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Last Glacial Maximum ocean thermohaline circulation: PMIP2 model intercomparisons and data constraints
Author(s) -
OttoBliesner B. L.,
Hewitt C. D.,
Marchitto T. M.,
Brady E.,
AbeOuchi A.,
Crucifix M.,
Murakami S.,
Weber S. L.
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 - 10.1029/2007gl029475
Subject(s) - thermohaline circulation , north atlantic deep water , shutdown of thermohaline circulation , last glacial maximum , glacial period , geology , climatology , ocean current , oceanography , forcing (mathematics) , geomorphology
The ocean thermohaline circulation is important for transports of heat and the carbon cycle. We present results from PMIP2 coupled atmosphere‐ocean simulations with four climate models that are also being used for future assessments. These models give very different glacial thermohaline circulations even with comparable circulations for present. An integrated approach using results from these simulations for Last Glacial Maximum (LGM) with proxies of the state of the glacial surface and deep Atlantic supports the interpretation from nutrient tracers that the boundary between North Atlantic Deep Water and Antarctic Bottom Water was much shallower during this period. There is less constraint from this integrated reconstruction regarding the strength of the LGM North Atlantic overturning circulation, although together they suggest that it was neither appreciably stronger nor weaker than modern. Two model simulations identify a role for sea ice in both hemispheres in driving the ocean response to glacial forcing.