Interrelation between microphysical and optical properties of cloud and rainfall in the Indian region

Abstract

Ground and satellite based measurements of microphysical and optical parameters of cloud are analysed for three tropical locations Kolkata, Guwahati and Bangalore during the year 2006 to find an interrelation between cloud optical depth, cloud effective radius, cloud liquid water content and rain. The present study suggests that a relation exists between cloud effective radius and cloud liquid water content. A minimum threshold of cloud optical depth is required for the precipitation to initiate. However, the threshold value depends on weather conditions of the tropical location. Cloud droplets with effective radii above 8 micron are mostly effective for the rain formation. Again, a threshold value of 5 is obtained for cloud optical depth for precipitation formation. There also exists a positive relation of accumulated rainfall with cloud effective radius and cloud optical depth as observed at a particular location.