Further Studies of El Niño-Southern Oscillation (ENSO) Dynamics

厄尔尼诺-南方涛动(ENSO)现象几乎是全球气候变化的原因。ENSO对整个热带和美洲的人类健康、安全和食品生产有重大影响。它在许多不同的时间尺度上显示出丰富的变化频谱。在这个奖项下，PI将解决有关ENSO动力学的基本问题：ENSO的稳定性在不同的模式中如何变化；它将如何随着气候变化而变化？ENSO不同周期的来源是什么？在更短的时间尺度上，ENSO和可变性之间的相互作用是否会影响ENSO的稳定性？这些问题将使用由PI在他之前的奖项下开发的大气-海洋稳定指数来解决。该指数将应用于各种表现出不同ENSO行为的海-气耦合气候模式，并评估不同气候条件下ENSO的稳定性。将研究慢的ENSO模和快的变率之间的尺度相互作用，并确定这些尺度相互作用对耦合的ENSO模的稳定性的影响。PI将探索导致类似ENSO的多个独立耦合模可能共存的物理机制，并将确定它们与其观察到的行为的相关性。将使用耦合模型的层次结构。这项研究将有助于更好地了解ENSO的动力学和可预测性。这项研究的更广泛影响是，它可能有助于改进对ENSO的预测，以及评估ENSO将如何随着全球气候变化而变化。

The El Nino - Southern Oscillation (ENSO) phenomenon is responsible for nearly global variations in climate. ENSO has major effects on human health, safety, and food production throughout the tropics and the Americas. It exhibits a rich spectrum of variations on many different timescales. Under this award the PI will address fundamental questions about the dynamics of ENSO: How does the stability of ENSO vary among different models; how will it change as climate changes? What are the sources of the different periodicities of ENSO? Do interactions between ENSO and variability on much shorter timescales influence the stability of ENSO? These questions will be addressed using an atmosphere-ocean stability index developed by the PI under his previous award. The index will be applied to various coupled atmosphere-ocean climate models, which exhibit different ENSO behavior, and to assess the stability of ENSO under different climate conditions. Scale-interactions between slow ENSO modes and fast variability will be investigated and the impact of these scale interactions on the stability of the coupled ENSO modes will be determined. The PI will explore the physical mechanisms leading to the possible co-existence of multiple independent coupled modes that resemble ENSO and will determine their relevance to its observed behavior. A hierarchy of coupled models will be used. The study will lead to a better understanding of the dynamics and predictability of ENSO. Broader impacts of this research are its potential contributions to improved predictions of ENSO and to assessments of how ENSO will change as the global climate changes.