This study examines different precipitation events (PEs) for 1951–2015 using 0.25°×0.25° India Meteorological Department data and diagnoses their associated dynamical and thermodynamical processes during the summer monsoon season over India using ERA5 reanalysis. Our results reveal a significant decreasing trend of mean precipitation, rain event days, light rain events and moderate rain events (MREs) for the overall period. However, the frequency of heavy rain events (HREs) and very heavy rain events (VhREs) has increased. Pettit's test for all PEs and mean precipitation indicates the changes nearly in the 1970s. In spite of this, the rate of change of LREs, MREs and HREs was increased by 17, 91 and 114% after the observed change point with respect to before change point, while for VhREs, this was reduced by 50%. These decreasing (increasing) trends of LREs (VhREs) are attributed to both thermodynamical and dynamical conditions. LREs are driven mainly by convective precipitation having a contribution of ~79%, whereas large‐scale precipitation contributes ~56% to the VhREs. It is observed that the dynamical (thermodynamical) effect largely drives VhREs (LREs) PEs. During VhREs, stronger moisture‐laden low‐level jet (LLJ) from the surrounding ocean converges over the Indian land mass, facilitating favourable conditions for enhanced precipitation. Simultaneously, weaker convective available potential energy (CAPE) during the VhREs underlines inconstancy in thermodynamics. Stronger LLJ and weaker CAPE during the extremes and vice versa for LREs highlight the dominance of the dynamical (thermodynamical) effect during the VhREs (LREs).

Climate change is leading to alterations in the dynamic climate systems worldwide. The Indian Summer Monsoon (ISM) is one such climate system that supports more than a billion population and drives the Indian economy. The ISM is governed by intra-annual to inter-decadal variabilities. However, anthropogenic climate change is inducing unprecedented transformations in this natural system, such as the increased probability of precipitation extremes (dry and wet), changes in their frequency and duration, spatial variabilities, etc. These changes, in turn, impact the human and ecological systems due to droughts, floods, and prolonged dry spells. In such scenarios, it is essential to gain insights into the projected precipitation extremes (PEs) changes. The velocity of climate change (VoCC) or climate velocity can help us project the temporal and spatial shift of PEs especially in terms of their intensities. VoCC is a regional metric of climate change, defined as the ratio of the temporal gradient of a particular climate variable (temperature, precipitation, humidity, etc.) with its spatial gradient, and the resultant units are in km/year. In the current study, the climate velocities of 50th, 75th, 95th, 99.5th, and 99.9th percentiles of precipitation for the JJAS season are projected over India and its different biogeographic zones for the four time periods: historical (1976-2000), near-future (2025-2049), mid-future (2050-2074) and far-future (2075-2099). ROM, a regional earth system model over the CORDEX-South Asia domain was used in the study. It was found that ROM showed a better resemblance with observation in simulating the PEs over other regional climate models (RCMs). The intense rainfall (95th percentile: R95) is expected to be enhanced over most of the study region in mid future and far future. Interestingly, very intense rainfall (99.9th percentile: R99) showed robust increases in the near and mid-future as compared to the far future. The PEs also exhibited higher velocities as compared to the median values. The detailed results will be discussed further in the presentation.

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.