摘要
为了解北京降雪的微物理机制,利用中尺度数值模式WRFV3.9.1(选取Thompson微物理方案),对2015年11月22-23日北京的一次降雪天气进行模拟,并利用常规降水资料、探空资料、雷达资料对模拟结果进行验证,在此基础上分析此次降雪的云微物理过程.结果表明,华西倒槽顶部的偏东风气流为此次降雪发生、发展带来了充足水汽,形成回流降雪天气.模式能够很好地模拟出雷达回波和降水的分布及时间演变特征.模拟的云雷达站点的反射率和水成物粒子的时空演变和Ka波段垂直指向雷达的观测结果较为一致.对云微物理结构的模拟结果分析表明,雪花主要的3个源项分别为雪花凝华、雪晶碰冻云水、冰晶自动转化成雪,在低层有雪花升华;高空的冰晶主要来源于凝华,经冰晶转化为雪的过程消耗;低层的霰粒主要来自雪晶撞冻云水.
In order to understand the microphysical mechanism of winter snowstorm in Beijing,a winter snowfall event in Beijing during 22〜23 November,2015 was simulated by the WRFV3.9.1 mesoscale numerical model with the Thompson microphysics scheme.The simulated results were verified by taking advantage of conventional precipitation data,sounding data and polarimetric radar data.On this basis obove,the cloud microphysical processes of the snowfall were analyzed in detail.The results show that the easterly airflow at the top of the inverted trough in West China has brought sufficient water vapor to the occurrence and development of the snowfall,so a inverse flow snowstorm forms.The model can quite well the distribution and temporal evolution of radar echoes and precipitation.The cloud radar station simulated and the temporal and spatial evolution of hydrate particles are consistent with the observation result when Ka-band is vertically pointing at radar.The simulation results of cloud microphysical structure show that three main source terms of snow are the depositional growth of snow,the accretion of cloud water by snow and ice crystals automatically converting into snow,and there is sublimation of snow in the lower layer.The upper layer ice crystal is mainly from condensation and is consumed in the process of ice crystal converting into snow.The graupel particles in the lower layer mainly come from the accretion of cloud water by snow.
作者
李一凡
肖辉
杨慧玲
孙跃
周筠珺
胡朝霞
冯小真
LI Yifan;XIAO Hui;YANG Huiling;SUN Yue;ZHOU Yunjun;HU Zhaoxia;FENG Xiaozhen(Chengdu University of Information Technology,Chengdu 610225,China;Key Laboratory of Cloud Precipitation Physics and Severe Storms,and Center of Disaster Reduction,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《成都信息工程大学学报》
2020年第1期55-68,共14页
Journal of Chengdu University of Information Technology
基金
国家重点研发计划资助项目(2016YFE0201900-02)
国家自然科学基金资助项目(41575037)
国家重点基础研究发展计划(973)资助项目(2014CB441403)
关键词
大气物理学与大气环境
云物理学
回流降雪
数值模拟
水成物粒子
冰相粒子源汇项
atmospheric physics and environment
cloud physics
inverse flow snowstorm
numerical simulation
hydrometeors
source and sink terms of solid particles
