Analysis of Cloud Microphysics Structure over Hebei Region during Autumn of 2007

The cloud microphysical properties are analyzed based on the aircraft measurements conducted over Hebei region,Northern China during autumn of 2007.The results show that the droplet number on the bottom layer of altostratus is greater than that on the upper layer,and the particle diameter increases with height.The maximumn content of liquid water is 0.25 g·m-3,and the average content of liquid water is 0.025 g·m-3 at the bottom.It is also shown that the concentration of cloud droplet on the upper layer were higher than that on the bottom,the droplet number concentration ranges from 10 to 80 cm-3.The diameters are around 7.56 μm,with height increasing the particle diameter increases first and then decreases.Cloud droplet spectrum narrows and the disappearance of two peaks are cloud droplet related with the change of water content.Comprehensive analysis of cloud microphysics structure suggests that planning in advance the flying pattern is possibly not the best scheme for cloud seeding in some cases,and the seeding operation should be designed based aircraft condition and weather as well as cloud conditions.In view of the temperature,it could be considered using the catalytic of liquid nitrogen or liquid CO2.