WMOD00373

• Title: Investigations of Winter Storms in Utah
• Prepared By: Alexis B. Long, Atmospheric Sciences Center
• Date: 12/1/1986
• State: UT
• Weather Modification - Doc Type: Report

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clllowed a more comprehensive field project and more penetrating analy-

s~s. This report presents the results of that analysis.

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The two major scientific objectives of the work reported here are

the following:

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1) to assess the transport and delivery of seeding material from
ground-based generators to clouds over the Tushar Mtns, and

2)

to describe the spatial and temporal distribution of super-
cooled liquid water in the clouds, the physical processes
responsible for precipitation development, and the trajec-
tories of cloud and precipitation particles.

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These objectives are closely similar to those of Hill (1982) and

Long (1984a).

Progress toward these objectives is important to the

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evaluation and improvement of the seeding hypothesis being used ~n the

Utah operational wintertime cloud seeding program. (That hypothesis is

discussed in Section 2 of this report.)

Progress. toward these objec-

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tives also will increase basic knowledge of wintertime clouds in moun-

tainous regions.

The analysis of the data collected in the 1985 field project is

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being completed at three different Levels. Levell analysis consists of

the reports of the individual participating technical groups submitted

to the Utah Division of Water Resources. Each such report covers a set

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of specific analysis questions assigned to an individual group as part

of the overall effort toward the two major objectives. The reports of

the individual groups are listed in Table 1 and in the References.

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Level 1 analysis has also resulted in a number of papers for scientific

conferences. These papers are listed in Table 2 and in the References.

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The Level 2 analysis is the subject of the present report. It draws

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