Atmosphere drives recent interannual variability of the Atlantic meridional overturning circulation at 26.5°N

Roberts, C. D., Waters, J., Peterson, K. A., Palmer, M., McCarthy, G. D., Frajka-Williams, E., Haines, K. ORCID: https://orcid.org/0000-0003-2768-2374, Lea, D. J., Martin, M. J., Storkey, D., Blockey, 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. 5164-5170. ISSN 0094-8276 doi: 10.1002/grl.50930

Abstract/Summary

The RAPID-MOCHA array has observed the Atlantic Meridional overturning circulation (AMOC) 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 2009/10. 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 RAPID observations. 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
URI	https://reading-clone.eprints-hosting.org/id/eprint/34301
Identification Number/DOI	10.1002/grl.50930
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > National Centre for Earth Observation (NCEO)
Publisher	American Geophysical Union
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