Drifter observations and Lagrangian tracking of the 2018 easterly wind event in the North Sea

Abstract

Persistent easterly winds in spring 2018 reversed the circulation in the North Sea for more than a month. This reversal has been documented by GPS-drifter observations, as well as by the stranding positions of wooden drifters released along the German North Sea coast. The latter information came from members of the public, the majority of which are likely to be non-scientists. It provided a valuable contribution to the GPS-drifter experiment and demonstrates an excellent example of the usefulness of citizen science. Lagrangian numerical experiments were also performed and helped explain and quantify the anomalous transport and the reversal of the circulation at the sea surface and in deeper layers. It has been shown that the CMEMS surface current products agree well with drifter observations, even under extreme wind conditions, which adds to their credibility.