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| Titel |
Parameterization of subgrid stirring in eddy resolving ocean models. |
| VerfasserIn |
Julien Le Sommer, Francesco d'Ovidio, Gurvan Madec |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052542
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| Zusammenfassung |
| Horizontal stirring by time-varying mesoscale flows contributes to forming submesoscale
tracer filaments. Here, we propose a parameterization of the transport associated with the
formation of submesoscale tracer filaments by mesoscale flows for use in O(10km) resolution
ocean models. Theoretical motivations are provided for modelling subgrid stirring by the
resolved mesoscale flows with an anisotropic generalization of Smagorinsky operator. For
level coordinate models, an isoneutral formulaton of the proposed subgrid operator is
provided. The proposed subgrid operator is diagnosed with DRAKKAR global 1/4°
eddy-resolving model output. In the Southern Ocean, the parameterization is shown
to provide diffusivities peaking at about 400m2s-1. If applied prognostically, the
proposed subgrid operator could drive meridional heat transports of about .5PW at
45°S. This suggests that a significant fraction of the transport by mesoscale flows
could be associated with tracer features of scale smaller than our model grid size
(~20km at 45°S). A large contribution to this transport is associated with differential
advection by the time-mean flow at the subgrid scale. Preliminary prognostic tests
indicating that the parameterization is both stable and accurate will be discussed. |
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