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Impact of Preceding Summer North Atlantic Oscillation on Early Autumn Precipitation over Central China |
XU Han-Lie1,2, FENG Juan1, SUN Cheng1 |
1State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics. Chinese Academy of Sciences, Beijing 100029, China
2University of Chinese Academy of Sciences, Beijing 100049, China |
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Abstract This study examined the impact of the preceding boreal summer (June–August) North Atlantic Oscillation (NAO) on early autumn (September) rainfall over Central China (RCC). The results show that a significant positive correlation exists between the preceding summer NAO and the early autumn RCC on the interannual timescale. In order to understand the physical mechanism between them, the role of ocean was investigated. It was found that the strong summer NAO can induce a tripole sea surface temperature anomaly (SSTA) in the North Atlantic; this SSTA pattern can persist until early autumn. The diagnostic analysis showed that the tripole SSTA pattern excites a downstream Atlantic-Eurasian teleconnection (AEA teleconnection), which contributes to an increase in RCC. The circulation anomalies related to SSTA caused by the weak NAO are opposite, so the RCC is less than normal. The results imply that the preceding summer NAO may be regarded as a forecast factor for the early autumn RCC.
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Received: 06 March 2013
Revised: 07 April 2013
Accepted: 16 April 2013
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Corresponding Author:
XU Han-Lie
E-mail: xuhanlie@mail.iap.ac.cn
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