Premium
Variability of the directly observed, middepth subpolar North Atlantic circulation
Author(s) -
Palter Jaime B.,
Caron CharlesAndré,
Law Kara Lavender,
Willis Joshua K.,
Trossman David S.,
Yashayaev Igor M.,
Gilbert Denis
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl067235
Subject(s) - oceanography , bathymetry , ocean current , north atlantic deep water , climatology , geology , ridge , thermohaline circulation , gulf stream , boundary current , structural basin , geomorphology , paleontology
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.