• tropical cyclone

[1] A global high-resolution (∼40 km) atmospheric general circulation model (ECHAM5 T319) is used to investigate the change of tropical cyclone frequency in the North Pacific under global warming. A time slice method is used in which sea surface temperature fields derived from a lower-resolution coupled model run under the 20C3M (in which historical greenhouse gases in 20th century were prescribed as a radiative forcing) and A1B (in which carbon dioxide concentration was increased 1% each year from 2000 to 2070 and then was kept constant) scenarios are specified as the lower boundary conditions to simulate the current and the future warming climate, respectively. A significant shift is found in the location of tropical cyclones from the western to central Pacific. The shift to more tropical cyclones in the central and less in the western Pacific is not attributable to a change in atmospheric static stability, but to a change in the variance of tropical synoptic-scale perturbations associated with a change in the background vertical wind shear and boundary layer divergence.