两类热带气旋在南海的移动速度

统计分析最近23a资料，得出热带气旋在南海的移动速度平均为3．3纬度，日，其中西太平洋热带气旋较快，达3．9纬度，日，南海热带气旋较慢，仅2．8纬度，日。两类热带气旋都是在7月最快。过去一天移动速度快于平均值，未来一天容易减慢，反之容易加快。西太平洋热带气旋以减慢为主，南海热带气旋以加快为主。天气系统对热带气旋移动速度影响较大。

Migration Velocities of the Two Types of Tropical Cyclone in the South China Sea

In the South China Sea the migration average velocity of the tropical cyclone is 3.3 latitude/day through statistically analyzing the recent data of 23 a. Among these the West Pacific tropical cyclone is faster, 3.9 latitude/day, and the South China Sea tropical cyclone is slower, 2.8 latitude/day. the two types of tropical cyclone migrate fastest in July. If the tropical cyclone's migration velocity of the former day is faster than the migration average velocity, it will slow down easily next day, otherwise it will speed up easily. Most West Pacific tropical cyclones decelerate, but most South China Sea tropical cyclones quickens. Tropical cyclone's migration velocity is influenced mainly by the synoptic system.