热带气旋的成因及其与温带气旋的比较

The Formation of the Tropical Cyclone and Its Comparision with the Exatratropical Cyclone

根据移动圆柱坐标系的准Lagrangian角动量收支方程和径向环流方程,利用FGGE资料,对“Nancy”台风过程进行了计算和分析,并同温带气旋的角动量收支作了比较。诊断研究表明,热带气旋的非绝热加热比典型温带气旋的非绝热加热大2—3倍。上述两种,气旋发生发展过程中的角动量收支都主要是来自侧边界的输送,即径向环流的作用是十分重要的,但驱动径向环流的主要因子有所不同。驱动热带气旋的径向环流的主要因子是非绝热加热;而在温带气旋中,相对重要的驱动因子是同锋区斜压不稳定有关的力矩。

In this paper by using FGGE data, and with the help of quasi-Lagrangian angular momentum budget equationand radial circulation equation in movingcylindrical coordinate system, the occurrence and development of South China Sea typhoon 'Nancy' are calculated and analyzed, meanwhile the comparision between the cxtrotropical cyclone and it is also made, furthermore, their formation is studied. The results show that, the diabatic heating of a tropical cyclone is 2 to 3 times larger than that of a typical extratropical cyclone. For both the tropical cyclone and the extratropical cyclone, the angular momentum budget required for their development is originated mainly from the lateral boundary transportation, or say that the radial circulation plays a very important role in it. But the main factors driving the radial circulation are different. In tropical cyclone, the driving factor is diabatic heating, while in extratropical cyclone, the relatively important factor is the torque relating to the baroclinic instability of frontal zone.