Simulation and Projection of Hadley Circulation in Coupled Climate Models

In order to address the possible change of the Hadley circulation in response to global warming in the future, the ability of coupled climate models in simulating the temporal and spatial features of Hadley circulation is assessed by a comparison with the observation during 1970-1999. On this basis, three models which can well reproduce the spatial structure and the temporal change of the intensity and expansion of Hadley circulation are selected as the ensemble to project its possible change under the A1B scenario. The projection results show that the Northern Hemispheric Hadley circulation tends to weaken in four seasons but with weaker change in spring during the late 21st century(2070-2099) as compared to the period 1970-1979. The Southern Hemispheric Hadley circulation will also weaken in winter and summer, while its change in spring and autumn is not significant. In addition, except a southward shift in summer, the Hadley circulation in the Northern Hemisphere will exhibit a northward expansion in the other three seasons during the late 21st century. The Hadley circulation in the Southern Hemisphere will move poleward in all seasons. Moreover, the upward shift of the Hadley circulation in the vertical may appear in both hemispheres in a warmer climate.