A Recent θ-S Shift in the Deep Water of the Northern North Atlantic
- James E. Hansen and
- Taro Takahashi
Published Online: 19 MAR 2013
Copyright 1984 by the American Geophysical Union.
Climate Processes and Climate Sensitivity
How to Cite
Swift, J. H. (1984) A Recent θ-S Shift in the Deep Water of the Northern North Atlantic, in Climate Processes and Climate Sensitivity (eds J. E. Hansen and T. Takahashi), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM029p0039
- Published Online: 19 MAR 2013
- Published Print: 1 JAN 1984
Print ISBN: 9780875904047
Online ISBN: 9781118666036
- Ocean-atmosphere interaction—Congresses
North Atlantic ocean data from the Transient Tracers in the Ocean North Atlantic Study (1981) show that a deep water θ-S shift has occurred since GEOSECS (1972). For a given density, the deep water north of 50°N is now colder by about 0.15°C and less saline by about 0.02×10−3. Other hydrographic properties such as dissolved oxygen have also changed, but the configuration of the deep density fields is nearly unchanged. The deep changes were observed in at least three distinct deep water masses. Although the shifts are nearly universal north of 50°N, they have not yet spread significantly south of the Grand Banks. The reduced deep water salinities are caused by a freshening since the mid-1970's of the upper layers in the deep water mass formation regions. This upper-layer freshening may in turn be related to shifts in the large-scale atmospheric forcing over the northern North Atlantic and Norwegian-Greenland Sea.