Simulated tropical response to a substantial weakening of the Atlantic thermohaline circulation

Abstract

In this study, a mechanism is demonstrated whereby a large reduction in the Atlantic thermohaline circulation (THC can induce global-scale changes in the Tropics that are consistent with paleoevidence of the global synchronization of millennial-scale abrupt climate change. Using GFDL's newly developed global coupled ocean-atmosphere model (CM2.0), the global response to a sustained addition of freshwater to the model's North Atlantic is simulated. This freshwater forcing substantially weakens the Atlantic THC, resulting in a southward shift of the intertropical convergence zone over the Atlantic and Pacific, an El Niño-like pattern in the southeastern tropical Pacific, and weakened Indian and Asian summer monsoons through air-sea interactions. © 2005 American Meteorological Society.