激光雷达对半干旱地区云层的观测

Lidar-observation of clouds in the semi-arid regions

采用532nm激光雷达在兰州的观测数据,根据计算得到的消光系数,分析了半干旱地区城区及乡村上层云的生消过程、云量分布、云的光学厚度。结果表明:半干旱地区云的分布有一定规律,中云春季所处的高度比冬季的高,厚度变化的振荡范围比高云的要大,平均光学厚度较高云的也略大。无论中云、高云,春季的厚度变化振荡范围都比冬季的要大。云形成的光学厚度占大气柱总光学厚度的比例为2.6%～99.3%,无明显的规律。订正模式需要进一步研究。

The returned signals were measured by lidar of 532 nm in Lanzhou and the extinction coefficient was calculated to analyze the cloud dissipation process, the distribution of cloud cover and the optical depth of clouds in city and countryside of the semiarid areas. The results show that the distribution of clouds is regular in the semiarid areas. The height of middle clouds in spring is higher than that in winter. The changes in thickness and the average optical depth of middle clouds are more than high clouds. The variations of the optical depth of clouds in spring are more active than in winter. The average optical depth of cloud accounts for 2.6%-99.3% of the total optical depth of the atmosphere. No obvious pattern was observed. The revised modification model will be further investigated.