Impacts of ENSO on autumn rainfall over Yellow River loop valley in observation: Possible mechanism and stability

Authors

  • Chun Li,

    1. Physical Oceanography Laboratory and Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao, China
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  • Gang Zeng

    1. Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science and Technology, Nanjing, China
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Corresponding author: C. Li, Physical Oceanography Laboratory and Key Laboratory of Ocean-Atmosphere Interaction and Climate in Universities of Shandong, Ocean University of China, Qingdao 266100, China. (lichun7603@ouc.edu.cn)

Abstract

[1] The Yellow River loop valley (YRLV) is one of major agricultural production zones in many Chinese dynasties. Predicting rainfall variability in the YRLV is important for the society and the economy. This study demonstrates impacts of El Niño–Southern Oscillation (ENSO) on autumn rainfall in the YRLV based on statistical analyses of instrumental rainfall in China and reanalyzed SST and atmospheric data. Results indicate that the autumn rainfall anomaly in the YRLV may be partially controlled by the ENSO-like sea surface temperature (SST) pattern. The YRLV rainfall is below normal (above normal) in the El Niño (La Niña) developing years. This impact is mediated by an atmospheric response to the ENSO-like SST anomaly forcing via a westward Rossby wave. Furthermore, Niño3.4 index may be used as a factor for autumn rainfall in the YRLV region with a lead of 4–5 months. However, the relationship between the autumn YRLV rainfall and ENSO does not persist and has gone through decadal weakening since the end of 1980s via a decadal response of atmospheric circulation to ENSO. The decadal change of the relationship between the autumn YRLV rainfall and ENSO may be modulated by climate decadal shifts.

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