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| Titel |
Tidal generation of large sub-mesoscale eddy dipoles |
| VerfasserIn |
W. Callendar, J. M. Klymak, M. G. G. Foreman |
| 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 ; 7, no. 4 ; Nr. 7, no. 4 (2011-08-03), S.487-502 |
| Datensatznummer |
250004720
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| Publikation (Nr.) |
 copernicus.org/os-7-487-2011.pdf |
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| Zusammenfassung |
| Numerical simulations of tidal flow past Cape St. James on the
south tip of Haida Gwaii (Queen Charlotte Islands) are presented that
indicate mesoscale dipoles are formed from coalescing tidal eddies.
Observations in this region demonstrate robust eddy generation at
the Cape, with the primary process being flow separation of buoyant
or wind driven outflows forming large anti-cyclonic, negative
potential vorticity, Haida Eddies. However, there are other times
where dipoles are observed in satellites, indicating a source of
positive potential vorticity must also be present. The simulations
here build on previous work that implicates oscillating tidal flow
past the cape in creating the positive vorticity. Small headland
eddies of alternating vorticity are created each tide. During
certain tidal cycles, the headland eddies coalesce and self organize
in such a way as to create large >20-km diameter eddies that then
self-advect into deep water. The self advection speed is faster
than the beta drift of anti-cyclones, and the propagation direction
appears to be more southerly than typical Haida Eddies, though the
model contains no mean wind-driven flows. These eddies are smaller
than Haida Eddies, but given their tidal origin, may represent a
more consistent source of coastal water that is injected into the
interior of the subpolar gyre. |
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