Climate impact on Extremes and Persistent events of Rainfall over the North-East India Summer Monsoon Rainfall during the last century

World's highest rainfall occurs over north-east India (NEI) during boreal summer and is characterized by large spatial inhomogeneity. Quantification of global warming impact on the north-east India rainfall (NEIR) is, therefore, a crucial factor for the region's food security and delicate biodiversity. Daily rainfall datasets for the past century (from year to year) derived from a network of 24 well distributed monitoring stations spread across low to high rainfall areas of NEI have been used in this study.From previous study, we have quantified the climate change impact on rainfall extremes. This study investigated the trends of various rainfall events with different consecutive days (such as 1-3 day, 4-7 day, etc.) and their contribution to seasonal rainfall during summer monsoon. To study the unbiased trend, we have separated out the oscillatory modes of variability from the secular trend using the Improved Ensemble Empirical Mode Decomposition (ICEEMD). 1-3 days of persistent rainfall over NEI has shown an increasing trend amongst all other persistent rainfall series. In addition, our previous results showed a strong increasing trend for both frequency and intensity rainfall events and extremes. The frequency of occurrence of daily extremes (exceeding the 99.5th percentile) over NEI showed an increasing trend at + 51 ± 4.99 %/K while the intensity increased at + 12.5 ± 3.32 %/K over the past century. The rate of increase of these events is observed to be faster compared to the Clausius-Clapeyron scaling. Therefore, our results imply that with climate warming, these isolated mesoscale rainfall events will dominate over the NEI and hence can cause catastrophic climate induced hydrological disasters in the near future.