The East Asian summer monsoon precipitation has exhibited a well-known “southern China flood and northern China drought” pattern in recent decades. The increase in aerosols and warming oceans are recognized as two important forcings that control of the precipitation trends over East Asian land. However, in this study, by using large ensemble simulations from the CMIP6 Polar Amplification Model Intercomparison Project (PAMIP), the influence of Arctic amplification, serving as the prominent feature of global warming, is very important in modulating the East Asian summer precipitation pattern, which is comparable to the influence of sea surface temperature (SST). Additionally, the observed “southern China flood and northern China drought” pattern only exists in July and August, whereas a triple pattern with the precipitation positive anomaly center over Middle China occurs in June. These patterns are closely connected with the regional differences in Arctic sea ice loss from June to July, affected through both the Rossby waves propagating in a weaker westerly jet and the decrease in the large-scale meridional thermal contrast in a warming climate.

近几十年来，东亚夏季风降水呈现出众所周知的“南涝北旱”格局。气溶胶的增加和海洋变暖被认为是控制东亚陆地降水趋势的两个重要强迫因素。然而，在本研究中，通过使用CMIP6极地放大模式比对项目（PAMIP）的大型集合模拟，北极放大的影响作为全球变暖的显着特征，对于调节东亚夏季降水格局非常重要，这与海面温度（SST）的影响相当。另外，观测到的“南涝北旱”格局只存在于7、8月份，而以华中地区降水正距平为中心的三重格局则出现在6月份。这些模式与六月至七月北极海冰损失的区域差异密切相关，受到在较弱的西风急流中传播的罗斯贝波和气候变暖时大规模经向热力对比减小的影响。