Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 1998
Publication Date: N/A
Technical Abstract: Precipitation measurements by radar systems are coming to the forefront of hydro-meteorology as the National Weather Service (NWS) is now using the NEXRAD (Next Generation Radar) systems for determining precipitation accumulations over most of the U.S. NEXRAD is an extremely useful instrument for spatially determining precipitation. Mountainous terrain poses a particularly difficult problem for measuring precipitation with radars, because of terrain blocking of the beam, bright-band effects, and variations in precipitation processes with elevation. Even if the standard Z-R relationship developed by the NWS is used for measuring precipitation, comparisons with rain gauge measurements cannot be relied on due to the many problems associated with these in situ gauges. This presentation addressed both the uncertainty in measuring precipitation with NEXRAD, as well as the uncertainty of measuring precipitation using standard recording gauges. The dual-gauge system is used to measure precipitation in an instrumented watershed in the Owyhee Mountains of Idaho. This system consists of one unshielded and the other shielded that are used to compute the actual precipitation catch. An analysis of several case studies show that variations in catch between the dual gauge and radar systems are significant, and need to be addressed further to accurately verify NEXRAD rain and snow estimates.