Understanding the Central-Pacific El Nino-Southern Oscillation

本项目考虑了发生在中赤道太平洋（CP）的厄尔尼诺/南方涛动（ENSO）。CP ENSO事件不同于典型的ENSO事件，后者发生在赤道东太平洋（EP），表现为从南美海岸沿赤道冷舌延伸的海表温度异常窄舌。与此相反，cpenso事件的海温异常从太平洋向极地和向东延伸至北美和南美的亚热带海岸，在北半球的延伸更强。此外，EP ENSO事件的演变与温跃层深度海底温度异常的传播或全盆地范围波动有关，而CP ENSO事件的地下温度异常是原位发展的，没有传播。PIs指出，自20世纪90年代以来，CP ENSO事件变得更加普遍，最近的研究表明，全球变暖可能导致CP ENSO活动比EP ENSO活动进一步增强。他们还注意到，与EP ENSO相比，CP ENSO在文献中受到的关注较少，并且关于ENSO及其与温带的联系（包括温带前体和温带影响）的研究没有单独考虑这两种ENSO类型。该项目解决了与CP ENSO事件相关的三个科学问题。首先，研究通过使用理想化模型和中等复杂性模型，解决了CP事件的潜在动力学以及CP与EP ENSO动力学之间的关系。其次，该项目在确定北半球副热带海表温度前兆模式的早期研究基础上，探讨了温带强迫在产生CP ENSO事件中的作用。第三，该研究考虑了太平洋和太平洋ENSO事件在全球影响上的差异，部分基于先前的工作表明，太平洋事件在美国产生南北模式的冬季温度异常，而太平洋事件产生东西导向的模式。除了科学价值之外，由于ENSO事件的社会影响，该项目具有更广泛的影响。ENSO是全球短期气候变率的主要模式，了解ENSO事件的动态和后果的研究可能有助于改进ENSO预测。此外，这项工作将支持和培养研究生和本科生，以及博士后研究人员，从而发展该领域的科学劳动力。

This project considers El Nino/Southern Oscillation (ENSO) which occur in the Central Equatorial Pacific (CP). CP ENSO events are distinct from the canonical ENSO events which occur in the Eastern Equatorial Pacific (EP) and appear as a narrow tongue of sea surface temperature (SST) anomalies extending along the equatorial cold tongue from the South American coast. In contrast, SST anomalies for CP ENSO events extend poleward and eastward from the CP to the subtropical coasts of North and South America, with stronger extension in the Northern Hemisphere. Furthermore, the evolution of EP ENSO events is associated with propagation or basin-wide fluctuation of subsurface ocean temperature anomalies at thermocline depth, while CP ENSO events have subsurface temperature anomalies which develop in situ, without propagation. The PIs note that CP ENSO events have become more common since the 1990s, and recent studies suggest that global warming may lead to further enhancement in CP over EP ENSO activity. They also note that the CP ENSO has received less attention in the literature than the EP ENSO, and studies of ENSO and its connections to the extratropics, including both extratropical precursors and extratropical impacts, have not considered the two ENSO types separately. The project addresses three scientific issues related to CP ENSO events. First, research addresses the underlying dynamics of CP events, and the relationship between CP and EP ENSO dynamics, through the use of idealized models and models of intermediate complexity. Second, the project addresses the role of extratropical forcing in generating CP ENSO events, based on earlier research which identified precursor patterns in sea surface temperatures in the Northern Hemisphere subtropics. Third, the research considers differences in the global impacts of CP and EP ENSO events, based in part on prevous work suggesting that EP events produce a north-south pattern of winter temperature anomalies over the US, while CP events produce an east-west oriented pattern.Beyond its scientific merit, the project has broader impacts due to the societal impacts of ENSO events. ENSO is the leading mode of short-term climate variability over the globe, and research to understand the dynamics and consequences of ENSO events could be instrumental in improving ENSO predictions. In addition, the work will support and train graduate and undergraduate students, as well as a postdoctoral researcher, thereby developing the scientific workforce in this area.