Coherent surface-subsurface fingerprint of the Atlantic meridional overturning circulation

• Published in: Geophysical research letters Vol. 35; no. 20
• Main Author: Zhang, Rong
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 01.10.2008; American Geophysical Union
• Subjects: AMOC; Earth sciences; Earth, ocean, space; Exact sciences and technology; Marine; SSH; subsurface temperature; Atlantic Ocean; North Atlantic; Gulf Stream; AN, North Atlantic; ANE, North Atlantic Subpolar Gyre; AN, North Atlantic, Gulf Stream; ANE, North Atlantic, Subpolar Gyre; satellites; trend-surface analysis; Quaternary; simulation; upper Quaternary; indicators; ocean-atmosphere interaction; subsurface; variability; Long term; Temperature measurement; Ocean-atmosphere model; interpretation; Decadal variation; thermohaline circulation; Dipole; temperature; Cenozoic; Phanerozoic; Vortex; Holocene; Atlantic; altimetry
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2008GL035463

Satellite altimeter data shows a weakening of the North Atlantic subpolar gyre during the 1990s, which is thought as an indicator of a slowdown of the Atlantic meridional overturning circulation (AMOC). However, whether the recent slowing subpolar gyre is a decadal variation or a long‐term trend remains unclear. Here I show that altimeter data is highly correlated with instrumental subsurface ocean temperature data in the North Atlantic, and both show opposite signs between the subpolar gyre and the Gulf Stream path. Such a dipole pattern is a distinctive fingerprint of AMOC variability, as shown for the first time by a 1000‐year coupled ocean‐atmosphere model simulation. The results suggest that, contrary to previous interpretations, the recent slowdown of the subpolar gyre is a part of a multidecadal variation and suggests a strengthening of the AMOC. The ongoing satellite and subsurface temperature measurements could be used to monitor future AMOC variations sensitively.