Comparing Global Precipitation Mission (GPM) Data With Ground Radar -- Interests Specific To The Aviation Community

Abstract

The Global Precipitation Mission (GPM) Core Observatory satellite was launched in February 2014 and is currently generating swaths of three dimensional precipitation structure. The Forecast Impact and Quality Assessment Section (FIQAS) at NOAA/ESRL/GSD is using the GPM dataset to investigate aviation-impactful convection in regions without ground radar coverage. Specifically, the GPM Dual-frequency Precipitation Radar (DPR) data is used, which provides a Storm Top variable and 3-d reflectivity field from which Vertically Integrated Liquid (VIL), an accepted aviation radar product, is derived. To better understand its characteristics and limitations, ground radar VIL and Echo Top products currently used by the aviation community to diagnose hazardous convection, are remapped to the GPM swath where observations overlap. Statistical comparisons of products are presented, and the sensitivity of the remapping technique is explored. Findings suggest good correlation; however, there is a tendency for GPM to underestimate VIL values compared to ground radar, while GPM Storm Top and ground radar Echo Top products are more similar in magnitude. In general, presented results highlight the usefulness of GPM data in regions lacking ground radar coverage. However, more conservative GPM VIL values must be considered by aviation community users since it is more widely accepted to use a worst-case scenario representation of weather given the safety concerns.