|
Read Full Article (file size: 6087315 bytes) Cited by
PALEOCEANOGRAPHY,
VOL. 18, NO. 4,
1094,
doi:10.1029/2003PA000916,
2003
Sensitivity of the Atlantic Intertropical Convergence Zone to Last Glacial Maximum boundary conditions
John C. H. Chiang
Department of Geography and Berkeley Atmospheric Sciences Center, University of California, Berkeley, California, USA
Michela Biasutti
Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
David S. Battisti
Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington, USA
Abstract
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 ice on glacial-interglacial timescales.
Received 22
April
2003;
accepted 15
September
2003;
published 11
December
2003.
Index Terms: 3344 Meteorology and Atmospheric Dynamics: Paleoclimatology; 3339 Meteorology and Atmospheric Dynamics: Ocean/atmosphere interactions (0312, 4504); 4215 Oceanography: General: Climate and interannual variability (3309).
Read Full Article (file size: 6087315 bytes) Cited by
Citation: Chiang, J. C. H., M. Biasutti, and D. S. Battisti
(2003),
Sensitivity of the Atlantic Intertropical Convergence Zone to Last Glacial Maximum boundary conditions,
Paleoceanography,
18(4),
1094,
doi:10.1029/2003PA000916.
Copyright 2003 by the American Geophysical Union.
|