Collaborative Research: Westerly Wind Bursts: El Nino Southern Oscillation's (ENSO) Driver or Slave?

西风爆发（WWB）事件在厄尔尼诺-南方涛动（ENSO）中起着重要的作用。这些事件通常被看作是独立于大尺度ENSO动力学之外的随机强迫。然而，有迹象表明，这些事件的发生及其特征受到大尺度SST结构的影响，因此也受到ENSO的影响。本研究将探讨WWB事件的时间和其他特征部分地受大尺度SST分布调控的可能性的动力学后果。也就是说，这项研究将检查这些事件发生的极端可能性，只有当大尺度SST结构是在一定的配置。例如，当暖池向东延伸超过日期变更线时。在这种情况下，WWB事件将被视为确定性ENSO动力学的内在组成部分，而不是外部随机强迫。本研究将首先分析观测结果，以试图建立大尺度SST场对WWB事件的时间或特征的可能调节的特征。接下来，将使用一系列模型研究大尺度ENSO动力学对WWB事件的这种调节转换的影响。该模式层次将包括一个混合耦合模式（海洋环流模式耦合到一个统计大气），一个中间耦合模式，和一个概念性的延迟振荡器模式。更广泛的影响的研究包括可能提高ENSO的预测技巧，如果拟议的研究找到一种方法，包括一个代表性的WWB调节的大规模SST场在目前的ENSO预测模型。一名研究生（在马克·凯恩的领导下）和一名博士后（在伊莱·齐珀曼的领导下）将在这笔赠款下接受教育、指导和培训。

Westerly wind burst (WWB) events are known to play an important role in El Nino Southern Oscillation's (ENSO) dynamics. The events are usually viewed as stochastic forcing that is independent of and external to the large scale ENSO dynamics. There are indications, however, that the occurrence of these events, and their characteristics, are influenced by the large scale SST structure, and hence by ENSO. This study will explore the dynamical consequences of the possibility that the timing and other characteristics of WWB events are partially regulated and controlled by the large scale SST distribution. That is, the study will examine the extreme possibility that these events occur only when the large scale SST structure is at a certain configuration. For example, when the warm pool is extended eastward beyond the dateline. In this scenario the WWB events will be treated as an inherent part of the deterministic ENSO dynamics rather than as external stochastic forcing. The study will first analyze observations in order to try and establish the characteristics of such a possible regulation of the timing or characteristics of WWB events by the large scale SST field. Next, the implications of such regulated switching of WWB events by the large scale ENSO dynamics will be studied using a hierarchy of models. The model hierarchy will include a hybrid coupled model (ocean general circulation model coupled to a statistical atmosphere), an intermediate coupled model, and a conceptual delayed oscillator model. Broader impacts of the research include possible improvement of ENSO's prediction skill, should the proposed research find a way to include a representation of WWB regulation by the large scale SST field in current ENSO prediction models. A graduate student (under Mark Cane) and a post-doc (under Eli Tziperman) will be educated, mentored and trained under this grant.