Ehret G, Kiemle C, Renger W, Simmet G
Appl Opt. 1993 Aug 20;32(24):4534-51. doi: 10.1364/AO.32.004534.
A near-infrared airborne differential absorption lidar (DIAL) system has become operational. Horizontal and vertical water vapor profiles of the troposphere during summer (nighttime) conditions extending from the top of the planetary boundary layer (PBL) up to near the tropopause are investigated. These measurements have been performed in Southern Bavaria, Germany. The system design, the frequency control units, and an estimation of the laser line profile of the narrow-band dye laser are discussed. Effective absorption cross sections in terms of altitude are calculated. Statistical and systematic errors of the water vapor measurements are evaluated as a function of altitude. The effect of a systematic range-dependent error caused by molecular absorption is investigated by comparing the DIAL data with in situ measurements. Typical horizontal resolutions range from 4 km in the lower troposphere to 11 km in the upper troposphere, with vertical resolutions varying from 0.3 to 1 km, respectively. The lower limit of the sensitivity of the water vapor mixing ratio is calculated to be 0.01 g/kg. The total errors of these measurements range between 8% and 25%. A sine-shaped wave structure with a wavelength of 14 km and an amplitude of 20% of its mean value, detected in the lower troposphere, indicates an atmospheric gravity wave field.
一种近红外机载差分吸收激光雷达（DIAL）系统已投入使用。对夏季（夜间）从行星边界层（PBL）顶部到对流层顶附近的对流层水平和垂直水汽廓线进行了研究。这些测量是在德国巴伐利亚南部进行的。讨论了系统设计、频率控制单元以及对窄带染料激光的激光线轮廓的估计。计算了有效吸收截面随高度的变化情况。评估了水汽测量的统计误差和系统误差随高度的函数关系。通过将DIAL数据与现场测量数据进行比较，研究了由分子吸收引起的与距离相关的系统误差的影响。典型的水平分辨率范围从对流层下部的4公里到对流层上部的11公里，垂直分辨率分别从0.3公里到1公里不等。计算得出水汽混合比灵敏度的下限为0.01克/千克。这些测量的总误差在8%到25%之间。在对流层下部检测到的波长为14公里、振幅为其平均值20%的正弦波结构表明存在大气重力波场。
