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Titel |
Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands |
VerfasserIn |
M. Kersalé, A. M. Doglioli, A. A. Petrenko |
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. 3 ; Nr. 7, no. 3 (2011-05-02), S.277-291 |
Datensatznummer |
250004642
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Publikation (Nr.) |
copernicus.org/os-7-277-2011.pdf |
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Zusammenfassung |
The oceanic circulation around the Hawaiian archipelago is characterized by a
complex circulation and the presence of mesoscale eddies west of the islands.
These eddies typically develop and persist for weeks to several months in the
area during persistent trade winds conditions. A series of numerical
simulations on the Hawaiian region has been done in order to examine the
relative importance of wind, inflow current and topographic forcing on the
general circulation and the generation of eddies. Moreover, numerical
cyclonic eddies are compared with the one observed during the cruise E-FLUX
(Dickey et al., 2008). Our study demonstrates the need for all three forcings (wind,
inflow current and topography) to reproduce the known oceanic circulation. In
particular, the cumulative effect plays a key role on the generation of
mesoscale eddies. The wind-stress-curl, via the Ekman pumping mechanism, has
also been identified as an important mechanism upon the strength of the
upwelling in the lee of the Big Island of Hawaii. In order to find the best
setup of a regional ocean model, we compare more precisely numerical results
obtained using two different wind databases: COADS and QuikSCAT. The main
features of the ocean circulation in the area are well reproduced by our
model forced by both COADS and QuickSCAT climatologies. Nevertheless,
significant differences appear in the levels of kinetic energy and vorticity.
The wind-forcing spatial resolution clearly affects the way in which the wind
momentum feeds the mesoscale phenomena. The higher the resolution, the more
realistic the ocean circulation. In particular, the simulation forced by
QuikSCAT wind data reproduces well the observed energetic mesoscale
structures and their hydrological characteristics and behaviors. |
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