An Improved Method of Retrieving Sea Surface Wind Speed Based on a Four-Layer Medium Model at High Sea States

Abstract

C onsidering about the effect of whitecaps and foams on pulse-limited Radar Altimeters, an improved algorithm of retrieving sea surface wind speed i s proposed in this paper. Firstly, a four-layer dielectric model i s established in order to simulate an air-sea interface. Secondly, the microwave reflectivity of a sea surface covered by spray droplets and foams at 13.5 GHz i s computed based on the established model. These computed results show that the effect of spray droplets and foams in high sea state conditions s hall not be negligible on retrieving sea surface wind speed. Finally, compared with the analytical algorithms proposed by Zhao and some calculated results based on a three-layer dielectric model, an improved algorithm of retrieving sea surface wind speed i s presented. At a high wind speed , the improved algorithm i s in a better accord with some empirical algorithms such as Brown, Young ones and et al . , and also in a good agreement with ZT and other algorithms at low wind speed. This new improved algorithm w ill be suitable not only for low wind speed retrieval, but also for high wind speed retrieval. Better accuracy and effectiveness of wind speed retrieval can also be obtained.