Abstract:

Clouds and aerosols have significant impact on globe climate change, and due to lack of information about clouds and aerosols vertical structure, there is large uncertainty to quantify their climatic effects. Lidar has been well known as a unique remote sensing for measuring the vertical structure of clouds and aerosols with high spatio-temporal resolution. To validate observations of spaceborne lidar, measurements from a developed ground-based polarized Raman lidar in Lanzhou on March 6 and March 22, 2014 were conducted. The results show that observations from CALIPSO lidar and ground-based lidar had a good consistency for clear day except for signals near ground surface because of overlap effect of ground-based lidar. So the geometric overlap factor of ground-based lidar could be calculated from the comparison. For cloudy condition, CALIPSO lidar observations had a good agreement with those of ground-based lidar for high cloud layer, but due to different direction of observation for ground-based and spaceborne lidar or inhomogeneous of cloud in the lower atmosphere, they were different.
 

Key words: polarized raman lidar, CALIPSO lidar, vertical structure of clouds and aerosols, comparative observations

摘要：

云和气溶胶具有显著的气候效应，且存在很大的不确定性，所以获取云和气溶胶的垂直结构信息对于研究全球气候变化具有重要意义。利用兰州大学半干旱气候变化教育部重点实验室自行研制的地基偏振拉曼激光雷达，将2014年3月6日和22日的观测资料与CALIPSO星载激光雷达的观测资料进行对比研究。结果表明：晴天条件下，CALIPSO星载激光雷达和地基激光雷达的反演结果总体上有较好的一致性，而2 km以下的差异主要是因为地基激光雷达受到几何重叠因子的影响。因此，在晴空条件下综合地基和星载激光雷达观测数据，可计算出地基激光雷达的几何重叠因子和盲区；多云条件下，CALIPSO星载激光雷达和地基激光雷达在中高层的观测结果具有较好的一致性，但低层存在较大差异，原因主要可能是由于两者观测方向的不同和云体分布不均。

关键词: 偏振拉曼激光雷达, CALIPSO激光雷达, 云和气溶胶垂直结构, 对比观测