WMOD00299

• Title: Physical Structure of Northern Colorado River Basin Cloud Systems
• Date: 9/1/1985
• State: CO
• Weather Modification - Doc Type: Report

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The purpose of this dissertation is to describe the physical structure

and temporal evolution of the wintertime cloud systems which occur over

the Northern Colorado River Basin. The specific objectives of this

research are to: (1) relate the physical structure of the cloud systems

over the region to the large scale environment in which they form; (2)

determine the physical distribution, temporal variation, microphysical

structure and climatological frequency of supercooled water; (3) examine

the physical processes associated with the development of the ice phase,

specifically, primary nucleation, ice multiplication, vapor deposition,

accretion and aggregation; (4) develop a coherent physical model of the

natural precipitation process in these clouds and (S) assess,

qualitatively, the potential of weather modification to augment

precipitation in this region.

This document is of considerable length. Chapter II contains a

disoussion of instrumentation. Chapters III and IV contain analyses of

liquid and ice phase processes respectively. Chapter V presents a

summary of the material in the previous two chapters. For those readers

not wishing to examine the detailed analyses, Chapter V is a concise

synopsis of this material in this thesis. Chapter VI contains a

qiscussion of precipitation augmentatiOn hypotheses and experiments and

Chapter VII summarizes the major conolusions.

1. Back2ro)Jnd

Weather modification research programs utilize three methods to

evaluate the results of experiments. The first method, statistical

analysis, uses randomization procedures over a sufficient data sample to

insure that a change in precipitation, if it exists, oan be recognized

. as. a statistically significant effect.. The precipitation data are, then