Studying the Norwegian Atlantic Current
The Norwegian Atlantic Current delivers relatively warm water from the Gulf Stream to the Nordic Sea, moderating the local climate considerably. It is suspected that climate change may disrupt this important circulation, possibly plunging the region into a colder regime. Accurate prediction of such an event requires an intimate understanding of the current. This was the aim of ASOF-N, a component of the Arctic-subarctic ocean flux (ASOF) research programme dedicated to the northern Atlantic. The Laboratoire d'Océanographie et du Climat (LOCEAN) collaborated with other ASOF-N partners to obtain new measurement data from the Nordic Sea. Eulerian (moorings), Lagrangian (floats) and ship-based methods were used to study the Norwegian Atlantic Current in detail between 2003 and 2005. The French oceanographers and their colleagues discovered that, contrary to common thinking, the current is not a narrow jet. Rather it is a broad, turbulent current with intense eddy activity and episodic fluctuations in temperature and salinity. The same was also true of the West Spitsbergen Current. With respect to the evolution of the Norwegian Atlantic Current over time, significant inter-annual variability was observed. In addition, LOCEAN detected a temperature increase on the order of half a degree Celsius as well as a rise in salinity over the past quarter century. Further research is necessary to determine the possible impact of this trend on the thermohaline circulation in the North Atlantic. These findings may also be of interest to marine biologists given the highly productive nature of the Nordic Sea.
