Open AccessContrasting Response of the Eastern and Western North Atlantic Circulation to an Episodic Climate Event*
Author(s) -
Abhishek Chaudhuri,
Avijit Gangopadhyay,
James J. Bisagni
Publication year - 2011
Publication title -
journal of physical oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 143
eISSN - 1520-0485
pISSN - 0022-3670
DOI - 10.1175/2011jpo4512.1
Subject(s) - north atlantic oscillation , oceanography , geology , climatology , north atlantic deep water , thermohaline circulation , atlantic multidecadal oscillation , salinity , mediterranean climate , atlantic equatorial mode , shutdown of thermohaline circulation , water mass , gulf stream , structural basin , front (military) , geography , geomorphology , archaeology
Regional observational studies in the North Atlantic have noted significant hydrographical shifts in 1997–98 because of the episodic drop in the North Atlantic oscillation (NAO) during 1996. Investigation using a basin-scale model finds that, although the western North Atlantic (WNA) witnessed unusually low-salinity water by 1997, the eastern North Atlantic (ENA) simultaneously evidenced intrusions of high-salinity water at intermediate depths. This study shows that a major source of high salinity in the ENA is from the northward penetration of Mediterranean Outflow Water (MOW) that occurred concurrently with a westward shift of the subpolar front. The authors confirm that the low-salinity intrusion in the WNA is from enhanced Labrador Current flow. Results from climatological high- and low-NAO simulations suggest that the NAO-induced circulation changes that occurred in 1997–98 are a characteristic North Atlantic basin response to different forcing conditions during characteristic high- and low-NAO periods.