Eastern Pacific Wind Effect on the Evolution of El Niño: Implications for ENSO Diversity
Eastern Pacific Wind Effect on the Evolution of El Niño: Implications for ENSO Diversity
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DOI：
10.1175/jcli-d-19-0435.1
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发表时间：
2020-03
影响因子：
4.9
通讯作者：
Qihua Peng;S. Xie;Dongxiao Wang;Y. Kamae;Hong Zhang;Shineng Hu;Xiao‐Tong Zheng;Weiqiang Wang
中科院分区：
文献类型：
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作者：
Qihua Peng;S. Xie;Dongxiao Wang;Y. Kamae;Hong Zhang;Shineng Hu;Xiao‐Tong Zheng;Weiqiang Wang
通过观测和模式试验研究了热带东太平洋(10°S-10°N，140°-80°W)风异常对厄尔尼诺的影响。极端厄尔尼诺和中等厄尔尼诺在厄尔尼诺高峰期和衰退期表现出不同的异常风型：极端厄尔尼诺期间的西风异常和中等厄尔尼诺期间赤道南(北)的东南(西南风)风异常。海洋环流模式的实验表明，对于极端厄尔尼诺，西风异常的东进入侵导致赤道东太平洋的正海温异常在整个北半球春季通过减弱的上升流和水平平流而延长。相反，对于温和的厄尔尼诺现象，EPAC上的经向风和纬向风通过平流和风-蒸发-SST反馈对赤道南(北)海温的快速(缓慢)冷却起着重要作用。大气模式试验证实，这些EPAC异常风主要是由热带海温异常强迫的。风和海温异常之间的相互作用表明，在厄尔尼诺的衰减期，EPAC上的正海气反馈。海洋模式的结果表明，当EPAC风异常被移除时，极端厄尔尼诺的频率增加，这表明EPAC风对厄尔尼诺多样性的重要性。
The influence of eastern tropical Pacific (EPAC; 10°S–10°N, 140°–80°W) wind anomalies on El Niño is investigated using observations and model experiments. Extreme and moderate El Niños exhibit contrasting anomalous wind patterns in the EPAC during the peak and decay phases: westerly wind anomalies during extreme El Niño and southeasterly (southwesterly) wind anomalies south (north) of the equator during moderate El Niño. Experiments with an ocean general circulation model indicate that for extreme El Niño, the eastward intrusion of westerly wind anomalies contributes to the prolonged positive sea surface temperature (SST) anomalies in the eastern equatorial Pacific throughout boreal spring by weakened upwelling and horizontal advection. For moderate El Niño, by contrast, both the meridional and zonal anomalous winds over the EPAC are important in the rapid (slow) SST cooling south (north) of the equator through advection and wind–evaporation–SST feedback. Atmospheric model experiments confirm that these EPAC anomalous winds are primarily forced by tropical SST anomalies. The interplay between wind and SST anomalies suggests positive air–sea feedbacks over EPAC during the decay phase of El Niño. Ocean model results show that the frequency of extreme El Niño increases when EPAC wind anomalies are removed, suggesting the importance of EPAC winds for El Niño diversity.