SVD-En3DVar方法同化多普勒雷达速度观测资料Ⅱ.实际资料试验  

Assimilation of Doppler Radar Velocity Observations with SVD-En3DVar Method. Part Ⅱ: Real Data Experiments

作　　者：徐道生[1] 邵爱梅[1] 邱崇践[1] 

机构地区：[1]半干旱气候变化教育部重点实验室,兰州大学大气科学学院,兰州730000

出　　处：《大气科学》2011年第5期818-832,共15页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目40875063;兰州大学中央高校基本科研业务费专项资金资助项目lzujbky-2010-9

摘　　要：文章的第I部分（徐道生等,2011）将基于SVD（singular value decomposition）技术和预报集合的三维变分同化方法（SVD-En3DVar）用于同化模拟的雷达速度观测资料,试验表明,通过3DVar（threedi mensional variational technique）方法产生预报集合的初始扰动场,可以缩短SVD-En3DVar中预报样本的积分时间,同化对改进暴雨的短期预报有一定好处。本文进一步将这一方法用于同化实际观测资料。选择2008年6月华南地区和2003年7月江淮地区的两个暴雨个例进行同化试验,并将其与WRF-3DVar（3DVar based onthe weather researchforecasting model）的同化结果进行比较。结果表明,同化雷达径向风资料以后,在模式初始场中包含了更多的中小尺度信息。对于使用了13部雷达资料的第一个个例,经SVD-En3DVar同化以后对18小时内每6小时一次的累计降水预报都有所改进,而WRF-3DVar的同化效果则不明显。对于只同化1部雷达观测资料的第二个个例,WRF-3DVar和SVD-En3DVar方法同化以后对前6小时的降水预报都有所改进,但对于第6~18小时的降水预报,两种方法都没有改进。In part I of this study（Xu et al.,2011）,The ensemble-based 3DVar（three-dimensional variational technique） method with SVD（singular value decomposition） technique（SVD-En3DVar） is used for assimilation of the simulated radar velocity data and the results demonstrate that using the initial perturbation samples produced with 3DVar method in SVD-En3DVar can shorten the time interval of assimilation cycle and improve the short-term forecast of precipitation.In the current study the feasibility of using SVD-En3DVar for assimilating radar velocity observations is tested with the real observational data.Two torrential rain cases（June 2008 in South China and July 2003 in the Changjiang-Huaihe region） are chosen for the test and the 18-hour forecast of rainfall is compared with that by WRF-3DVar（3DVar based on the weather research forecasting model） assimilation.For the first case（2008） the observational data from 13 radars are assimilated and the forecast of rainfall within 18 hours is improved after assimilation with SVD-En3DVar,but the improvement is not evident with WRF-3DVar assimilation.For the second case（2003）,only single-radar observations are used and the forecast of rainfall is improved in the first 6 hours after assimilation with SVD-En3DVar,however the forecasts are not improved by using either SVD-En3DVar or WRF-3DVar in the subsequent 12 hours.

关 键 词：DOPPLER雷达 集合同化 3DVAR SVD 

分 类 号：P413[天文地球—大气科学及气象学]