HR: 17:05h
AN: OS24A-04 INVITED     [Abstracts]
TI: The South Atlantic Valve Regulating THC Stability
AU: * Hazeleger, W
EM: wilco.hazeleger@knmi.nl
AF: KNMI, PO BOX 201, De Bilt, 3730 AE, Netherlands
AB: Abrupt climate change is often related to a collapse of the thermohaline circulation (THC). However, the THC in most IPCC-class ocean-atmosphere models do not fully collapse under global warming. Only unrealistically large fresh water perturbations in the North Atlantic can trigger a collapse, but the circulation often recovers afterward. This indicates that multiple equilibria in these models do not exist. In this talk the inflow in the South Atlantic is considered as regulating the fresh water budget of the Atlantic Ocean and the existence of multiple equilibria of the THC. The compensating or amplifying effects of the azonal circulation in the South Atlantic and coupled ocean-atmosphere feed backs in the Atlantic region are further discussed. Results from intermediate complexity and state-of-the-art coupled ocean-atmosphere models are used to illustrate these processes. The results motivate a South Atlantic observing system to monitor changes in the THC.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1630 Impacts of global change (1225)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly