摘要
利用1949—2008年共60年的《台风年鉴》、《热带气旋年鉴》资料及CMA-STI热带气旋最佳路径数据集,2001—2008年美国联合台风警报中心(JTWC)热带气旋尺度相关资料及日本气象厅(JMA)的TBB资料,统计分析西北太平洋(包括南海)热带气旋(TC)在登陆台湾过程中强度和结构变化的基本特征,主要结论有:(1)TC登陆台湾时强度为台风及以上级别的样本数占总样本数约60%,主要出现在6—9月,东部登陆TC的强度一般比在西部登陆的强;(2)大部分TC在岛上维持6 h左右,登陆时最大风速≤5级和强度为超强台风的TC穿越台湾岛时移动比较缓慢;(3)126个登陆台湾的TC样本过岛后近中心海平面气压平均增加5.61 hPa,近中心最大风速平均减小3.58 m/s,在台湾东部地区登陆TC的衰减率比在西部登陆的大3倍左右;(4)TC在登陆台湾前6 h至离岛后6 h期间其8级和10级风圈半径均明显减小,TC形状略呈长轴为NE-SW向的椭圆状,而其最大风速的半径却逐渐增大;(5)TBB分析结果显示,TC登陆台湾前,其外围对流主要出现在南侧和西侧,结构不对称,登陆以后,TC北部及东部的对流显著发展,外围结构区域对称;但中心附近的强对流则从登陆前6 h开始逐渐减弱消失。表明TC穿越台湾过程中内核结构松散、强度减弱。
This is a statistical analysis on the intensity and structure changes of the western North Pacific （ including the South China Sea） tropical cyclones （TCs） crossing Taiwan Island, based on 60 years （1949--2008） TC data from Typhoon Yearbooks and Tropical Cyclone Yearbooks compiled by Chinese Meteorological Administration（CMA）, TC size information from the U.S. Joint Typhoon Warning Center （JTWC）, and temperature of black body （TBB） data from Japan Meteorological Agency （JMA）. Results show as follows. （1） About 60% of the TC samples keep their intensity as typhoon, severe typhoon or super typhoon, when they make landfall on Taiwan island, mainly in June--September, and the TCs landing from the east side of the island are generally stronger than the ones from the west side. （2） Most of the TCs can maintain over the island for about 6 h, and TCs with the maximum wind speed 45 level or at the level of super typhoon category at landfall have a slower movement than the others. （3） After passing the island, the minimum sea level pressure increases by 5.61 hPa and the maximum wind speed decreases by 3.58 ngs averaged on 126 TC samples and the eastern landing TCs＇ decay rates are about three times larger than the western. （4） TCs＇ Force 8 and 10 wind circle radii clearly decrease from 6 h before landfall to 6 h after landfall, and the length of radius in SE-NW winds decrease slightly than that in NE-SW displaying an oval shape in TCs＇ structure, while the radius of maximum wind speed gradually increases. （5） Analysis on the TBB data shows that the strongest convection before landfall mainly occurs in the southern and western part and it develops in northern and eastem areas when passing the island, resulting in a relatively symmetric structure in TC periphery. However, strong convection near the core region of TC gradually decays, even dissipates, at the same time, indicating that TC structure becomes loose and the intensity decreases when crossing the island of Taiwan.
出处
《热带气象学报》
CSCD
北大核心
2012年第3期300-310,共11页
Journal of Tropical Meteorology
基金
国家重点基础研究发展规划项目(2009CB421504)
国家自然科学基金项目(40975032
41175063)
公益性行业(气象)科研专项(GYHY200706020)共同资助
关键词
热带气旋
强度/结构变化
统计特征
tropical cyclones
intensity and structure change
statistical analysiscal analysis
