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| Titel |
A mimetic, semi-implicit, forward-in-time, finite volume shallow water model: comparison of hexagonal–icosahedral and cubed-sphere grids |
| VerfasserIn |
J. Thuburn, C. J. Cotter, T. Dubos |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 7, no. 3 ; Nr. 7, no. 3 (2014-05-20), S.909-929 |
| Datensatznummer |
250115621
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| Publikation (Nr.) |
 copernicus.org/gmd-7-909-2014.pdf |
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| Zusammenfassung |
A new algorithm is presented for the solution of the shallow water
equations on quasi-uniform spherical grids. It combines a mimetic
finite volume spatial discretization with a Crank–Nicolson time
discretization of fast waves and an accurate and conservative
forward-in-time advection scheme for mass and potential vorticity
(PV). The algorithm is implemented and tested on two families of
grids: hexagonal–icosahedral Voronoi grids, and modified equiangular
cubed-sphere grids.
Results of a variety of tests are presented, including convergence
of the discrete scalar Laplacian and Coriolis operators, advection,
solid body rotation, flow over an isolated mountain, and
a barotropically unstable jet. The results confirm a number of
desirable properties for which the scheme was designed: exact mass
conservation, very good available energy and potential enstrophy
conservation, consistent mass, PV and tracer transport, and good
preservation of balance including vanishing ∇ × ∇,
steady geostrophic modes, and accurate PV advection. The scheme is
stable for large wave Courant numbers and advective Courant numbers
up to about 1.
In the most idealized tests the overall accuracy of the scheme
appears to be limited by the accuracy of the Coriolis and other
mimetic spatial operators, particularly on the cubed-sphere grid.
On the hexagonal grid there is no evidence for damaging effects of
computational Rossby modes, despite attempts to force them
explicitly. |
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