A radiative transfer model function for 85.5 GHz Special Sensor Microwave Imager ocean brightness temperatures

Abstract

We analyze vertically and horizontally polarized brightness temperatures at 85.5 GHz that were measured by F15 Special Sensor Microwave Imager (SSM/I) over the world oceans. The columnar liquid cloud water content is restricted to below 0.04 mm. We develop a radiative transfer model function in this frequency region that provides a functional relationship between the measured microwave brightness temperatures and the essential geophysical parameters, which are the atmospheric temperature, ocean surface temperature, and wind speed. This will provide the basis for including the higher SSM/I, Tropical Rainfall Measurement Mission Microwave Imager (TMI), and Advanced Microwave Scanning Radiometer frequency channels into oceanic and atmospheric retrieval algorithms, which rely on an accurate forward model.