Type of Document	Dissertation
Author	Jacobsen, Douglas William
Author's Email Address	dwj07@fsu.edu
URN	etd-07112011-194801
Title	Parallel Grid Generation and Multi-Resolution Methods for Climate Modeling Applications
Degree	Doctor of Philosophy
Department	Scientific Computing, Department of
Advisory Committee	Advisor Name Title Max Gunzburger Committee Chair Gordon Erlebacher Committee Member Ionel Michael Navon Committee Member Janet Peterson Committee Member John Burkardt Committee Member Todd Ringler Committee Member Doron Nof University Representative
Keywords	spherical centroidal voronoi tessellation grid generation high performance computing spherical delaunay triangulation adaptive mesh refinement shallow-water equations ocean modeling
Date of Defense	2011-06-14
Availability	unrestricted
Abstract Spherical centroidal Voronoi tessellations (SCVT) are used in many applications in a variety of fields, one being climate modeling. They are a natural choice for spatial discretizations on the surface of the Earth. New modeling techniques have recently been developed that allow the simulation of ocean and atmosphere dynamics on arbitrarily unstructured meshes, including SCVTs. Creating ultra-high resolution SCVTs can be computationally expensive. A newly developed algorithm couples current algorithms for the generation of SCVTs with existing computational geometry techniques to provide the parallel computation of SCVTs and spherical Delaunay triangulations. Using this new algorithm, computing spherical Delaunay triangulations shows a speed up on the order of 4000 over other well known algorithms, when using 42 processors. As mentioned previously, newly developed numerical models allow the simulation of ocean and atmosphere systems on arbitrary Voronoi meshes providing a multi-resolution modeling framework. A multi-resolution grid allows modelers to provide areas of interest with higher resolution with the hopes of increasing accuracy. However, one method of providing higher resolution lowers the resolution in other areas of the mesh which could potentially increase error. To determine the effect of multi-resolution meshes on numerical simulations in the shallow-water context, a standard set of shallow-water test cases are explored using the Model for Prediction Across Scales (MPAS), a new modeling framework jointly developed by the Los Alamos National Laboratory and the National Center for Atmospheric Research. An alternative approach to multi-resolution modeling is Adaptive Mesh Refinement (AMR). AMR typically uses information about the simulation to determine optimal locations for degrees of freedom, however standard AMR techniques are not well suited for SCVT meshes. In an effort to solve this issue, a framework is developed to allow AMR simulations on SCVT meshes within MPAS. The resulting research contained in this dissertation ties together a newly developed parallel SCVT generator with a numerical method for use on arbitrary Voronoi meshes. Simulations are performed within the shallow-water context. New algorithms and frameworks are described and bench-marked.
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