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| Titel |
Observations of the upper ocean response to storm forcing in the South Atlantic Roaring Forties |
| VerfasserIn |
R. Marsh |
| 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 ; 13, no. 10 ; Nr. 13, no. 10, S.1027-1038 |
| Datensatznummer |
250012005
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| Publikation (Nr.) |
 copernicus.org/angeo-13-1027-1995.pdf |
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| Zusammenfassung |
| In the austral summer of 1992–1993 the
passage of a storm system drove a strong upper ocean response at 45°S in the
mid-South Atlantic. Good in situ observations were obtained. CTD casts revealed
that the mixed layer deepened by ~40 m over 4 days. Wind stirring dominated
over buoyancy flux-driven mixing during the onset of high winds. Doppler shear
currents further reveal this to be intimately related to inertial dynamics. The
penetration depth of inertial currents, which are confined to the mixed layer,
increases with time after a wind event, matched by a downward propagation of low
values of the Richardson number. This suggests that inertial current shear is
instrumental in producing turbulence at the base of the mixed layer. Evolution
of inertial transport is simulated using a time series of ship-observed wind
stress. Simulated transport is only 30–50% of the observed transport, suggesting
that much of the observed inertial motion was forced by an earlier (possibly
remote) storm. Close proximity of the subtropical front further complicates the
upper ocean response to the storm. A simple heat balance for the upper 100 m
reveals that surface cooling and mixing (during the storm) can account for only
a small fraction of an apparent ~1 °C mixed layer cooling. |
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