Observed and simulated estimates of the meridional overturning circulation at 26.5 degrees N in the Atlantic
Name
Baehr-2009-Observed and simulated estimates of the meridional overturning.pdf
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Author(s)
Baehr, Johanna
Cunningham, S.
Haak, H.
Heimbach, Patrick
Kanzow, T.
Marotzke, J.
Date Issued
November 2009
Journal
Ocean Science
Publisher
European Geosciences Union / Copernicus
Citation
Baehr, J. et al. “Observed and Simulated Estimates of the Meridional Overturning Circulation at 26.5° N in the Atlantic.” Ocean Science 5.4 (2009) : 575-589. © Author(s) 2009
Version
Final published version
Abstract
Daily timeseries of the meridional overturning circulation (MOC) estimated from the UK/US RAPID/MOCHA array at 26.5° [26.5 degrees] N in the Atlantic are used to evaluate the MOC as simulated in two global circulation models: (I) an 8-member ensemble of the coupled climate model ECHAM5/MPI-OM, and (II) the ECCO-GODAE state estimate. In ECHAM5/MPI-OM, we find that the observed and simulated MOC have a similar variability and time-mean within the 99% confidence interval. In ECCO-GODAE, we find that the observed and simulated MOC show a significant correlation within the 99% confidence interval. To investigate the contribution of the different transport components, the MOC is decomposed into Florida Current, Ekman and mid-ocean transports. In both models, the mid-ocean transport is closely approximated by the residual of the MOC minus Florida Current and Ekman transports. As the models conserve volume by definition, future comparisons of the RAPID/MOCHA mid-ocean transport should be done against the residual transport in the models. The similarity in the variance and the correlation between the RAPID/MOCHA, and respectively ECHAM5/MPI-OM and ECCO-GODAE MOC estimates at 26.5° [26.5 degrees] N is encouraging in the context of estimating (natural) variability in climate simulations and its use in climate change signal-to-noise detection analyses. Enhanced confidence in simulated hydrographic and transport variability will require longer observational time series.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution 3.0
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DOI of Published Version
https://doi.org/10.5194/os-5-575-2009
