Changes in Deep Ocean Contribute to a “see‐sawing” Gulf Stream Path

This study demonstrates that a decrease of the water-mass density below 1,000 m has led to a pattern of see-saw shift in the Gulf Stream (GS) position between 74 and 50 degrees W in longitude during 1993-2017, with the New England Seamounts as the pivot point. The GS moved northward in the upstream region and shifted southward in the downstream. Our empirical orthogonal function analyses of satellite altimeter data demonstrate that the second mode (EOF2) represents changes in the GS strength and therefore can be used as an index for the Atlantic Meridional Overturning Circulation. Decreasing water density below 1,000 m is also the principal mechanism driving the weakening of the GS.