西北太平洋热带气旋活动特征

Characteristics of Northwest Pacific Tropical Cyclones

为掌握近年来西北太平洋热带气旋的活动规律,利用2006—2015年热带气旋资料,对西北太平洋热带气旋活动特征进行统计分析,结果表明:西北太平洋热带气旋主要发生在5°N^20°N的纬度带内,南海中部海面、菲律宾以东海面和关岛附近海面是主要发生源地;平均每年发生热带风暴(Tropical Strom,TS)等级以上的热带气旋 23.5个,较常年平均偏少;热带气旋移动路径以西行、西北行和转向路径为主,占所有路径出现频数的80%以上,其中转向路径频数最多;热带气旋的移速与纬度关系密切,在东风带中移速较慢,进入西风带中移速加快;平均每年约有8个热带气旋在我国登陆,少于常年平均;热带气旋 10级和7级以上大风圈半径平均值分别约为100n mile和200n mile;热带气旋最大波高与其强度关系密切,中心气压低于950hPa的强热带气旋,平均最大波高在8m以上,出现狂浪和狂涛的概率在95%以上。

The Northwest Pacific tropical cyclone data from 2006 to 2015 are analyzed to investigate the characteristics of the tropical cyclone in recent years. The analysis shows the following facts: The tropical cyclones in the Northwest Pacific mainly occurred in the latitudes between 5°N-20°N, mostly, the sea surface of the South China Sea, the sea of the east of Philippines and the sea near Guam;23.5 tropical cyclones above TS(Tropical Strom) grade formed on a yearly average, which were less than the perennial average;The westbound, north-west and steering paths were dominating, accounting for more than 80% of all paths, and the steering paths were the most frequent of all;The average speed of the tropical cyclone was closely related to the latitude, relatively slow in the easterly belt and quicker in the westerly belt;There were about 8 tropical cyclones landing in China on a yearly average, less than the perennial average;The mean semi-diameters of the tropical cyclones were about 100 n mile and 200 n mile for Beaufort numbers 10 and 7, respectively;The maximum wave height was closely related to the strength of the tropical cyclone, and in the tropical cyclone with a central pressure lower than 950 h Pa, the average maximum wave height was above 8 m, and the probability of the high and very high seas was above 95%.