WMOD00308

• Title: 1991 Final Report of Desert Research Institute Field Operations, Data Collections and Data Processing
• Prepared For: Utah Department of Natural Resources Division of Water Resources
• Prepared By: Arlen W. Huggins
• Date: 8/1/1991
• State: UT
• Weather Modification - Doc Type: Report

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1. INTRODUCTION

Research is currently being conducted in several states, in cooperation

with the National Oceanic and Atmospheric Administration (NOAA), as part of the

Federal-State Atmospheric Modification Research Program (AMP). Initiated after

a 1978 recommendation of the Weather Modification Advisory Board, this program

has been successful in investigating a wide variety of summertime and wintertime

weather modification problems. The overall intent of the AMP was, and remains,

to better understand, evaluate and improve some well designed and controlled

State cloud seeding programs.

The goals and scientific objectives of the Utah/NOAA research program are
stated in the 1991 UtahjNOAA Field Operations Plan (Utah Division of Water
Resources, 1991), and adhere well to the original ideas of the the Federal-State
Program. Utah/NOAA is evaluating the effectiveness of the Utah State operational
winter cloud seeding program, and will, through its field research results, make
recommendations for improvements to the operational program. The research during
the 1991 winter field effort concentrated on evaluating the effectiveness of the

operational program in delivering silver iodide (Agn seeding material to regions

of cloud containing supercooled liquid water (SLW). Secondarily, the field

program continued to research the development of SLW in winter storms which

affect the mountains of Utah.

This report describes work performed by the Desert Research Institute (DRI)
in support of the 1991 UtahjNOAA Field Program. The primary research task of the
DR! was to describe the spatial and temporal distributions of SLW over the
Wasatch Plateau in central Utah, and to evaluate the factors controlling SLW
development. The DRI has made similar studies in the Tushar Mountains of

so~thern Utah (see Long, 1986 and Huggins, 1990a, 1990b) with results providing

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