Copula based Assessment of Climate Extremes across India: Past and Future

Climate change significantly influences the global hydrological cycle and consequently affects climatic extremes. The present study is focussed upon varying patterns of climate extremes using observed daily precipitation (1989-2019), daily temperature from Global Meteorological Forcing Dataset (GMFD) (1985-2016) and simulated daily meteorological forcing data (2025-2055 and 2065-2095) of 21 GCMs attained from the statistically downscaled dataset, NEX-GDDP (NASA Earth Exchange Global Daily Downscaled Projections) under RCP4.5 and RCP8.5 scenario across India. The copula method was employed to estimate the joint return period based on different climate extreme indices. Here, we found that R20, R95p and CWD attain an increasing trend and CDD mostly shows a decreasing trend in major segments of country in future. Based upon the 10-year joint return periods (1989-2019), it is found that parts of north-western, north-eastern, southern, western region and Western Ghats are highly prone towards floods and a large portion of the country is susceptible to co-occurrence of floods and droughts. Moreover, the study shows that many regions with less vulnerability towards precipitation extremes would become more vulnerable in future. Furthermore, TXx, TNx, TX90p, TN90p, TNn and TXn are found to be significantly increasing in future except increasing during 2065-2095 under RCP4.5 predominantly across the country. And, TX10p and TN10p follows a significantly decreasing trend in future across the except exhibiting a decreasing trend during 2065-2095 under RCP4.5, throughout the country. With the projected increase in hot days/nights, the frequency of concurrence of extreme number of hot days (TX90p) and nights (TN90p) within a year would increase in the future across the country. The present study provides useful information on the regional distribution of climate extremes and how they might change in the future. This information can further contribute to facilitate an effective planning strategy to improve resilience towards climate extremes.