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Atlantic thermohaline circulation and its response to increasing CO 2 in a coupled atmosphere‐ocean model
Author(s) -
Sun Shan,
Bleck Rainer
Publication year - 2001
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 - 10.1029/2001gl013325
Subject(s) - thermohaline circulation , isopycnal , climatology , atmosphere (unit) , ocean general circulation model , sea surface temperature , environmental science , atmospheric sciences , ocean current , shutdown of thermohaline circulation , north atlantic deep water , geology , oceanography , general circulation model , meteorology , climate change , physics
We discuss aspects of the Atlantic thermohaline circulation (THC) and its response to increased greenhouse gas concentration, using a coupled atmosphere‐ocean general circulation model (AOGCM) whose oceanic component is a new hybrid‐isopycnal model. Two 200‐year model integrations are carried out—a control run assuming fixed atmospheric composition and a perturbation run assuming gradual doubling of CO 2 . We employ no flux corrections at the air‐sea interface, nor do we spin up the ocean prior to coupling. The surface conditions in the control run stabilize after several decades. When doubling CO 2 at the rate of 1% per year, the model responds with a 2°C increase in global mean surface air temperature (SAT) after 200 years and a virtually unchanged Atlantic meridional overturning circulation. The latter is maintained by a salinity increase that counteracts the effect of global warming on the surface buoyancy.