WMOD00453

• Project Name: Park Range Atmospheric Water Resources Program
• Title: Park Range Atmospheric Water Resources Program - Phase I
• Date: 1/1/1967
• Weather Modification - Doc Type: Report

40

PARK RANGE ATMOSPHERIC WATER RESOURCES PROGRAM
. STEAMBOAT CLIMATOLOGICAL STATION 1 TOTAL PRECIP. = 4.58 in. 1 W.G. 270- 300 = 74 %
o VALLEY VIEW LODGE WEIGHING GAGE 1 TOTAL PRECIP. = 4.69 in. 1 W. G. 270-300 = 75 %
. WIND GROUP 2700- 3000
1 FEB. - 1 MAY 1965

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2 3 4 5 6 7 8 9 10 11 12 13 14 15 .16 17 18 19 20 21 22 23 24 25 26

ANALYSIS PERIOD

Figure 46.-Relation of Storm Precipitation and Wind Group 2700-3000.

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contamination. Samples should be gathered as soon
as possible after a storm period, preferably within 1
day. Since Ag analysis is relatively expensive and
ZnS analysis inexpensive, early Phase II tests should
determine whether ZnS concentrations adequately
describe the artificial plume dimensions and con-
centrations-if so, ZnS analysis may be substituted
for Ag analysis-with periodic cross-checks-as the
source of targeting information at reduced cost and
analysis time.

Did Artificial Freezing Nuclei Participate?
Method.-Gather snowcrystal replicas from the
target area during storm periods. Analyze replicas
by the activation technique and determine Ag con-
tent. Confirm that AgI present is actually the
nucleating substance by electron microscope analysis
of representative snowflake replicas.

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Data.-Replicas containing artificial snow pro-
duced in a cold box, table 6. Sncw samples pro-
duced by nucleating supercooled water vapor in an
area of very low natural nuclei count. Work of
Kumai 8 in identifying snowcrystal nuclei by elec-
tron microscope and diffraction-pattern technique.
Analysis.-Replicas of artificial snow were made
in a cold box using the polyvinylformal-chloroform
vapor technique. They were then analyzed by the
activation technique at Battelle-Northwest, Rich-
land, Wash. The results show Ag content about
three orders of magnitude above the minimum
detectable by the technique. Therefore, if AgI
nuclei participate in snowflake formation within a
storm only on the order of 1 percent, we should be
able to detect the AgI content with a safety factor

8 op, Cit, Kumai, M" p, 34.