An Improved Microwave Radiative Transfer Model For Ocean Emissivity At Hurricane Force Surface Wind Speed

An electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR), which routinely flys on the National Oceanic and Atmospheric Administration\u27s hurricane hunter aircraft. This thesis presents the methods used in the wind speed model development and validation results for wind speeds up to 70 m/sec. The ocean emissivity model relates changes in measured C-band radiometric brightness temperatures to physical changes in the ocean surface. These surface modifications are the result of the drag of surface winds that roughen the sea surface, produce waves, and create white caps and foam from the breaking waves. SFMR brightness temperature measurements from hurricane flights and independent measurements of surface wind speed are used to define empirical relationships between microwave brightness temperature and surface wind speed. The wind speed model employs statistical regression techniques to develop a physics-based ocean emissivity model dependent on geophysical parameters, such as wind speed and sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle