WMOD00591

• Title: Investigations of Winter Storms over the Wasatch Plateau during the 1994 NOAA-Utah Field Research Program - Final Report
• Date: 7/1/1996
• State: UT
• Weather Modification - Doc Type: Report

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Only data from storms on 26 January and 19 February have been analyzed in detail. For the
special analysis needed on these (and other) days, 1\\'0 programs were \\Titten~ one to read and select
data oyer specific ground points, and another to integrate these data into files of parameters in time
and height format that can be manipulated with objective analysis schemes for plotting and
displaying o\'er a uniform grid. These programs are suited to the development of relationships
bem'een radar retlectivity factor and precipitation rate. and for analyzing regions inside and outside
seeding plumes for differences in radar reflectivity factor.
Instruments at the target site (TAR in Fig. 1) were similar to those at RRS, but TAR had no
radiometer or radar. Included in the data collection at TAR were snow samples for trace chemical
analysis of silver. These samples and snow particle photographs were collected time sequentially
during seeding experiments. Huggins (1994) documents the snow sample history. As \\ith data from
RRS_ the DRI acquired 6-min averages of the TAR data after it was processed at the USBR in
Denver.
The other ground-based data used in this report are precipitation data from the 12" orifice
recording gages, whose locations are sho\\TI in Fig.!, and data from the Doppler acoustic sounder
located at DAS in Fig. 1. The USBR also reduced and processed these data and sent the final
products to DR!. Precipitation data consisted of amounts at 30 min intervals. Doppler data were
averaged over 10 min periods. The maximum vertical range of the data varied depending on the
structure of the atmosphere over the sounder. The maximum height of useable data was generally
less than 1 km above the surface.
Finally, data from a ~OAA-operated King Air research aircraft were also used in some of
the subsequent storm analyses. The King Air data system is thoroughly described by Heimbach
(1994). Studies in this report take advantage of processed data, primarily I-see data from a fast
response sulfur hexaflouride (SF J detector, I-sec data from an NCAR ice nucleus counter, and 3-sec
averages of temperature, height, FSSP concentration, 2DC concentration, and position.

III. 1994 STOR\I PERIOD DESCRIPTIOSS

The 1994 ~OA~.t\-Utah field program took place bet\veen 15 January and 15 March. There

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