Long-term changes in the East Asian summer monsoon (EASM) lifecycle since 1979 are analyzed based on observational datasets and historical simulations of the Coupled Model Intercomparison Project Phase 6 (CMIP6). According to the observation, the active and break phases of EASM have intensified resulting in a shorter but stronger rainy season, followed by a longer dry spell. This intensification in the active-phase precipitation is accompanied by increased lower tropospheric southwesterly wind and subsequent convergence of water vapor flux. These changes are accompanied by the widely reported westward extension of the North Pacific Subtropical High, which has been associated with the warming climate. CMIP6 models generally underestimated the observed intensification of the EASM lifecycle and the monsoon precipitation. However, some of the models did simulate the intensified EASM lifecycle similar to that observed. The result highlights the reasonable performance on EASM shown in...

中文翻译：

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基于观测和CMIP6的东亚夏季风生命周期强化

基于观测数据集和耦合模型比较项目第6阶段（CMIP6）的历史模拟，分析了1979年以来东亚夏季风（EASM）生命周期的长期变化。根据观察，EASM的活动和休息阶段加剧，导致雨季缩短但更强，随后的干旱期更长。活跃期降水的加剧伴随着对流层较低的西南风的增加以及随后水汽通量的收敛。这些变化伴随着北太平洋副热带高压向西扩展的广泛报道，这与气候变暖有关。CMIP6模型通常低估了观测到的EASM生命周期加剧和季风降水。然而，一些模型确实模拟了与观察到的相似的强化EASM生命周期。结果突出显示了如图所示的EASM的合理性能。