集合方根滤波同化多普勒雷达资料在一次飑线过程中的应用研究  

Assimilation of Doppler radar observations with an ensemble square root filter:A squall line case study

作　　者：秦琰琰[1,2] 龚建东[3] 李泽椿 盛日锋[5] 

机构地区：[1]国家海洋环境预报中心,北京100081 [2]国家海洋局海洋灾害预报技术研究重点实验室,北京100081 [3]中国气象局数值预报中心,北京100081 [4]国家气象中心,北京100081 [5]山东省人民政府人工影响天气办公室,济南250031

出　　处：《气象学报》2014年第1期133-151,共19页Acta Meteorologica Sinica

基　　金：国家自然科学基金青年项目(41105067);国家高技术研究发展计划(863计划)项目(2013AA09A506-5)

摘　　要：针对2005年7月12日发生在山东省中西部地区的一次飑线天气过程,采用集合方根滤波方法开展基于WRF模式的多普勒雷达资料的同化应用试验,考察了此同化系统对实际雷达资料的同化效果。主要结论如下:(1)集合方根滤波同化系统能有效同化实际雷达资料,雷达资料的加入增加了模式的中小尺度信息,使分析场得到了显著改善,有效缩短了模式起转时间,改进了对地面降水的预报。(2)利用三次同化分析后的集合平均分析场进行的确定性预报表明,与控制试验相比,同化后分析场能更准确地预报飑线系统的微物理量场,预报的流场结构符合风暴的动力特征,动力场和热力场的分布与配置也基本合理。(3)集合平均分析场对飑线系统传播方向的预报与实况一致,但预报的系统传播速度较实况快,由于对流系统的非线性发展迅速,对系统的预报时效为5—6 h。The effectiveness of using an Ensemble Square Root Filter （EnSRF）to assimilate real Doppler radar observations is investigated by applying the technique to a case of squall line occurred on 12 July 2005 in the midwestern part of Shandong Province as done by the Weather Research and Forecasting （WRF）model.The experimental results show that,（1）the EnSRF system has the ability to effectively assimilate Doppler radar data：since the information at convective scale is added into the nu-merical model through radar data assimilation the analyzed field is improved noticeably,the model spin-up time is shortened, and the surface precipitation forecast is improved correspondingly;（2）compared with the forecast of control run,the forecast initiated from the EnSRF analysis can give a more accurate prediction of the microphysical field,and the predicted wind field and thermal field are reasonable and they are in accordance with the characteristic of convective storm;（3 ）the propagation di-rection of the squall line forecasted by the ensemble mean analysis is consistent with observations,but the propagation speed is faster than observed speed,because of the nonlinear development of the convective storm,the period of validity of forecast is a-bout 5 to 6 hours.

关 键 词：雷达资料同化 集合方根滤波 飑线 

分 类 号：P435.1[天文地球—大气科学及气象学] P456.7