On the currents and transports connected with the atlantic meridional overturning circulation in the subpolar North Atlantic

Results from an interannually forced, 0.08 degrees eddy-resolving simulation based on the Hybrid Coordinate Ocean Model, in conjunction with a small but well-determined transport database, are used to investigate the currents and transports associated with the Atlantic meridional overturning circula...

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Bibliographic Details
Published in:Journal of Geophysical Research: Oceans
Main Authors: Xu, X., Hurlburt, H. E., Schmitz, W. J., Zantopp, Rainer J., Fischer, Jürgen, Hogan, P. J.
Format: Article in Journal/Newspaper
Language:English
Published: AGU (American Geophysical Union) 2013
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Online Access:https://oceanrep.geomar.de/id/eprint/21326/
https://oceanrep.geomar.de/id/eprint/21326/1/jgrc20065.pdf
https://doi.org/10.1002/jgrc.20065
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Summary:Results from an interannually forced, 0.08 degrees eddy-resolving simulation based on the Hybrid Coordinate Ocean Model, in conjunction with a small but well-determined transport database, are used to investigate the currents and transports associated with the Atlantic meridional overturning circulation (AMOC) in the subpolar North Atlantic (SPNA). The model results yield a consistent warming in the western SPNA since the early 1990s, along with mean transports similar to those observed for the trans-basin AMOC across the World Ocean Circulation Experiment hydrographic section AR19 (16.4 Sv) and boundary currents at the exit of the Labrador Sea near 53 degrees N (39.0 Sv) and east of the Grand Banks near 43 degrees N (15.9 Sv). Over a 34 year integration, the model-determined AMOC across the AR19 section and the western boundary current near 53 degrees N both exhibit no systematic trend but some long-term (interannual and longer) variabilities, including a decadal transport variation of 3-4 Sv from relatively high in the 1990s to low in the 2000s. The decadal variability of the model boundary current transport near 53 degrees N lags the observed winter time North Atlantic Oscillation index by about 2 years and leads the model AMOC across the AR19 section by about 1 year. The model results also show that the long-term variabilities are low compared to those on shorter time scales. Thus, rapid sampling of the current over long time intervals is required to filter out high-frequency variabilities in order to determine the lower frequency variabilities of interest