Analysis of Spatial-temporal Variation Characteristics and Causes of Precipitation over Shanxi Province in Autumn

Based on autumn precipitation data from 1961 to 2021 in Shanxi Province， NCEP/NCAR reanalysis data， and sea surface temperature data， the spatial-temporal variation characteristics and cause diagnosis of autumn precipitation in Shanxi Province were analyzed and discussed by using EOF analysis， correlation analysis and regression analysis.The results show that the autumn precipitation in Shanxi Province was relatively high before the mid-1970s， but decreased afterwards， and began to increase again in the mid-2000s.Further exploration of the causes of this interdecadal variation from the perspective of atmospheric circulation reveals that， during periods of excessive precipitation， the 200 hPa latitudinal wind field is located in the north of the East Asian westerly jet， which is beneficial for enhancing the upward movement in Shanxi； The 500 hPa geopotential height field exhibits a significant “+-+” anomaly distribution in the Europe and Asia region， which is conducive to the southward eruption of high latitude cold air； The 850 hPa wind field is conducive to the transport of low latitude water vapor to Shanxi， and under such high and low altitude circulation configuration， it is conducive to an increase in precipitation in Shanxi.At the same time， there is a close relationship between autumn precipitation and sea surface temperature anomaly in Shanxi.When the sea surface temperature in the central North Pacific is higher and in the tropical Middle East Pacific is lower from March to May， the autumn precipitation in the southern part of Shanxi is prone to behigher.