双涡藤原效应的数值模拟研究

本文利用正压无辐散模式在无环境基本气流的情况下对双涡的藤原效应及其“合并”后涡旋移动路径的特征进行了数值模拟研究。结果表明，只有当双涡间的距离小于某一临界距离时才会出现藤原效应，这一临界距离决定于涡旋的结构及双涡的相对强度；双涡的“合并”过程实际上是其中一个涡旋减弱消失而另一涡旋维持的过程；在考虑β效应的情形下，两个同等强度的涡旋“合并”后表现为较平直的向西北的β飘移，而两个不同强度的涡旋“合并”后表现为陀螺运动和β飘移的叠加。这些结果与实际大气中双台风相互作用的许多现象极为相似。

A Numerical Simulational Study on Fujiwhara Effect of Binary Cyclone

In this paper, the Fujiwhara effect of binary cyclone and the characteristics of the track of cyclone after merging of the binary cyclone have been simulated and studied by using a nondivergent barotropic model. The experimental results show that the Fujiwhara effect can occur only when the initial separation distance between the two cyclones is less than the critical distance which depends on the structure of the cyclone and the relative intensity of the binary cyclone. The merging of binary cyclone, in fact, is the processes that one of them decays and vanishes while the other still maintains. In the case of consideration of βeffect, the resulting cyclone after merging of the two cyclones with the same intensity only drifts along straight line toward northwest, while it travels under the combined effect βdrift and the movement of a top when the two cyclones with the different intensity merge. These results obtained here are in many ways similar to behaviors of the interactions of binary typhoon in the actual atmosphere.