Ocean Circulation and Climate Dynamics

North Atlantic Circulation

In the North Atlantic Ocean, the warm surface currents from the south collide with the cold waters from the Norwegian Sea and the Arctic. Here is where the most important transformation of warm water masses into cold deep water takes place, and the western margin of the ocean is the initial formation region of the deep western boundary current, part of the global circulation or conveyor belt that transports cold and oxygen-enriched deep water southward into the subtropics, tropics and southern hemisphere, spreading into the other oceans as well. Of particular interest today are long-term variations of circulation and their effects on climate, CO2 uptake and the fresh water cycle. Hence we observe, in close collaboration with research groups of the other neighboring countries, the slow warming of the subpolar North Atlantic at depth, and one of the most pressing questions is whether these changes have an impact on the North Atlantic circulation, in particular, whether the deep western boundary current weakens as a result of this warming.


The deployment and recovery of moored instrumentation on the high seas often require difficult and intense work by scientists, technicians and crew. Especially during the winter months, operations are hampered by storms, pack ice and drifting icebergs, and so long-term observations are preferably made with autonomous instruments, such as moored stations or freely floating platforms (floats, drifters, gliders). Measurements are concentrated, if possible, where a large portion of the deep circulation and its variability can be readily observed - the so-called key regions. Our commitment to the North Atlantic focuses on such a key position, namely the exit of the Labrador Sea. These issues are investigated as part of national (BMBF - RACE) and international (EU-THOR) projects, and the long-term focus of these studies is particularly suitable for a Helmholz Centre.


pers. Page
Prof. Dr. Martin Visbeck +49 431 600-4100 http://www.geomar.de/en/mitarbeiter/fb1/po/mvisbeck/
Dr. Jürgen Fischer +49 431 600-4106 http://www.geomar.de/en/mitarbeiter/fb1/po/jfischer/
Dr. Johannes Karstensen +49 431 600-4156 http://www.geomar.de/en/mitarbeiter/fb1/po/jkarstensen/