Recent heterogeneous warming and the associated summer precipitation over eastern China

The recent heterogeneous warming and the associated summer precipitation over eastern China are investigated in this study. In 1990-1999, there exist warming over northwestern Pacific and cooling over eastern equatorial Pacific, which can be quantified by temperature gradient index (TGI). Positive and negative cases are chosen based on TGI. In positive cases, a southern flood and northern drought summer rainfall pattern dominates over eastern China. The atmospheric circulations show that associated with the southward receding of western Pacific subtropical high (WPSH), ascending motion accompanied with more water vapor exists over southern China. Furthermore, cold-warm air activity affected by weakened East Asian subtropical jet (EASJ) and strengthened East Asia polar front jet (EAPJ) may also be responsible for this rainfall anomaly pattern. In negative cases, significant positive Meiyu-like rainfall anomaly concentrated over Yangtze Huaihe River Basin (YHRB). Associated with the northward shift of WPSH, more water vapor is transported to YHRB. Additionally, the enhanced ascending motion over YHRB may be related with the northward shift of the EAPJ and westward shift of the EASJ. The results reinforce the notion that the configuration of EASJ and EAPJ in both intensity and position has large impacts on the precipitation variations over eastern China.