NUMERICAL SIMULATION OF OROGRAPHIC EFFECTS OF CONVECTIVE PRECIPITATION

该文利用地形追随坐标三维云模式，对湖北的一次对流降水过程进行了平坦地面和理想斜坡地形的模拟试验。结果发现：平坦地面模拟的回波强度、最大降水强度和累积降水都与实况有相当的差距。理想地形的对流过程虽然不能模拟出对流群中多单体的生消过程，但最大降水强度和累积降水都比平坦地面的大，更接近实测结果。模拟试验表明，在地形坡度较大时，会产生较强的上升气流，从而使系统对流发展旺盛，产生较大的降水和较强的回波。所以在模拟山区和丘陵地带的对流系统时，采用地形坐标并考虑地形将会改善模式的模拟结果。Using a three-dimension terrain-following coordinate cloud model with detailed microphysical processes,a convective precipitation process is simulated. In order to simplify the simulation,an idealized slope is used. Simulated results with and without orographic effects are compared and analyzed. Simulations of echo intensity,maximum precipitation without orographic effects are much weaker than observations;and they are much improved and closer to the reality after consideration of orographic effects.Experiment also indicates that different slope grades produce different results. The results will be improved if terrain coordinate is used and orographic effects are considered when simulating convective processes over mountainous or hill areas.国家重点基础研究发展计划(973计划); 国家科技攻关项目; 中国气象局资助项目中文核心期刊要目总览(PKU)中国科学引文数据库(CSCD)0z1113-1211