WMOD00317

• Contract/Permit #: 14-06-D-6999
• Project Name: CAWRP
• Title: Cascades Atmosphere Water Resources Program - Volume I
• Prepared For: US Department of the Interior Bureau of Reclaimation
• Date: 7/1/1970
• Weather Modification - Doc Type: Report

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2.6 Silver Concentrations

Only a small portion of the snow collected in the polyethylene bags was

needed for the determination of the concentrations of freezing nuclei by the

drop-freezing technique. The bulk of the snow was analyzed with an atomic

absorption spectr~meter to determine the amo\U1t of silver it contained. This

technique can detect concentrations down to about 3 x 10-11 grams of silver

per milliliter of water. A total of 323 samples of snow collected during the

1970-71 seaso~ were analyzed in this way.

2.7 Rawinsonde Measurements

Rawinsondes were launched and tracked from Greenwater (see Fig, 2.1)

using a GMD-l unit on loan from the National Center for Atmospheric Research.

The sonde could generally be tracked up to the 100 rob level except when the

winds were unusually strong. The raw data were transmitted to the University

of Washington and then relayed for analysis via a computer terminus to the

Bureau of Reclamation's RCA time sharing computer in Denver. The reduced data

(temperature, dewpoint, wind speed and direction at standard al ti tudes) were

then relayed back to the University of Washington where they were available

while the aircraft .and ground measurements were still in progress.

2.8 Radars

The objectives of the radar studies in the Cascade Program are to

investigate the intensity of precipitation and the fall speeds of solid

precipitation particles in winter storms over the Cascade Hountains and to

relate these to simultaneous airQorne and ground observations and, where

appropriate, to artificial seeding. During the summer of 1970 a small CW
. mobile Doppler radar was built for this purpose and tested at l<eeche1us Dam