HR: 15:20h
AN: U33B-06 INVITED     [Abstracts]
TI: Global scale impact of thermohaline circulation changes linked to high-latitude hydrology changes
AU: * Delworth, T L
EM: tom.delworth@noaa.gov
AF: GFDL/NOAA, P.O. Box 308 Princeton University, Princeton, NJ 08542 United States
AU: Zhang, R
EM: rong.zhang@noaa.gov
AF: Princeton University, P.O. Box 308, Princeton, NJ 08542 United States
AB: Fluctuations in freshwater export from the Arctic can potentially modulate the characteristics of the North Atlantic thermohaline circulation (THC). Such fluctuatons can arise from either internal variability of the climate system, or forced change. In this presentation we focus on simulations of the global-scale response of the climate system to large changes in the North Atlantic THC induced by freshwater forcing. The simulations use GFDL's CM2.0 and CM2.1 global coupled ocean-atmosphere models. We show that a substantial THC reduction has global scale impacts, including a southward shift of the intertropical convergence zone over the Atlantic and Pacific, an El Nino-like pattern in the southeastern tropical Pacific, and weakened Indian and Asian summer monsoons through air-sea interactions. In addition, we examine changes in the Arctic and North Atlantic in ensembles of 20th century climate change simulations. We show that both increasing greenhouse gases and aerosols alter the large-scale hydrology of higher latitudes, although with opposing tendencies. These hydrologic changes contribute to forced THC changes.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1626 Global climate models (3337, 4928)
DE: 1655 Water cycles (1836)
DE: 4513 Decadal ocean variability (1616, 1635, 3305, 4215)
SC: Union [U]
MN: Fall Meeting 2005