近58年来登陆中国热带气旋气候变化特征

The climatic changes of landfall tropical cyclones in China over the past 58 years.

利用1949—2006年《台风年鉴》和《热带气旋年鉴》资料,主要分析了1949—2006年登陆中国热带气旋的频数、登陆位置、登陆季节延续期和登陆强度等要素及其概率分布的年际和年代际变化特征。结果表明:近58年来,登陆中国热带气旋年频数有减少趋势,但登陆时达台风强度的年频数变化不明显;按登陆地点分区统计发现,登陆华南地区的热带低压及(强)热带风暴年频数以减少为主,而登陆东部地区的热带气旋年频数变化不明显。登陆点历年最北位置(最南位置)有南移(弱的北移)趋势,导致登陆点历年南北最大纬度差逐渐减小,这表明热带气旋登陆区域更为集中,在23°—35°N增多,而在35°N以北和23°N以南以减少为主。登陆中国热带气旋季节延续期缩短了近1个月。热带气旋年平均登陆强度及其概率分布偏度有增加趋势,表明登陆的强台风有增加;登陆中国华南和东部地区的台风强度都有增强趋势,前者比后者趋势更明显。另外,热带气旋年最大登陆强度差长期呈现减小的趋势。

By using the data from the Tropical Cyclone Yearbooks, changes of landfall tropical cyclones （TCs） in China over the past 58 years （1949-2006） were analyzed , in terms of their tracks, numbers, duration, intensity, probability distributi ons as well as interannual and decadal variabilities. The results indicate that the landfall TCs numbers have decreased but the numbers hardly changed for typho ons. The frequency decreased evidently for tropical depressions and （strong） tro pical storms landed in southern China, but the variation of frequency of TCs ove r eastern China is not obvious. Over the past 58 years, the most northern latitu de of landfall TCs for each year tends to be more southward, and the most southe rn latitude turns to be more northward, resulting in a decrease of the southno rth range of landfall TCs, i.e., more TCs tend to make landfall between 23°N an d 35°N, and fewer in the north of 35°N and south of 23°N . The landfall se ason is decreased by about one month. The intensity of landfall TCs has increased, and the intensity difference between the strongest and the weakest TCs reduced. Furthermore, the skew of intensity shows an upward tendency, indicating the proportion of stronger landfall TCs has increased. Finally, the annual averaged intensity of landfall TCs has enhanced for both southern China and eastern China, with a stronger increase appearing in the former than the latter.