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Response of thermohaline circulation and thermal structure to removal of ice sheets and high atmospheric CO 2 concentration
Author(s) -
Chan WingLe,
Motoi Tatsuo
Publication year - 2005
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 - 10.1029/2004gl021951
Subject(s) - thermohaline circulation , geology , convection , shutdown of thermohaline circulation , north atlantic deep water , salinity , climatology , atmospheric sciences , oceanography , precipitation , environmental science , meteorology , physics
The thermohaline circulation (THC) response to ice sheet removal and quadrupling of atmospheric CO 2 in a coupled model and the equilibrium thermal structure are examined. After THC weakening, diffusion of heat and salt to the northern North Atlantic at deep layers increases the temperature and salinity there, in response to CO 2 ‐quadrupling. Resulting convective instability induces the exchange of warmer, saltier water in deep layers and cooler, fresher water near the surface. This contributes to a gradual increase in the THC intensity, culminating in its complete and rapid recovery due to positive haline feedback overcoming negative thermal feedback on the THC. Removal of ice sheets prolongs the overall recovery and strengthens the final THC due to precipitation changes over the northern North Atlantic and Labrador Sea. Bottom water and high‐latitude sea‐surface temperatures are higher without ice sheets, leading to a smaller meridional temperature gradient as indicated by Cenozoic reconstructions.