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North Atlantic Deep Water collapse triggered by a Southern Ocean meltwater pulse in a glacial climate state
Author(s) -
Trevena J.,
Sijp W. P.,
England M. H.
Publication year - 2008
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 - 10.1029/2008gl033236
Subject(s) - north atlantic deep water , thermohaline circulation , geology , oceanography , meltwater , glacial period , gulf stream , antarctic bottom water , shutdown of thermohaline circulation , climatology , paleontology
It is generally accepted that surface freshwater anomalies in the Southern Ocean drive increases in North Atlantic Deep Water (NADW) formation via a bipolar density see‐saw. We find that a Southern Ocean freshwater pulse of comparable magnitude to meltwater pulse 1A, shuts down, instead of strengthens, NADW in a glacial climate simulation. Unlike the modern‐day simulation, the glacial experiment is associated with a more fragile North Atlantic thermohaline circulation, whereby freshwater anomalies that propagate into the North Atlantic are able to dominate the bipolar density see‐saw. Meltwater pulses over the North Atlantic and subsequent NADW shut down are often invoked to explain cold ‘Heinrich Events’ appearing in the paleoclimate record. Our results suggest that triggers for NADW collapse may also originate from the southern hemisphere in glacial epochs. Once NADW collapses, North Pacific Deep Water develops, consistent with a North Pacific/North Atlantic see‐saw triggered from the Southern Ocean.