中文摘要：

过冷云水生消演变规律是云物理学和人工影响天气的重要研究领域。根据 Hobbs 1974年提出的假定，利用飞机、卫星、雷达和雨量计等观测资料，对2012年9月21日河北一次西风槽天气过程进行观测研究，分析其过冷云水分布特征及演变规律。结果表明，槽前云系过冷水区宽厚并且过冷水含量较高，云滴浓度和均立方根直径较大并且均匀，冷云区厚而且没有分层，没有暖云配合；近槽云系中冷云区小粒子浓度降低但云滴直径增大，冷云区夹有干层，云系变厚出现暖云配合，冷暖云液态水含量较高，冷暖云区大粒子和降水粒子浓度和尺度增大，中尺度云团移动较快；槽后云系中云滴浓度最大，但云滴均立方根直径明显减小，过冷水区出现的高度下降、厚度很薄、过冷水含量较低，冷、暖云之间有干层，暖云对应的大粒子浓度和降水粒子浓度非常大，地面降水主要由暖云过程产生；云水（过冷水）含量峰值常出现在云内逆温层的上方；利用云粒子测量系统（P MS ）资料分析过冷云水生消演变特征与卫星和雷达资料具有较高的一致性。

英文摘要：

The growth and evolution of supercooled water are always a concern in the cloud physics and weather modification science.Based on the hypothesis proposed by Hobbs in 1974,a westerly trough in Hebei Province on 21 September,2012 is analyzed by using the airplane observation data,satellite monitoring data,radar monitoring data,and other regular observation data.Results show that （1 ）a wide and thick area of supercooled water exists in front of the trough where the supercooled wa-ter is abundant,the concentration and root mean cube diameter of the forward scattering spectrometer probe （FSSP）are rela-tively of high value,and the cold cloud is thick without dry layers and warm cloud;（2）as the trough draws near,the cloud near the trough develops rapidly,the concentration and depth of the area of the supercooled water increases significantly,the cloud becomes more thick with dry layers,the liquid water content （LWC）in cold and warm cloud is abundant,meanwhile the con-centration of 2DC and 2DP is of high value,and the mesoscale structures move quickly;（3）in the rear of the trough,the root-meancube diameter of the droplets and the amount of the supercooled water are remarkably small,and the height and width of the supercooled water decreases a lot,although the cloud concentration is still high,the cold cloud is very thin with a dry layer between warm cloud,and the warm cloud has several layers with high value concentration of 2DC and 2DP.The precipitation is produced by the warm rain process.Usually the peak of the LWC stays over the temperature inversion layer.The results based on the analysis of the particle measurement system （PMS）data are well consistent with those based on the satellite and radar monitoring data.