Clear Sky Water Vapour Winds - MFG - Indian Ocean 57 degrees E

Vectors are derived by tracking structures in the WV image from non-cloudy areas. It uses essentially the same algorithm as the other Meteosat First Generation vector products and the low resolution 80x80 segment matrix. Height information is supplied - the 10%, 50% and 90% levels of the cumulative contribution function (based on ECMWF forecast data) - and the levels of the maximum gradient of the cumulative contribution function are inserted. These values allow characteristics of the layer being tracked to be determined. A typical WVW product contains about 1000 Clear Sky WV vectors.