Microphysical Characteristics of Cyclonic Rainfall: A GPM-DPR Based Study Over the Arabian Sea

The precipitation characteristics of tropical cyclone (TC) formed over the Arabian Sea during the onset phase of the Indian summer monsoon (i.e., late-May and early-June months) and in the post-monsoon season were investigated during the period from 2014 to 2021 using the Global Precipitation Measurement (GPM) satellite level 2 V07 data. For the cyclonic precipitation, 2-D frequency distribution between liquid water content (LWC) and non-liquid water content, that is, ice water content (IWC) shows significant variation with the rain type and season. A large proportion of rain droplets are within the LWC (IWC) range of 0-800 (0-350) g/m2 for the stratiform precipitation of TCs in both seasons. The average value of the mass-weighted mean diameter (Dm), for the stratiform and convective precipitation at 2 km above the mean sea level in the monsoon (post-monsoon) season is 1.29 (1.27) mm and 1.47 (1.31) mm, respectively. A gradual decrease in the normalized intercept parameters (Nw) is found to occur with an increase in Dm, irrespective of cloud type and season. There is an enormously high concentration of supercooled liquid and ice particles observed above the melting layer during the convection precipitation in both seasons. In the stratiform cyclonic cloud, the contribution of the collision-coalescence and breaking-up process is about 36.62% (47.58%) and 52.52% (41.52%) during the monsoon (post-monsoon) season. However, the collision-coalescence process (63.45% in monsoon and 70.2% in post-monsoon) is acting as dominating microphysical process in the convective precipitation as compared to the break-up process. Tropical cyclone, a natural hazard causing significant economic loss and human life in the coastal region. As there is substantial improvement in forecast skill of the tropical cyclone movement and region of landfall, while prediction of the tropical cyclone's intensity is still challenging. The knowledge about the precipitation characteristics of the cyclonic cloud is helpful to improve the intensity of the tropical cyclone through the parameterization in the numerical models. For this, we study the microphysical characteristics of the tropical cyclone formed in the Arabian Sea. The cyclonic rainfall characteristics were investigated over the Arabian Sea using Global Precipitation Measurement-dual-frequency precipitation radarTropical cyclone formed during the monsoon onset phase, characterized with high fraction of intense rain rate, strong reflectivity and bigger raindropsThe contribution of collision-coalescence (break-up) is significantly high in convective (stratiform) rain