Modulation of monthly precipitation patterns over East China by the Pacific Decadal Oscillation

Qing Yang,Baoliang Xu,Zhuguo Ma

doi:10.1007/s10584-016-1662-9

Qing Yang, Baoliang Xu + Show 1 more

Open Access

https://doi.org/10.1007/s10584-016-1662-9

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Abstract

Previous studies suggest that the Pacific Decadal Oscillation (PDO) modulates annual and summer precipitation patterns over East China. In this study, the effect of the PDO on monthly precipitation anomalies over this region is investigated. The new results show that the effect is month-dependent. The well-known North–South dipole patterns of annual precipitation are dominated by the July–August precipitation. In other months, the corresponding patterns vary in strength, position, and even shape. For example, the May and June precipitation patterns show opposite signs to the July–August or annual mean patterns, whereas the September–December monthly precipitation anomalies show a triple pattern. Monthly precipitation patterns over East China are largely determined by large-scale moisture transport controlled by atmospheric circulation. The PDO affects East China precipitation patterns by modulating the large-scale circulation pattern.

Highlights

The East Asian Summer Monsoon weakened in the late 1970s (Wang 2001; Zhou et al 2009), which led to significant rainfall changes over East China with more precipitation in the South and less in the North
The recent two phases transitions of the Pacific Decadal Oscillation (PDO) occurred in the late 1970s and around 2000 (Qian and Zhou 2014)
It suggests that the modulation of PDO on the precipitation over South China is less significant than that over North China, which can be explained by the fact that the precipitation over South China is influenced by several other factors except the PDO

Summary

Introduction

The East Asian Summer Monsoon weakened in the late 1970s (Wang 2001; Zhou et al 2009), which led to significant rainfall changes over East China with more precipitation in the South (south of the Yangtze River Valley) and less in the North. This North–South dipole pattern of precipitation anomalies has often been referred to as Bsouthern flooding and northern drought^ (BSF–ND^, hereafter) in China (Yatagai and Yasunari 1994; Nitta and Hu 1996; Zhou et al 2009; Li et al 2010). The PDO has a strong effect on the interdecadal variations of the East Asian Summer Monsoon and rainfall over East China (Chang et al 2000; Yang and Lau 2004; Zeng et al 2007; Li et al 2010)

Results

Discussion

Conclusion