Decade-to-decade variations in summer precipitation patterns in eastern China since the 1960s: roles of water vapor transport and sea surface temperature

Abstract

Based on the observational precipitation data and multiple reanalysis datasets, this study analyzes the decade-to-decade spatiotemporal evolution of anomalous summer precipitation in eastern China (SPEC) for 1961-2019 and explores the roles of water vapor transport and global sea surface temperatures (SSTs). Results show that SPEC patterns in the last 60 yr were mainly classified into 3 categories: dipole (the 1960s and 1970s), tripole (the 1990s) and quadrupole (the 1980s and 2000s), with marked decade-to-decade variations. In the 2010s, the precipitation pattern exhibited a more complex nature. Obvious differences can be detected in the water vapor channels (WVCs) associated with the 3 SPEC patterns. Specifically, the dipole pattern of the SPEC was mainly related to the Pacific Ocean WVC (POW) and the westerly WVC (WW). The tripole pattern was mainly associated with the Tibetan Plateau Southern Side WVC (TPW), the South China Sea WVC, the POW and the WW. The quadrupole pattern was quite clearly correlated with the Indian Ocean WVC, the Bay of Bengal WVC, the TPW, the POW and the WW. Furthermore, the dipole SPEC pattern was correlated with the Pacific decadal oscillation (PDO), the Indian Ocean basin mode (IOBM) and the Atlantic multi-decadal oscillation. The tripole and quadrupole patterns were related to the IOBM and PDO, respectively. The PDO has a marked influence on the interdecadal shifting of the SPEC pattern in the late 1970s, favoring the formation of the quadrupole SPEC pattern. However, the decadal shifting of the SPEC pattern in the early 1990s is mainly influenced by the IOBM, which favored the formation of the tripole precipitation pattern.