一种初始涡旋重定位方法及热带气旋路径数值模拟试验

A METHOD OF INITIAL VORTEX RELOCATION AND NUMERICAL SIMULATION EXPERIMENTS ON TROPICAL CYCLONE TRACK

采用平滑滤波和柱形滤波技术,从背景场中分离出初始涡旋环流和大尺度环境场,然后把分离出的涡旋环流进行平移和再植入到观测位置,最终得到一种初始涡旋重定位方法。针对2006—2007年7个热带气旋共23个时次,采用背景场直接加入热带气旋bogus模型和背景场进行初始涡旋重定位后加入热带气旋bogus模型2种方案,分别进行了对比模拟试验。结果表明:对背景场进行初始涡旋重定位后加入热带气旋bogus模型的方案模拟的24和48小时热带气旋路径平均误差都相对较小,初始涡旋重定位方法可以减小热带气旋模式因热带气旋初始位置偏差而引起的误差,有助于提高热带气旋模式的路径预报水平,有较好的业务应用前景。

Using the technique of smooth filtering and cylindrical filtering,the initial vortex circulation and large-scale environmental field are separated from the background field.Then the separated initial vortex circulation is translated and reinserted in the location where the observation takes place.Finally,a method of initial vortex relocation is obtained.For seven tropical cyclones at 23 levels of time in the years 2006—2007,two schemes,of either directly adding a tropical cyclone bogus model in the background or adding it after the relocation of initial vortex in the background field,are employed.Simulation experiments are compared,respectively.The results show that the mean errors of simulated tropical cyclones tracks at 24 and 48 hours are both smaller with the scheme of adding tropical cyclone bogus model after the relocation of initial vortex in the background field.The relocation method of the initial vortex can decrease the error caused by the bias of initial tropical cyclone location in tropical cyclone models.The relocation method is conducive to improving the track forecast of tropical cyclone models and has a good operational perspective for application.