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| 南海台风Vongfong(2002)登陆前后内核结构和近海加强原因的数值模拟研究 | |
| 引用本文： | 李江南,吴国强,王刚,冯瑞权,王安宇.南海台风Vongfong(2002)登陆前后内核结构和近海加强原因的数值模拟研究[J].热带气象学报,2008,24(5):441-448. |
| 作者姓名： | 李江南 吴国强 王刚 冯瑞权 王安宇 |
| 作者单位： | 1. 中山大学环境科学与工程学院,广东,广州,510275 2. 江门市气象局,广东,江门,529020 3. 澳门地球物理暨气象局,澳门 |
| 基金项目： | 国家重点基础研究发展计划(973计划)，国家自然科学联合资助基金，国家自然科学基金 |
| 摘 要： | 利用6 km细网格区域的显式模拟结果分析了Vongfong(2002)的内核结构;对Vongfong近海加强的动力学机制进行了研究.结果表明:(1) 轴对称性结构中,Vongfong最大风速半径(RMW)在强盛期随高度递减.Vongfong在近海时,低层最强的流入在其移行的前方,而流出区在其后方.这些特征与大西洋飓风和西太平洋台风相反.(2) 动力场和热力场都有明显的不对称结构.在强盛期,对流西北强、东南弱;强对流云带与最大风速区的位置一致.在加强期,低层西冷东暖、中高层西暖东冷;到强盛期,低层和中高层都有明显的暖心结构.(3) 中纬度中上层冷低压系统和台风的相互作用是Vongfong近海加强的重要原因.①由于冷低压系统外围的冷空气从西北侧进入台风的中层,低层有暖湿空气配合,使得位势不稳定能量增加,对流发展.②因为冷低压中心的下沉气流正是二级环流的下沉支,冷低压南移填塞,台风近海加强.两个方面最终通过CISK(第二类条件不稳定)机制来实现. |
| 关 键 词： | 南海台风 内核结构 近海加强 |
| 收稿时间： | 2007/4/28 0:00:00 |
| 修稿时间： | 2008/4/21 0:00:00 |
NUMERICAL STUDY OF THE INNER-CORE STRUCTURES AND THE MECHANISM FOR INSHORE STRENGTHENING DURING THE LANDFALLING OF TYPHOON VONGFONG(2002) IN THE SOUTH CHINA SEA |
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| LI Jiang-nan,WU Guo-qiang,WANG Gang,FONG Soi-kun and WANG An-yu.NUMERICAL STUDY OF THE INNER-CORE STRUCTURES AND THE MECHANISM FOR INSHORE STRENGTHENING DURING THE LANDFALLING OF TYPHOON VONGFONG(2002) IN THE SOUTH CHINA SEA[J].Journal of Tropical Meteorology,2008,24(5):441-448. | |
| Authors: | LI Jiang-nan WU Guo-qiang WANG Gang FONG Soi-kun and WANG An-yu |
| Institution: | School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275; China;Jiangmen Metorological Bureau, Jiangmen 529020, China;School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275; China;Macao Geophysical and Meteorological Bureau, Macao, China;School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275; China |
| Abstract: | An explicit simulation with a fine grid domain at the intervals of 6km is used to explore the inner-core structures of Vongfong(2002). The dynamics for Vongfong strengthening inshore are examined. It is found as follows. (1) The radius of maximum wind of the axisymmetric structures of the typhoon decreases with height during its mature stage. When Vongfong is inshore,the strongest low-layer inflow locates in the front and the outflow is in the rear,which are just the reverse from the Atlantic hurricanes and other Pacific typhoons. (2) The dynamic and energetic fields are highly asymmetric in structure. Convection is stronger in the northwest of the typhoon than in the southeast; the strongest convective cloud bands are consistent with the maximum wind region. During its strengthening stage,it is cold west of and warm east of the typhoon center in the lower layer but warm in the west and cold in the east in the mid-upper layer. During its mature stage,there are evidently warm-core structures in the lower and mid-upper layer. (3) The interactions between mid-latitude cold lows in the middle-upper troposphere and typhoons are the cause for the typhoon to strengthen inshore. Firstly,the outer circulation of the cold low enters into the typhoon in middle troposphere when an outer cold airflow from the cold low flows into the northwest of the typhoon so that geopotentially instable energy increases and convection develops. Secondly,downdraft in the cold low contributes just as the secondary circulation of the typhoon system so that the cold low weakens while moving south and the typhoon strengthens inshore. Due to the CISK mechanics. these two factors might help strengthen the typhoon. |
| Keywords: | typhoons in the South China Sea the inner-core structures strengthening inshore |
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