东海热带气旋登陆后转向入海问题的探讨

应用合成分析及相关分析方法研究了影响热带气旋登陆后转向入海路径趋势的若干因素,结果表明:登陆后转向入海路径趋势随时间和登陆地点的变化分布说明热带气旋登陆后路径仍受基本气流的引导和制约;热带气旋登陆时的惯性和地转力的变化对热带气旋登陆后的路径趋势有一定影响;环境场对热带气旋登陆后转向入海路径有较大影响,尤其对流层中层流场对登陆后的热带气旋的移动仍有明显的引导作用;中国东部至黄海区域是环境场影响热带气旋登陆后转向入海路径趋势的关键区,当区域内西北太平洋副热带高压加强西伸,西风槽北撤,则热带气旋登陆后在副高南侧东风气流引导下向内陆西行至消亡,当区域内副高减弱东退,西风槽南压,则热带气旋登陆后受副高西侧偏南气流与西风槽前西南气流引导转向入海;登陆后18—36h是转向入海路径趋势受环境场影响的敏感时段。

Prelininary analysis on the track-turning of tropical cyclones after landfall in the East China Sea

In this paper,major factors affecting the track of tropical cyclones(TCs) after their landfall in the East China Sea are carried out by the composite and correlation analysis.It is shown that the trend of re-entering the seas is varying with time and landing location,which indicates that the TCs are still largely controlled by the mean atmospheric flow after the landfall.In addition,the change of inertia and Coriolis forces make landfall ex-ert significant influence on their moving tracks afterward.The east of China and Yellow Sea is revealed as key re-gions where the environmental flow significantly affects the movement of the TCs.When the subtropical high in this region is strengthened and extends westward,accompanied by a northward shrink of the westerly trough,the TC tends to move westward after landfall and die away inland.However,when the subtropical high in this region is weak and shrinks eastward,accompanied by southward push of the westerly trough,the track of TC tends to turning after landfall and re-enter the sea at the north of landfall point.The environment before the landfall of a TC has little impact on its track turning,while it is sensitive to the environmental change in approximately 18 — 36 hours after landfall.