HR: 17:35h
AN: PP54B-07    [Abstracts]
TI: Tectonically Induced Changes of the Global Thermohaline Circulation
AU: * von der Heydt, A
EM: a.s.vonderheydt@phys.uu.nl
AF: Institute for Marine and Atmospheric Research, Utrecht University, Princetonplein 5, Utrecht, 3584CC Netherlands
AU: Dijkstra, H A
EM: dijkstra@atmos.colostate.edu
AF: Department of Atmospheric Sciences, Colorado State University, Colorado State University, Fort Collins, CO 80523-1371 United States
AB: The climate changes that took place on Earth during the Tertiary are thought to be partly due to changes in the global thermohaline circulation. At present, there is a conveyor type of circulation with sinking mainly in the North Atlantic Ocean and no sinking in the North Pacific. Climate simulations of the Cretaceous climate have indicated a state of the thermohaline circulation with deep convection occurring at high latitudes on both hemispheres and upwelling at the equator. Within a fully-coupled climate model with continental geometries corresponding to the late Oligocene and early Miocene, we find a northern sinking state of the global thermohaline circulation, with a (shallow and weak) overturning circulation in both the Pacific and the Atlantic Oceans. In this presentation, we study the evolution of the thermohaline circulation during the Tertiary with the use of coupled climate simulations and idealized ocean models. We focus on the circulation changes which are induced by tectonic changes, as, e.g., the opening of the Southern Ocean gateways and the gradual closing of the equatorial seaways.
DE: 9604 Cenozoic
DE: 4267 Paleoceanography
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting