Preliminary Evaluation of Sentinel-1A Wind Speed Retrievals

The accuracy of wind speed retrievals from synthetic aperture radars (SARs) is strongly dependent upon the accuracy of the normalized radar cross section measurement. Here, we make a preliminary assessment of wind speed retrievals from Sentinel-1A. In particular, we use Sentinel-1A SAR imagery to compute wind speed at 500-m resolution. These measurements are averaged to 25 km and compared with advanced scatterometers (ASCAT) wind speed measurements from the METOP-A and METOP-B satellites. Spatially coincident measurements separated by less than 2 h are shown to agree to better than 2 m/s in standard deviation for wind speeds less that 20 m/s. Particularly, good agreement is found for Sentinel-1A VV-polarization measurements, though both HH- and VV-measurements exceed the 2 m/s accuracy standard.