An Estimate of the Daily Variation of Cloudiness Over the GATE A/B Area

Abstract

The daily variation of cloudiness, as measured by the Synchronous Meteorological Satellite (SMS-1), was studied for the GATE A/B area (outer hexagon). The amplitude of the diurnal variation was found to be more pronounced on convectively enhanced days than undisturbed days. A primary maximum in both upper and total cloudiness was observed at 1800 GMT (about 1630 local time) and a secondary maximum at 0900 GMT (0730 local time) was observed in the total cloudiness. The existence of a semidiurnal oscillation in cloudiness suggests the influence of the semidiurnal solar atmospheric tide on the cloudiness. The lack of a nighttime maximum in cloudiness implies no nighttime maximum in precipitation, in contrast to other observations of maritime precipitation.