Cooperative effects of tropical Pacific and Atlantic SST forcing in southern China winter precipitation variability
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Cooperative effects of tropical Pacific and Atlantic SST forcing in southern China winter precipitation variability Yunyun Liu1,2 · Zeng‑Zhen Hu3 · Renguang Wu4 Received: 3 April 2020 / Accepted: 18 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract This study investigates the variability of winter precipitation over southern China (SC) and the impacts of sea surface temperature (SST) forcing in the tropical Pacific and Atlantic Oceans. The SC winter precipitation displays two major spatial modes: a same-sign mode with the maximum center located in southeastern China, and a north–south dipole mode with opposite variations between the lower reach of the Yangtze River and the southeastern coast of China. Both modes are associated with the variation of the western North Pacific (WNP) anticyclone. The same-sign mode is associated with canonical El Niño through the Pacific-East Asian teleconnection in the lower troposphere. The north–south dipole mode is subject to the impact of the western Pacific warm pool associated with the central Pacific El Niño and equatorial Atlantic forcing. The influence of equatorial Atlantic warming is through an upper-tropospheric zonal wave pattern from the tropical Atlantic to the mid-latitudes of East Asia. Both the tropical Pacific and Atlantic oceanic forcing induce a north–south dipole pattern of winter precipitation anomalies over SC by affecting the northward extension of the WNP anticyclone. Moreover, the observed statistical relationship between the dipole mode and the equatorial Atlantic SST anomalies is present in hindcasts/ forecasts of the NCEP Climate Forecast System version 2 (CFSv2), confirming a potential source of the predictability of the north–south dipole-like variation of the winter precipitation in SC. Keywords Winter precipitation over southern china · Same-sign mode · North–south dipole mode · ENSO · Equatorial atlantic warming · Predictability
1 Introduction Southern China (SC) is a climate-sensitive region due to the large population and active economic flow. Also, the precipitation in this region presents an obvious interannual variability in both summer and winter. The precipitation-related * Yunyun Liu [email protected] 1
National Climate Center, Chinese Meteorological Administration, #46 Zhong‑Guan‑Cun South Road, Beijing 100081, China
2
Collaborative Innovation Center On Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Sciences & Technology, Nanjing 210044, China
3
Climate Prediction Center, NCEP/NOAA, College Park, MD 20740, USA
4
School of Earth Sciences, Zhejiang University, Hangzhou 310027, Zhejiang, China
climate extreme events have resulted in huge economic and social damage. Previous studies indicated that the interannual variability of precipitation in China is partially driven by the oceanic forcing, and the El Niño-Southern Oscillation (ENSO) is considered of paramount importance (Lau and Nath 2003; Wu et al. 2003; Chang et al. 2004; He and Wang 2013; He and
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