Assessment of CMIP6 models for precipitation simulation and prediction of future extreme precipitation in China

This article evaluates the performance of 20 models from the Coupled Model Intercomparison Project phase 6 (CMIP6) in simulating precipitation over China from 1981 to 2014, with a focus on interannual and seasonal variations. The evaluations results varying levels of performance among the models, with CNRM-CM6-1 identified as the best model for simulating summer extreme precipitation. Based on CNRM-CM6-1, future projections of extreme precipitation in China have been conducted. The results indicate that under the SSP245 scenario, maximum rainfall is projected to increase primarily in southern China and southeastern Tibet. Across all extreme indices, a distinct spatial pattern emerges, characterized by a "Southeastern High–Northwestern Low" distribution throughout the study period. Under the SSP585 scenario, the spatial distribution of extreme indices mirrors that of the SSP245 scenario. However, in the late 21st century, peak values of extreme rainfall indices under the SSP585 scenario are significantly higher than those observed under the SSP245 scenario. For total precipitation, the differences between the SSP585 and SSP245 scenarios are not significant prior to 2070. However, for other indices (SDII, RX1day, R95p), the differences between the two scenarios remain minimal before 2050. After 2050, extreme precipitation indices under the SSP585 scenario become significantly higher than those under the SSP245 scenario.