935nm差分吸收激光雷达系统及对流边界层水汽廓线探测

935nm Differential Absorption Lidar System and Water Vapor Profiles in Convective Boundary Layer

研制了一套935nm水汽探测差分吸收激光雷达(DIAL)系统。种子注入的环形腔光参量振荡器,在窄线宽脉冲激光的抽运下,通过Ramp-Hold-Fire方法锁定光参量振荡器谐振腔,产生脉冲能量为45mJ、波长为935nm、重复频率为10Hz、脉冲持续时间为6ns的窄线宽、波长稳定的脉冲激光。接收望远镜直径为305 mm,使用雪崩光电二极管作为探测器,以935.776nm作为探测光波长(λon)、935.860nm作为参考光波长(λoff)进行了地基垂直差分探测实验,获得了上海地区对流边界层水汽浓度廓线。数据时间分辨率为60s,距离分辨率为30 m,在高度600m至对流边界层顶的范围内,水汽浓度昼夜有效测量误差小于0.1g/m^3,将DIAL数据与附近气象观测站无线电探空仪数据进行对比,结果证实了DIAL数据的有效性。

A differential absorption lidar （DIAL） system at 935 nm is built for water vapor detection. Its transmitter is based on seed injection ring optical parametric oscillator （OPO）, and a narrow linewidth pulse laser is used as pump source. The resonant cavity of OPO is locked by Ramp-Hold-Fire method, and the OPO can generate narrow linewidth and stable wavelength pulse laser with pulse power of 45 mJ, wavelength of 935 nm, repetition frequency of 10 Hz and pulse duration of 6 ns. To obtain water vapor concentration profile of convective boundary layer in Shanghai, the foundation vertical differential detection test is carried out. The detection wavelength is 935.776 nm and the reference wavelength is 935.860 nm. The receiver mainly includes a telescope of 305 mm diameter and an avalanche photo diode sensor. The range resolution is 30 m and the temporal resolution is 60 s. Signals in a range from 600 m to the top of troposphere boundary layer in the daytime and in the nighttime are effective, with water vapor concentration error not exceeding 0.1 g/m3. When we compare the DIAL data with the radiosonde data nearby the meteorological station, the availability of the DIAL data is confirmed.