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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CHAPTER II INSTRUMENTATION AND EXPERIMENTAL PROCEDURES

1. The Colorado Oro~raDhic Seeding EXDeriment

The Colorado Orographic Seeding Experiment (CaSE) was organized in

1979 by CSU to study the structure of cloud systems occurring in winter

over the Northern Colorado River Basin and to assess their potential for

modification to enhance mountain snowpack. During the 1981-82 field

phase of the experiment, a comprehensive network of aircraft, remote

sensors and ground based observation stations was assembled to

investigate the physical and microphysical characteristics of these

storms. Because the 1981-82 instrumentation network was specifically

designed to study the natural conditions occurring in these storm

systems, no seeding operations were conducted during major storm events

throughout the experiment. Figure 2, a map of the experimental area,

shows the local topography, the location of the major instrumentation,

and the location of the experimental area in the state of Colorado.

Figure 3 shows a vertical west-east cross-section of the topography over

the region. A complete list of all cloud physiCS instrumentation used

during the experiment and the organizations that supplied the

instruments is included in Table 1. The 1979 program was similar to the

1981-82 program, but operated with a much smaller instrumentation base.

The instrumentation network and data collection procedures associated

with the 1979 program have been described by Rauber (1981). Data

obtained during the 1979 program with the Queen Air aircraft (N306D)

provideq by the National Center for Atmospheric Research are used in

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