多层引导气流与热带气旋移速移向突变的统计分析

Statistical Analysis on the Multi level Steering Flows and Sudden Changes in Speed and Direction of Tropical Cyclones Movement

对２９个热带气旋资料进行统计，分析了多层引导气流与热带气旋的移速、移向及其突变的关系．结果表明：用多层气流作引导气流优于仅用某一层．多层引导气流方向与热带气旋移向比较接近，而其速度变化与热带气旋移速变化有密切关系．当引导气流微弱且风向不稳定时，热带气旋易出现移速。

We make statistics on 29 cases of tropical cyclone and analyse the relationship between the multi level steering flow (MLSF) and the speed and direction (including their sudden changes) of tropical cyclone movement. The results show that the MLSF is more indicative than a single lever streering level flow. The direction of MLSF approaches relatively the direction of tropical cyclones movement. Furthermore,the change in speed of MLSF closele relates to that of tropical cyclone. When the speed of MLSF is weak and its direction is varible, sudden changes in the speed or direction of tropical cyclone will occur frequently.