LAUSR

Using a high-resolution precipitation dataset, the present study detected that the mountainous area of central China (MACA) is a hotspot of ENSO’s impact on the summer rainfall variability. Further analysis suggests that both ENSO and atmospheric forcing make contributions to the summer rainfall variability in MACA. The dominant rainfall-related SST mode features as a seasonal transition from an El Niño-like warming in the preceding winter to a La Nina-like cooling in the following autumn, and it explains about 29% of the total variance of the rainfall during 1951–2018. It indicates that ENSO with a rapid phase transition is responsible for inducing summer rainfall anomalies in MACA. Besides, an upper-level circumglobal wave mode in the Northern Hemisphere during summer also explains about 29% of the summer rainfall variance. Contributions of both the SST and the atmospheric modes have experienced interdecadal changes. The influence of the SST mode gradually increases and plays a dominant role in the recent decades, suggesting that ENSO with a rapid phase transition becomes more important for rainfall prediction in MACA. 利用一个高分辨率降水资料, 本文发现中国中部山区是 ENSO 影响中国夏季降水变率的热点区域. 利用偏最小二乘回归方法, 我们揭示与中国中部山区夏季降水年际变化联系最紧密的热带太平洋海温模态是一个从前期冬季 El Niño 型暖海温异常到后期秋季 La Nina 型冷异常的转换模态. 这种海温模态解释了 1951–2018 年中国中部山区夏季降水 29% 的年际变化方差. 该结果表明与普通 ENSO 事件相比, 位相快速转变的 ENSO 事件对该地区夏季降水有更大的影响. 除开热带海温外, 北半球夏季环球遥相关波列对中国中部山区夏季降水也有显著影响. 海洋模态和遥相关波列对该地区夏季降水影响存在着年代际变化. 最近三十年来, 太平洋海温模态对该地区夏季降水影响越来越强.