摘要
本文建立了一个用于研究“雅安天漏”的有限区域数值预报模式，并用该模式对１０个“雅安天漏”个例进行了数值预报试验，取得了较满意的结果。该模式动力框架的主要特点是：（１）模式的基本方程组便于构造出完全能量守恒的差分格式；（２）采用了静力扣除；（３）模式的垂直坐标选用了η坐标；（４）选用Ｅ网格作为变量的水平分布形式；（５）位势高度与其他预报量在垂直方向交错分布；（６）对Ｅ网格的波解分离问题采取了特殊的处理技巧；（７）首次采用“半格距”差分解决了矩形Ｅ网格及球坐标Ｅ网格沿对角线的差分计算；（８）采用显示分解的时间积分方案；（９）尽量保留初始场信息。模式的物理过程主要包括：（１）大尺度凝结降水；（２）对流调整及对流降水；（３）水平扩散和垂直通量输送；（４）地面辐射收支和边界层参数化。试报降水的主要降水中心及降水范围与观测分析比较相似。大于１０ｍｍ和２５ｍｎ降水的ＴＳ平均评分分别为０．４１和０．３２。
This paper, describes a grid-point limited area model for studying the 'Ya-An-Tian-Lou' (YATL), and ten trial-forecasted Ya'an heavy rain cases as well as the results.The general characteristics of the model dynamical processes are as follows : (1) the basic equations can design a perffectly energy-conservative time-space finite-diffefpnce scheme conveniently; (2) uses the departures of temperature and geopotential from their 'standards' as predicted variables; (3) vertical coordinate is the step mountain, η coordinate; (4) uses the semi-staggered E grid for the horizontal atrangement of variables; (5) the geopotential and vertical velocity are defined at the interface of the model layers, staggered with wind field and temperature field in the vertical; (6) uses a special technique to prevent grid separation (7) the special technique of 'half-grid' finite difference was used to design the difference schemes along the E-grid diagollal; (8) uses the split-explicit time difference; (9) uses the initial information as sufficiently as possible.The physical processes of the model consists of : (1) large scale precipitation; (2) modified Betts convective adjustment scheme; (3) horizontal and vertical diffusion; (4) a simple Bulk Aerodynamic PBL parameterization scheme.The trial-forecasted precipitation area and centres are very similar to the observations. The average Threat Scores for the 10 mm and 25 mm threshold are 0.41 and 0.32, respectively.
出处
《大气科学》
CSCD
北大核心
1994年第5期535-551,共17页
Chinese Journal of Atmospheric Sciences
基金
大气科学和地球流体力学数值模拟国家重点实验室(LASG)资助
关键词
数值预报
陡峭地形
模式设计
降水
numerical weather prediction
precipitous topography
model design
precipitation forecast.
