中文摘要：

2011年3～4月和2013年4～5月利用车载多普勒激光雷达在北京观象台分别进行了为期约1个月的大气综合观测实验。采用改进的微分零交叉法给出激光雷达观测个例并与同步探空数据进行比对，体现出较好一致性。统计结果表明167组天顶方向上的激光雷达廓线中含有云的数据占62．9％，其中单层、2层及3层云所占比例分别为34．1％、16．2％和6．6％。所有云层结构中，低云、中云、高云及直展云的比例分别为30．2％、51．4％、17．3％和1．1％，平均云底高度、云顶高度及云厚分别为4．26、4．99、0．73km。北京春季出现单层云频率最高，且存在多层云时顶层云最厚，其云厚与单层云云厚较为接近。与同步探空仪相对比，共61对含云匹配数据，二者计算的云底、云顶高度的相关系数为0．86、0．83，均方根偏差为1．31、1．74km，探空观测的云底较激光雷达偏高。

英文摘要：

The Doppler wind lidar was deployed at Beijing Meteorological Observatory from March to April, 2011 and April to May, 2013, respectively. Laser radar observational case using a modified differential zero crossing method shows a good agreement with radiosonde measurements. The statistic analysis of 167 Zenith-pointing lidar profiles indicates that the averaged frequency of cloud occurrence is 62. 9%, which single-layer, two-layer, and three-layer clouds account for 34.1%, 16.2%, and 6. 6% of all profiles, respectively. Low, middle, high and deep convective clouds account for 30.2 %, 51.4 %, 17.3 %, and 1.1% of all cloud observations, respectively. The cloud-base height, cloud-top height, and cloud thickness for all clouds are 4.26, 4.99, and 0.73 km, respectively. The occurrence frequency of single-layer cloud is the highest. Among the multi-layer clouds, the thickness of upper level clouds is the thickest, which has same magnitude as the thickness of single-layer clouds during spring in Beijing. Lidar observations are compared with the radiosonde for 61 matched profiles. The validations of the synchronous measurements show that the corresponding correlation coefficients of the cloud-base height and the cloud-top height from the lidar and the radiosonde are 0.86 and 0.83, respectively, and the root mean square deviation are 1.31 km and 1.74 km, respectively. The cloud-base heights from the radiosonde appear systematically higher than those from the lidar.