一次积层混合云降水实例的数值模拟分析  

Numerical Study on the Complex of the Stratiform and Embedded Convective Cloud Precipitation:A Case Study

作　　者：于翡[1] 姚展予[1] 

机构地区：[1]中国气象科学研究院中国气象局云雾物理重点开放实验室,北京100081

出　　处：《气象》2009年第12期3-11,I0001-I0002,共11页Meteorological Monthly

基　　金：国家科技支撑计划课题"混合云人工增雨技术研究"(批准号:2006BAC12B02);科技部公益性行业(气象)科研专项项目"京津经济区及华北区域气溶胶对云的改变导致的降水变化及其在天气预报中的应用"(GYHY200706036)

摘　　要：观测显示,积层混合云有自己独特的动力热力结构,降水过程也有自己的特点,但过去关于积层混合云的实例模拟工作较少。2007年9月28日在我国华北地区发生了一次积层混合云降水过程。利用WRF-ARW中尺度数值模式,对这一个例进行了实例模拟,并结合常规观测、卫星和雷达资料分析模拟结果,表明:此次积层混合云系是降水云系减弱,层状云发展形成的。在降水物理过程中,此次积层混合云不仅具有积云和层云形态混合的特征,还具有冷云过程和暖云过程共存的相态混合的特征;中层的大范围辐合和相应的较均匀上升气流场支撑着层状云,而在均匀上升气流场中的波动导致了对流云镶嵌其中;有迹象表明,条件对称不稳定是维持此次积层混合云发展的动力因子。Observation shows that the complex of stratiform and embedded convective percipitation has its own unique thermal and dynamic structure,and the precipitation process has its own characteristics.However,the numerical study of real cases has been published much less so far.In this paper,a case on the 28 September 2007 complex of stratiform clouds and embedded convective clouds in North China is simulated by using the WRF-ARW model.It shows that,the clouds are weakened by the shear line,and formed by the development of stratiform clouds.It also reveals that the complex of stratiform clouds and embedded convective clouds is not only the complex of clouds with different shapes,but also the complex of different microphysical processes.And the large-scale convergence on the middle level and the corresponding uniform updraft make the stratiform clouds develop,while the dramatic fluctuations of updraft lead to embedded convective clouds,which may be initiated and supported by conditional symmetric instability.

关 键 词：积层混合云 WRF数值模拟 

分 类 号：P426.5[天文地球—大气科学及气象学] TP391.7[自动化与计算机技术—计算机应用技术]