Radar backscatter data measured by the EUMETSAT MetOP-ASCAT sensor are used to compute the wind vector over ice-free open water surfaces. The ASCAT sensor is a C-Band scatterometer which measures the surface radar backscatter along two about 500 km wide swaths parallel to its orbit with about 25 km spatial resolution at the Earths's surface. The ocean surface radar backscatter is a function of the ocean surface roughness which is in turn a function of the wind speed.
Remote Sensing Systems (REMSS, http://www.remss.com) used the EUMETSAT MetOP-ASCAT data to compute the surface wind vector at 10 m height above the ocean surface. This is done by using a so-called Geophysical Model Function (GMF) which has been developed specifically for MetOp-ASCAT (C-2015 GMF) paying special attention to extend the ocean surface wind speed data set produced from QuikSCAT Ku-Band data which ends in 2009. We refer to data set web page at REMSS: http://www.remss.com/missions/ascat and the references section for details. We refer further to the section about the data quality to learn more about potential limitations.
The product offered here is a modified version of the daily EUMETSAT MetOp-ASCAT ocean surface wind vector product v02.1 released by REMSS in April, 2016. The modification applied by ICDC is the conversion from flat binary into netCDF file format, the computation of the u- and v-wind vector components from wind speed and direction, and translation of the bit-wise to be read rain flag / rate information into two separate layers: a rain flag and a rain rate.
Last data set update at ICDC: January 26, 2018.