登陆北上台风暴雨突发性增强的一种机制研究

A Mechanism Study of Torrential Rain Intensifying due to Landing Typhoon

采用一个三维混合模式对１９９２年８月３０日至９月２日一次登陆北上台风暴雨过程进行了模拟。模式可以较准确地预报出与地面倒槽相一致的地面降水位置及降水量值。模拟的台风云系结构与卫星云图比较表明，外围云场与实例云况吻合很好，验证了本模式模拟卫星云图的能力，对卫星云图预报有实际意义；暴雨突然增幅的直接原因是高层冰云与低层供水云的突然北移重叠造成的。受地面倒槽附近强烈辐合抬升的动力作用，各相态云系的分布与垂直运动紧密相关；辐合线右侧的东南低空急流为降水的增幅及维持提供水汽来源；云的相变潜热非绝热加热作用对暴雨的增幅及维持具有正反馈作用，它对暴雨维持具有积极贡献。

Using a three-dimensional mixing model, the numerical simulation for the process of the torrential rain caused by the landing and moving northward typhoon from 30 August to 2 September 1992 is performed The model can predict the precipitation area and amount associated with surface inverted trough The simulated cloud system structure of typhoon is compared with the satellite cloud pictures and it is showed that the simulated periphery of cloud field coincides with the actual The ability of the model to simulate satellite cloud pictures is examined The direct reason of the rainfall increasing sharply is that the low clouds supplying water vapour for high cloud moved suddenly northward and is overlapped by the high ice clouds Because of the dynamic effects of the strong convergence and lifting from the surface inverted trough, the distribution of all phase cloud system is related to vertical motion The southeast wind jet in low layer on the right of convergence line supplies the water vapour source for rainfall so violent and lasting The adiabatic heating produced by cloud phase change has a positive feedback effect on the rainfall intensifying and maintaining