Increased intra-seasonal variability in Indian summer monsoon precipitation in a warming climate

The characteristics of Indian summer monsoon (ISM) precipitation have been changing in a warming climate. We examined the intra-seasonal variability of daily mean ISM rainfall over central India in 20 CMIP6 models. The daily precipitation variance is found to have increased in the last 20 years of SSP585 runs compared to the 1981 – 2000 period of historical all forcing simulations. The mean ISM precipitation also shows an increase in the same period. The future changes in seasonal mean precipitation and the intra-seasonal variance in daily precipitation with respect to the historical period are scaled with the corresponding change in the surface temperature over the ISM domain. The changes in the seasonal mean precipitation do not show any significant relationship with the surface temperature change. However, the changes in the daily variance of ISM precipitation scale linearly with the changes in temperature. These results suggest that the ISM precipitation will become more erratic in a warming environment.