Spatiotemporal variability of weather extremes over eastern India: evidences of ascertained long-term trend persistence and effective global climate controls

The present study acknowledged climate variability induced periodic variation in localized extreme weather event occurrences under diverse agro-eco regions of Eastern Himalayas of India during the past five decades. The widespread rise in warm nights (TN90p; 0.31–1.67 days year−1), reduced daily rainfall intensity (SDII), and changes in other weather extremes, viz. temperature and precipitation extremes, signified clear signals on regional atmospheric warming across eastern India. The agro-ecological regions under extended Bramhaputra valley and coastal belts of south Bengal experienced the most persistent shifts in temperature extremes, while the upper Himalayan range extended from North Bengal to Arunachal Pradesh experienced the steepest decline in average daily rainfall intensity and other absolute quantitative estimates of precipitation extremes over past five decades. Together with El Niño and La Niña events, large-scale global atmospheric circulations particularly expansion of warmer Pacific Warm Pool (PWP) and changes in Atlantic Meridional Mode (AMM) contributed to the periodic dynamics in weather extreme occurrences from monthly to annual time scale over eastern India. Our findings will be useful for better understanding of regional climatology, designing, and successful implantation of location-specific suitable agricultural policies towards climate change adaptation in near future.