Overestimation of Interannual Temperature Variability Over China by CMIP6 Simulations: The Role of Snow Cover and Cloud Representation

Abstract Climate models have overestimated the interannual variability in surface air temperature over China for decades. This issue has been widely discussed but without a clear attribution. Using the latest sixth phase of the Coupled Model Intercomparison Project models, we investigate the relevant physical processes contributing to the greater simulated temperature variability in China based on the atmospheric energy budget. The results show that a strong overestimation exists in Northwest, Southwest, North, Central, and East China, which is dominated by the poor reproduction of snow cover and cloud. Exaggerated snow cover variability enhances the fluctuations of the clear‐sky shortwave radiation reflected back to the top‐of‐the‐atmosphere, inducing positive biases in the Tibetan Plateau, North, Central, and East China. This snow‐albedo feedback also explains why the overvalued temperature variability in winter and spring is larger than that in summer and autumn. The shortwave cloud radiative forcing is also responsible for the overvalued temperature fluctuations in North and Northwest China, as well as south of 30°N in Central and East China. The contributions of snow‐albedo feedback and shortwave cloud radiative forcing vary with seasons and regions. Additionally, the overvalued tropospheric temperature variability leads to the temperature variability overestimation in Northwest China.