Lagrangian approaches enable to study circulation patterns in coastal oceans in great spatial and temporal detail. Here, we present a large data set on circulation patterns in the North Sea with a focus on the frontal systems in the Skagerrak – the transition area between the Baltic and North Sea. The data set encompasses measurements obtained from Lagrangian surface drifters which were deployed during several cruises between 2017 to 2021. Our research group at the ICBM (University of Oldenburg) designed the low-cost drifters for studying coastal dynamics and exchange processes in tidal systems. We also used clusters of drifters to analyze in detail fine sub-mesoscale fluid dynamics, such as divergence and eddy dynamics.  Based on the large data set, we provide high-resolution surface current maps and show representations of tidal dynamics in the North Sea. Our data reveal significant differences between the mostly shallow areas of the North Sea and the deep Skagerrak. While tidal currents dominate the shallow coastal areas, deep areas are characterized by a high mean residual circulation driven by high density gradients. The data sets are well suited for model validation and further studies on sea surface dynamics in frontal zones including mixing processes. The detailed knowledge of surface currents obtained by the measurements also help study the impact of hydrodynamics on processes at the sea-air-interface.

Primary Presenter: Thomas Badewien, University of Oldenburg (thomas.badewien@uni-oldenburg.de)

Authors:

Thomas Badewien, Universtity of Oldenburg / ICBM  (thomas.badewien@uni-oldenburg.de)

Lisa Deyle, University of Oldenburg / ICBM  (lisa.deyle1@uni-oldenburg.de)

Andrea Luebben, University of Oldenburg / ICBM  (andrea.luebben1@uni-oldenburg.de)

Jens Meyerjuergens, University of Oldenburg / ICBM  (jens.meyerjuergens@uni-oldenburg.de)