Analysis of cirrus properties based on micro-pulse lidar and millimeter wave cloud radar

Macro-physical characteristics of cirrus above Shouxian were studied using data from micro-pulse lidar (MPL ) and millimeter wave cloud radar (MWCR) on mobile facilities of atmospheric radiation measurement (ARM). Enlarged profile and comprehensive information of cirrus were retrieved when combined data of these two facilities were used, which indicated the necessity of joint observation. On this basis, statistical analysis was performed using cirrus cases occurred above Shouxian during observation period. The results showed that the averaged height of cloud base ranged from 5 to 10 km, and cirrus with a base height of 6-11 km had higher occurrence frequency. The averaged thickness of cloud ranged from 0.25 to 5 km, among which cirrus with a thickness of 0.5-2.5 km accounted for 90.8%. The statistical results also showed the occurrence frequency of cirrus process reduced with the increase of duration, the maximum and mean duration were 35.5 h and 3.6 h respectively, and cirrus with duration less than 5 h accounted for 82.5%.