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| Titel |
A practical scheme to introduce explicit tidal forcing into an OGCM |
| VerfasserIn |
K. Sakamoto, H. Tsujino, H. Nakano, M. Hirabara, G. Yamanaka |
| 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 ; 9, no. 6 ; Nr. 9, no. 6 (2013-12-13), S.1089-1108 |
| Datensatznummer |
250085283
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| Publikation (Nr.) |
 copernicus.org/os-9-1089-2013.pdf |
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| Zusammenfassung |
| A practical scheme is proposed to explicitly introduce tides into ocean
general circulation models (OGCM). In this scheme, barotropic linear response
to the tidal forcing is calculated by the time differential equations
modified for ocean tides, instead of the original barotropic equations of an
OGCM. This allows for the usage of various parameterizations specified for tides,
such as the self-attraction/loading (SAL) effect and energy dissipation due
to internal tides, without unintentional violation of the original dynamical
balances in an OGCM. Meanwhile, secondary nonlinear effects of tides, e.g.,
excitation of internal tides and advection by tidal currents, are fully
represented within the framework of the original OGCM equations. That is, this
scheme drives the OGCM by the barotropic linear tidal currents which are
predicted progressively by a tuned tide model, instead of the equilibrium
tide potential, without large additional numerical costs. We incorporated
this scheme into Meteorological Research Institute Community Ocean Model and
executed test experiments with a low-resolution global model. The results
showed that the model can simulate both the non-tidal circulations and
the tidal motion simultaneously. Owing to the usage of tidal parameterizations such
as a SAL term, a root-mean-squared error in the tidal heights is found to be
as small as 10.0 cm, which is comparable to that of elaborately tuned tide models.
In addition, analysis of the speed and energy of the barotropic tidal
currents is found to be consistent with that of past tide studies. The model also
showed active excitement of internal tides and tidal mixing. In the future, the
impacts of internal tides and tidal mixing
should be examined using a model with a finer resolution, since
explicit and precise introduction of tides into an OGCM is a significant step
toward the improvement of ocean models. |
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