中文摘要：

使用中国科学院大气物理研究所的X波段双线极化雷达系统探测资料,讨论了双极化雷达各种观测参量所反映的水凝物粒子的物理本质。提出了对存在融化层的层状云使用雷达探测变量确定零度层高度以及结合地面温度反演温度廓线的方法。在存在融化层的层状云中,对雷达探测资料在层状云降水期间的RHI资料进行分层统计,结合国际上已有的研究结果,获得了几种主要水凝物粒子的极化雷达参数（即反射率、差分反射率、单位差分传播相移、相关系数）范围;在此基础上使用模糊逻辑方法,对水凝物粒子进行分类,分类结果反映了层状云的相态结构分布特点。最后,根据两个实例,使用反射率、差分反射率衰减订正后的数据,结合层状云的基本特点,分析了层状云的垂直结构和粒子的相态结构以及层状云中可能的降水机制,并使用反演的粒子分布结构代替雷达反射率因子结构对降水微物理过程进行了讨论,结果验证了顾震潮（1980）在20世纪60年代提出的层状云降水的三层概念模型。本文结果为使用双极化雷达研究云降水机制提供了方法,表明双极化雷达在云降水物理的研究中具有广阔的应用前景。

英文摘要：

Using data from X-band dual-polarization radar system set up by the Institute of Atmospheric Physics, Chinese Academy of Sciences, the paper discusses various dual-polarization radar parameters and their physical essence of representing hydrometeors. On the basis of reflectivity and differential reflectivity attenuation correction, the paper analyzes vertical structure and hydrometeor phase distribution structure of stratiform cloud, puts forward methods to position the melting layer and retrieve the vertical temperature profile in combination with the ground temperature. Statistical analysis for specific layers in the stratiform cloud is conducted, and with reference to international C- and S-hand radar studies, ranges of X-band radar parameters, i.e. reflectivity, differential reflectivity,specific differential phase shift, and correlation coefficient, for several main hydrometers are acquired. On the basis of above results, hydrometeors are classified using the fuzzy logical method. The results reflect the phase distribution characteristics of stratiform cloud and hydrometeors. Then, possible precipitation mechanism is discussed according to two cases. The retrieved hydrometeor distribution is used to study microphysical processes of precipitation instead of using the radar echo structure. The results verify the three-layer conceptual model introduced by Koo Zhen-Chao （1980） in the 1960s. The studies provide the method for dual-polarization radar application to cloud and precipitation physics studies, and indicate its broad potential application prospect.