Abstract:Based on meteorological data and JRA 55 reanalysis data, the dominant interannual patterns of summer precipitation over Shandong Province and their circulation characteristics were investigated by using the EOF, correlation analysis and composite analysis methods. The results indicate that the spatial distributions of interannual summer precipitation over Shandong Province can be classified into ‘consistent distribution’, ‘northwest southeast seesaw distribution’ and ‘northeast southwest seesaw distribution’ modes. In the consistent more (less) precipitation year, there is a dipole anomaly pattern with high (low) pressure over the Sea of Japan and low (high) pressure over Mongolia Plateau; a meridional wave train resembles EAP teleconnection pattern is distributed as ‘-+-’ (‘+-+’) over East Asia; the Arabian Sea, the Bay of Bengal and the Philippine regions are characterized by anomalous low level anticyclones. In the years of more precipitation over northwest (southeast) and less precipitation over southeast (northwest) of Shandong, the activities of Ural blocking high and Okhotsk blocking high are enhanced (suppressed) and a wave train which is analogous to ‘Silk Road’ teleconnection pattern propagating eastward along the upper westerly jet stream. In the years of more precipitation over northeast (southwest) and less precipitation over southwest (northeast) of Shandong, a northeast southwest wave train is distributed as ‘-+-’ (‘+-+’) over western and central Eurasia and the tropical zone is characterized by anomalous east (west) wind. In addition, the ‘consistent distribution’ mode is mainly influenced by the latitude position of West Pacific subtropical high (WPSH) ridge while the ‘northwest southeast seesaw distribution’ mode is largely affected by the westward extending and eastward retreating of WPSH. As for the upper westerly jet stream, a dipole anomaly pattern is located in the south and north sides of jet axis over Shandong and its vicinal region in all of the three modes with position differences of the anomalous centers. These results would be helpful in further understanding anomalous summer precipitation and its atmospheric circulation to improve the predictability of summer precipitation over Shandong Province.