Thermohaline residual circulation of the Wadden Sea

Verfasser / Beitragende:
[Hans Burchard, Thomas Badewien]
Ort, Verlag, Jahr:
2015
Enthalten in:
Ocean Dynamics, 65/12(2015-12-01), 1717-1730
Format:
Artikel (online)
ID: 605546657
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024 7 0 |a 10.1007/s10236-015-0895-x  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s10236-015-0895-x 
245 0 0 |a Thermohaline residual circulation of the Wadden Sea  |h [Elektronische Daten]  |c [Hans Burchard, Thomas Badewien] 
520 3 |a In this study, we present estuarine circulation driven by horizontal density gradients generated by spatially homogeneous surface buoyancy fluxes over sloping bathymetry as a dynamical feature in the coastal zone being potentially relevant for cross-coastal transports. A combination of downward buoyancy flux (net precipitation, net heating) together with tidal mixing may generate a classical estuarine circulation with landward near-bottom residual currents. The Wadden Sea of the south-eastern North Sea is a prototype for such a coastal regime. It is characterised by extensive inter-tidal flats along the coast separated from the open sea by barrier islands. Here, we present long-term observations from the Wadden Sea covering the years 2006-2011. We investigated the statistics of the density gradients. Typical values for the landward density gradient were ∂ x ρ≈−3⋅10−5 kg m−4 and maximum values were ∂ x ρ≈−6.5⋅10−5 kg m−4. The magnitude of the density gradient resulted from the magnitude of the salinity gradient, with some modifications by the positive (towards the coast, in spring) or negative (towards the sea, in autumn) temperature gradient. To explain the generation of estuarine circulation by the surface buoyancy flux, we construct an analytical model representing the geometry and dynamics of a Wadden Sea Basin. With downward buoyancy flux, a weak classical estuarine circulation due to gravitational forcing results, whereas upward buoyancy flux drives inverse estuarine circulation. Finally, a two-dimensional (vertical-longitudinal) numerical model was set up for the idealised geometry, including tidally asymmetric turbulent mixing. This results in significantly stronger estuarine circulation due to the presence of tidal straining. The model assesses the circulation due to neutral and upward surface buoyancy fluxes. We conclude that these mechanisms may be important in many coastal areas and may substantially contribute to coast-to-sea exchange in these areas. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Wadden Sea  |2 nationallicence 
690 7 |a Estuarine circulation  |2 nationallicence 
690 7 |a Surface buoyancy flux  |2 nationallicence 
690 7 |a Horizontal density gradients  |2 nationallicence 
700 1 |a Burchard  |D Hans  |u Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, D-18119, Rostock, Germany  |4 aut 
700 1 |a Badewien  |D Thomas  |u Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Schleusenstraße 1, D-26382, Wilhelmshaven, Germany  |4 aut 
773 0 |t Ocean Dynamics  |d Springer Berlin Heidelberg  |g 65/12(2015-12-01), 1717-1730  |x 1616-7341  |q 65:12<1717  |1 2015  |2 65  |o 10236 
856 4 0 |u https://doi.org/10.1007/s10236-015-0895-x  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s10236-015-0895-x  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Burchard  |D Hans  |u Leibniz Institute for Baltic Sea Research Warnemünde, Seestraße 15, D-18119, Rostock, Germany  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Badewien  |D Thomas  |u Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Schleusenstraße 1, D-26382, Wilhelmshaven, Germany  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Ocean Dynamics  |d Springer Berlin Heidelberg  |g 65/12(2015-12-01), 1717-1730  |x 1616-7341  |q 65:12<1717  |1 2015  |2 65  |o 10236