El Niño and Southern Oscillation (ENSO): A Review
El Niño and Southern Oscillation (ENSO): A Review
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DOI：
10.1007/978-94-017-7499-4_4
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发表时间：
2017
影响因子：
4
通讯作者：
Chunzai Wang;C. Deser;Jin‐Yi Yu;P. DiNezio;A. Clement
中科院分区：
文献类型：
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作者：
Chunzai Wang;C. Deser;Jin‐Yi Yu;P. DiNezio;A. Clement
热带太平洋ENSO观测系统在监测ENSO、提高对ENSO的认识和预测方面发挥着重要作用。ENSO的发生被解释为一种海洋-大气耦合系统的自我持续和自然振荡模式，或一种由随机强迫触发的稳定模式。在任何一种情况下，ENSO都涉及Bjerknes假设的正海洋-大气反馈。在El Niño达到成熟期后，需要负反馈来终止中太平洋和东太平洋成熟El Niño异常的生长。提出了四种负反馈：大洋西边界反射开尔文波、由Sverdrup输送引起的放电过程、西太平洋风强迫开尔文波和异常纬向平流。这些负反馈可能共同作用于终止El Niño，它们的相对重要性随时间而变化。由于最大海温异常的位置不同以及与之相关的大气加热，El Niño事件被划分为太平洋东部和中部变暖事件。确定两种不同类型的厄尔尼诺Niño提供了一种新的方法来检查厄尔尼诺Niño的全球影响，并考虑厄尔尼诺Niño如何响应和反馈气候变化。除了与ENSO相关的年际变化外，热带太平洋海温也在较长的时间尺度上波动。太平洋年代际变率（PDV）与ENSO非常相似。热带东太平洋海温异常为正时，西太平洋和南北太平洋中部海温异常为负，热带印度洋和高纬度太平洋东北部海温异常为正。人们提出了许多解释PDV的机制。全球变暖下ENSO的变化是不确定的。温室气体的增加改变了热带太平洋的平均状态，进而引起ENSO变化。由于全球变暖下平均热带条件的变化具有很大的不确定性，即使在过去的几十年里，也很难说ENSO是会增强还是减弱，但未来ENSO很可能不会消失。
The ENSO observing system in the tropical Pacific plays an important role in monitoring ENSO and helping improve the understanding and prediction of ENSO. Occurrence of ENSO has been explained as either a self-sustained and naturally oscillatory mode of the coupled ocean-atmosphere system or a stable mode triggered by stochastic forcing. In either case, ENSO involves the positive ocean-atmosphere feedback hypothesized by Bjerknes. After an El Niño reaches its mature phase, negative feedbacks are required to terminate growth of the mature El Niño anomalies in the central and eastern Pacific. Four negative feedbacks have been proposed: reflected Kelvin waves at the ocean western boundary, a discharge process due to Sverdrup transport, western Pacific wind-forced Kelvin waves, and anomalous zonal advections. These negative feedbacks may work together for terminating El Niño, with their relative importance varying with time. Because of different locations of maximum SST anomalies and associated atmospheric heating, El Niño events are classified as eastern and central Pacific warming events. The identification of two distinct types of El Niño offers a new way to examine global impacts of El Niño and to consider how El Niño may respond and feedback to a changing climate. In addition to interannual variations associated with ENSO, the tropical Pacific SSTs also fluctuate on longer timescales. The patterns of Pacific Decadal Variability (PDV) are very similar to those of ENSO. When SST anomalies are positive in the tropical eastern Pacific, they are negative to the west and over the central North and South Pacific, and positive over the tropical Indian Ocean and northeastern portions of the high-latitude Pacific Ocean. Many mechanisms have been proposed for explaining PDV. Changes in ENSO under global warming are uncertain. Increasing greenhouse gases change the mean states in the tropical Pacific, which in turn induce ENSO changes. Due to the fact that the change in mean tropical condition under global warming is quite uncertain, even during the past few decades, it is difficult to say whether ENSO will intensify or weaken, but it is very likely that ENSO will not disappear in the future.