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Adjustment of the coupled ocean–atmosphere system to a sudden change in the Thermohaline Circulation
Author(s) -
Dong B.W.,
Sutton R. T.
Publication year - 2002
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 - 10.1029/2002gl015229
Subject(s) - thermohaline circulation , climatology , tropical atlantic , north atlantic deep water , sea surface temperature , shutdown of thermohaline circulation , atlantic equatorial mode , atmosphere (unit) , atlantic multidecadal oscillation , environmental science , anomaly (physics) , geology , oceanography , ocean current , atmospheric circulation , atmospheric sciences , meteorology , geography , physics , condensed matter physics
The adjustment of the coupled ocean–atmosphere system to a fresh water anomaly in the North Atlantic Ocean is investigated using a coupled GCM. In response to the anomaly the Atlantic Thermohaline Circulation (THC) collapses, and the associated reduction in northward heat transport causes sea surface temperatures (SST) to fall over the North Atlantic, and to increase over the tropical South Atlantic. Atmospheric feedbacks are excited as soon as the SST anomalies reach sufficient magnitude. A key stage in the adjustment process occurs 4–6 years after the perturbation is introduced when a significant SST dipole develops in the tropical Atlantic. This dipole causes a southward shift of the ITCZ and leads, in year 7, to the triggering of an El Niño event. It is concluded that atmospheric feedbacks could spread globally the influence of a sudden change in the THC much more quickly and efficiently than could ocean processes alone.