Main Influencing Factors of Summer Precipitation and Prediction Method of Annual Increment in Shaanxi

Basic conditions that affect main factors of summer precipitation in Shaanxi are determined,which means that the correlation coefficient is high and the significance is verified,the physical meaning is clear,abnormalities of meteorological factors could be reflected and have lasting effect.NCEP/NCAR reanalysis data of the monthly mean 500 hPa height,sea surface temperature,ERA-40 climate index,and 74 meteorological characteristics of National Climate Center are used in the investigation.Six main climatic factors are met by the census,including the western Pacific subtropical high intensity,equatorial strata,zonal wind,lower-level equatorial airflow,atmospheric angular momentum,equatorial Pacific SST,and the equatorial 500 hPa height field.The analysis of the correlation between anomalies of inter-annual increment,the standard deviation in the six incremental factors and the summer precipitation in Shaanxi,showing that the inter-annual increment factor have obvious signal amplification effect.The standard devi