Spatial and temporal homogeneity in a half-hourly sequence of satellite-derived upper winds

Abstract

Cloud motion vectors were derived over three oceanic sectors around the Indian Peninsula with seven INSAT-1B image pairs on 2 June 1985 between 0300 and 1030 GMT. The spatial and temporal homogeneity of the CMVs obtained over this small period is examined. Analysis of data over 2° squares in the form of wind roses shows excellent directional coherence in 42% of squares, and a lack of it in only 13 %. A further examination of selected squares shows that where the wind directions agree well, the wind speeds and heights also tend to agree. Time series of CMVs at selected grid points throw further light on whether a CMV is representative of the synoptic Bow or not.