Comparing Radar Reflectivity Values of Convective and Stratiform Precipitation Retrieved from Satellite- and Ground-based Radars in Tropical Cyclones

Keywords: Tropical Cyclones, Hurricanes, Remote Sensing, Radar, Satellite
Abstract Type: Paper Abstract

Abstract

Ground radars (GRs), such as the Weather Surveillance Radar-1988 Doppler (WSR-88D), are instrumental in the detection of landfalling Tropical Cyclones (TCs) with their continuous scanning of the atmosphere. However, GRs suffer from beam spreading which limits their effective range and data from neighboring stations must be mosaicked to view a TC. Space-based radars (SRs) provide more accurate measurements in a vertical column but have a limited horizontal extent and overpasses that are hours apart. This study compares reflectivity observations from the Global Precipitation Mission’s Dual-frequency Precipitation Radar (DPR) and WSR-88D to identify differences in stratiform and convective precipitation detection within TC rainbands. Stratiform clouds may be observed more similarly by both platforms due to their horizontal extent while convective clouds might return higher reflectivity values by the DPR due to its superior detection vertically. We test this by interpolating values from each dataset onto a common 5 km x 5 km grid and subtracting DPR from WSR-88D. We identified over 25 DPR overpasses that had at least 1000 jointly observed points for TCs during 2014-2021. The average mean error of the TC cases was 0.61 (Standard deviation=1.17) and the average mean absolute error of the TC cases was 3.27 (Standard deviation = 0.63). Variations among the cases will be explored.