Polarimetric Microwave Remote Sensing of the Ocean Surface

Abstract

Abstract : In this study, we seek to improve our physical understanding of polarimetric thermal emission from random media where volumetric and surface scattering effects are significant. The foam-covered ocean surface provides a rich and complex environment for which to apply our theories and models. We aim to develop electromagnetic models that yield physical insights and provide accurate numerical results for the polarimetric passive remote sensing of the wind-driven, foam-covered ocean surface. A wind-driven ocean surface is characterized by both large- and small-scale roughness that are azimuthally dependent. This has significant effects on the polarimetric thermal emission and makes it possible to retrieve wind parameters from microwave remote sensing of the ocean. Moreover, under high wind conditions, the presence of foam over water surface could significantly enhance the polarimetric brightness temperatures of the ocean surface. Previous studies of foam emission based on theoretical models such as film-layer and solid water particles do not reflect realistic physical situation nor accurately predict foam emissivity for various observation angles. As a result, one must resort to empirical formulae derived from measurement data to incorporate foam emission in passive remote sensing studies of the ocean surface. Our goal is to provide a physically realistic, quantitatively accurate model for polarimetric thermal emission from the rough ocean surface that properly takes into account of foam contribution.