David Wolff
National Aeronautics and Space Administration Goddard Space Flight Center
Greenbelt, MD

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This proposal is aimed towards improving Tropical Rainfall Measuring Mission (TRMM) Ground Validation (GV) Rain Estimates at Kwajalein, Republic of the Marshall Islands, and Melbourne, Florida. It is our goal to provide improved TRMM-era validation products, while also transitioning validation approaches towards Global Precipitation Measurement (GPM)-era goals. The authors have considerable experience addressing validation research from their work in the development, implementation and operation of the Tropical Rainfall Measuring Mission Ground Validation program. The PI manages and directs the TRMM GV Program at NASA GSFC. The PI and two of the Co-I (Dr. Tokay and Dr. Amitai) are members of the GPM GV Working Group tasked with formulating the GPM GV program requirements in conjunction with the GPM GV Project Manager and GPM GV Advisory Panel. Dr. Carey is a recognized expert in the development and application of polarimetric radar algorithms and this effort will be well complemented by his knowledge and experience. We emphasize that this is not a proposal for routine GV operations, but rather a research proposal designed to evaluate and improve current GV algorithms using new methodologies and improved technology.

The key objectives of this proposal are as follows:

1. To improve quality control and rain estimates at Kwajalein, Republic of the Marshall Islands, and Melbourne, Florida using the latest available technology (e.g. polarimetric and conventional radars, disdrometers and rain gauges). This work will be aimed towards both physical and statistical validation of satellite and other precipitation estimates in order to help determine not only when significant differences between GV and satellite estimates occur, but also why these differences occur. We also propose to provide error estimates of our proposed products.
2. To mitigate range effects evident in current GV products and to examine the development and implementation of physically based reflectivity-rain rate relationships for improved rain estimates and feasibility of extending these relationships beyond the domain of a single GV site.
3. To use improved GV rainfall products for comparison to and validation of TRMM and other space-borne precipitation estimates, including the Precipitation Radar (PR), TRMM Microwave Imager (TMI), and Combined (COM) algorithms, as well as the TRMM Multi-Satellite Precipitation Analysis (TMPA), Special Sensor Microwave/Imager (SSM/I), Advanced Microwave Sounding Unit (AMSU), and Advanced Scanning Microwave Radiometer (AMSR-E) instruments, in order to provide critical feedback to algorithm developers during the transition phase towards GPM.