A Typhoon Wind-Field Retrieval Method for the Dual-Polarization SAR Imagery

Synthetic aperture radar (SAR) is widely used to detect sea surface wind. It has been found that the signals of co-polarization SAR tend to become saturated under high wind-speed conditions. Also, low signal-to-noise ratios of cross-polarization SAR have been observed under low wind-speed conditions. In this letter, a typhoon wind-field retrieval method is developed by compositing the wind speeds retrieved from dual-polarized SAR images. This letter then applies the proposed method to eight typhoons (four from the Canadian RADARSAT-2 satellite and four from the Chinese Gaofen-3 satellite). The results show that the method is successful in regard to fine typhoon wind structure retrieval, with a root-mean-square error of wind direction of 12° and a wind speed of 1.7 m/s, against 12 oceanic buoy measurements in the South China Sea.