ASCAT – Metop’s Advanced Scatterometer

Introduction Wind scatterometers already flown on ESA’s ERS-1 and ERS-2 satellites have demonstrated the value of such instruments for the global determination of sea-surface wind vectors. These highly successful instruments – part of the Active Microwave Instrument (AMI) – were conceived about twenty years ago. During the intervening period, there has been a considerable evolution in the capabilities of spaceborne hardware. Figure 1 indicates the form of the variation of backscattering coefficient with relative wind direction (at a fixed incidence angle) for a range of wind speeds.