are shown (~), from Stith et a1.
(1990).

Model-predicted nucleation mode contributions to ice
formation in the simulation of the 22 June case (a), and
those predicted if seeding had been done with AgI-AgC1-
4NaCl aerosols (b).

As in Figure 7.1, for the 28 June case.

Predicted ice concentration versus time (temperature) for
28 June cloud. The range of concentrations observed in the
upshear cloud region is shown by brackets.

As in Figure 7.3,
below cloud base.

but for the 28 June cloud seeded from

Deposition/sorption nucleation active site density (D )
dep
on an ice supersaturation-temperature plane, as
parameterized in the original model version.

Fractional percentage activity (PCT - F ) by contact-
ctf.:
freezing nucleation as a function of aerOSOl size and ice
supersaturation.

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