Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises

• Published in: Science (American Association for the Advancement of Science) Vol. 348; no. 6241; p. 1330
• Main Authors: Srokosz, M. A., Bryden, H. L.
• Format: Journal Article
• Language: English
• Published: Washington American Association for the Advancement of Science 19.06.2015; The American Association for the Advancement of Science
• Subjects: Altimetry; Circulation; Climate; Climate change; Climate models; Climate variability; Enthalpy; Global warming; Heat transport; Intergovernmental Panel on Climate Change; Latitude; Mathematical models; Ocean circulation; Ocean models; Oceans; REVIEW SUMMARY; Sea surface temperature; Spring; Temperature measurement; Time series; Transport; Upper ocean; Water circulation; Water flow
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1255575

Atlantic Meridional Overturning Circulation (AMOC) transports huge amounts of heat from low to high latitudes and has a major influence on climate. Climate models have predicted that global warming will cause the AMOC to slow, but concrete evidence of such a slowdown has been scarce. Srokosz and Bryden review a decade of observations of the AMOC that reveal an unexpected amount of variability over time scales from seasonal to decadal, as well as a general weakening over this time. Science , this issue 10.1126/science.1255575 The importance of the Atlantic Meridional Overturning Circulation (AMOC) heat transport for climate is well acknowledged. Climate models predict that the AMOC will slow down under global warming, with substantial impacts, but measurements of ocean circulation have been inadequate to evaluate these predictions. Observations over the past decade have changed that situation, providing a detailed picture of variations in the AMOC. These observations reveal a surprising degree of AMOC variability in terms of the intraannual range, the amplitude and phase of the seasonal cycle, the interannual changes in strength affecting the ocean heat content, and the decline of the AMOC over the decade, both of the latter two exceeding the variations seen in climate models.