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| Titel |
Changes in Mediterranean circulation and water characteristics due to restriction of the Atlantic connection: a high-resolution ocean model |
| VerfasserIn |
R. P. M. Topper, P. Th. Meijer |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 2 ; Nr. 11, no. 2 (2015-02-16), S.233-251 |
| Datensatznummer |
250117166
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| Publikation (Nr.) |
 copernicus.org/cp-11-233-2015.pdf |
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| Zusammenfassung |
A high-resolution parallel ocean model is set up to examine how the
sill depth of the Atlantic connection affects circulation and water
characteristics in the Mediterranean Basin. An analysis of the model
performance, comparing model results with observations of the
present-day Mediterranean, demonstrates its ability to reproduce
observed water characteristics and circulation (including deep water
formation). A series of experiments with different sill depths in
the Atlantic–Mediterranean connection is used to assess the
sensitivity of Mediterranean circulation and water characteristics
to sill depth. Basin-averaged water salinity and, to a lesser
degree, temperature rise when the sill depth is shallower and exchange
with the Atlantic is lower. Lateral and interbasinal differences in
the Mediterranean are, however, largely unchanged. The strength of
the upper overturning cell in the western basin is proportional to
the magnitude of the exchange with the Atlantic, and hence to sill
depth. Overturning in the eastern basin and deep water formation in
both basins, on the contrary, are little affected by the sill depth.
The model results are used to interpret the sedimentary record of
the Late Miocene preceding and during the Messinian Salinity
Crisis. In the western basin, a correlation exists between sill depth
and rate of refreshment of deep water. On the other hand, because
sill depth has little effect on the overturning and deep water
formation in the eastern basin, the model results do not support the
notion that restriction of the Atlantic–Mediterranean connection may
cause lower oxygenation of deep water in the eastern basin. However,
this discrepancy may be due to simplifications in the surface
forcing and the use of a bathymetry different from that in the Late
Miocene. We also tentatively conclude that blocked outflow, as found
in experiments with a sill depth ≤10 m, is a plausible
scenario for the second stage of the Messinian Salinity Crisis
during which halite was rapidly accumulated in the Mediterranean.
With the model setup and experiments, a basis has been established
for future work on the sensitivity of Mediterranean circulation to
changes in (palaeo-)bathymetry and external forcings. |
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