Winds over the sea cause disturbances of the sea surface which modify its radar backscattering characteristics in a particular way. These backscattering properties are well known and are dependent on both the wind speed over the sea and the direction of the wind with respect to the point from which the sea surface is observed. ASCAT, carried on MetOp-A, exploits this fact by using radar to measure these backscatter coefficients, which can then be applied to deduce actual wind speed and direction for weather forecasting. ASCAT will provide data at 50-kilometre resolution, which will be distributed in near real-time to key meteorological offices. In addition to wind vector determination, data from ASCAT will also find roles in areas such as ice, snow and soil moisture monitoring.