一次高原低涡过程云微物理特征模拟研究

Simulation of Cloud Microphysical Characteristics during a Plateau Vortex Process

为探究高原涡降水的云微物理机制,利用中尺度数值模式WRFV4.3(选取Lin微物理方案),针对2018年8月10-13日青藏高原一次高原涡降水过程进行模拟,分析了此次高原涡过程的云微物理特征。结果表明:模式能够很好地模拟出本次高原低涡发生发展过程,也能模拟出降水的量级和范围。同时各粒子的时空分布说明冰相粒子的分布范围比云水粒子广,同时其分布高度也远高于云水粒子,其中冰相粒子大值区主要分布在500~250 hPa,而云水粒子大多位于500 hPa以下。基于各粒子的源汇项特征,发现位于高层的霰粒子碰并雪粒子降落至低层融化成雨水并与云水碰并是这次高原涡降水的主要因素,其次凝华、贝基隆过程和碰并是冰相粒子生长的主要过程,同时在整个高原涡东移过程中,冰相粒子对其降水产生起到了非常重要的作用,而霰的融化在其中占比最大,雪的融化对降水的贡献比较小。

In order to explore the cloud microphysical mechanism of plateau vortex precipitation,the mesoscale numerical model WRFV4.3(Lin microphysics scheme was selected)was used to simulate a plateau vortex precipitation process over the Tibetan Plateau from August 10 to 13,2018,and the cloud microphysical characteristics of this plateau vortex process were analyzed.The results show that the model can well simulate the occurrence and development process of the plateau vortex,as well as the magnitude and range of precipitation.At the same time,the spatial and temporal distribution of each particle indicates that the distribution range of ice particles is wider than that of cloud water particles,and its distribution height is much higher than that of cloud water particles.The large value area of ice particles is mainly distributed in 500-250 hPa,while cloud water particles are mostly located below 500 hPa.Based on the characteristics of the source and sink terms of each particle,this paper found that located at the top of graupel particles touch and particles down to lower melt into the rain and snow and rapid touch and is the main factor of the plateau vortex rainfall,followed by sublimation,Bergeron process and touch and ice phase particles growth is the main process,at the same time in the process of the whole plateau vortex eastward,ice phase particles on the precipitation played a very important role.The melting of graupel accounts for the largest proportion among them,and the melting of snow contributes less to precipitation.