条件非线性最优扰动在长江中下游地区冬季暴雨中的应用研究  

A STUDY OF THE APPLICATION OF CNOP IN A WINTER STORM IN THE MIDDLE-LOWER BRANCHES OF YANGTZE RIVER

作　　者：刘段灵[1,2,3] 孙照渤[1] 彭世球[2] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]中国科学院南海海洋研究所/热带海洋环境国家重点试验室,广东广州510301 [3]广东省气象台,广东广州510008

出　　处：《热带气象学报》2013年第5期782-792,共11页Journal of Tropical Meteorology

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-EW-208;KZCX2-YW-Q11-02);国家自然科学资金面上项目(41076009)共同资助

摘　　要：为了提高长江中下游地区高影响天气的数值预报,利用条件非线性最优扰动(CNOP)方法,对一次长江中下游地区冬季降水个例(高影响天气事件)进行目标观测研究,并通过观测系统模拟试验(OSSE)检验了该方法确定敏感区的有效性和可行性。试验结果表明,CNOP方法可有效识别对应于高影响天气事件的敏感区。通过对敏感区进行初始场修正后,可明显改善验证区内24 h累积降水预报误差和总能量预报误差。进一步分析发现,通过改善敏感区内的初始场信息(如水汽通量场和低层冷空气活动等),使得数值模式不仅能更真实刻画该天气系统的初始结构,还能更好模拟出该天气系统随时间的演变特征,因而减少了验证区内对该天气系统的预报误差。这一结果表明可以把CNOP方法应用于长江中下游地区高影响天气事件的目标观测研究或实践中。In order to improve the numerical prediction of winter storms in the middle-lower branches of Yangtze River,a targeting observation experiment for a winter storm case（a high-impact weather event） is presented in this paper using the conditional nonlinear optimal perturbation（CNOP） method.A set of observing system simulation experiments（OSSEs） is performed to evaluate the feasibility of the method in determining the sensitivity area.The results show that the sensitivity area corresponding to the high-impact weather event is effectively identified by the CNOP method.By improving the quality of the initial conditions in the sensitivity area,the 24 h accumulated rainfall prediction errors and total energy prediction errors in the verification region are significantly reduced compared to the ＂truth＂.Further analyses reveal that the improvements of the initial conditions （such as the water vapor flux and the low-level cold air activities） in the sensitivity area can not only well describe the initial structures of the high-impact weather system but also more accurately reproduce the temporal evolution features of the weather system,thus resulting in the decrease of the prediction errors in the verification region.The results indicate that it is feasible to use the CNOP method in the study or practice of the targeting observations of high-impact weather events in the middle-lower branches of Yangtze River.

关 键 词：天气学 高影响天气 条件非线性最优扰动 目标观测 观测系统模拟试验 

分 类 号：P426.62[天文地球—大气科学及气象学]