Further Studies of Dynamics for El Nino-Southern Oscillation (ENSO) Diversity and Complexity

厄尔Niño-Southern涛动（ENSO）现象表现出复杂的行为，主要有两组模式，即中太平洋和东太平洋厄尔Niño事件，它们在时间上的演变非常不同。ENSO的时空复杂性（STC）对全球气候的各个方面都有重要影响。迄今为止，导致这种ENSO复杂性的基本动力学和必要的多尺度相互作用仍不清楚。本提案旨在促进目前对ENSO STC相关的基本动力学的理解。这项工作的结果可以提高预测技能，提高对ENSO及其全球影响的气候变化预估的信心。这项工作将培养一名研究生和一名年轻的研究科学家。拟议的研究将通过开发和应用新的理论方法，并使用一套（不同复杂程度的）模型，以及现有的观测和气候模型输出，对ENSO STC进行系统的调查。研究人员将评估主要耦合ENSO模式的线性和非线性敏感性如何产生ENSO STC的独特机制，ENSO如何与年循环、短暂的热带现象（例如，Madden-Julian涛动）和其他热带变率模式相互作用，以及ENSO STC如何响应各种气候平均状态偏差和气候变化情景。除了培养下一代科学家外，这项工作还可以导致(1)新的ENSO概念模型，扩展简单的规范ENSO补给振荡器范式，以更好地捕捉ENSO复杂性的基本机制；(2)更好地理解ENSO复杂性的关键物理和动力学过程；(3)对气候模式模拟ENSO复杂性不足的原因以及提高ENSO预测技能和评估变化的潜力有新的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The El Niño-Southern Oscillation (ENSO) phenomenon exhibits complex behaviors with two main groups of patterns known as the Central Pacific and Eastern Pacific El Niño events that evolve very differently in time. Such spatio-temporal complexity (STC) of ENSO has great implications on various aspects on the global climate. To date, the fundamental dynamics and essential multiscale interactions resulting in this ENSO complexity remains unclear. This proposal aims to advance current understanding of the fundamental dynamics associated with ENSO STC. The results from this work can lead to an improved prediction skills and increased confidence in climate change projections of ENSO and its global impacts. The work will train a graduate student and a young research scientist.The proposed study will conduct a systematic investigation of ENSO STC by developing and applying new theoretical approaches and using a set of models (of differing complexity) together with existing observations and climate model outputs. The investigator will assess how linear and nonlinear sensitivity of the leading coupled ENSO mode gives rise to a unique regime of ENSO STC, how ENSO interacts with the annual cycle, transient tropical phenomena (e.g., the Madden-Julian Oscillation), and other tropical modes of variability, and how ENSO STC responds to various climate mean state biases and scenarios of climate changes. In addition to training the next generation of scientists, this work can lead to (i) new ENSO conceptual models extending the simple canonical ENSO recharge oscillator paradigm to better capture the essential mechanism of ENSO complexity, (ii) better understandings of key physical and dynamical processes for ENSO complexity, and (iii) new insights into causes of deficiency in climate model simulation of ENSO complexity and potentials for improving ENSO’s forecasting skill and assessed changes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.