Simultaneous retreival of surface wind speed and rain rate using radar and radiometer measurements

A retrieval algorithm has been developed which simultaneously estimates the over ocean near-surface wind speed and rain rate profile using data from a 10.7 GHz microwave radiometer and a dual-frequency Doppler radar. The algorithm uses the radar backscatter measurements to estimate two parameters of the gamma drop size distribution (GDSD) at each range gate. The parameterized GDSD can be integrated to determine the rain rate profile. The wind speed is estimated from the 10.7 GHz brightness temperatures (T_Bs) by removing the contribution from the atmosphere and isolating the contribution from the surface wind speed. The atmospheric optical depth at 10.7 GHz is estimated by integrating the extinction coefficient determined at each radar range gate using the parameterized GDSD and Mie theory. Results of wind speed and rain rate retrievals are presented from a field campaign in June of 2003 in which several precipitation overflights were made with a NASA DC-8 equipped with the PR-2 radar and the LRR-X microwave radiometer