WMOD00505

• Contract/Permit #: 14-06-D-5640
• Project Name: Park Range Atmospheric Resources Program
• Title: Park Range Atmospheric Resources Program - Final Report
• Date: 9/30/1969
• Weather Modification - Doc Type: Report

36

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~ PREDICTED

Figure 43e.-Plume Dimensions and Pibal SOUllldings for 11
March 1965.

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even a I percent concentration of Ag nuclei in a
replica can be detected with at least a 10: I SIN
ratio by present activation analysis techniques,
table 6.

Table 6.-Silver Content in Snowaystal Replicas Produced
by Silver Iodide Seeding.

Sample No.
1
2
3_
4

Silver content (in pgrams) .
67 X 10"
27 X 10"
53 X 10"
55 X 10"

Analysis sensitivity :::::: 10 pgrams
Hence, I percent occurrence of AgI nuclei would
give S IN of

30 X 10" X 1()-2 30
10

pgrams = picograms = 10-12 grams.

Conclusion.- The presence and quantity of super-
cooled water drops-and their variation with time
-can be used as indicators of a deficiency in natural
freezing nuclei.

~
PARK RANGE ATMOSPHERIC WATER RESOURCES PROGRAM

Operational Consequence.-Natural freezing
nuclei count must be monitored routinely through-
out Phase II, say at l2-hour intervals during non-
storm periods and at I-hour intervals during a
storm. Replicas must be taken in the target area and
environs-Rabbit Ears Pass, the laboratory, Steam-
boat Springs, Emerald Mountain-during storm
periods for evidence of supercooled water drops.

How Many Artificial Nuclei
Were Being Dispersed?
Method.-Calibrate artificial nuclei generators
during dispersing periods using the cold box
technique.
Data.-Calibration data from Skyfire reports!;
Colorado State University calibration data.
Analysis.- The calibration curve for a typical AgI-
Acetone-Propane Skyfire generator! is shown in
figure 49. CSU calibration data, for the Skyfire

· Fuquay, D., 1957: "The Project Skyfire Cloud-Seeding
Generator". Research Paper No. 48, Intermountain Forest
and Range Experiment Station, Forest Service, USDA, Ogden,
Utah, p. 8.

PIBAL POINTS

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C-IOIllOO'
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~ PREDICTED

__ MEASURED ~ Ale TRACkS

Figure 43f.-Plume Dimensions and Pibal Soundings for 25
March 1965.

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