Variability of the directly observed, middepth subpolar North Atlantic circulation

Satellite views of the ocean have suggested a decline of the subpolar North Atlantic surface circulation during the 1990s and 2000s. This was a period of unprecedented observational capacity in the basin, thanks to the presence of many hundreds of profiling floats. We use more than 40,000 subsurface...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Palter, Jaime B., Caron, Charles André, Law, Kara Lavender, Willis, Joshua K., Trossman, David S., Yashayaev, Igor M., Gilbert, Denis
Format: Text
Language:unknown
Published: DigitalCommons@URI 2016
Subjects:
Argo
boundary currents
decadal variability
ocean circulation
profiling floats
subpolar North Atlantic
Mid-Atlantic Ridge
Labrador Sea
north atlantic current
North Atlantic
Online Access:https://digitalcommons.uri.edu/gsofacpubs/2049
https://doi.org/10.1002/2015GL067235
Description
Summary:Satellite views of the ocean have suggested a decline of the subpolar North Atlantic surface circulation during the 1990s and 2000s. This was a period of unprecedented observational capacity in the basin, thanks to the presence of many hundreds of profiling floats. We use more than 40,000 subsurface displacements of these floats to characterize the circulation at 1000 m depth, and its evolution from 1997-2013. We show a statistically significant slowdown in the Labrador Sea boundary currents of -0.8 cm s-1 per decade (95% confidence interval of -1.4 to -0.15 cm s-1 per decade, a conservative estimate of the uncertainty). Otherwise, the middepth circulation field was largely stable. Our analysis of the location where the North Atlantic Current crosses the Mid-Atlantic Ridge shows that profiling floats can reveal steering by bathymetric features, but do not reveal of decadal variability in the position where the current crosses the ridge.

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