中文摘要：

利用2009年5月8日多普勒雷达资料和飞机穿云观测资料,综合分析了西风槽影响下山西省一次积层混合云的形成过程和微物理结构。结果表明,此次飞机探测到的积层混合云是由对流单体多次并合形成的带状对流云团减弱后形成的,云中嵌有明显的对流泡,最大强度为45～50dBZ,最大垂直尺度在6km左右。CDP（cloud droplet probe,前向散射粒子谱探头）、CIP（cloud ima-ging probe,二维灰度云粒子探头）、PIP（precipitation imaging probe,二维灰度降水粒子探头）测量的平均数浓度变化范围分别是132.4～220.2cm-3、1.54×10-1～6.28×100cm-3、9.09×10-4～7.34×10-3cm-3。二维图像表明,冷层中的固态粒子主要是形状不规则的霰粒子,说明过冷水供应充足;在-7℃左右观测到柱状聚合体和凇附程度不同的冰雪晶粒子,表明柱状冰晶通过凝华形成后,碰并和凇附是其增长为霰粒子的重要机制。不同高度的CDP平均谱（2～50μm）存在一定的差异,因低层水汽凝结作用较强,2～18μm的云粒子数浓度基本随高度的增加而降低;因暖层中碰并效率低和冷层中小冰晶浓度随高度增加,24～35μm粒子数浓度随高度增加而增大。CIP平均谱（25～1550μm）,除4100m为双峰谱外,其他高度均为单峰谱。PIP平均谱（100～6200μm）,4450m高度处的粒子谱宽和数浓度最大,3200～4000μm之间出现大值区域,表明对流单体及周边区域为较大固态降水粒子的形成提供了良好的环境。

英文摘要：

Based on the Doppler radar data and cloud microphysical data collected by aircraft,the formation and microphysics of a convective-stratiform mixed cloud（CSMC for short） impacted by westerly trough have been analyzed.The results are as follows.CSMC came into being from weakened zonal convective which was merged by small convective clouds.Apparent convection cells with the maximum intensity of 45—50 dBZ and the maximum vertical height of 6 km were embedded in the CSMC.The particle number concentrations measured by CDP,CIP,and PIP were 132.4—220.2 cm-3,1.54×10-1—6.28×100 cm-3and 9.09×10-4—7.34×10-3 cm-3,respectively.Two dimensional images show that graupel is the main ice particles in the cold layer,which implies that supercooled water is adequate;columnar aggregates and riming particles found at-7 ℃ imply that after columnar crystal is formed by sublimation,collision and riming are important mechanisms for graupel＇s formation.The average CDP spectra（diameter：2—50 μm） are different with the heights,and the concentration of particles between 2 and 18 μm decreases with height rising,because water vapor condensation is stronger in the low-level,but the concentration of those between 24 and 35 μm increases,because the collision efficiency is lower in the warm cloud and small ice particle number increases with the height rising.The average CIP spectra（diameter：25—1 550μm） follow unimodal distributions except for that at 4 100 m.The average PIP spectra（diameter：100—6 200 μm） are discontinuous at the larger size;the largest concentration and the spectral width occur at 4 450 m and the high number concentration between 3 200 and 4 000 μm implies that convective cells and the surrounding area provide a good environment for the growth of larger solid precipitation particles.