Using observations and reanalysis data, this study investigates the interannual relationship between the winter Aleutian Low (AL) and the rainfall anomalies in the following summer in South China (SC). Results show that the winter AL is significantly positively (negatively) correlated with the SC rainfall anomalies in the following July (August). Specifically, SC rainfall anomalies have a tendency to be positive (negative) in July (August) when the preceding winter AL is stronger than normal. The winter AL-related atmospheric circulation anomalies in the following summer are also examined. When the winter AL is stronger, there is a significant anticyclonic (cyclonic) circulation anomaly over the subtropical western North Pacific in the following July (August). Southerly (northerly) wind anomalies to the west of this anomalous anticyclonic (cyclonic) circulation increase (decrease) the northward moisture transportation and contribute to the positive (negative) rainfall anomalies over SC in July (August). This study indicates that the AL in the preceding winter can be used as a potential predictor of the rainfall anomalies in the following July and August over SC.
本文利用观测资料和再分析资料，研究了冬季阿留申低压和后期华南夏季降水之间的年际关系。结果表明，冬季阿留申低压和后期华南7月份（8月份）降水存在显著的正（负）相关关系。当前冬阿留申低压偏强时，华南7月份（8月份）降水容易偏多（少）。这是因为当前冬阿留申低压偏强时，后期7月份（8月份）在副热带西北太平洋有一个异常反气旋（气旋）性环流，该反气旋（气旋）西侧的偏南（北）风使得向北输送到华南的水汽增加（减少），从而导致华南降水偏多（少）。本文的研究结果表明，前冬阿留申低压可以作为华南夏季7月份和8月份降水异常的一个潜在预报因子。