Abstract:Based on the observed precipitation data from 756 stations in China, ERA-interim reanalysis dataset, and HadISST dataset for 1979-2014, this paper investigates the Intensity of Interannual Variation (ⅡV) of spring precipitation over southern China during 1979-2014 and the related large-scale atmospheric and oceanic signal through Empirical Orthogonal Function (EOF) method and other statistical analysis methods. Results show that the ⅡV of spring precipitation over South China (SC) was stronger during 1979-1994, which is related to the spring Western Pacific (WP) Sea Surface Temperature Anomaly (SSTA) and the previous winter South Pacific Tripole (SPT) pattern of SSTA. Anomalous cooler (warmer) SSTA over WP triggers anomalous descending (ascending) motion and lower-level anticyclone (cyclone) in local areas, which in turn induces anomalous ascent (descent) over SC through an anomalous vertical circulation. The SPT can influence the spring precipitation over SC by impacting SST over WP. The stronger ⅡV of SST over WP and SPT led to an intensified ⅡV of spring rainfall over SC. The ⅡV of spring precipitation over middle and lower reaches of the Yangtze River (YZR) was more intense during 1995-2006. The intensified interannual variability of spring rainfall over YZR is interrelated with the increase in the amplitude of the spring southern Indian Ocean dipole (SIOD) in early 1990s. During the positive (negative) SIOD, the Western Pacific Subtropical High (WPSH) is stronger (weaker), which is favorable (unfavorable) for the transportation of vapor from Pacific to YZR. At the same time, the pressure ridge over Siberia and East Asian trough is weaker (stronger), enhancing (weakening)the spring precipitation over YZR.