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North Atlantic climate and deep‐ocean flow speed changes during the last 230 years
Author(s) -
Boessenkool K. P.,
Hall I. R.,
Elderfield H.,
Yashayaev I.
Publication year - 2007
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 - 10.1029/2007gl030285
Subject(s) - north atlantic oscillation , geology , oceanography , north atlantic deep water , hydrography , ridge , climatology , thermohaline circulation , deep sea , atlantic multidecadal oscillation , gulf stream , range (aeronautics) , mid atlantic ridge , period (music) , paleontology , materials science , composite material , physics , acoustics
Variations in the near‐bottom flow speed of Iceland‐Scotland Overflow Water (ISOW) are documented in a 230‐year‐long deep‐sea sediment record from the eastern flank of Reykjanes Ridge in the subpolar North Atlantic at (sub)decadal time scales. For recent decades, the ISOW palaeocurrent reconstructions show similarities with observational hydrographic data. Furthermore, recent ISOW flow changes fall mostly within the range of its variability of the past 230 years. The record also reveals a hitherto unrecognized coupling of deep flow speeds in the subpolar North Atlantic with the North Atlantic Oscillation (NAO) index, with more (less) vigorous ISOW flow during negative (positive) phases of the NAO. Our results suggest that the changes in ISOW vigor are largely controlled by the transport and characteristics of Labrador Sea Water rather than variations in the overflow itself, with implications for the meridional overturning of the Atlantic Ocean and climate.