Hydrometeor categorization in stratiform and convective precipitation systems over a tropical coastal region

The stratiform and convective precipitation regions are examined in three phases (Phase 1 to Phase 3) during the Indian summer monsoon season 2022 using C-band radar observations over Thiruvananthapuram, India. Nearly 72% of the pixels are identified with stratiform precipitation region and the radar reflectivity value peaks near the melting layer in all phases of the monsoon. The convective precipitation accounts for ∼ 28% of the precipitating area, and radar reflectivity profiles peak near 2 km height. An estimation of convective and stratiform precipitation amounts using Doppler Weather Radar (DWR) and Global Precipitation Mission (GPM) measurements shows the ratio is 32–68% over the study region. A fuzzy-logic-based hydrometeor identification method is implemented using the radar polarimetric variables, which shows stratiform (convective) precipitation is dominated by drizzle (rain) hydrometers near the surface levels. Above the melting layer, the aggregates and crystals are the dominant hydrometeors types in both stratiform and convective precipitation. The WRF simulation using the Thompson and SBM scheme for a heavy precipitating event (70 mm) on 17th October 2022 shows that the graupel and snow mixing ratio above the melting layer contributed to the precipitation. The simulated hydrometeor properties differ considerably between the SBM and bulk microphysics, partly due to variations in their ice particle size distributions, as revealed by comparisons with polarimetric measurements.