一个新动力因子在登陆台风“凤凰”强降水过程中的应用  

Application of a new dynamic factor on the strong precipitation of landing typhoon “Fung-wong”

作　　者：周冠博[1] 冉令坤[2] 高守亭[2] 

机构地区：[1]中国气象局国家气象中心,北京100081 [2]中国科学院大气物理研究所,北京100029

出　　处：《大气科学学报》2014年第6期786-793,共8页Transactions of Atmospheric Sciences

基　　金：中国科学院重点部署项目(KZZD-EW-05);灾害天气国家重点实验室开放课题(2011LASW-B15);国家自然科学基金项目(41175060);公益性行业科研专项(GYHY201406006)

摘　　要：根据波动和风场辐合辐散与登陆台风强降水密切相关的特点,利用高分辨率的数值模拟资料,采用分别表征强降水区波动特征和辐合辐散特征的两个动力参数——位势散度波作用密度和散度垂直通量,对登陆台风"凤凰"的强降水过程做诊断分析;同时结合波扰动和辐合辐散两特征,发展了一个新的物理量——热力切变散度参数,并据此对台风"凤凰"的强降水过程做进一步诊断分析,结果表明在整个研究时段内,地面雨区被热力切变散度参数的异常值区始终覆盖,二者具有较一致的空间分布和时间演变趋势。基于GFS(Global Forecast System)预报产品的动力释用分析表明,利用数值预报场计算的热力切变散度参数的强信号出现在强降水区,而弱信号出现在非降水区,该参数对强降水落区有较好的指示作用。Baed on the characteristic that there are close relations between the wave, convergence and divergence of wind field and the strong precipitation of landing typhoon, with the high-resolution simu- lation data, using two dynamic parameters：potential divergence wave action density and divergence ver- tical flux（ they represent the wave features and the convergence and divergence features of strong pre- cipitation area,respectively） ,this paper carried out a diagnostic analysis on the strong precipitation of landing typhoon ＂Fung-Wong＂ .Combining the wave disturbance features and the convergence and di- vergence features, a new physical quantity：thermal shear divergence parameter is defined.Based on the parameter, a further diagnostic analysis is carded out on the strong precipitation of ＂Fung-Wong＂ .Re- sults show that the rainfall area is always covered by the abnormal value area of thermal shear diver- gence parameter, and they have the similar spatial distribution and time evolution trend.The dynamic in- terpretation analysis of GFS （ Global Forecast System） forecast products shows that the strong signals of thermal shear divergence parameter locates in the rainfall area and the weak ones in the non-rainfall are- a, which has a good indicative meaning for forecasting strong precipitation area.

关 键 词：散度垂直通量 位势散度波作用密度 热力切变散度参数 垂直速度 

分 类 号：P458.124[天文地球—大气科学及气象学]