A161-06
Ground-based Radar Validation Networks for GPM satellite products
Monday, 14 December 2020: 10:13
Virtual
Patrick N Gatlin, NASA Marshall Space Flight Center, Huntsville, AL, United States, Pierre-Emmanuel Kirstetter, University of Oklahoma, School of Civil Engineering and Environmental Sciences and School of Meteorology, Norman, OK, United States, Walter Arthur Petersen, NASA MSFC, Science Research and Projects Office, Huntsville, AL, United States, Todd Berendes, University of Alabama in Huntsville, Huntsville, AL, United States, Sarah M. Stough, The University of Alabama in Huntsville, Earth System Science Center, Huntsville, AL, United States, David A Marks, Science Systems and Applications, Inc., Lanham, MD, United States, Jason L Pippitt, Science Systems and Applications, Inc., Code 612, Lanham, MD, United States and David B Wolff, NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
The Global Precipitation Measurement (GPM) Mission maps precipitation around the globe using a constellation of satellite-based microwave instruments. In addition to traditional precipitation gauges, ground-based radar networks are used to validate the retrievals from these satellite instruments. As part of the GPM Ground Validation (GV), two such validation infrastructures have been developed for this purpose, both relying largely on the use of dual-polarimetric (DP) radar products. The GPM Validation Network (VN) that is maintained by NASA includes approximately 93 DP radars composed of U.S. operational WSR-88D and numerous international partner DP radars (e.g,. Australia, Brazil, France, Netherlands) to cover a geographic domain from the tropics to high mid-latitudes. The VN radar databases are constructed by geometrically locating and volume-matching the intersection of DP radar range gates and GPM Core satellite Dual-Frequency Precipitation Radar (DPR) rays and sample bins for the 3-D volume of space located within 100 km of each VN DP radar. The GPM VN also produces similar matchups between the GPM Microwave Imager (GMI) and DP samples intersecting the GMI swath. The subsequent database enables robust statistical comparisons to be conducted between GPM Level 2 precipitation products, VN ground-radar DP moments (Z, ZDR, KDP, PhiDP, RhoHV etc.) and DP-derived precipitation parameters such as rain and snow intensity, DSD parameters (e.g. D
m, N
w), hydrometeor types, and variability of these parameters within the matched volumes. Additionally, a subset of the GPM VN contains multi-Doppler derived 3-D winds that can be used together with the DP information to gain insights into precipitation processes, especially within deep convection.
In addition to the GPM VN, the University of Oklahoma/NOAA National Severe Storms Laboratory (OU/NSSL) performs GV using their Ground Validation Multi-Radar/Multi-Sensor System (GV-MRMS) derived from MRMS that integrates about 176 operational radars and over 7,000 rain gauges across the conterminous United States (CONUS) and southern Canada to produce gridded, high quality surface precipitation products with a 1-km / 2-min resolution across the CONUS. The GV-MRMS products are designed for comparison with satellite Level 2 and Level 3 surface precipitation products and consist of a host of quality control metrics and MRMS radar products. Similar to VN data, GV-MRMS data are measured at a resolution below the pixel sizes any GPM estimates. They can be used to examine the consistency of the ground and space-based sensors in term of precipitation detection, typology (e.g. convective, stratiform), and quantification. After matching, precipitation features are computed within the satellite sensor footprint or product pixel to analyze estimates under various precipitation processes, especially non uniform beam filling. This study will present an overview of these two DP-based satellite validation tools and how they are being used for assessing GPM satellite products and for investigating precipitation processes.
