Indo-Pacific climate during the decaying phase of the 2015/16 El Niño: role of southeast tropical Indian Ocean warming
This study investigates the influence of southeast tropical Indian Ocean (SETIO) sea surface temperature (SST) warming on Indo-Pacific climate during the decaying phase of the 2015/16 El Niño by using observations and model experiments. The results show that the SETIO SST warming in spring 2016 enhanced local convection and forced a “C-shape” wind anomaly pattern in the lower troposphere. The “C-shape” wind anomaly pattern over the eastern tropical Indian Ocean consists of anomalous westerly flow south of the equator and anomalous easterly flow north of the equator. The anomalous easterly flow then extended eastward into the western North Pacific (WNP) and facilitates the development or the maintenance of an anomalous anticyclone over the South China Sea (SCS). Correspondingly, the eastern part of the Bay of Bengal, the SCS and the WNP suffered less rainfall. Such precipitation features and the associated “C-shape” wind anomaly pattern shifted northward about five latitudes in summer 2016. Additionally, the SETIO warming can induce local meridional circulation anomalies, which directly affect Indo-Pacific climate. Numerical model experiments further confirm that the SETIO SST warming plays an important role in modulating Indo-Pacific climate.
KeywordsSETIO SST warming 2015/16 El Niño Anomalous anticyclone “C-shape” wind anomaly pattern Indo-Pacific climate
We thank two anonymous reviewers for their comments and suggestions which help improve the manuscript. This work is supported by the National Key Basic Research and Development Projects of China (2016YFA0600601), the National Natural Science Foundation of China (41525019, 41530530, 41530425 and 41275081), the State Oceanic Administration of China (GASI-IPOVAI-02), the Chinese Academy of Sciences (XDA11010000), the Pioneer Hundred Talents Program of the Chinese Academy of Sciences and the leading talents of Guangdong province program and the support of the Independent Research Project Program of State Key Laboratory of Tropical Oceanography (LTOZZ1603).
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Conflict of interest
The authors declare that they have no conflict of interest.
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