Publication Date:
2019-01-21
Description:
The free surface version of the GFDL model is used to study inflow and outflow through the
Danish Straits, which connect the Baltic with the North Sea. Three problems are addressed:
(i) the piling up of inflowing water in the Arkona basin; (ii) the transport ratios between Belt
and Sound; (iii) the dominance of hydraulic or geostrophic control. Model results show that a
cyclonic eddy (dome) is formed by the inflowing saline water that prevents this water from
passing rapidly into the Bornholm basin. This eddy is enforced with increasing inflow due to a
sea level difference between Kattegat and western Baltic. If density gradients along the straits are
weak and the flow is dominantly driven by sea level differences between Kattegat and Baltic, the
well-known ratio of 70% : 30% for the transports through Belt and Sound are confirmed.
Strong density gradients can change this ratio considerably, especially in the outflow case, when
the light water of the Baltic flows against the heavier water of the Kattegat. Under variable wind
conditions, no fixed ratio is found. The flow in the Straits is geostrophically controlled; however,
the strong baroclinic density field does not allow us to derive the transport simply from sea level
inclination.
Type:
Article
,
PeerReviewed
Format:
text
