Simulation Of Global Tropical Cyclone Activity Using50-Km-resolution SNU-AGCM

Tropical cyclone is one of the most destructive natural disasters in the world and brings people’s lives and property a serious threat. In order to more effectively prevent and reduce the loss, it’s necessary to understand changes of the tropical cyclones activity’ and the related mechanism in the climate change. At present, the simulation of tropical cyclones in High-Resolution climate model has become a hot issue.With higher resolution and physical processes improving, SNU-AGCM(Seoul National University Atmospheric General Circulation Model) has a certain ability to simulate the characteristics of tropical cyclones(TCs).To assess its ability of simulating the climatic features of TCs, the model is used to simulate30-years’ TCs using observed monthly mean sea surface temperature from Hadley Centre in the period1980-2009.Compared with observations, the model with two different convective schemes is found to be capable of reproducing the basic features of observed tropical cyclone behaviors such as TC structure, number of total cyclones, track locations and seasonality. However, differences exist in different oceans. The mean number of cyclones per year in two different convective schemes’ experiments is21.5%and31.3%more than observations in the Northwest Pacific and the Southern Pacific and11.4%,41.1%and50%less in the Northern Atlantic, the Southern Indian Ocean and the Northern Indian Ocean, respectively. Especially, the genesis of the Eastern Pacific cyclones in model is88%less than observation and there are nearly1.5unexpected cyclones per year happening in the Southern Atlantic.With further researching, the differences of TC frequency between simulation and observation are mainly associated with the Indian monsoon, the Northwest Pacific monsoon trough, vertical wind shear and850hPa relative vorticity.