Possible future projection of Indian Summer Monsoon Rainfall (ISMR) with the evaluation of model performance in Coupled Model Inter-comparison Project Phase 5 (CMIP5)

The Indian Summer Monsoon (ISM) is crucial for agriculture and water resources in India. The large spatial and temporal variability of Indian Summer Monsoon Rainfall (ISMR) leads to flood and drought especially over northern plains of India, so quantitative and qualitative assessment of future projected rainfall will be important for policy framework. Evaluation of models performance in simulating rainfall and wind circulation of the Historical experiment (1961-2005) and its future projected change in RCPs (2006-2050) 4.5 and 8.5 in CMIP5 are carried out. In the Historical experiment, the model simulated rainfall is validated with observed rainfall of IMD (1961-2005) and GPCP (1979-2005) and only six (6) models BCC-CSM1.1(m), CCSM4, CESM1(BGC), CESM1(CAM5), CESM1(WACCM), and MPI-ESM-MR are found suitable in capturing ISMR and JJAS wind circulation at 850 & 200 hPa as in NCEP reanalysis, which shows anticyclonic circulation over Arabian Sea at 850 hPa and cyclonic circulation at 200 hPa along with excess and deficit rainfall over monsoon regions of NWI, NEI, WCI, CNI and PI at 99% & 95% confidence levels. Future projected change of JJAS wind shows anticyclonic circulation over Arabian Sea at 850 hPa and cyclonic circulation around 40° N,70°E-90°E at 200 hPa which may be a possible cause of changes in JJAS rainfall over Indian regions.