边界层过程是数值天气预报模式和气候模式中一个重要的物理过程。针对目前GRAPES模式中MRF边界层参数化方案存在的一些问题,引入考虑夹卷过程的改进方案,并从单柱试验和实际个例试验进行了验证。Wangara单柱试验表明,改进方案产生的边界层高度和边界层结构更合理;并在对临界Richardson数的敏感性试验的基础上,确定了适合于GRAPES模式的边界层夹卷方案。另外,对2010年第11号台风“凡亚比”进行的试验表明,改进方案的台风路径预报误差小于MRF方案,且其对降水和各物理量时空分布的描述更接近实测。
Boundary layer process is one of the most important physical parameterization schemes in numerical weather prediction and climate models. In this paper, in order to resolve the existing problems of planetary boundary layer (PBL) schemes for medium-range forecast, a revised scheme involving explicit treatment of entrainment processes is incorporated, and a single-column model and real-time forecasts are used to validate the performance of the new scheme. The single-column experiment shows that the revised scheme produces more realistic PBL height and structure, and finally a more suitable PBL scheme for GRAPES model is realized based on sensitive tests of the bulk Richardson number. A case simulation of typhoon FANAPI indicates that the typhoon track forecast error of an improved PBL scheme is smaller than that of PBL scheme for medium-range forecast, and the temporal and spatial distribution of physical elements are closer to the analysis.