On the estuarine transport reversal in deep layers of the Gulf of Finland
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
Also appears in:Ohlson, M.; Omstedt, A.; Turner, D. (Ed.) (2003). Proceedings of the 22nd Conference of the Baltic Oceanographers (CBO), Stockholm, Sweden, 25-29 November 2001. Journal of Sea Research, 49(4). Elsevier: Amsterdam. 227-374 pp., more
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| Keywords |
Layers > Water column > Deep layer
Models > Mathematical models
Motion > Fluid motion > Baroclinic motion
Motion > Fluid motion > Fluid flow > Density flow
Motion > Water motion > Circulation > Water circulation > Shelf dynamics > Estuarine dynamics
Motion > Water motion > Circulation > Water circulation > Wind-driven circulation
Motion > Water motion > Water currents > Subsurface currents > Deep currents
Transport > Volume transport
ANE, Baltic, Finland Gulf [Marine Regions]
Marine/Coastal |
| Author keywords |
estuarine dynamics; volume transport; wind-driven circulation; numericalmodels; Baltic Sea; Gulf of Finland |
| Authors | | Top |
- Elken, J.
- Raudsepp, U.
- Lips, U., more
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| Abstract |
The Gulf of Finland is a 400-km long and 48-135-km wide tributary estuary of the Baltic Sea featuring the longitudinal two-layer estuarine flow modified by transverse circulation. Longitudinal volume transport in the deep layer is investigated by decomposing it into an averaged, slowly changing estuarine component (due to large-scale density gradients, river discharge and mean wind stress) and wind-driven fluctuating component. The derived expression relates the total deep-layer transport to the projection of wind stress fluctuation to a site-specific direction. The relationship is tested and calibrated by the results from numerical experiments carried out with the three-dimensional baroclinic circulation model. For the entrance to the Gulf of Finland, winds from northeast support standard estuarine circulation and winds from southwest work against the density-driven and riverine flow. The deep estuarine transport may be reversed if the southwesterly wind component exceeds the mean value by 4-5.5 m s-1. According to the data from hydrographic observations in the western Gulf of Finland, an event of advective halocline disappearance was documented in August 1998. Comparison of the deep-water transport estimates calculated from the wind data in 1998 with the observed salinity variations showed that the events of rapid decay of estuarine stratification were coherent with the estimated reversals of deep-layer volume transport, i.e. events of salt wedge export from the gulf. |
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