Preliminary Evaluation of Sentinel-1A Wind Speed Retrievals

Abstract

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.