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| Titel |
Numerical simulation and decomposition of kinetic energy in the Central Mediterranean: insight on mesoscale circulation and energy conversion |
| VerfasserIn |
R. Sorgente, A. Olita, P. Oddo, L. Fazioli, A. Ribotti |
| 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 (2011-08-22), S.503-519 |
| Datensatznummer |
250004721
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| Publikation (Nr.) |
 copernicus.org/os-7-503-2011.pdf |
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| Zusammenfassung |
The spatial and temporal variability of eddy and mean kinetic energy of the
Central Mediterranean region has been investigated, from January 2008 to
December 2010, by mean of a numerical simulation mainly to quantify the
mesoscale dynamics and their relationships with physical forcing. In order
to understand the energy redistribution processes, the baroclinic energy
conversion has been analysed, suggesting hypotheses about the drivers of the
mesoscale activity in this area. The ocean model used is based on the
Princeton Ocean Model implemented at 1/32° horizontal resolution.
Surface momentum and buoyancy fluxes are interactively computed by mean of
standard bulk formulae using predicted model Sea Surface Temperature and
atmospheric variables provided by the European Centre for Medium Range
Weather Forecast operational analyses. At its lateral boundaries the model
is one-way nested within the Mediterranean Forecasting System operational
products.
The model domain has been subdivided in four sub-regions: Sardinia channel
and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and
Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been
analysed, on each of the four sub-regions,
showing different behaviours. On annual scales and within the first 5 m
depth, the eddy kinetic energy represents approximately the 60 % of the
total kinetic energy over the whole domain, confirming the strong mesoscale
nature of the surface current flows in this area. The analyses show that the
model well reproduces the path and the temporal behaviour of the main known
sub-basin circulation features. New mesoscale structures have been also
identified, from numerical results and direct observations, for the first
time as the Pantelleria Vortex and the Medina Gyre.
The classical kinetic energy decomposition (eddy and mean) allowed to
depict and to quantify the permanent and fluctuating parts of the circulation
in the region, and to differentiate the four sub-regions as function of
relative and absolute strength of the mesoscale activity. Furthermore the
Baroclinic Energy Conversion term shows that in the Sardinia Channel the
mesoscale activity, due to baroclinic instabilities, is significantly larger
than in the other sub-regions, while a negative sign of the energy
conversion, meaning a transfer of energy from the Eddy Kinetic Energy to the
Eddy Available Potential Energy, has been recorded only for the surface
layers of the Sicily Channel during summer. |
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