Combining SAR and scatterometer data to improve high resolution wind speed retrievals

With the December 14, 2002 launch of the SeaWinds scatterometer on Adeos-2 complimenting a similar instrument aboard QuickSCAT, we now enjoy global wind speed measurements at 25 km resolution from two active microwave scatterometers. WindSat launched on January 6, 2003 with the mission to test the possibility of making wind vector measurements of comparable precision and resolution as conventional scatterometry by using polarimetric radiometry. However, the relatively coarse resolution of these instruments makes it difficult to measure winds in coastal areas. Here we show that by combining scatterometer wind direction measurements with high, sub-kilometer resolution radar cross section measurements from the RADARSAT-1 synthetic aperture radar (SAR) we can make significantly improved wind speed retrievals in coastal areas. Recently ASAR data from ENVIASAT have become available. We have just begun using this data source for SAR wind speed retrievals and have found that these data avoid some of the problems encountered with RADARSAT-1 imagery.