广东近海台风路径异常的统计特征

STATISTICAL CHARACTERISTICS OF UNUSUAL TROPICAL CYCLONE TRACKS IN OFFSHORE GUANGDONG

对 1 949～ 2 0 0 0年的 5 2年间在广东沿海近岸转折或沿海岸移动的热带气旋异常路径进行了统计分析 ,同时还研究了广东沿海的地形特征。结果发现 ,转折点 (或靠岸点 )主要集中在有明显山脉地形的区域 ,同时靠岸前热带气旋有移速减慢的特征。另外还发现 ,转折前强度越强 ,则转折点离岸越近 ;靠岸前平均移速越小 ,则转折角度越大 ;靠岸前强度越强 ,则其沿海岸移动所需入射角越小。

Statistical analyses are made on unusual tropical cyclone tracks with sudden changes of directions in offshore Guangdong based on the data from Typhoon Almanac for the period of 1949 to 2000. Studies are also carried out on characteristics of intensity, moving speed, offshore distance, and turning points of typhoons with unusual tracks, as well as their relationships. Meanwhile, the impact of topography in the Guangdong coastal area on tropical cyclones is also studied. The results show that the locations where these tropical cyclones turned suddenly (or close to the coast) were concentrated in the mountainous coastal areas, and tropical cyclones tend to slow down when they approach the coast. It is also shown that prior to turning, the more intense the tropical cyclones are, the closer the turning points are to the coast, and the smaller incident angle they need. In addition, near the coast, the slower the tropical cyclones move, the more markedly they turn.