Wind retrieval over the ocean using advanced synthetic aperture radar

Sea surface wind is a crucial parameter for the studies of marine environment, which can help us to get a better understanding of processes in coastal areas and the lower atmospheric boundary layer. Synthetic aperture radar (SAR) with the unique advantages of high spatial resolution, typically below 100 m, can provide detailed wind vector information of marine and coastal areas. The wind fields retrieval include wind speeds and wind directions. The most widely used CMOD4 are suitable for ocean SAR data to extract wind speeds information. In addition, the CMOD4 algorithms are originally developed for the C-band, VV-Polarized data and thus need to be extended for HH polarization. The wind directions are obtained from wind-induced streaks that are visible in SAR images. And the 180° ambiguity is removed using the additional data from ECMWF. Compared with the data from ECMWF, the error in the wind direction and average wind speed are very small. The results show that image radiometric calibration and image filtering, smoothing, together with CMOD4 algorithms, can offer high quality specification on wind fields.