A team of US researchers has found a significant increase in the amount of fresh water in the Arctic Ocean as well as a significant change in the distribution of fresh water, as compared with average winter values. Fresh water flowing into or out of the Arctic Ocean plays an important role in ocean circulation and may be a factor in the response of the world ocean to climate change. The study appears in the current issue of the AGU journal Geophysical Research Letters.
To study recent changes in freshwater content of the Arctic, a team from McPhee Research; Woods Hole Oceanographic Institute; the Polar Science Center at the University of Washington, Seattle; and Oregon State University analyzed data from an extensive aerial hydrographic survey carried out in March and April 2008.
In particular, the authors find that freshwater volume in the Canada and Makarov basins on the Pacific side of the Lomonosov Ridge increased by about 8,500 cubic kilometers (about 2,000 cubic miles), while the freshwater volume on the Eurasian area decreased by about 1,100 cubic kilometers (about 260 cubic miles).
The freshening of the Arctic occurred in conjunction with the recent dramatic loss of Arctic sea ice, the authors note. They find that these changes have altered Arctic Ocean circulation, with a large increase in northward transport of fresh water in the Canada Basin.
The dramatic reduction in minimum Arctic sea ice extent in recent years has been accompanied by surprising changes in the thermohaline structure of the Arctic Ocean, with potentially important impact on convection in the North Atlantic and the meridional overturning circulation of the world ocean.—McPhee et al.
McPhee, M. G., A. Proshutinsky, J. H. Morison, M. Steele, and M. B. Alkire (2009), Rapid change in freshwater content of the Arctic Ocean, Geophys. Res. Lett., 36, L10602, doi: 10.1029/2009GL037525