Sensitivity of the Atlantic intertropical convergence zone to last glacial maximum boundary conditions. Paleoceanography 18

• Main Authors: John C. H. Chiang, Michela Biasutti, David S. Battisti
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Ice Sheet; North Atlantic; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.472.4757; http://www.ldeo.columbia.edu/~biasutti/papers/TALGM.pdf

[1] Recent paleoproxy records suggest that the mean latitude of the Atlantic Intertropical Convergence Zone (ITCZ) varied synchronously with North Atlantic climate over a range of timescales throughout the Holocene and Last Glacial Maximum. We show that the present-day ‘‘meridional mode’ ’ of atmosphere-ocean variability in the tropical Atlantic is a potentially useful model for understanding these paleoclimate changes. The tropical Atlantic in a coupled atmospheric general circulation and slab ocean model responds to Last Glacial Maximum conditions with a southward displacement of the ITCZ. This response arises primarily through the land ice sheet that forces increased North Atlantic trades analogous to the forcing on the present-day meridional mode. Changes to sea ice coverage and to ocean heat transport associated with a weakened Atlantic thermohaline circulation also cause a meridional mode response, though through different mechanisms. Our results highlight the potential for tropical Atlantic paleoclimate to be driven from the high latitude influences, in particular, land