河北省降水性层状云宏微观物理特征

利用2009年河北省春秋季17架次飞机宏观观测资料和相应的机载PMS云微物理探测数据，经过回放处理、筛选和计算，统计分析近年河北省降水性层状云物理特征。结果表明：河北省降水性层状云是以Ns、Sc、As为主的多层云系，且多伴随有干层结构。云底平均高度、过冷层厚度、0℃层高度分别为2002、1106 m和3811 m。微物理方面，云滴数浓度平均为54.6 cm^-3，平均直径为8.64 μm。云粒子浓度和尺度均比20世纪90年代各特征值有所减少。统计计算的降水性层状云中液态水含量为0.13 g·m^-3，远大于20世纪90年代的值。

Macro and microphysical characters of precipitable stratiform cloud over Hebei province

Based on the observational data from the 17 flights and the corresponding detecting data from the air- borne new-generation particle measuring system （PMS） in spring and autumn of 2009 in Hebei province, the mi- crophysical characters of precipitable stratiform cloud were analyzed. The results indicate that the precipitable strati- form cloud is mainly the multi-layer cloud system including nimbostratus （Ns） altostratus （As） and stratiform cloud （Sc） in Hebei province, and it often accompanies with layer-separating phenomena. The mean height of cloud base,the supercooled layer thickness and 0 ~C layer height are 2002 m, 1106 m and 3 811 re,respectively. For the microphysical characters, the mean number concentration and mean diameter of cloud droplet are 54. 6 cm-3 and 8.64μm and both are smaller than those in 1990s,while the liquid water content is 0. 13 g-m-3 that is larger than that in 1990s.