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Titre du document / Document title

Stable centered-difference schemes, based on an unstaggered a grid, that eliminate two-grid interval noise

Auteur(s) / Author(s)

KAR Sajal K. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Bureau of Meteorology Research Centre, Melbourne, AUSTRALIE

Résumé / Abstract

ABSTRAC T The use of a centered-difference scheme on an unstaggered horizontal grid in time-dependent atmospheric or oceanic models leads to spurious two-grid-interval wave solutions that may appear as small-scale noise and mask the physically significant large-scale flow patterns. Although the problem is independent of the time-difference schemes used in such models, the original time-difference schemes can be slightly modified to eliminate this problem. Following an established approach, the divergence field on the grid is modified in such a way that the height perturbation at a single grid point is propagated by gravity waves to all other grid points so that no spurious, two-grid-interval noise can develop. In this paper, a family of modified explicit, two-step iterative, two-time-level schemes is developed and studied systematically for the unstaggered grid. The family of schemes is first developed for two-dimensional, nondispersive, surface gravity waves in a linearized shallow water model. The stability and phase properties of the original and the modified schemes are compared. The modified family of schemes is then implemented in a nonlinear shallow water model and its effectiveness is demonstrated by applying the model to an idealized forced initial value problem. Then the schemes are implemented in a multilevel, limited-area gridpoint NWP model. Results of 48-h time integrations using the model, once again, demonstrate the effectiveness of the modified family of schemes.

Revue / Journal Title

Monthly weather review    ISSN  0027-0644   CODEN MWREAB 

Source / Source

2000, vol. 128, no10, pp. 3643-3653 (18 ref.)

Langue / Language

Anglais

Editeur / Publisher

American Meteorological Society, Boston, MA, ETATS-UNIS  (1872) (Revue)

Mots-clés anglais / English Keywords

Difference scheme

;

Grid pattern

;

Surface gravity wave

;

Shallow-water equations

;

Mots-clés français / French Keywords

Schéma différences

;

Maillage

;

Onde surface gravité

;

Equation eau peu profonde

;

Mots-clés espagnols / Spanish Keywords

Esquema diferencias

;

Celdarada

;

Onda superficie gravedad

;

Localisation / Location

INIST-CNRS, Cote INIST : 141, 35400009270027.0170

Nº notice refdoc (ud4) : 823765



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