Evaluation of INSAT-3D-derived Hydro-Estimator and INSAT Multi-Spectral Rain Algorithm over Tropical Cyclones

Tropical cyclones or typhoons or hurricanes are basically an intense rotating circular system, characterized by intense low pressure at the center, high winds associated with intense convective cells in the wall cloud, associated heavy rains and storm surge. Tropical cyclones affect the life of millions of people around the globe. INSAT-3D is the second dedicated meteorological satellite which was launched on July 26, 2013, with two meteorological payloads: Imager and Sounder. It is placed at 83 °E over the equator in the geostationary orbit. Receiving, processing and dissemination of imageries and derived products from INSAT-3D are taken care by INSAT Meteorological Data Processing System (IMDPS), which is operational at National Meteorological Satellite Centre, India Meteorological Department, New Delhi. Currently, three satellite-derived rain estimates are generated at IMDPS, New Delhi: Qualitative Precipitation Estimate (QPE), Hydro-Estimator (HE) and INSAT Multi-Spectral Rain Estimate (IMSRA). In this study, the performance of HE and IMSRA over very severe cyclonic storm Vardah and severe cyclonic storm Mora has been evaluated with respect to GPM (IMERG). The statistical and skill score analysis is performed both over half-hourly scale with respect to various stages of cyclone genesis, intensification and weakening and on the daily scale. At the instantaneous time during half-hourly analysis, IMSRA has displayed better relation and skill with GPM (IMERG). However, during daily accumulated analysis, it is found that IMSRA tends to underestimate after a specific value. On a daily scale, HE has exhibited better skill with IMSRA.