Performance of regional climate model in simulating Indian summer monsoon over Indian homogeneous region

The performance and validation of regional climate model (RegCM-4.3) simulation of Indian summer monsoon rainfall (ISMR) have been conducted with a futuristic view of climate change study with the convective parameterization schemes (CPSs) over the different homogeneous regions of India. The dynamical downscaling of RegCM-4.3 has been done over South Asian Coordinated Regional Climate Downscaling Experiment (CORDEX) domain with the lateral boundary forcing provided by ERA-Interim at 50-km horizontal resolution. The interannual and seasonal variability of ISMR over India and its different homogeneous region has been done by comparing model-simulated rainfall with observed rainfall dataset of India Meteorological Department (IMD) during 1986–2010. The analysis includes the performance and validation of RegCM-4.3 in capturing regionalized rainfall of Indian subcontinent. The analysis is done over five homogeneous regions of India, i.e., northwest India (NWI), R1; northcentral India (NCI), R2; west peninsular India (WPI), R3; eastern peninsular India (EPI), R4; and southern peninsular India (SPI), R5 during 1986–2010. The Grell CPSs simulate monsoon rainfall reasonably good over northwest India. Over northcentral India, predictability/simulation of Kuo and Grell are best performing parameterize scheme of RegCM-4.3. The western and eastern peninsular parts of India, i.e., R3 and R4 simulation of Emanuel and Mix99 schemes, are better respectively. The region consisting southern peninsular along with Western Ghats shows Tiedtke scheme, as the best simulated scheme of RegCM-4.3. The overall diversification of simulation depending upon the topographical difference of Indian subcontinent causes the regionalize difference in simulating monsoon rainfall over the Indian subcontinent.