All-Weather Geophysical Model Function for Wind Speed Retrievals from AMSR2

This paper describes the development of a new all-weather geophysical model function (AW-GMF) for the purpose of retrieving sea surface wind (SSW) under all weather conditions. The AW-GMF makes use of the Advanced Microwave Scanning Radiometer-2 (AMSR2) dual-polarized C-, X-, and K-band channels. We show how the linear combination of these channels significantly mitigate the effect of rain contamination while maintaining sensitivity to SSW regimes including tropical and extra-tropical cyclones. AW-GMF was trained using ~750 AMSR2 hurricane overpasses from 2013 - 2021. The Global Data Assimilation System (GDAS) 0.25° resolution product and the Hurricane Weather Research and Forecasting Model (HWRF) were used as the assumed surface truth. Preliminary results show that SSW retrievals using the AW-GMF are much less susceptible to rain and capable of retrieving hurricane force winds.