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

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.