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| Titel |
Variability of synoptic-scale quasi-stationary thermohaline stratification patterns in the Gulf of Finland in summer 2009 |
| VerfasserIn |
T. Liblik, U. Lips |
| 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 ; 8, no. 4 ; Nr. 8, no. 4 (2012-08-13), S.603-614 |
| Datensatznummer |
250005753
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| Publikation (Nr.) |
 copernicus.org/os-8-603-2012.pdf |
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| Zusammenfassung |
| We present and analyze high-resolution observational data of thermohaline
structure and currents acquired in the Gulf of Finland (Baltic Sea), using
an autonomous buoy profiler and bottom-mounted acoustic Doppler current
profiler during July–August 2009. Vertical profiles of temperature and
salinity were measured in the upper 50-m layer with a 3 h time resolution,
and vertical profiles of current velocity and direction were recorded with a
10 min time resolution. Although large temporal variations of vertical
temperature and salinity distributions were revealed, it was possible to
define several periods with quasi-stationary vertical thermohaline
structure. These quasi-stationary stratification patterns persisted for
4–15 days and were dominated by certain physical processes: upwelling,
relaxation of upwelling, estuarine circulation and its wind-induced
reversal, and downwelling. Vertical profiles of current velocities supported
the concept of synoptic-scale, quasi-stationary periods of hydrophysical
fields, characterized by distinct layered flow structures and current
oscillations. To estimate the contribution of different processes to the
changes in stratification, a simple conceptual model was developed. The
model accounts for heat flux through the sea surface, wind mixing,
wind-induced transport (parallel to the horizontal salinity gradient) in the
upper layer, and estuarine circulation. It reproduced observed changes in
vertical stratification reasonably well. The largest discrepancies between
observations and model results were found when water motions across the Gulf
and associated vertical displacements of isopycnals (upwelling or
downwelling) were dominant processes. |
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