气旋客观判别方法在两次江淮气旋过程中的应用

引用一种气旋客观判别方法——气旋相空间法,采用NCEP-FNL再分析资料等,对两次江淮气旋个例进行研究,验证江淮气旋的结构演变和降水分布特征。结果表明:该方法对江淮气旋的结构演变有很好的指示意义,低层热成风参数与中心气压的演变有较好的对应关系,低层热力不对称性参数的大幅下降和低层冷核的减弱对主要降水时段有明显的指示意义,效果优于基于温度平流偶极子的分析方法。同时探讨了该方法对江淮气旋的适应性及可改进处;该方法适用于格点数据,计算简便,有望投入气象业务使用。

Application of an objective discriminating method in the processes of two Jiang-Huai cyclones

An objective discriminating method of cyclone(the cyclone phase space method) is introduced.Based on the NCEP-FNL reanalysis data,two Jiang-Huai cyclones are studied with the objective method,which verifies the features of structure evolution and precipitation distribution of Jiang-Huai cyclones.Results show that the objective method has a good indicative significance for the structure evolution of two Jiang-Huai cyclones.There is a good corresponding relation between the low level thermal wind parameter and the minimum pressure.The significant decline of low level thermal asymmetry parameter and the decrease of low level cold core have an obvious indicative significance for main precipitation period.This objective method is obviously better than the diagnosis method based on the temperature advection dipole used before in the weather analysis.This method also has some deficiencies and needs to be improved.It is suitable for grid data,easy to calculate,and convenient for operational use too.