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我国登陆热带气旋引起的大陆地面风场分布

Characteristic Distribution of Surface Winds Associated with Landfalling Tropical Cyclones in Mainland China

  • 摘要: 利用逐小时风速观测资料以及台风年鉴资料,分析了2008~2014年登陆我国大陆地区的51次热带气旋(TC)的地面风场分布特征,包括TC登陆期间大陆地面风场演变和大风分布特征、海岛站和内陆站的风速差异以及海拔对风力造成的影响等。结果表明:6级及以上大风主要发生在距离TC中心300 km内、TC强度达到台风(TY)以上时,并主要位于TC移动方向的右侧,尤其是右前象限;华南区TC风场分布主要由在此区域登陆的TC(Ⅰ类)造成,较大风速区包括广东西南部沿海、雷州半岛附近和海南西部沿岸;华东区TC风场分布主要由在此区域登陆的TC(Ⅱ类)造成,杭州湾出海口以及浙闽沿海是较大风速区;6级及以上大风广泛分布在华南和华东沿海,6~7级地面大风高频站主要位于杭州湾附近,8级及以上地面大风高频站点在杭州湾和福建沿海分布比广东西南部更为密集;TC登陆前后均可能造成大风,大风出现时间与站点至TC中心的距离密切相关;同等强度TC在海岛站造成的风速比陆地站更大,对高海拔站点造成的风力大于低海拔站点。本文研究结论对于TC大陆地面风场的预报具有一定参考价值。

     

    Abstract: Based on hourly wind observations in combination with the Chinese Tropical Cyclone (TC) Year Book, characteristic distribution and evolution of surface winds associated with 51 landfalling TCs in mainland China in 2008-2014 and the frequency distribution of strong winds during the landing time are analyzed.Differences in wind speed between inland and island stations and the impact of altitude on wind speed are also investigated.Results show that strong winds exceeding the Beaufort scale 6 mainly occur within a radius of 300 km from the TC center when the TC intensity reaches the level of typhoon (TY) or above.Such strong winds are mostly located on the right side of the moving direction of TC, especially in the right front quadrant divided by the center and moving direction of the TC.The distribution of surface winds in southern and/or eastern China is mainly associated with TCs that are classified as type Ⅰ or Ⅱ based on their landing locations.The region of large wind speeds in eastern China mainly includes the coastal region of southwestern Guangdong, the coastal portion of Leizhou Peninsula and western Hainan, while that in southern China mainly includes the Hangzhou Bay and the coastal region of Zhejiang and Fujian.Stations where the wind-force ranges from the Beaufort scale 6 to 7 are mainly located around the Hangzhou Bay.Stations where wind-force could exceed the Beaufort scale 8 are more densely distributed in the Hangzhou Bay and coastal area of Fujian than in the coastal region of southwestern Guangdong.Strong winds may occur before or after TC landfall, and the time of occurrence is highly related with the distance between the observational station and TC center.For TCs with the same intensity, the wind speed is lager at island stations than that at inland stations, and stronger at high altitude stations than at low altitude stations.The conclusions of this study have valuable implications for surface wind forecast of TC.

     

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