Decreasing trend of tropical cyclone frequency in 228-year high-resolution AGCM simulations
Article first published online: 10 OCT 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 19, 16 October 2012
How to Cite
2012), Decreasing trend of tropical cyclone frequency in 228-year high-resolution AGCM simulations, Geophys. Res. Lett., 39, L19805, doi:10.1029/2012GL053360., and (
- Issue published online: 10 OCT 2012
- Article first published online: 10 OCT 2012
- Manuscript Accepted: 6 SEP 2012
- Manuscript Revised: 4 SEP 2012
- Manuscript Received: 30 JUL 2012
- climate chnage;
- tropical cyclone
 We conducted 228-year long, three-member ensemble simulations using a high resolution (60 km grid size) global atmosphere model, MRI-AGCM3.2, with prescribed sea surface temperature and greenhouse gases and aerosols from 1872 to 2099. We found a clear decreasing trend of global tropical cyclone (TC) frequency throughout the 228 years of the simulation. We also found a significant multidecadal variation (MDV) in the long term variation of Northern Hemisphere and Southern Hemisphere TC count in addition to the decreasing trend. The decreasing trend and MDV in the long term variation of TC count correspond well to a similar decreasing trend and MDV of upward mass flux averaged over the TC genesis region and active TC season. It has been shown that the upward mass flux decreases primarily because the rate of increase of dry static stability, which is close to that of surface specific humidity, is much larger than the rate of increase of precipitation, which is nearly the same as that of atmospheric radiative cooling. Thus, it is suggested that the decreasing trend of TC count is mainly caused by the decreasing trend of upward mass flux associated with the increasing dry static stability.