地形对台风Megi(2010)过岛阶段路径偏折影响的数值研究
投稿时间: 2017-09-04  最后修改时间: 2017-11-10  点此下载全文
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作者单位E-mail
郭兴亮 国防科技大学气象海洋学院;32035部队 guo_xingliang@126.com 
钟玮 国防科技大学气象海洋学院 wzhong_vivian@126.com 
张入财 78127部队  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:本文在采用谱逼近方法减小大尺度环境场模拟偏差的基础上,通过地形敏感性试验,研究吕宋岛山脉地形高度对台风Megi(2010)过岛阶段路径偏折的影响。模拟试验表明,谱逼近700hPa高度层以上天气尺度风场分量的数值试验不仅能够反映大尺度环流对台风路径的引导作用,同时保留了中低层环流对地形影响的响应,较为准确地反映了Megi靠近和登陆吕宋岛过程中的持续南压过程,以及离开吕宋岛后的突然北折过程。在此模拟基础上,通过对地形高度敏感性试验结果诊断和影响区域空气质点进行后向轨迹分析表明:在台风向山脉靠近过程中,台风外围和内核环流均受地形影响,迎风坡存在明显气流辐合,有利于台风流场与南北向山脉之间出现北风急流和轨迹汇聚带,从而产生狭管效应,造成台风移动路径南折;而台风过山后,不仅受到地形次生低压涡旋的吸引,其东侧同样出现以南风急流和轨迹汇聚为特征的狭管效应,有利于台风路径向北偏折。
中文关键词:台风路径 地形影响 狭管效应 谱逼近
 
Numerical study on topographic influence to the track deflection of Typhoon Megi(2010) during passing-island period
Abstract:Based on reducing the simulation deviation of large-scale environment by spectral nudging method, sensitivity tests are conducted to investigate the impact of terrain height on the track deflection of Typhoon Megi(2010) during its passing-island period. Simulation typhoon track of SNV700, which uses the configration of nudging synoptic-scale wind component above 700hPa, can reproduce the southward movement when the typhoon passes by the island and sudden north turn after leaving the island by reflecting both the steering role of large-scale environmental flow and the response of lower-level flow to the terrain. The sensitivity tests of terrain height and backward trajectory analysis indicate that both outer and inner circulations of typhoon are affected by the terrain when the typhoon is approaching the high terrain above the island. The strong flow convergence in the windward slope results in the establishment of northly low-level jet and confluent trajectories band along the terrain range. Then Channeling effect is induced and leads the typhoon to the south. After climbing over the high terrain, the typhoon system appears to be north deflection for the attraction of terrain-induced secondary depression and the effects of southly low-level jet and confluent trajectories occur in the east side of the typhoon.
keywords:typhoon track  topographic influence  channeling effect  spectral nudging
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