台风暴雨成因的螺旋度和Q矢量研究——影响浙闽两省的台风“风棠”案例

Study on helicity and Q vector in formation cause of rainstorm by typhoon:a case of typhoon,Haitang influencing Zhejiang and Fujian provinces

0505号台风"海棠"是一个路径怪异、变化复杂的台风,它在浙闽地区产生了强降水,并造成了重大的经济损失和人员伤亡。应用螺旋度和Q矢量的理论与方法,着重研究了台风登陆前后螺旋度和Q矢量散度场的演变特征,探讨了台风在浙闽地区造成的强降雨的基本成因。研究表明,低层相对螺旋度的分布与高低层不同符号的螺旋度的配置可能是暴雨发生和维持的机制之一;低层Q矢量辐合区与地面强降水有较好的对应关系;Q矢量辐合随高度发生倾斜时对未来强降水的发生有预示作用。

The No. 0505 Typhoon ＂Haitang＂, which was very complicated with zigzag trace, brought heavy rainfall and immense loss in Zhejiang and Fujiang provinces. This paper explores the evolution of the helicity and Q vector before and after landfall of the typhoon and the formation cause of rainstorm during the typhoon in Zhejiang and Fujing provinces. The result shows that the distribution of relative helicity on lower level and the collocation of helicities with different signs on different levels may be one of the mechanism triggering and maintaining the rainstorm; there is a better correlation between Q vector convergence zone on lower level and heavy rainfall on the ground; the inclination of Q vector convergence with height indicates the heavy rainfall in the near future.