Abyssal warming in the Nordic Seas

• Main Authors: Dickson, R. R., Osterhus, S., Klages, Michael, Soltwedel, Thomas
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: Arctic Ocean; Fram Strait; Greenland; Greenland Sea; Jan Mayen; Lofoten; Nordic Seas; Norwegian Sea
• Online Access: https://epic.awi.de/id/eprint/25908/; https://hdl.handle.net/10013/epic.38840

Since Greenland Sea Deep Water (GSDW) is the coldest of the three local Deep Waters, Meincke & Rudels (1995) concluded that the sustained warming in the deep Greenland Sea from the early 1970s to the present was due to a progressive shift from vertical exchange (with the cool surface layers) to horizontal exchange [with the relatively warm Arctic Ocean Deep Water (AODW) through Fram Strait], and the accompanying changes in silicate and oxygen were consistent with that view. Dickson & Østerhus (2007) later explained the parallel warming of Norwegian Sea Deep Water at 2000m beneath OWS M as being due to the spread of this warming GSDW through the Jan Mayen Channel (sill 2000m). Here we follow the warming signal northwards from OWS M through the Lofoten Basin to the Fram Strait, where we conclude that it may explain the steady rise in temperature observed close to the seabed over the last ten years in the deepest part of the water column (2500m) at the HAUSGARTEN-centre site. Since sea-floor temperature is a known control on the dissociation of gas hydrates from sediments in this area, it is important to develop an understanding of the cause of such a sustained warming trend. If our conclusion is correct, the observed warming there may be just the recent expression of a longer trend involving changes in the exchange of deep waters between three ocean basins (Eurasian, Greenland and Norwegian) over a period of 4 decades. And at OWS M and Fram Strait, the deep warming continues.