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 airborne new-generation particle measuring system(PMS) in spring and autumn of 2009 in Hebei province,the microphysical characters of precipitable stratiform cloud were analyzed.The results indicate that the precipitable stratiform 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 ℃ layer height are 2002 m,1106 m and 3 811 m,respectively.For the microphysical characters,the mean number concentration and mean diameter of cloud droplet are 54.6 cm-3 and 8.64 μm 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.