On the computation of the barotropic mode of a free-surface world ocean model
The free-surface formulation of the equations of our world ocean model is briefly described. The barotropic mode equations are solved according to the split-explicit method, using different time steps for the external and internal modes. Because the numerical algorithm is implemented on the B-grid,...
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ftdoajarticles:oai:doaj.org/article:a29b1a6c6160417c828c76b240c9dede 2023-05-15T18:25:37+02:00 On the computation of the barotropic mode of a free-surface world ocean model E. Deleersnijder J.-M. Campin https://doaj.org/article/a29b1a6c6160417c828c76b240c9dede EN eng Copernicus Publications http://www.ann-geophys.net/13/675/1995/angeo-13-675-1995.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/a29b1a6c6160417c828c76b240c9dede Annales Geophysicae, Vol 13, Iss 6, Pp 675-688 (0000) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article ftdoajarticles 2022-12-30T21:58:17Z The free-surface formulation of the equations of our world ocean model is briefly described. The barotropic mode equations are solved according to the split-explicit method, using different time steps for the external and internal modes. Because the numerical algorithm is implemented on the B-grid, a spurious, free-surface, two-grid interval mode may develop. This mode must be filtered out. The properties of two filters are theoretically investigated and their actual performance is tested in a series of numerical experiments. It is seen that one of these filters may severely perturb the local mass conservation, rendering it impossible to enforce the impermeability of the surface or the bottom of the ocean. The dynamics of the external mode is also examined, by studying the depth-integrated momentum equations. The depth-integral of the pressure force due to the slope of the ocean surface is approximately balanced by the depth-integral of the force ensuing from the horizontal variations of the density. The depth-integral of the Coriolis force is an order of magnitude smaller, except in the Southern Ocean. Two variational principles are resorted to for computing the fictitious ocean surface elevation corresponding to the approximate equilibrium between the dominant forces of the barotropic momentum equations. Article in Journal/Newspaper Southern Ocean Directory of Open Access Journals: DOAJ Articles Southern Ocean |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 E. Deleersnijder J.-M. Campin On the computation of the barotropic mode of a free-surface world ocean model |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
The free-surface formulation of the equations of our world ocean model is briefly described. The barotropic mode equations are solved according to the split-explicit method, using different time steps for the external and internal modes. Because the numerical algorithm is implemented on the B-grid, a spurious, free-surface, two-grid interval mode may develop. This mode must be filtered out. The properties of two filters are theoretically investigated and their actual performance is tested in a series of numerical experiments. It is seen that one of these filters may severely perturb the local mass conservation, rendering it impossible to enforce the impermeability of the surface or the bottom of the ocean. The dynamics of the external mode is also examined, by studying the depth-integrated momentum equations. The depth-integral of the pressure force due to the slope of the ocean surface is approximately balanced by the depth-integral of the force ensuing from the horizontal variations of the density. The depth-integral of the Coriolis force is an order of magnitude smaller, except in the Southern Ocean. Two variational principles are resorted to for computing the fictitious ocean surface elevation corresponding to the approximate equilibrium between the dominant forces of the barotropic momentum equations. |
format |
Article in Journal/Newspaper |
author |
E. Deleersnijder J.-M. Campin |
author_facet |
E. Deleersnijder J.-M. Campin |
author_sort |
E. Deleersnijder |
title |
On the computation of the barotropic mode of a free-surface world ocean model |
title_short |
On the computation of the barotropic mode of a free-surface world ocean model |
title_full |
On the computation of the barotropic mode of a free-surface world ocean model |
title_fullStr |
On the computation of the barotropic mode of a free-surface world ocean model |
title_full_unstemmed |
On the computation of the barotropic mode of a free-surface world ocean model |
title_sort |
on the computation of the barotropic mode of a free-surface world ocean model |
publisher |
Copernicus Publications |
url |
https://doaj.org/article/a29b1a6c6160417c828c76b240c9dede |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Annales Geophysicae, Vol 13, Iss 6, Pp 675-688 (0000) |
op_relation |
http://www.ann-geophys.net/13/675/1995/angeo-13-675-1995.html https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 0992-7689 1432-0576 https://doaj.org/article/a29b1a6c6160417c828c76b240c9dede |
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1766207191604264960 |