本文利用中国气象科学研究院(CAMS)中尺度云分辨模式对2007年10月的一次积层混合云降水过程进行了数值模拟。利用模拟结果结合实测资料, 研究了积层混合云系的宏微观结构和降水特征, 并分析了云系的水分收支及降水效率。结果表明:积层混合云是导致此次北京降水的主要云型;积层混合云降水分布不均匀, 云系中微物理量的水平和垂直分布都不均匀, 具有混合相云的云物理结构。冷云降水过程占主导地位, 雪的融化对雨水的形成贡献最大。北京区域降水过程的主要水汽源地为黄海海面及蒙古国, 两支气流在陕西北部汇合后的西南气流将水汽输送到华北地区, 北京区域以外, 水汽和水凝物主要从西边界和南边界输送到域内。北京区域降水主要时段内, 水物质通量在水平方向上为净流入。对北京区域水汽、水凝物和总水物质的水分收支各项的估算表明, 水物质基本达到平衡。北京区域从2007年10月5日20时至6日14时, 总水成物降水效率、凝结率、凝华率及总水凝物降水效率分别为5.6%、4.77%、4.19%、44.9%。
In this study, the precipitation process of stratiform and embedded convective cloud during 5-6 October 2007 in the Beijing area was simulated using the Chinese Academy of Meteorological Sciences mesoscale cloud model. Based on observation data, the characteristics of the macro- and micro-structure of the cloud system and precipitation were analyzed. The authors also analyzed the moisture budget and precipitation efficiency of the cloud system. The results show that the stratiform and embedded convective cloud was the main precipitation cloud system in this Beijing-precipitation process. The precipitation distribution of the stratiform and embedded convective cloud was not uniform. In addition, the microphysical variables in the cloud system were not uniform in the horizontal and vertical directions. The stratiform and embedded convective cloud over the Beijing area had microphysical structural characteristics of a mixed phase cloud. The melting of snow was the main microphysical process contributing to raindrop formation. The main source region of water vapor for this precipitation process in the Beijing area was the Yellow Sea and Mongolia. Two air flows merged in the north of the Shaanxi Province forming a southwest airflow that transported water vapor to northern China. Outside the Beijing area, water vapor and hydrometeor was mainly transported to the region from the western and southern boundaries. In the main precipitation period in the Beijing area, the flux of the total water substance in the horizontal direction was the net inflow. The estimation of the water budget of the water vapor, hydrometeor, and total water substance showed that the water substance was generally balanced. The precipitation efficiency, condensation rate, deposition rate, and hydrometeor precipitation efficiency were 5.6%, 4.77%, 4.19%, and 44.9%, respectively, in the Beijing area from 2000 BJT (Beijing time) 5 October to 1400 BJT 6 October 2007.
陶玥,李军霞,党娟,李宏宇,孙晶.北京一次积层混合云系结构和水分收支的数值模拟分析.大气科学,2015,39(3):445~460 TAO Yue, LI Junxia, DANG Juan, LI Hongyu, SUN Jing. A Numerical Study on Precipitation Process and Moisture Budget of Stratiform and Embedded Convective Cloud over Beijing Area. Chinese Journal of Atmospheric Sciences (in Chinese),2015,39(3):445~460复制