The present study employed the latest high-resolution regional climate model (RegCM4), driven by MPI-ESM-MR boundary conditions from the CORDEX-CORE South Asia framework to investigate the possible projected changes in the mean and intra-seasonal variability of the Indian summer monsoon (ISM) precipitation and their associated dynamics during near future (NF; 2041–2060) and far future (FF; 2080–2099) with respect to the historical period (1995–2014) under RCP8.5 scenario. Extensive evaluation analysis indicates that the RegCM4 is fairly able to simulate the spatial–temporal distribution of the observed mean and extreme precipitation, low-level jet, and intra-seasonal variability i.e. active and break composite patterns of the precipitation anomalies over India during the historical period. A substantial decline in the projected precipitation during ISM is estimated over central and northwest India in NF (about 10–30%) as well as in FF (upto 50%), which may be attributed to the weakening and northward shift of low-level winds. The occurrences as well as the intensity of the extreme precipitation events are expected to increase over India in the future. The precipitation during the projected active spells will escalate over the monsoon core region. This is supported by the decrease in sea level pressure over land, which favors the winds to transport more moisture from the adjoining seas for the formation of convective clouds, which is partly indicated through the decline in net surface longwave radiation. On the other hand, the precipitation intensity during the projected break spells is expected to further decrease in the future.

本研究采用了最新的高分辨率区域气候模型（RegCM4），该模型是由CORDEX-CORE南亚框架的MPI-ESM-MR边界条件驱动的，以调查印度洋平均和季节内变异性的可能预测变化。在RCP8.5情景下，相对于历史时期（1995-2014），夏季风（ISM）的降水及其在近期（NF； 2041-2060）和远期（FF； 2080-2099）的动态变化。广泛的评估分析表明，RegCM4相当有能力模拟观测到的平均和极端降水，低空急流和季节内变化的时空分布，即印度在整个历史时期内降水异常的活跃和断裂复合模式。时期。估计ISM期间印度中部和西北部NF（约10％至30％）以及FF（最高50％）中预计降水的大幅下降，这可能是由于低空水平减弱和向北移动风。预计未来印度各地的极端降水事件的发生率和强度将增加。预计的活跃期期间的降水将在季风核心区域上空升级。这是由于陆地上海平面压力的降低而得到支持的，这有利于风从相邻海域输送更多的水分以形成对流云，这在一定程度上通过净表面长波辐射的下降来表明。另一方面，预计在未来的间歇期降雨强度会进一步降低。