Greenland Sea Surface Temperature Change and Accompanying Changes in the Northern Hemispheric Climate

Abstract

sudden change in the reference Greenland Sea surface temperature (GSST) in 1979 is identified. It is found to be a part of complex changes in the northern North Atlantic seas. The GSST change, in particular, resulted in a major change in the near-surface baroclinicity in the region, in addition to a large change in the net surface heat flux at the air?sea boundary over the Greenland Sea. The differences in the atmospheric mean state between two periods, one before and the other after the GSST change in the late 1970s, resemble those between the high and low North Atlantic Oscillation (NAO) index states. In addition to the changes in the mean state, major changes in the interannual variability of the atmosphere are found. A particularly interesting change in the interannual variability is found in the relationship between July GSST and the NAO phase in the following February. There is a strong correlation between July GSST and the NAO phase in the following February before the late 1970s but not at all after the late 1970s. The characteristics of these changes suggest that they may be a part of the high-frequency details of the Atlantic multidecadal oscillation.