热带气旋路径趋势数值预报的试验研究

A STUDY ON THE NUMERICAL PREDICTION OF TROPICAL CYCLONE TRACK TENDENCY

给出了一个嵌套于欧洲中期天气预报中心全球谱模式中的套网格模式,用于预报热带气旋路径趋势;提出了一种以欧洲中期天气预报中心提供的时距为24小时的预报场为基础的“接力预报”方法;设计了五种不同的“接力预报”方案;并对8507号和8509号两个热带气旋就各种不同预报方案进行了数值预报试验。结果表明,本模式对热带气旋路径趋势具有较强的预报能力,对疑难路径也具有一定的预报能力,为开展热带气旋的路径趋势预报提供了一个新的途径。文中还对影响热带气旋路径趋势的一些主要因子结合各预报结果进行了分析,为模式尽早投入业务提供了一定的依据。

A one-way nested barotropic model used for predicting tropical cyclone track tendency is de-veloped.The so-called“relay forecasting”time integral method is suggested.That is the grid datasupplied by ECMWF through GTS are used not only for determining the boundary value of fine-mesh forecasting domain,but also for updating large sclae circulation during integral time.Fivedifferent“relay forecasting”schemes are designed and are all tested on tropical cyclones No.8507and No.8509.After comparing and analysing the results obtained from various forecastingschemes,the main factors which caused the forecast errors are identified.The experimental results show that“relay forecasting”method has great capability for pre-dicting tropical cyclone track tendency.It may forecast not only the normal tracks more accurate-ly than the operational models,but also the anomalous tracks and erratic paths of tropical cy-clones.The longer the integral time is,the more obvious the superiority of this method is.Thisshows that the“relay forecasting”method has not only suggested a new possible way for predictingtropical cyclone track tendency,but also has made a first encouraging step to develop a medium-range forecasting method of tropical cyclone tracks.Furthermore,the results from various forecast schemes indicate that they can be used to fa-cilitate the operational forecast.