92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012: 4:45 PM
Up-Scaling Disdrometer, Profiler, and Scanning Radar Observations to Satellite Footprints
Room 256 (New Orleans Convention Center )
Christopher R. Williams, CIRES/Univ. of Colorado and NOAA ESRL, Boulder, CO; and A. Tokay and D. B. Wolff

In order to link surface hydrologic applications and satellite observations, we need to understand how the spatial distribution of precipitation at sub-satellite footprint scales impacts satellite retrieved precipitation products. In most ground-based precipitation radar estimates, it is assumed that the rain is uniformly distributed throughout the sample volume. If this assumption was true, then the reflectivity probability distribution function (PDF) from disdrometers and scanning radars would have similar shapes. But in many NASA Global Precipitation Mission (GPM) Ground Validation (GV) program field campaigns, the reflectivity PDF from disdrometers is wider than the reflectivity PDF from scanning radars. This difference is consistent with scanning radars averaging the reflectivity over a larger spatial domain reducing the range of observed reflectivity values whereas the disdrometers sample the higher range of reflectivities in their smaller sample volume.

This study investigates the temporal correlations in disdrometer and vertically pointing profiler observations to up-scale consistent precipitation features to spatial scales larger than the original point and columnar observations. This temporal-to-spatial transformation assumes the precipitation structure does not vary as the precipitation system passes over the disdrometer and profiler sites. Simultaneous scanning radar observations are used to scale the precipitation features to the 5 by 5 km footprint of the GPM Dual-frequency Precipitation Radar (DPR).

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