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JIGSAW-GEO (1.0): Locally Orthogonal Staggered Unstructured Grid Generation for General Circulation Modelling on the SphereAn algorithm for the generation of non-uniform, locally orthogonal staggered unstructured spheroidal grids is described. This technique is designed to generate very high-quality staggered VoronoiDelaunay meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric simulation, ocean-modelling and numerical weather prediction. Using a recently developed Frontal-Delaunay refinement technique, a method for the construction of high-quality unstructured spheroidal Delaunay triangulations is introduced. A locally orthogonal polygonal grid, derived from the associated Voronoi diagram, is computed as the staggered dual. It is shown that use of the Frontal-Delaunay refinement technique allows for the generation of very high-quality unstructured triangulations, satisfying a priori bounds on element size and shape. Grid quality is further improved through the application of hill-climbing-type optimisation techniques. Overall, the algorithm is shown to produce grids with very high element quality and smooth grading characteristics, while imposing relatively low computational expense. A selection of uniform and non-uniform spheroidal grids appropriate for high-resolution, multi-scale general circulation modelling are presented. These grids are shown to satisfy the geometric constraints associated with contemporary unstructured C-grid-type finite-volume models, including the Model for Prediction Across Scales (MPAS-O). The use of user-defined mesh-spacing functions to generate smoothly graded, non-uniform grids for multi-resolution-type studies is discussed in detail.
Document ID
20170005575
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Engwirda, Darren
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Date Acquired
June 14, 2017
Publication Date
June 6, 2017
Publication Information
Publication: Geoscientific Model Development
Publisher: Copernicus Publications
Volume: 10
Issue: 6
ISSN: 1991-959X
e-ISSN: 1991-9603
Subject Category
Numerical Analysis
Meteorology And Climatology
Report/Patent Number
GSFC-E-DAA-TN43447
Distribution Limits
Public
Copyright
Other
Keywords
geophysical fluid dynamics
atmospheric modelling
grid-optimisation
grid-generation
Voronoi tesselation
Frontal-Delaunay refinement
ocean modelling
numerical weather predication

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