WMOD00296 ‎(2)‎

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

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SECTION 2. 0
INSTRUMENTATION, OPERATIONS, AND DATA COLLECTION

2. 1

Nuclei Generation

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Near the end of the first data collection season, several generator types
were constructed, or procured, and tested on Emerald Mountain. Two of
these were needle types (Colorado State University (CSU) modified Skyfire
and Bollay modified Skyfire) and one a pressure nozzle type generator (the
Bollay modified Skyfire Hi Output Type). The latter proved to be the most
reliable and easiest to keep clean. This type of generator (shown in Figure
2) was chosen for Park Range nucleation operations and performed flawlessly
for four winter seasons of intensive operation. Shortly after operations
were started, a flow metering system was added to the generator system.
With the flow metering system, these generators make an extremely reliable
and effective generating system. The generators were operated using a 4%
solution of AgI in acetone complexed with sodium iodide. The burn rate of

AgIwasjustover~gmmin-1. =- \Lor!hv _ L->e U5.,,- -E='OtJ"'j~.v ~\ (C'<'-C"',
"O:~~
The units were calibrated extensively at Colorado State University's facility
at Fort Collins and gave a consistent calibration curve. The output of the
modified Skyfire high output generator is conservatively 3 x 1014 nuclei
gram-I at -20oC. (Calibration curves for several generators are presented
in Figure 3.) The burn rate used was 0.035 gm see-I, so that the output per lD/~
generator was approximately 1 x 1013 nuclei see-I. The assumptions under J
which the experimental plan was devised were: it was desired to fill a target
volume 20,000 m long by 3000 m high with a nuclei concentration of 10t4 m -.3
effective at -20oC, with a flow through the volume of 15m see-I. The required
generator output is therefore

434
2.0 x 10 x 3.0 x 10 x 15.0 x 10

= 9.0 x 1012

13 -1
or '" 1 0 nuclei see

If we conservatively assume the nuclei output to be 1014 nuclei gm-l, then
about O. 10 gm see -1 would have to be burned to produce this output. The two
generators that were used routinely burned a total slightly less than this
amount.

An AgI - isopropylamine generator was also tested. Based on an aircraft
tracking diffusion test, it was determined to have an output at least as great
as the two Skyfire high output generators. Calibration tests at CSU showed
a higher output. Due to the toxic and corrosive nature of the solvent, this
generator was not used for routine operations.

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