The trends of extreme precipitation events during the Indian summer monsoon measured by two different indicators have been analyzed for the period of 1901–2020, covering the entire India in 9 regions segregated by a clustering analysis based on rainfall characteristics using the Indian Meteorological Department high-resolution gridded data. In seven regions with sufficiently high confidence in the precipitation data, 12 out of the 14 calculated trends are found to be statistically significantly increasing. The important climatological parameters correlated to such increasing trends have also been identified by performing for the first time a multivariate analysis using a nonlinear machine learning regression with 17 input variables. It is found that man-made long-term shifting of land-use and land-cover patterns, and most significantly the urbanization, play a crucial role in the prediction of the long-term trends of extreme precipitation events, particularly of the intensity of extremes. While in certain regions, thermodynamical, circulation, and convective instability parameters are also found to be key predicting factors, mostly of the frequency of the precipitation extremes. The findings of these correlations to the monsoonal precipitation extremes provides a foundation for further causal relation analyses using advanced models.

<p class="western" lang="en-US">The urban areas can modify the local and regional climate through various processes. They can indeed modify the water cycle and precipitations, either through the modification of land-use, or through effects induced by the emissions of anthropogenic aerosols. The thermodynamical perturbations induced by the presence of urban land-use, including the urban heat island effect, are known to induce rainfall modification due to perturbation of the flow and enhancement of the convective activity. However, this impact has yet to be clarified in a large scale, highly energetic system like the Asian Monsoon system. Using the high resolution meso-scale atmospheric model Meso-NH, we investigated the impact of urban land-use on the precipitation during the Indian Summer Monsoon, including the influence on extreme events. The results of this study will be presented and discussed.</p>

<p>The South Asian monsoon system impacts the livelihoods of over a billion people. While the overall monsoon rainfall is believed to have decreased during the 20<sup>th</sup> century, there is a good agreement that the extreme precipitation events have been rising in some parts of India. As an important part of the Indian population is dependent on rainfed agriculture, such a rise in extremes, along with resulting flood events, can be all the more problematic. Although studies tend to link this rise in extreme events with anthropogenic forcing, some uncertainties remain on the exact causes. In order to examine the correlation between anthropogenic forcings and the different trends in extreme events, we have analyzed the high-resolution daily rainfall data in the past century delivered by the Indian Meteorological Department alongside several other economic and ecological estimates. The results from this analysis will be presented in detail.</p>

<p>The trends of extreme precipitation events during the Indian summer monsoon measured by two different indicators have been analyzed for the period 1901-2020, covering the entire India in 9 regions segregated by a clustering analysis based on rainfall characteristics using the Indian Meteorological Department high-resolution gridded data. The important climatological parameters correlating to such increasing trends have also been identified by performing for the first time a multivariate analysis using a nonlinear machine learning regression with 17 input variables. It is found that man-made long-term shifting of land-use and land-cover patterns, and most significantly the urbanization, play a crucial role in the prediction of the long-term trends of extreme precipitation events, particularly of the intensity of extremes. To further study this urbanization impact, a regional cloud-resolving model has been used to examine causal relation between drastic long-lasting change brought by urbanization and extreme precipitation events. The preliminary results will be presented.</p>