中尺度数值模式中湿过程参数化的敏感性试验  

^Sensitivity Test with Different Schemes for the Moist Processes Parameterization in a Hydrostatic Mesoscale Model

作　　者：俞小鼎[1] Richa.,E 

机构地区：[1]北京气象学院

出　　处：《大气科学》1995年第6期645-653,共9页Chinese Journal of Atmospheric Sciences

基　　金：国家教委留学回国人员科研资助

摘　　要：本文利用一个三维中尺度模式，分别采用两种不同的湿过程处理方案ＦＰＡ和ＮＣＡ模拟同一个洋面冷锋个例，以考察模拟结果对湿过程参数化方案的敏感性。两种方案的区别在于前一种使用了次网格温对流参数化而后者没有。通过比较分别使用ＦＰＡ和ＮＣＡ方案所进行的模拟ＦＰＳ和ＮＣＳ，发现冷锋结构在两者间出现较大差异。从８５０ｈＰａ等压面｜△θｅ｜等值线图所显示的结构看，ＮＣＳ中冷锋呈现为一长一短两条锋带，而ＦＰＳ中冷锋仅呈现为一条锋带。在相应的冷锋横向垂直剖面中，ＮＣＳ中存在两个相邻的锋面垂直环流，而ＦＰＳ中只有一个。另外，ＮＣＳ中对流不稳定的冷锋区出现垂直运动过分发展的现象，而ＦＰＳ中不存在这个问题。通过与卫星云图比较，我们注意到，ＮＣＳ中尽管出现了垂直运动过分发展的现象，但相对于ＦＰＳ而言，其模拟的冷锋结构与实际较为接近，成功地模拟出云图上显示的双冷锋结构。ＮＣＳ中垂直运动过分发展的一个重要原因是模式中采用的静力平衡近似。ＦＰＳ中次阿格对流参数化方案的使用，通过减少甚至消除对流不稳定度，一方面使垂直运动的过分发展倾向受到约束，另一方面也可能使在对流不稳定层结下的锋区环境中本应出现的中尺度结构失去了形成的机会。Sensitivities to different schemes of the moist physics in a hydrostatic mesoscale model is studied by applying this model in cold front case (FRONTS87-IOP2),in which large area of moist static unstable stratification is present within the frontal zone. Two kinds of moist simulations, one (called FPS) with a subgrid convection scheme and the other (called NCS) without it, are conducted. The cold front showed quite different structures between FPS and NCS. In FPS, only a single strong cold frontal band is present; but in NCS, two strong cold frontal bands, one long one short, are present. Besides, NCS experienced the dramatic development of vertical velocity in the moist static unstable frontal zone, whereas such problem did not appear in FPS. Having compared with satellite images and the ground-based observations, we found that although the overdevelopment problem is better controlled in FPS than in NCS, NCS gives a more realistic cold frontal structure in which a mutiple banded structure is found. We think that the hydrostatic approximation in the model is mainly responsible for the overdevelopment problem in the moist static unstable frontal zone in NCS. The use of the subgrid convection scheme in FPS, at one hand, has the development of vertical velocity get controlled by reducing or even eliminating the moist static unstable stratification, but at another hand, may filter out some significant mesoscale frontal structure which would otherwise have develooped in the most static unstable cold frontal zone.

关 键 词：中尺度模式 湿过程 参数化 敏感性 大气 

分 类 号：P432.1[天文地球—大气科学及气象学]