A Geophysical Model Function for S‐Band Reflectometry of Ocean Surface Winds in Tropical Cyclones

Abstract

AbstractOcean surface wind remote sensing using reflectometry measurements from S‐band (2.3 GHz) digital communication satellite transmissions is demonstrated in tropical cyclones. Twelve days of airborne data were collected during the 2014 Atlantic hurricane season. An empirical model function, relating the sensed ocean surface mean square slope to wind speed, was first developed by fitting mean square slope estimates to comparison wind speed data from the Stepped Frequency Microwave Radiometer on the same aircraft and wind direction data from the Hurricane Weather Research and Forecasting model. This model function was then applied for wind speed retrievals using an independent set of reflectometry measurements and validated against four data sources: Stepped Frequency Microwave Radiometer, the Hurricane Weather Research and Forecasting model, dropsondes, and flight‐level winds. Good agreement between these retrievals and comparison data was found, with a root‐mean square error between 4.9 and 6.6 m/s and a bias between −1.4 and −0.2 m/s for wind speeds up to 50 m/s.