| 摘要: |
| 通过分析浙江省区域自动站加密资料、常规观测资料、NCEP/NCAR 1°×1°和0.25°×0.25°再分析资料以及卫星TBB （Black Body Temperature）资料，研究2019年第17号台风“塔巴”影响期间，浙江沿海风场分布的特点及其成因，以寻找台风影响时浙江沿海风场预报的着眼点。此次台风大风具有影响时间早、持续时间长、影响范围大和大风强度强的特点。台风环流与浙江沿海地面弱冷空气之间形成一定气压梯度的堆积，以及后续随着台风环流的发展加强，两者之间气压梯度进一步增大，是导致此次台风大风提早出现的原因之一。垂直环流有利于水平的动量输送和高层动量下传，导致此次台风大风范围大、强度强。冷空气在这次台风大风中起到非常重要的作用。随着台风外围环流与冷空气距离拉近，部分干冷空气侵入台风环流，冷、暖气团之间θse等值线密集，环流附近风速增强。由于干冷空气的继续侵入，冷、暖空气相互作用累积并释放斜压能。同时台风低层的暖心结构被冷空气占据，高层暖心结构上抬，形成上暖下冷的中心结构，导致台风开始变性减弱。地形的辐合、阻挡和摩擦作用对风场的再分布也有一定影响。 |
| 关键词: 海洋气象学 台风大风 气压梯度 垂直环流 干冷空气 地形 浙江 |
| DOI：10.3969/J.ISSN.2095-4972.2021.02.016 |
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| 基金项目:台州市科技局资助项目(1902gy04） |
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| Analysis of the impacts and formation cause of coastal wind field in Zhejiang by 1917 typhoon Tapah |
| QIU Wang-ze-he,ZHANG Lan-wen |
| (Jiaojiang Meteorological Bureau of Taizhou City, Taizhou 318000, China;Huangyan Meteorological Bureau of Taizhou City, Taizhou 318020, China) |
| Abstract: |
| In this paper, the characteristics of coastal wind field in Zhejiang and its formation associated with typhoon Tapah (1917) are investigated in order to provide prediction clues using the data from conventional radiosonde and automatic station, the reanalysis data from NCEP/NCAR 1°×1° and 0.25°×0.25° and the data from TBB. Results show that strong winds had the characteristics of early influence, long duration, wide scope and strong intensity. The accumulation of pressure gradient between the typhoon circulation and the weak cold air along the coast of Zhejiang Province and the further increase of pressure gradient after development of typhoon circulation were one of the reasons for the early appearance of the typhoon wind. Vertical circulation was conducive to horizontal transmission and the downward transport of highlevel momentum, which leaded to a large range and strong intensity of wind. Dry cold air played a very important role in the process of strong winds. As the distance between the periphe-ral circulation of typhoon and the cold air getting closer, part of the dry cold air invaded the typhoon circulation. As the θse contour lines between the cold and warm air masses getting denser, the wind speed near the circulation increased. When the cold air continued to invade, the cold and warm air interaction accumulated and baroclinic energy released. At the same time, the warm structure in the lower layer of typhoon was occupied by cold air and the warm structure in the upper layer elevated, thus the formation of the upper warm and lower cold central structure leaded the denaturation and weakening of typhoon. The convergence and friction of the terrain also affected the redistribution of the wind field. |
| Key words: marine meteorology typhoon strong wind pressure gradient vertical circulation dry cold air terrain Zhejiang Province |
