Roberts, C.D. and Waters, J. and Peterson, K.A. and Palmer, M.D. and McCarthy, Gerard and Frajka-Williams, Eleanor and Haines, K. and Lea, D.J. and Martin, M.J. and Storkey, D. and Blockley, E.W. and Zuo, H. (2013) Atmosphere drives recent interannual variability of the Atlantic meridional overturning circulation at 26.5°N. Geophysical Research Letters, 40 (19). pp. 5164-5171. ISSN 0094-8276

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Abstract

[1] The Atlantic meridional overturning circulation (AMOC) has been observed at 26.5°N since 2004. During 2009/2010, there was a transient 30% weakening of the AMOC driven by anomalies in geostrophic and Ekman transports. Here, we use simulations based on the Met Office Forecast Ocean Assimilation Model (FOAM) to diagnose the relative importance of atmospheric forcings and internal ocean dynamics in driving the anomalous geostrophic circulation of 2009/2010. Data‐assimilating experiments with FOAM accurately reproduce the mean strength and depth of the AMOC at 26.5°N. In addition, agreement between simulated and observed stream functions in the deep ocean is improved when we calculate the AMOC using a method that approximates the observing array at 26.5°N. The main features of the geostrophic circulation anomaly are captured by an ensemble of simulations without data assimilation. These model results suggest that the atmosphere played a dominant role in driving recent interannual variability of the AMOC.

Item Type:	Article
Keywords:	AMOC; variability; ocean model; data assimilation; ocean circulation; Atlantic meridional overturning circulation;
Academic Unit:	Faculty of Social Sciences > Geography Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
Item ID:	12194
Identification Number:	https://doi.org/10.1002/grl.50930
Depositing User:	Gerard McCarthy
Date Deposited:	22 Jan 2020 15:43
Journal or Publication Title:	Geophysical Research Letters
Publisher:	American Geophysical Union
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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