Abstract:  Using the ground temperature and precipitation data, the monthly circulation eigenvalue, the NCEP reanalysis data of height field and so on, the climatic characteristics of air temperature and precipitation in June in Heilongjiang province were analyzed by a conventionally climatic statistic method. The correlations of air temperature and precipitation with geopotential height field at 500 hPa in the northern hemisphere were discussed, and their relationships with circulation factors in the middle and higher latitudes were established. The results show that the abnormal climate in Heilongjiang province in the early summer is related to circulation anomaly in the middle and higher latitudes. The main impacting factors include latitudinal circulation index in Asia, Aleutian low index, polar vortex area index in Asia and Okhotsk blocking high index and so on. On the basis of the above analysis, the background of atmosphere, the indirect action of sea temperature as an outside forcing factor, the background and variation of circulation factors in the middle and higher latitudes are considered, which are the essential premise predicting the climate in the early summer in Heilongjiang province.

Key words: font-family: "Times New Roman", mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, Circulation anomaly')">mso-fareast-font-family: 宋体">Circulation anomaly, Polar vortex index, Wavelet analysis