CMIP6 Model-Projected Future Changes in Extreme Precipitation over Central Asia in the 21st Century

Based on the numerical simulations provided by the latest 14 coupled models of the sixth phase of the coupled model intercomparison project (CMIP6), the spatial and temporal distribution characteristics of extreme precipitation over Central Asia (CA) and its relationship with regional climate warming in the middle and late 21st century under two shared socioeconomic paths (SSP2-4.5 and SSP5-8.5) are analyzed in this study. The results show that most CMIP6 models can essentially simulate the spatial distribution characteristics of observed precipitation climate states from 1979–2018. However, the model simulations underestimate the observations in the southwest and southeast of CA and overestimate the observations in northern and southern CA. Compared with the historical period (1981–2010), the precipitation intensity at the end of the 21st century (2071–2100) increased by 0.54 mm/10 a and 2.4 mm/10 a under the scenarios of SSP2-4.5 and SSP5-8.5, respectively, while the frequency of extreme precipitation events increased by 5%–7% and 6%–10%, respectively, particularly in the high-altitude mountains in central and southern regions. The signal-to-noise ratio of the predicted precipitation intensity and frequency in northeast CA to the north of the Tianshan Mountains is more reliable. Climate warming will have an obvious regulatory effect on the frequency of extreme precipitation events in CA. Under the scenarios of SSP2-4.5 and SSP5-8.5, a temperature increase of 1 K increased the frequency of extremely heavy precipitation events by approximately 7 and 9 days and the maximum continuous dry days by approximately 3 and 6 days, respectively.