登陆中国大陆、海南和台湾的热带气旋及其相互关系

首先,针对登陆中国热带气旋的登陆地点资料仅为地名的现状,利用1951-2004年西北太平洋热带气旋资料和登陆中国热带气旋资料,研究制定了登陆资料信息化方案.该方案包括海岸线近似、登陆位置计算、其他特征量计算和误差订正4个方面.对资料信息化结果的分析表明:信息化登陆资料效果是良好的.在此基础上,对登陆中国热带气旋的基本气候特征进行研究,重点分析了在大陆、海南和台湾登陆的3类热带气旋以及它们的相互关系.结果表明:登陆热带气旋频繁的地区为台湾东部沿海、福建至雷州半岛沿海和海南东部沿海;台湾东部沿海和浙江沿海部分地区是登陆热带气旋平均强度最大的地区,平均登陆强度达到台风级别,其中台湾南端的平均登陆强度为最强,达到强台风级别;5-11月为热带气旋登陆中国季节,集中期为7-9月,8月最多;登陆热带气旋的强度主要集中在热带低压-台风,尤其以强热带风暴和台风最多.对于全部大陆、海南和台湾三地,50多年来登陆热带气旋频数都存在不同程度的减少趋势,但只有登陆海南热带气旋的减少趋势是显著的;而所有登陆风暴(含以上强度)频数均无明显增多或减少趋势.总体而言,登陆大陆的TC最多、初旋最早、终旋最晚、登陆期最长;登陆海南的TC居中;而登陆台湾的TC最少、初旋最晚、终旋最早、登陆期最短.从登陆方式看,登陆一地的TC最多、登陆两地的TC次之,分别占总数的79.2%和20.6%,仅有1个TC登陆三地.在登陆两地的TC中,经台湾登陆大陆的TC频数最多、强度减弱最快,经海南登陆大陆的TC频数次之、强度减弱较慢,经大陆登陆海南的TC频数排行第3、强度减弱较快.

Tropical cyclones landfalling in the mainland, Hainan and Taiwan of China and their interrelations.

In consideration of the fact that the position data of landfalling tropical cyclone (TC) in China includes only place names, using the Northwest Pacific TC dataset and landfalling TC dataset during 1951-2004 from Shanghai Typhoon Institute of CMA, a computerization scheme for landfalling TC information is developed. The scheme consists of four aspects: approximation of coastal line, calculation of landfalling position, calculation of other parameters, and error correction. The assessment of the computerized data shows that the result of landfalling information computerization is satisfactory. Based on the above computerized data, climatic characteristics of landfalling TCs in China are investigated with a focus on three sorts of TCs landfalling in the mainland, Hainan and Taiwan and their interrelations. The results include the following six aspects. Firstly, regions most frequently affected by landfalling TCs were the eastern coast of Taiwan, the coastal region from Fujian Province to Leizhou Peninsula and the eastern coast of Hainan. Secondly, the eastern coast of Taiwan and parts of the coastal Zhejiang Province saw the strong landfalling TCs and their average intensity reached the typhoon level, with the strongest landfalling TCs up to the strong typhoon level in the southernmost of Taiwan. Thirdly, the TC landfalling season for China was from May to November, especially between July and September, with the highest frequency in August. Frequent intensity levels of landfalling TCs were mainly between tropical depression and typhoon, with the most frequent ones being strong tropical storm and typhoon. Fourthly, although frequencies of landfall TCs for the mainland, Hainan, Taiwan and the whole China all showed to different extents decreasing trends during the past 54 years, only the decreasing trend of landfalling TCs for Hainan is significant, while no obvious increasing or decreasing trend is found in frequencies of landfalling TCs with an intensity level of tropical storm or above. Fifthly, generally, the mainland had the highest frequency of landfalling TCs, the earliest date of the first-landfall, the latest date of the last-landfall, and thus the longest landfalling season, while Taiwan had the lowest frequency of landfalling TCs, the lastest date of the first-landfall, the earliest date of the last-landfall, and thus the shortest landfalling season. Finally, viewing from an angle of the way of landfall, TCs landfalling in one region were the most frequent (79.2%), those in two regions the next (20.6%), and only one TC made landfall in three regions. Among the TCs landfalling in two regions, those with a track from Taiwan to the mainland had the highest frequency and weakened quickest in intensity, those with a track from Hainan to the mainland had the secondary highest frequency and weakened slowly, and those with a track from the mainland to Hainan had the third largest frequency and weakened quicker.