WIND DIRECTION FROM SENTINEL-1 SAR IMAGES IN REGIONAL SEAS

A method based on the 2D Continuous Wavelet Transform has been developed and applied to 30 Sentinel-1 SAR images to retrieve the wind direction. The resulting wind directions have been compared with ECMWF model winds. The 2D-CWT method produces good direction estimates: in 90% of cases the SAR-ECMWF wind direction difference is < +/- 30%, while in 83% of cases it is < +/- 20%, with a mean direction bias of 8 degrees and a RMS error of 19 degrees. Among others, the knowledge of the wind direction is essential to retrieve the wind speed by using the radar-backscatter versus wind speed algorithms.