Thursday, 17 January 2002: 1:57 PM
Investigation of a WSR-88D Z-R relation for snowfall in northern Utah
The Weather Surveillance Radar 1988 Doppler (WSR-88D) has available several reflectivity-rain rate relations. One of them, Z=75R2, is intended for use during cool season stratiform precipitation in the western U.S. In this study, radar data and special snow gauge data from 44 winter storms in northern Utah are examined to understand the performance of the cool season Z-R relation in complex terrain. Hourly precipitation estimates were derived from radar reflectivity for eight snow gauges at various ranges and altitudes. Results show that the cool season Z-R underestimates precipitation in the mountains and slightly over-estimates precipitation upstream of the mountains. Analysis of mountain snow/valley rain cases shows that regression correction factors decrease with surface temperature for valley locations.