段丽,陈联寿,徐祥德. 2006. 山脉地形对热带风暴Fitow结构和运动影响的数值试验[J]. 气象学报, 64(2):186-193, doi:10.11676/qxxb2006.018
山脉地形对热带风暴Fitow结构和运动影响的数值试验
THE NUMERICAL SIMULATION ON THE IMPACT OF TOPOGRAPHY ON THESTRUCTURE CHANGE AND MOTION OF TROPICAL STORM FITOW (0114)
投稿时间:2005-05-18  修订日期:2005-08-08
DOI:10.11676/qxxb2006.018
中文关键词:  热带风暴,中尺度结构,海南岛地形
英文关键词:Tropical storm, Mesoscale Structure, Topography of Hainan Island.
基金项目:973国家重点基础研究发展规划项目01课题(2004CB418301)国家自然科学基金项目(40575018),海南省2002年度自然科学基金
作者单位
段丽 北京市气象台 北京 100089 
陈联寿 中国气象科学研究院 北京 100081 
徐祥德 中国气象科学研究院 北京 100081 
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中文摘要:
      热带风暴自东向西穿越琼州海峡时常常与海南西部的强天气相对应,尤其当风暴中心在海峡中部或海峡西端出口处有向西南方向的偏折时。Fitow(0114)是这类热带风暴的一个典型。通过对Fitow热带风暴的研究和分析,揭示了一个事实:Fitow在沿海峡西行过程中,其外围中尺度结构发生明显变化——风暴中心西南象限有一个 中尺度对流(MCS)小涡生成和发展。受到这个诱生MCS小涡的“吸引”,Fitow在穿行海南岛北部和琼州海峡时,路径向西南方向偏折。数值模拟结果表明,海南岛中部的五指山地形对Fitow自东向西穿行海峡时的这种结构变化有显著影响:(1)当热带风暴Fitow(0114)自 东向西穿过岛屿北部和琼州海峡时,其外围西北气流与山脉的辐合地带往往会诱生出中尺度 强对流涡旋系统(MCS)。这种系统经过尺度分离和滤波处理后便会在山脉西北麓显现出来。(2)MCS小涡只生成在地形高度之下的大气层;地形高度之上并不显现这一小涡。用0高度作敏感试验的结果,在相同位置并不生成这种MCS小涡。(3)诱生小涡(MCS)的存在,对Fitow会产生“吸引”作用,使其向西南方向MCS所在处偏折。且MCS越深厚,维持时间越长,对Fitow中心的“吸引”程度越大,其中心向西南方向的偏折和移动越明显。0.0 km高 度无MCS小涡时,Fitow中心并无这种偏折,而是向西北方向移动,在雷州半岛登陆。
英文摘要:
      The Hainan Island is one of the provinces where tropical cyclones made landfall frequently. There are 2.7 landfall tropical cyclones in average annually only less than Guandong province. A severe tropical strom, Fitow (0114) crossing Qiongz hou Strait would has a great structure change due to the topographic forcing. A mesoscale convective vortex system (MCS) could be appeared in the southwest periphery of a storm Fitow (0114) where is the convergence area between the mountain range and the NW flow of Fitow. This small vortex (MCS) would affect the struct ure change and motion of Fitow. Intensive conventional observations, satellite i mages and radar reflectivity data have identified the genesis and existence of t he MCS in the northwest side of the mountain range. The numerical simulation was performed with PSU/NCAR MM5V3 model to study the genesis of the small vortex of MCS. The results of the simulation and filtering analysis show that a mesoscale convective vortex system (MCS) appeared clearly in a topographic convergent area caused by the peripheral flow field of Fitow and the mountain range which was favorable to form the MCS when Fitow was passing through the Qiongzhou Strait. The results also show that the MCS only occurred in the layer below the mountain altitude and disappeared in the level higher than the mountain. Higher altitude of the mountain is more favorable to the formation of MCS than the lower one. Many studies showed that tropical cyclone motion can be influenced by some mesos cale vorticies or topographic induced low in its periphery when it made landfall . One of the results from the simulation indicates that the MCS southwest to the Fitow's center caused the storm to turn direction towards southwest. It seems to be some attraction existed between the MCS and the Fitow. The another results showed that the Fitow would move towards northwest if without the MCS or the altitude of the mountain range in Hainan island is zero (no influence of the topogr aphy).
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