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Titel |
Impact of currents on surface flux computations and their feedback on dynamics at regional scales |
VerfasserIn |
A. Olita, I. Iermano, L. Fazioli, A. Ribotti, C. Tedesco, F. Pessini, R. Sorgente |
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. 4 ; Nr. 11, no. 4 (2015-08-31), S.657-666 |
Datensatznummer |
250117271
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Publikation (Nr.) |
copernicus.org/os-11-657-2015.pdf |
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Zusammenfassung |
A twin numerical experiment was conducted in the seas around the island of
Sardinia (Western Mediterranean) to assess the impact, at regional and
coastal scales, of the use of relative winds (i.e., taking into account ocean
surface currents) in the computation of heat and momentum fluxes through
standard (Fairall et al., 2003) bulk formulas. The Regional Ocean Modelling
System (ROMS) was implemented at 3 km resolution in order to well resolve
mesoscale processes, which are known to have a large influence in the
dynamics of the area. Small changes (few percent points) in terms of
spatially averaged fluxes correspond to quite large differences of such
quantities (about 15 %) in spatial terms and in terms of kinetics (more
than 20 %). As a consequence, wind power input P is also reduced by
~ 14 % on average.
Quantitative validation with satellite SST suggests
that such a modification of the fluxes improves the model solution especially
in the western side of the domain, where mesoscale activity (as suggested by
eddy kinetic energy) is stronger. Surface currents change both in their
stable and fluctuating part. In particular, the path and intensity of the
Algerian Current and of the Western Sardinia Current (WSC) are impacted by
the modification in fluxes. Both total and eddy kinetic energies of the
surface current field are reduced in the experiment where fluxes took into
account the surface currents. The main dynamical correction is observed in the SW
area, where the different location and strength of the eddies influence
the path and intensity of the WSC.
Our results suggest that, even at local scales and in temperate regions, it would be
preferable to take into account such a contribution in flux computations. The modification
of the original code, substantially cost-less in terms of numerical computation, improves
the model response in terms of surface fluxes (SST validated) and it also likely improves
the dynamics as suggested by qualitative comparison with satellite data. |
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