“百合”台风近海加强成因分析

Causes analysis of typhoon Lily’s strengthening on near waters

利用卫星云图、常规观测资料对“百合”台风减弱为低压后在台湾海峡南部海面强度再次加强,又发展成强热带风暴的过程分析诊断结果表明:“百合”台风近海加强的主要原因是台风上层强辐散流场的叠加,加强了台风环流的垂直上升运动;台湾海峡南部的暖洋区的增暖增湿、中低层辐合流场的加强和低层适度冷空气的侵入对台风的加强也起了一定的作用.

Based on the cloud photograph and normal observation data, the course of typhoon Lily was analyzed, which strengthened to be a strong tropical storm again at southern Taiwan Strait after it weakened as a tropical depress .It showed that the major reason of typhoon (Lily ′s) intensifying on the near waters is the superposition of divergence field on the upper layer,which strengthend the verfical uplift of the typhoon circulation.And then the warming and humidifiying on the warm water area of the southern Taiwan Strait is also helpful to its development. In addition, the convergence field strengthened on middle and lower layer and the incursion of cold air at lower level also did good to typhoon′s intensifying.