WMOD00454

• Title: Preliminary Analysis of the Hypotheses Used in the Utah Operational Weather Modification Program - Final Report
• Date: 11/1/1983
• Weather Modification - Doc Type: Report

I. INTRODUCTION
The NOAA Federal/State Design Reportl considered the research problems

that could be most advantageously investigated by superimposing a research

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effort on the Utah operational weather modification program. This study

examined the seeding hypotheses used for the Utah operational program

and presented a specific approach for testing these hypotheses and evaluating

the effectiveness of the Utah seeding program.

The initial field program to test and evaluate the seeding hypotheses

described in the design study was carried out during the winter of 1980-81
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over the Tuahar Mountains east of Beavert Utah. Initial cloud studies

during this field effort verified the usefulness of this sitE~ for the detailed

studies of both the natural and treated cloud processes and the suitability

of the site for testing the seeding hypotheses as discussed in the design

report. The studies also showed that several years of very specifict

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coordinated observations and analyses along the lines discussed i.n the

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design report would be required to evaluate the Utah program. In the 1980-81

field effortt only limited amounts of supercooled cloud liquid water were

observed. Dry meteorological conditions during the study period were

evaluated as unfavorable for the development of greater cloud liquid water

concentrations and not necessarily representative of common orographic cloud

systems over the barrier.

A second phase field program during the winter of 1982-83 was undertaken

with appreciation for (1) the types of observations required,. (2) the need

for parallel remote and in situ observationst (3) the types of analysis neededt

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lGrantt L.O. and P.W. Mielket Jrq 1982: A program for federal/state/local
cooperative weather modification research. Final report to National Oceanic
and Atmospheric Administrationt Atmospheric Science Departmentt Colorado State
UniversitYt 70 pp.

2Hillt G.E't 1982: Evaluation of the Utah operational weather modification
program. Final report to National Oceanic and Atmospheric Administration,
Utah State UniversitYt Atmospheric Water Resources Series UURL/A-82l02t 291 pp.

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