Abstract:
Based on the precipitation data of 72 national meteorological stations in Shanxi province,monthly mean reanalysis data of NECP/NCAR and UKMO HADISST1 sea surface temperature data from April to May in 1961-2020,the temporal-spatial variations of precipitation and circulation anomalies features are analyzed during spring sowing period,by using EOF,climatic tendency,moving average,wavelet and composite analysis.The results show that:(1) There are three main modes of precipitation during spring sowing period in Shanxi province,which are completely consistency,northsouth distribution,north-south and central distribution type,accounting for 63.3%,25% and 11.7%respectively.(2) The increasing trend of precipitation is unobvious in spring sowing period,it experiences five variation phases and has two oscillation periods of 2-3 a and 12-13 a.(3) In the abnormal rainy years,the 850 hPa wind field exhibits prevailing southerly airflow in mid-eastern China,the 500 h Pa geopotential height and sea level pressure field shows the patterns of “higher in the east and lower in the west”and“higher in the north and lower in the south”,respectively.Besides,the equatorial middle-east Pacific,Indian Ocean and Atlantic Ocean display the typical El Nino distribution,Dipole distribution and Triode distribution in early winter,respectively.However,the features of circulation and sea surface temperature are opposite in the abnormal rainless years.