伴随同化系统中用云导风修正模式地形的试验  

Study on Model Terrain Parameter Modification Using Cloud-Derived Wind in the MM5 Adjoint-Model Assimilation System

作　　者：何芬[1] 沈桐立[1] 贺哲 赖绍钧[1] 马镜娴[1] 

机构地区：[1]南京信息工程大学气象灾害与环境变化重点开放实验室,江苏南京210044 [2]河南省气象台,河南郑州450003

出　　处：《高原气象》2007年第2期300-308,共9页Plateau Meteorology

基　　金：国家重点基础研究发展规划项目(2004CB418301);国家自然科学基金项目(40075023)共同资助

摘　　要：以2002年7月23日的天气过程为例,利用中尺度模式MM5伴随模式同化系统,进行了修正模式地形高度的试验研究。结果发现,MM5伴随模式同化系统可以对地形进行修正,并得到与资料更为协调一致的地形高度。另外,利用非常规云导风资料能够比仅使用常规资料更有效地修正模式地形高度。将修正后的地形场作为模式地形,所得的预报结果比未经修正的地形有所改进。Model terrain adjustment is carried （PSU）/National Center for Atmospheric Research out by means of the Pennsylvania State Unive （NCAR） non-hydrostatic mesoscale model MM5 rsity with its adjoint-model assimilation system （AMAS）. Two different initially-estimated terrains are given and modified by use of the AMAS, which indicates much the same assimilation for the terrains differing from each other. For the terrain parameter of identical errors, the adjiont model with inclusion of non-conventional cloud-derived wind will even more effectively improve the AMAS modification to the terrain parameter. As shown in the subsequent sensitivity runs, 500 and 200 hPa wind fields are of more importance to the adjustment of orographic terrains, respectively, to the east and west of 110°E. To verify the effects of modified terrain on NWP, experiment is conducted on a large-scale rainstorm over the Changjiang-Huai basins on 23～24 July 2002, indicating that the terrain modified especially the one adjusted by cloud-derived wind used as the MM5 surface feature will improve prediction precision. TS （threat score） of 〉50 mm rainfall （non-modification compared to modification by cloud-derived winds） is found to go from 0.074 to 0. 077, increasing by 4%, with other meteorological element fields accordingly ameliorated. These results show that the adjusted terrain goes more satisfactorily with observations. It is worth noting that to obtain reliable topographic modification needs cloud-derived wind from multiple operations to get rid of errors in observations. We now come to the conclusion that the application of AMAS to the improvement of NWP model parameters is found to be a new feasible approach.

关 键 词：MM5 伴随模式同化系统 地形高度 云导风 

分 类 号：P445[天文地球—大气科学及气象学]