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| Titel |
A high resolution ocean model of restriction of the Mediterranean-Atlantic connection: Changes in Mediterranean circulation and water characteristics |
| VerfasserIn |
Robin Topper, Paul Meijer |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095679
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| Publikation (Nr.) |
 EGU/EGU2014-11148.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 on 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 less 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, on the other hand, 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 explained by simplifications in the surface forcing and a different
bathymetry than 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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