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| Titel |
Extreme winter 2012 in the Adriatic: an example of climatic effect on the BiOS rhythm |
| VerfasserIn |
M. Gačić, G. Civitarese, V. Kovačević, L. Ursella, M. Bensi, M. Menna, V. Cardin, P.-M. Poulain, S. Cosoli, G. Notarstefano, C. Pizzi |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2014-06-23), S.513-522 |
| Datensatznummer |
250117006
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| Publikation (Nr.) |
 copernicus.org/os-10-513-2014.pdf |
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| Zusammenfassung |
| Adriatic and Ionian seas are Mediterranean sub-basins linked through the
Bimodal Oscillating System mechanism responsible for decadal reversals of the
Ionian basin-wide circulation. Altimetric maps showed that the last cyclonic
mode started in 2011 but unexpectedly in 2012 reversed to anticyclonic. We
related this "premature" inversion to the extremely strong winter in 2012,
which caused the formation of very dense Adriatic waters, flooding Ionian
flanks in May and inverting the bottom pressure gradient. Using Lagrangian
float measurements, the linear regression between the sea surface height and
three isopycnal depths suggests that the southward deep-layer flow coincided
with the surface northward geostrophic current and the anticyclonic
circulation regime. Density variations at depth in the northwestern Ionian
revealed the arrival of Adriatic dense waters in May and maximum density in
September. Comparison between the sea level height in the northwestern
Ionian and in the basin centre showed that in coincidence with the arrival of
the newly formed Adriatic dense waters the sea level was lowered in the
northwestern flank, inverting the surface pressure gradient. Toward the end
of 2012, the density gradient between the basin flanks and its centre went to
zero, coinciding with the weakening of the anticyclonic circulation and
eventually with its return to the cyclonic pattern. Thus, the premature and
transient reversal of Ionian surface circulation originated from the
extremely harsh winter in the Adriatic, resulting in the formation and
spreading of highly dense bottom waters. The present study highlights the
remarkable sensitiveness of the Adriatic–Ionian BiOS to climatic forcing. |
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