Future changes in extremes across China based on NEX-GDDP-CMIP6 models

Abstract

Abstract In this study, we assess the performance of the NASA Earth Exchange Global Daily Downscaled Projections’ (NEX-GDDP) CMIP6 models in simulating extreme climate indices over China and its eight subregions. Future projections of these indices for the period 2081–2100 are investigated under three scenarios. The findings suggest that the models reasonably reproduce the spatial patterns of absolute indices related to extreme temperature, except for the percentile indices. There are larger model spreads for warm days, heat wave frequency, and heat wave days. The models effectively capture the climatological distributions of most extreme precipitation indices, although limitations are observed for consecutive wet days (CWDs) and extremely heavy precipitation days (R50). Among the subregions, the multimodel ensemble performs best in simulating the spatial patterns of extreme climate indices in Northeast China. Compared to CMIP6 models, NEX-GDDP-CMIP6 exhibits enhanced capability in simulating the spatial distributions of extreme climate events, displaying higher spatial correlation coefficients and improved model consensus. Consistency among different models is high for temperature extremes, with northwest, southwest and southern regions projected to experience the most significant increase during the 21st century. Precipitation extremes are also projected to increase, except for consecutive dry days (CDDs). Inconsistencies among models are observed, particularly for the CDD and CWD indices in the whole country and for the total precipitation in the southern region. However, with higher emission scenarios, consistency improves for other precipitation indices. The extreme precipitation indices in Southwest, East and South China exhibit the most substantial and noticeable increases.