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| Titel |
Tidal forcing, energetics, and mixing near the Yermak Plateau |
| VerfasserIn |
I. Fer, M. Müller, A. K. Peterson |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2015-03-27), S.287-304 |
| Datensatznummer |
250117178
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| Publikation (Nr.) |
 copernicus.org/os-11-287-2015.pdf |
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| Zusammenfassung |
| The Yermak Plateau (YP), located northwest of Svalbard in Fram Strait, is
the final passage for the inflow of warm Atlantic Water into the
Arctic Ocean. The region is characterized by the largest barotropic
tidal velocities in the Arctic Ocean. Internal
response to the tidal flow over this topographic feature locally
contributes to mixing that removes heat from the Atlantic Water. Here,
we investigate the tidal forcing, barotropic-to-baroclinic energy
conversion rates, and dissipation rates in the region using
observations of oceanic currents, hydrography, and microstructure
collected on the southern flanks of the plateau in summer 2007,
together with results from a global high-resolution ocean
circulation and tide model simulation. The energetics
(depth-integrated conversion rates, baroclinic energy fluxes and
dissipation rates) show large spatial variability over the plateau
and are dominated by the luni-solar diurnal (K1) and the
principal lunar semidiurnal (M2) constituents. The
volume-integrated conversion rate over the region enclosing the
topographic feature is approximately 1 GW and accounts for
about 50% of the M2 and approximately all of the K1
conversion in a larger domain covering the entire Fram Strait
extended to the North Pole. Despite the substantial energy
conversion, internal tides are trapped along the topography,
implying large local dissipation rates. An
approximate local conversion–dissipation balance is found over
shallows and also in the deep part of the sloping flanks. The
baroclinic energy radiated away from the upper slope is dissipated
over the deeper isobaths. From the microstructure observations,
we inferred lower and upper bounds on the total dissipation rate
of about 0.5 and 1.1 GW, respectively, where about 0.4–0.6 GW can be attributed to the
contribution of hot spots of energetic turbulence. The domain-integrated dissipation from
the model is close to the upper bound of the observed dissipation,
and implies that almost the entire dissipation in the region can be
attributed to the dissipation of baroclinic tidal energy. |
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