Investigation of the Evolution of the Height Profiles of Rain Microphysical Parameters: A Seasonal Comparison at a Tropical Location

The present study reveals the role of atmospheric instabilities towards varied raindrop size distribution scenarios below and above the atmospheric boundary layer over a tropical location, Kolkata ($22.57^{\mathrm{o}}$ N, $88.37^{\mathrm{o}}$ E), India near the land-sea boundary. The investigation has been undertaken from a set of experimental measurements which includes impact type disdrometer, Ka-band micro rain Doppler radar, multi-frequency radiometer, along with the outputs of ERA-5 re-analysis data. A detailed statistical and case study analysis revealed that significant drop break-up above the atmospheric boundary layer induces deviations in the usual power law relationship exhibited by rain rate (R) and mass-weighted mean drop diameter $(D_{m})$. The enhanced drop break-up phenomenon is seen to be more significant during the pre-monsoon season compared to the monsoon season.