近50年黄河流域夏季降水的时空变化及其与东亚副热带西风急流的关系

Spatial and Temporal Changes of Summer Rain in the Yellow River Basin and Its Relation to the East Asia Subtropical Westerly Jet in Last 50 Years

基于1959-2008年黄河流域92个测站降水量和NCEP/NCAR再分析资料,研究黄河流域夏季降水的时空变化和周期特征,及其与东亚副热带西风急流的关系。结果表明,黄河流域夏季降水呈现由东南向西北逐渐减少的分布特点,其夏季降水的异常空间型主要有3种:全流域一致型,东南多(少)西北少(多)型,西南多(少)东北少(多)型。当夏季东亚副热带西风急流中心异常偏北(南)时,同期黄河流域中上游地区降水偏多(少),下游降水偏少(多);东亚副热带西风急流中心异常偏东(西)时,黄河流域上游降水偏多(少),中下游地区降水偏少(多)。

Based on the precipitation data of 92 stations of the Yellow River Basin and NCEP / NCAR daily reanalysis data,the spatial and temporal changes and period characteristic of summer rain in the Yellow River Basin and its relation to the east Asia subtropical westerly jet in last 50 years has been analyzed. The spatial anomaly features of summer precipitation in the Yellow River Basin are mainly three kinds: wet or dry in all area pattern,wet(or dry) in southeast and dry(or wet) in northwest pattern,wet(or dry) in southwest and dry(or wet) in northeast pattern. When anomalies north of the east Asian subtropical westerly jet center,more summer rainfall in the upper reaches of the Yellow River Basin and less in the low er reaches of the Yellow River Basin,when the anomalies south of the east Asian subtropical westerly jet center,the summer precipitation in the upstream region of the Yellow River Basin less than normal and the dow nstream region is above normal. Anomalies east of the east Asian subtropical westerly jet center,the summer rainfall of the Yellow River Basin in upstream region above normal and less in the middle and low er reaches of the Yellow River,when anomalies west of the east Asian subtropical westerly jet center,the middle and low er reaches of the Yellow River Basin precipitation above normal,the upper reaches of the Yellow River Basin rainfall less than normal.