关键词: 高层卷云, 消光后向散射比, 激光雷达, 光学厚度

Abstract:

High cirrus clouds have a large influence on weather and climate, and its lidar ratio is an important optical property. Suppose that there is only molecule without aerosol above and below the clouds, the transmittance and the optical thickness of clouds can be retrieved from lidar data, and the lidar ratio of the clouds. Analysis was performed on the clouds data acquired from 532nm lidar of Hampton University. Observation has been performed from January to October 2007. 798 samples with optical thickness between 0.08 and 1.5 have been selected. Results show that Cirrus clouds observed are mostly in 7~13.5 km altitudes. The lidar ratio is 21.4sr in average， the change of the lidar ratio with season is not obvious, the probability distribution function of lidar ratio appears normal distribution feature. The probability distribution function of optical thickness indicates that most clouds are thin clouds.

Key words: high cirrus clouds, lidar ratio, lidar, optical thickness