Type of Document	Dissertation
Author	Herbei, Radu
Author's Email Address	herbei@stat.fsu.edu
URN	etd-07102006-131014
Title	Quasi-3d Statistical Inversion of Oceanographic Tracer Data
Degree	Doctor of Philosophy
Department	Statistics, Department of
Advisory Committee	Advisor Name Title Kevin Speer Committee Co-Chair Marten Wegkamp Committee Co-Chair Fred Huffer Committee Member Louis St. Laurent Committee Member Xufeng Niu Committee Member
Keywords	Inverse Problem Bayesian Approach Advection-Diffusion Thermal Wind
Date of Defense	2006-05-12
Availability	unrestricted
Abstract We perform a quasi-3D Bayesian inversion of oceanographic tracer data from the South Atlantic Ocean. Initially we are considering one active neutral density layer with an upper and lower boundary. The available hydrographic data is linked to model parameters (water velocities, diffusion coefficients) via a 3D advection-diffusion equation. A robust solution to the inverse problem considered can be attained by introducing prior information about parameters and modeling the observation error. This approach estimates both horizontal and vertical flow as well as diffusion coefficients. We find a system of alternating zonal jets at the depths of the North Atlantic Deep Water, consistent with direct measurements of flow and concentration maps. A uniqueness analysis of our model is performed in terms of the oxygen consumption rate. The vertical mixing coefficient bears some relation to the bottom topography even though we do not incorporate that into our model. We extend the method to a multi-layer model, using thermal wind relations weakly in a local fashion (as opposed to integrating the entire water column) to connect layers vertically. Results suggest that the estimated deep zonal jets extend vertically, with a clear depth dependent structure. The vertical structure of the flow field is modified by the tracer fields over that set a priori by thermal wind. Our estimates are consistent with observed flow at the depths of the Antarctic Intermediate Water; at still shallower depths, above the layers considered here, the subtropical gyre is a significant feature of the horizontal flow.
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