WMOD00426

• Title: Desert Research Institute Fields Operations - 1994 NOAA/UTAH Field Program - Final Report
• Date: 11/1/1994
• Weather Modification - Doc Type: Report

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E. K.-13and Radar Operations
The! Utah K.-Band radar was substantially modified by DRI prior to the 1994 field
program 10 allow data to be collected in a scanning mode of operation. The data
acquisition and antenna control computers were replaced with a single 486 pc with a 540
Mbyte hard drive and an Exabyte tape system. The data acquistition and antenna
control software were also replaced with a new system, and a 17" color monitor was
added to IJpgrade the display. The new system was programmed to create data files in
an NCAR.compatible format in PPI, FIHI and time-height modes of operation. The
antenna control system is now operated from the screen using the point and click
capability of a standard mouse. Data files are initially written to the hard drive and
automatically limited to 60 minutes of data. The hard drive capacity allows for 8-10 hours
of continuous operation before some fill3s need to be offloaded onto Exabyte tapes. For
the NOAA/Utah experiments, which typically lasted 4-6 hours, this provided ample space
for continuous recording. The current characteristics of the Utah K.-Band radar are
provided in Table 4.
Tho primary functions of the radar were to characterize the spatial distribution of
echo during all seeding experiments and collect data during chaff-release experiments
in relatively clear weather to aid in studies of transport and dispersion over the Plateau.
The radar was located at RRS in Fig. 1. The radar is pictured in Fig. 7 at the 1994 RRS
field site. The maximum radar range! was 38.4 km (512 75 m gates). The region
between the seeding generators and the target site (TAR in Fig. 1) was well sampled
within the 10 km range ring shown in Fig. 1. All project precipitation gages were within
13 km of the radar, and will allow for good comparisons of radar returns and precipitation
rates.

ThH main contributors to radar ec:ho in winter storms are ice particles, so the radar
provided a comprehensive portrayal 01: the evolution of cloud ice upwind of, over and
downwind of the Wasatch Plateau. In combination with radiometer liquid water data, the
relative potential for cloud seeding can be assessed from these data sets.

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