Effect of vertical wind on rain drop size distributions in the boundary layer

The height profiles of rain drop size distribution have been studied to understand the role of the vertical drift velocity in the atmospheric boundary layer in changing drop number densities at different heights during convective rain events. The observations with a micro rain radar (MRR) over Kolkata, a tropical location, of rain events pertaining to the period of 2011-15 have been analyzed. A prominent dip in radar reflectivity profiles has been observed near the boundary layer at high rain rates. The results indicate break-up of rain drops into smaller sizes around 2 km height due to strong downdrafts during convective events.