利用改进的有限区域数值预报模式(AREM),对“艾利”台风在福建省登陆所造成的特大暴雨过程进行了数值模拟;采用空间带通滤波技术,对模拟结果进行尺度分离,揭示出对此次暴雨天气过程有直接影响的中尺度系统,即中尺度低压和中尺度辐合线;对这些中尺度系统的物理量场特征和它们与强降水的关系进行了分析研究。结果表明:强降水与中尺度系统的散度场有较好的对应关系,中尺度系统与地形相互作用形成很强的辐合抬升作用是造成中尺度暴雨的直接原因。
A heavy storm rainfall, caused by Typhoon "AERE" when landing at Fujian, has been successfully simulated by using AREM model. The simulation result is scale-separated by spatial band-pass filtering, which reveals the mesoscale low pressure and convergence line that had direct impact on this rainfall process. The physical characteristics of the two mesoscale systems and their relation with rainfall is also analyzed. Study shows that there exists a well corresponding relationship between the storm rainfall and mesoscale divergence and strong updraft arising from convergence, which is caused by the interactions between the mesoscale systems and topographic features, is directly responsible for the rainfall.