热带气旋迁移加速度的统计规律

Statistical trends of drift acceleration of tropical cyclones

热带气旋运动规律的研究对于揭示热带气旋运动的机理,进而提高热带气旋预报的精度具有重要意义。本文对联合台风预警中心和美国国家飓风中心发布的1979—2016年间全球4907个热带气旋事件的观测数据进行统计分析,得到了全球范围内热带气旋中心迁移加速度的若干规律。研究表明,纬度变化对于热带气旋的迁移具有重要的影响,热带气旋迁移加速度沿纬线方向分量的平均值在低纬度地区接近于0,随着纬度增大,呈现出向东加速且加速度有不断增加的趋势。南北半球的规律具有明显的相似性。不同区域内平均经线方向加速度随纬度变化的规律不如纬向加速度明显,随着纬度的增加,差异增大。

Understanding the statistical trends of tropical cyclone movement is of great significance to revealing its mechanism and improving forecast accuracy.We examine certain trends of drift acceleration of tropical cyclones using the data observed for tracking the histories of 4907 cyclone events during 1979-2016,published by Joint Typhoon Warning Center(JTWC) and the National Hurricane Center(NHC).We found that tropical cyclones have a mean zonal acceleration close to 0 at low latitudes,while at high latitudes they tend to accelerate towards the east with an increasing mean zonal acceleration.And similar trends can be observed in the northern and southern hemispheres.Along the meridian,however,the acceleration trends vary across different basins,and the difference becomes more noticeable at higher latitudes.