Signature of the Atlantic meridional overturning circulation in sea level along the east coast of North America

Abstract

In this letter we examine the relationship between the North Atlantic Meridional Overturning Circulation (MOC) and sea level (SL) along the east coast of North America. In the eddy permitting ocean model OCCAM we find a distinctive, topography‐following pattern of SL variability in the western North Atlantic that is closely linked with the changing strength of the MOC, with a 2 cm drop in SL along the US east coast corresponding to a 1Sv increase in the MOC. We find a similar pattern of SL variability in the altimetry record and show that this meridionally coherent SL mode dominates interannual SL variability at tide gauges along the North American east coast between 40–50°N. Hence we conclude that North American coastal sea‐level may indeed be a useful indicator of MOC variability on interannual timescales, allowing an observationally‐based estimate of the likely range of interannual MOC fluctuations to be determined.