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| Titel |
On the numerical resolution of the bottom layer in simulations of oceanic gravity currents |
| VerfasserIn |
N. Laanaia, A. Wirth, J. M. Molines, B. Barnier, J. Verron |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 6, no. 2 ; Nr. 6, no. 2 (2010-06-08), S.563-572 |
| Datensatznummer |
250003471
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| Publikation (Nr.) |
 copernicus.org/os-6-563-2010.pdf |
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| Zusammenfassung |
The role of an increased numerical vertical resolution, leading
to an explicit resolution of the bottom Ekman layer dynamics, is investigated.
Using the hydrostatic ocean model NEMO-OPA9, we demonstrate
that the dynamics of an idealised gravity current (on an inclined plane),
is well captured when a few (around five) sigma-coordinate
levels are added near the ocean floor.
Such resolution allows to considerably improve the representation of
the descent and transport of the gravity current
and the Ekman dynamics near the
ocean floor, including the important effect of Ekman veering,
which is usually neglected in today's simulations of the ocean dynamics.
Results from high resolution simulations (with σ and z-coordinates)
are compared to simulations with a vertical
resolution commonly employed in today's ocean models.
The latter show
a downslope transport that is reduced by almost an order of magnitude
and the decrease in the along slope transport is reduced six-fold.
We strongly advocate for an increase of the numerical resolution at the ocean floor,
similar to the way it is done at the ocean surface and at
the lower boundary in atmospheric models. |
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