Synergistic Interdecadal Evolution of Precipitation over Eastern China and the Pacific Decadal Oscillation during 1951-2015

By using the multi-taper method (MTM) of singular value decomposition (SVD), this study investigates the interdecadal evolution (10- to 30-year cycle) of precipitation over eastern China from 1951 to 2015 and its relationship with the North Pacific sea surface temperature (SST). Two significant interdecadal signals, one with an 11-year cycle and the other with a 23-year cycle, are identified in both the precipitation and SST fields. Results show that the North Pacific SST forcing modulates the precipitation distribution over China through the effects of the Pacific Decadal Oscillation (PDO)-related anomalous Aleutian low on the western Pacific subtropical high (WPSH) and Mongolia high (MH). During the development stage of the PDO cold phase associated with the 11-year cycle, a weakened WPSH and MH increased the precipitation over the Yangtze River Basin, whereas an intensified WPSH and MH caused the enhanced rain band to move northward to North China during the decay stage. During the development stage of the PDO cold phase associated with the 23-year cycle, a weakened WPSH and MH increased the precipitation over North China, whereas an intensified WPSH and the weakened MH increased the precipitation over South China during the decay stage. The 11-year and 23-year variabilities contribute differently to the precipitation variations in the different regions of China, as seen in the 1998 flooding case. The 11-year cycle mainly accounts for precipitation increases over the Yangtze River Basin, while the 23-year cycle is responsible for the precipitation increase over Northeast China. These results have important implications for understanding how the PDO modulates the precipitation distribution over China, helping to improve interdecadal climate prediction.