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| Titel |
Intercomparison of oceanic and atmospheric forced and coupled mesoscale simulations Part I: Surface fluxes |
| VerfasserIn |
P. Josse, G. Caniaux, H. Giordani, S. Planton |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 17, no. 4 ; Nr. 17, no. 4, S.566-576 |
| Datensatznummer |
250013717
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| Publikation (Nr.) |
 copernicus.org/angeo-17-566-1999.pdf |
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| Zusammenfassung |
A mesoscale non-hydrostatic atmospheric model
has been coupled with a mesoscale oceanic model. The case study is a four-day
simulation of a strong storm event observed during the SEMAPHORE experiment over
a 500 × 500 km2 domain. This domain encompasses a thermohaline front
associated with the Azores current. In order to analyze the effect of mesoscale
coupling, three simulations are compared: the first one with the atmospheric
model forced by realistic sea surface temperature analyses; the second one with
the ocean model forced by atmospheric fields, derived from weather forecast
re-analyses; the third one with the models being coupled. For these three
simulations the surface fluxes were computed with the same bulk parametrization.
All three simulations succeed well in representing the main oceanic or
atmospheric features observed during the storm. Comparison of surface fields
with in situ observations reveals that the winds of the fine mesh atmospheric
model are more realistic than those of the weather forecast re-analyses. The
low-level winds simulated with the atmospheric model in the forced and coupled
simulations are appreciably stronger than the re-analyzed winds. They also
generate stronger fluxes. The coupled simulation has the strongest surface heat
fluxes: the difference in the net heat budget with the oceanic forced simulation
reaches on average 50 Wm-2 over the simulation period. Sea
surface-temperature cooling is too weak in both simulations, but is improved in
the coupled run and matches better the cooling observed with drifters. The
spatial distributions of sea surface-temperature cooling and surface fluxes are
strongly inhomogeneous over the simulation domain. The amplitude of the flux
variation is maximum in the coupled run. Moreover the weak correlation between
the cooling and heat flux patterns indicates that the surface fluxes are not
responsible for the whole cooling and suggests that the response of the ocean
mixed layer to the atmosphere is highly non-local and enhanced in the coupled
simulation.
Key words. Oceanography: physical (air · sea interac-
tion; eddies and mesoscale processes). Meteorology and atmospheric dynamics
(ocean · atmosphere interactions) |
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