A Theoretical Study of Climate Dynamics

研究者研究大尺度地球物理流体流的结构、鲁棒性和稳定性，以及大尺度地球物理流体流的转变，以便更好地理解与气候低频变化的典型来源相关的这些流体流的预测和可预测性。该工作研究了两个领域的具体主题：1)原始方程的理论问题，以及2)年际变率特征对潜在物理空间中模型参数变化的存在、敏感性和鲁棒性。在区域1，研究者研究大尺度海洋/大气流动的原始方程。具体问题包括原始方程和相关简单模型的稳定性和分岔问题，特别是与气候低频变率有关的问题。区域2的主要目标是分类与边界层现象相关的典型大尺度大气/海洋环流流型，并研究其结构分岔。这个领域的部分工作是基于研究者和T. Ma最近发展的一种新的几何理论。研究者将物理建模、渐近方法、严格的数学理论和大规模计算相结合，以产生对物理现象的新见解。这项工作涉及与大气/海洋科学家的具体合作。该项目的主要目标是通过仔细的理论研究，记录北美大陆附近海洋盆地年际和年代际变化规律的存在，验证这种变化特征对模式参数变化的稳健性，并帮助解释其物理机制。对这种变率的透彻理解，对确定次大陆和更小空间尺度上的气候系统的可预测性和预测至关重要，这些时间尺度等于或超过几年。相关的现象包括双涡旋风驱动的海洋环流和厄尔尼诺-南方涛动（ENSO）现象，后者主导了太平洋大部分地区乃至全球的年际气候变化。这些研究可以改善天气、气候和环境现象的预测。

Wang0072612 The investigator studies the structure, its robustness andstability, and the transitions of large scale geophysical fluidflows, to arrive at a better understanding of the prediction andpredictability of these flows relevant to the typical sources oflow frequency variabilities in climate. The work studies specifictopics in two areas: 1) theoretical issues of the primitiveequations, and 2) the presence, sensitivity and robustness ofinterannual variability characteristics to changes in modelparameters in the underlying physical space. In Area 1, theinvestigator studies the primitive equations of large scaleocean/atmosphere flows. Specific problems include stability andbifurcation issues of the primitive equations and related simplermodels, especially in connection to climate low frequencyvariabilities. The main objectives in Area 2 are to classifytypical large scale atmosphere/ocean circulation flow patternsassociated with boundary layer phenomena, and to study theirstructural bifurcations. Part of the work in this area is basedon a new geometric theory developed recently by the investigatorand T. Ma. The investigator uses a combination of physicalmodelling, asymptotic methods, rigorous mathematical theory, andlarge scale computing to yield new insights into physicalphenomena. The work involves specific collaborations withatmosphere/ocean scientists. The primary goal of this project is to document, throughcareful theoretical studies, the presence of regular interannualand interdecadal variability in the ocean basins adjacent to theNorth American continent, to verify the robustness of thisvariability's characteristics to changes in model parameters, andto help explain its physical mechanisms. The thoroughunderstanding of this variability is of the essence indetermining the climate system's predictability and prediction onsubcontinental and smaller spatial scales, for time scales thatequal and exceed a few years. The associated phenomena includethe double-gyre wind-driven ocean circulation and the ElNino-Southern Oscillation (ENSO) phenomenon, which dominatesinter-annual climate variability over much of the Pacific Ocean,and hence the world. The studies could lead to improvedpredictions of weather, climate, and environmental phenomena.