WRF-Hybrid背景误差协方差调整在台风同化及预报中的应用研究  

WRF-Hybrid background error covariance adjustment in typhoon assimilation and forecasting

作　　者：沈菲菲[1,2] 闵锦忠[1,2] 许冬梅[1,2] 王世璋[1,2] 

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044 [2]南京信息工程大学气象灾害教育部重点实验室,南京210044

出　　处：《气象科学》2015年第2期150-159,共10页Journal of the Meteorological Sciences

基　　金：国家重点基础研究计划(973计划)项目(OPPAC-2013CB430102);国家自然科学基金资助项目(41375025);江苏省普通高校研究生科研创新计划(CXZZ11-0606;CXZZ12-0490;CXZZ13-0501)

摘　　要：利用雷达径向风单点试验和2006年8月超强台风"桑美"个例,首先研究了静态背景误差协方差的尺度化因子和方差在台风系统雷达资料同化中对台风路径和强度预报的影响。结果表明:在高时空分辨率的雷达资料同化中,较小的尺度化因子能显著改进对台风路径的预报;尺度化因子的影响比方差的影响更为显著。基于上述实验结果,进一步研究了WRFDA-Hybrid系统中"流依赖"控制变量的水平局地化和垂直局地化对台风预报的影响。试验结果表明:当"流依赖"的水平局地化距离与静态背景误差协方差的尺度化因子具有等效影响范围的时候,WRFDA-Hybrid能够得到比较合理的分析结果。同时针对雷达观测资料的空间分布特征,本文提出了一种新的基于雷达探测高度的垂直局地化方案,对台风的强度和路径预报均有显著的改进。By using the single observation test case in August, 2006, the influences of length scale on radar radial wind and the super typhoon Saomai factor and covariance static background error covari- ance in typhoon data assimlation on the typhoon track and intensity forecasting are studied. Results show that in high spatial and temporal resolution typhoon radar data assimilation, smaller scale factor can sig- nificantly improve the typhoon track prediction, and the impact of scale factor is larger than that of covari- ance. Furthermore, based on the above test results, the influence of the horizontal and vertical localiza- tion coefficient of the ＂flow dependent＂ in WRFDA-Hybrid system on typhoon prediction is investigated. Results indicate that reasonable analysis can be obtained when the equivalent influence radius occurrs in both horizontal localization of ＂flow dependent＂ and the length scale factor of static background error co-variance. Meanwhile, aimed at the spatial distribution features of radar observation data, a new vertical localization scheme for the radar detection height is proposed, which is able to better forecast typhoon in- tensity and track.

关 键 词：台风 背景误差协方差 WRF模式 多普勒雷达资料 

分 类 号：P444[天文地球—大气科学及气象学]