A Theoretical Study of Climate Dynamics

Indiana University, Bloomington IN

Investigators

Abstract

Wang 0072612 The investigator studies the structure, its robustness and stability, and the transitions of large scale geophysical fluid flows, to arrive at a better understanding of the prediction and predictability of these flows relevant to the typical sources of low frequency variabilities in climate. The work studies specific topics in two areas: 1) theoretical issues of the primitive equations, and 2) the presence, sensitivity and robustness of interannual variability characteristics to changes in model parameters in the underlying physical space. In Area 1, the investigator studies the primitive equations of large scale ocean/atmosphere flows. Specific problems include stability and bifurcation issues of the primitive equations and related simpler models, especially in connection to climate low frequency variabilities. The main objectives in Area 2 are to classify typical large scale atmosphere/ocean circulation flow patterns associated with boundary layer phenomena, and to study their structural bifurcations. Part of the work in this area is based on a new geometric theory developed recently by the investigator and T. Ma. The investigator uses a combination of physical modelling, asymptotic methods, rigorous mathematical theory, and large scale computing to yield new insights into physical phenomena. The work involves specific collaborations with atmosphere/ocean scientists. The primary goal of this project is to document, through careful theoretical studies, the presence of regular interannual and interdecadal variability in the ocean basins adjacent to the North American continent, to verify the robustness of this variability's characteristics to changes in model parameters, and to help explain its physical mechanisms. The thorough understanding of this variability is of the essence in determining the climate system's predictability and prediction on subcontinental and smaller spatial scales, for time scales that equal and exceed a few years. The associated phenomena include the double-gyre wind-driven ocean circulation and the El Nino-Southern Oscillation (ENSO) phenomenon, which dominates inter-annual climate variability over much of the Pacific Ocean, and hence the world. The studies could lead to improved predictions of weather, climate, and environmental phenomena.