Modeling of radar signatures of rain cells over the sea

Abstract

On synthetic aperture radar (SAR) images of the ocean, rain showers (rain cells) often cause distinct signatures which consist of irregularly-shaped bright and dark patches and which strongly depend on radar frequency and polarization. They arise from (a) scattering and attenuation of the microwaves by raindrops in the atmosphere and (b) a modification of the sea surface roughness (and thus the radar backscatter) induced by the impact of raindrops and by wind field variations associated with rain cells. The authors present results from numerical simulations of radar signatures of rain cells. The model used for these simulations takes into account all of the above-mentioned effects. Simulations are performed for various configurations of the modeled rain cell, i.e. its shape and size, and the rain intensity. The results of the simulations are compared with data derived from SAR images of rain cells over the sea that were acquired during the Shuttle Imaging Radar-C/X band SAR missions.