Wednesday, April 1, 2015
12:45 pm to 1:45 pm; Room 4078
A DROP in Global Precipitation Measurement Mission Ground Validation
Walter A. Petersen, Ph.D.
NASA GPM Deputy Project Scientist, Ground Validation
Chief, NASA GSFC/Wallops Flight Facility, Earth Sciences Office of Field Support
The Global Precipitation Measurement (GPM) mission is an international satellite mission consisting of 11 research and operational satellites designed to unify and advance precipitation measurements made from space. Toward achieving GPM science objectives as they pertain to advancing precipitation science the GPM mission also maintains a Ground Validation (GV) program. The GV program supports validation of GPM science products using three core approaches: 1) Direct statistical comparisons between space and ground-based precipitation products; 2) Measurement and study of cloud and precipitation physical properties as related to the testing and improvement of precipitation retrieval algorithms; and 3) integrated assessment of GPM product utility in, and impacts of estimation uncertainty on, applications such as hydrology, climate and weather prediction. The GPM GV program forms a backbone that interconnects measurement uncertainty, precipitation physics, and application.
In this presentation I will discuss evolution of the GPM GV program in the context of my own research path, to include the legacy and current impact(s) of the Disdrometer and Radar Observations of Precipitation (DROP) effort originally developed at NSSTC. Importantly, the DROP “team” continues as a coherent GV research group (and concept), but with expanded collaborations that leverage both field and operational measurements of precipitation to better understand precipitation properties impacting the quality of GPM satellite precipitation retrieval algorithms and data products. Overarching themes of DROP research include consideration of the complexities of the precipitation physical process (liquid, frozen, space-time variability), how it should be measured, and the use of combined ground and multi-parameter radar-based instrument networks to bridge space-time scales between point (e.g., a rain gauge or disdrometer) and area measurements (e.g., a satellite footprint) of precipitation. Examples of specific research topics include observed constraints on hydrometeor size distributions, precipitation spatial correlations and measurement uncertainty, assessment of orbit level and merged-satellite precipitation products, and variability of precipitation structure in the column as related to GPM dual-frequency precipitation radar algorithms. Finally, DROP research has played, and does play a key role in the development of previous and current field campaign ground-instrument sampling philosophy; this is manifest in the design/development of the current NASA Wallops Flight Facility GPM Precipitation Research Facility which will also be discussed.