华南“94·6”特大暴雨的中尺度对流系统及其环境场研究 Ⅱ.物理过程、环境场以及地形对中尺度对流系统的作用  

A Study of Mesoscale Convective Systems and Its Environmental Fields during the June 1994 Record Heavy Rainfall in South China Part Ⅱ: Effect of Physical Processes, Initial Environmental Fields and Topography on Meso-β Convective System

作　　者：孙建华[1] 赵思雄[1] 

机构地区：[1]中国科学院大气物理研究所,北京100029

出　　处：《大气科学》2002年第5期633-646,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目G1998040907"我国重大气候;天气灾害形成机理;预测理论的研究"第Ⅱ部分;国家自然科学基金资助项目49735180以及国家科技部攀登专项95-专-3共同资助

摘　　要：在该文第Ⅰ部分中选取1994年6月12日～13日过程进行了较深入的研究,在确定云雨、垂直运动的模拟基本正确以后,利用模式的输出资料对在此期间的β中尺度对流系统的结构和演变进行了分析研究。第Ⅱ部分继续探讨物理过程、初始环境场以及地形对β中尺度对流系统的发生、发展的影响。结果表明:潜热释放对强对流系统发生、发展都有重要的作用。行星边界层过程对对流的发生阶段影响较为明显,而对发展阶段的影响似乎还不大。地面感热和潜热通量对对流系统的强度有影响。对初始场的试验表明,初始湿度场的改变会很明显地影响模拟结果,温度场的影响次之。地形的改变对大尺度的雨带影响不是很大,主要影响强暴雨的强度和落区,地形尤其是喇叭口地形对“94·6”暴雨的增幅作用十分明显。In the first part of this study, a case (12 June-13 June, 1994) was selected for a deep study. Due to successful simulations of cloud water and vertical motion, the shear line and the meso-β systems along it are studied by using the model output data. In this part of study, the physical processes, initial environmental fields and topography, which are related to the heavy rainfall, are tested by using numerical model. The results show that latent heat can affect the triggering and developing of strong convective systems. Sensible heat flux, latent heat flux and PBL process also affect the developing of strong convective systems. The effects of large scale environmental fields on simulation of the strong heavy rainfall are tested by modifying the relative humidity and temperature of initial field. The effect of the relative humidity, especially at the low level, is the most significant to simulation of the strong convective systems. The effect of temperature of initial field is smaller than that of humidity field. The results of topography experiments show that topography seems to be not important to simulation of large-scale rain belts when its height is modified. However, the effect of the ' trumpet'-shaped topography in the north of Guangxi Autonomous Region, is very important to simulation of the strong heavy rainfall.

关 键 词：环境场 地形 Β中尺度对流系统 数值模拟 物理过程 华南地区 1994年 

分 类 号：P458.121.1[天文地球—大气科学及气象学]