Model assessments and future projections of spring climate extremes in China based on CMIP6 models

This study reports model assessments and future projections of the Coupled Model Intercomparison Project Phase 6 (CMIP6) models in simulating spring climate extremes over China and its eight subregions. The CMIP6 models are generally able to capture mean climate extremes and trends but have common deficiencies such as topography-related cold-temperature biases and precipitation overestimations. The CMIP6 multimodel median ensemble (MME) typically outperforms the individual models in simulating spring climate extremes. However, in terms of the model performance metrics, almost no models show better performance in reference to all indices compared to the observations. Furthermore, we investigate the future changes in these indices on national and regional scales over the near-term (2021-2040), mid-term (2041-2060), and long-term (2081-2100) future periods relative to the 1995-2014 reference period under four Shared Socioeconomic Pathway (SSP) scenarios: SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. By the end of the 21st century, wet and warm extreme climate events are projected to increase, particularly in northern and western China. While dry and cold extreme climate events are projected to decrease, particularly in southern China. Additionally, the future projections of both temperature and precipitation extreme indices are remarkable under the high-greenhouse-gas (GHG)-emission scenarios, with the projected changes exceeding those expected under the low-GHG scenarios.