Precipitation Extremes over central India - Past, Present, and Future: Regional Earth System Model Perspective

In the warming climatic scenario, Indian Summer Monsoon (ISM) rainfall and its extremes, especially on the local scale, is expected to alter that profoundly impact the societal, environmental, and economic well-being of the million people residing in central India. Therefore, understanding ISM mean and extreme rainfall for the past, current, and reliable projection are crucial for effective adaptation strategies, remains a major scientific challenge. The Regional Earth System Model (ROM) driven by MPI-ESM-LR over the CORDEX-South Asia framework under the RCP8.5 scenario at a finer horizontal resolution of 0.22° was used to investigate the future of mean and extreme precipitation over central India. The ROM’s performance is demonstrated with respect to observed precipitation data from India Meteorological Department. ROM shows its skill in capturing the mean and extreme precipitation (PEs) during the ISM along with its intraseasonal variability.  Further, an effort is made to investigate the projected changes in precipitation extremes (PEs) during the mid-future (MF; 2040-2069) and far-future (FF; 2070-2099) concerning the historical period (1969-2000) under the RCP8.5 scenario. The results highlight, two-fold rise in the frequency of PEs is likely to be expected by the end of the century. In addition to this, the study also projects the intraseasonal variability, i.e., the active and break spells that crop up during the peak monsoon months (July and August). The active spells were found to be more persistent in the projected period. The changes in the different precipitation events are subjected to strong cyclonic circulation, reduced vertical wind shear, and enhanced moisture transport.