全球50 km分辨率SNU-AGCM模式模拟热带气旋活动

为了验证50 km分辨率的SNU-AGCM模式(Seoul National University Atmospheric General Circulation Model)模拟TC活动的能力, 利用Hadley中心月平均海温资料驱动模式, 模拟了1980—2009年全球热带气旋的活动特征。与观测资料对比分析, 两组利用不同对流参数化方案的试验, 都能够模拟与观测类似的TC结构以及全球TC活动的主要特点, 包括全球生成总频数、各海区路径分布和TC活动的季节变化。但是各个海域TC生成的年平均频数与观测还存在明显差异。模式中西北太平洋和南太平洋两组试验平均的TC频数较观测分别偏多21.5%和31.3%;而北大西洋、南北印度洋分别偏少11.4%、41.1%和50%。模拟的东北太平洋TC比观测少了将近88%, 而观测中TC极少的南大西洋在两组试验中平均每年却有1.5个TC生成。模拟的TC频数较观测的差异主要与模拟的北印度洋季风、西北太平洋季风槽、垂直风切变、850 hPa相对涡度与观测的差异有关。

Simulation of global tropical cyclone activity by 50 km resolution SNU-AGCM

To assess the ability of Seoul National Atmospheric General Circulation Model(SNU-AGCM) AGCM in simulating the characteristics of tropical cyclones(TC₁), the driven model of the observed monthly mean sea surface temperature data from Hadley Centre during 1980-2009 is used to simulate the characteristics of global TCs. Comparison with observations shows that the model with two different convective parametric schemes is capable in reproducing the basic features of the observed tropical cyclone such as TC structure, number of total cyclones, track locations and seasonality. However, differences exist in different oceans. The mean yearly TC frequency in two different experiments is 21.5% and 31.3% more than that in the observations in the Northwest Pacific and the southern Pacific, while 11.4%, 41.1% and 50% less in the northern Atlantic, the southern and the northern Indian Ocean, respectively. Furthermore, the genesis of TC in the eastern Pacific in model is 88% less than in the observation while nearly 1.5 unexpected cyclones per year happen in the southern Atlantic. Further research shows that the differences of TC frequency between simulation and observation are mainly associated with the differences of Indian monsoon, the Northwest Pacific monsoon trough, vertical wind shear and 850 hPa relative vorticity.