A STUDY ON THE CRITERION OF EXTRATROPICAL TRANSITION OF WESTERN NORTH PACIFIC TROPICAL CYCLONES
GUO Rong
LEI Xiao-tu
TANG Jie
Abstract：A number of the tropical cyclones (TC) moving into the mid-latitude regions sometimes undergo a process of extra-tropical transition (ET). It can frequently produce intense precipitation and strong winds which can be a serious threat to land and maritime activities. As the phase space method considers mainly the thermodynamic characteristics but rarely the dynamic characteristics of TC, two more parameters are proposed here to improve the method of determining the extra-tropical transition. One is an inclined vortex parameter and the other is the vertical wind shear. More than 200 cases of TC are analyzed by using the two parameters to examine their reliability. According to the study above, an objective criterion of ET is developed for operational application. And there is also a general flow which can separate the TC and extra-tropical cyclones. And then a test based on the data from 2000 to 2007 is carried out. The results show that the objective criterion to distinguish TC from extra-tropical cyclones is much better than the phase space method only.
Keywords：tropical cycloneextra-tropical transitionphase spacevortex-tiltwind shear
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 353-359 )