Meteorological water vapor Raman lidar - advances

摘要

We present the design and preliminary results of a water vapor Raman lidar, developed explicitly for meteorological applications. The lidar was designed for Meteoswiss as a fully automated, eye-safe instrument for routine water vapor measurements in the troposphere. The lidar is capable of day and nighttime vertical profiling of the tropospheric water vapor with 15 to 30 min temporal resolution. The daytime operation is achieved by decreasing the solar background employing the narrow field-of-view, narrow-band technique. The daytime vertical operational range exceeds 4 km, while the nighttime range is above 7.5 km. The lidar receiver is built on a compact multi-telescope configuration coupled with fibers to a grating polychromator used for spectral separation and partial background suppression. An additional "near range" fiber in one of the telescopes increases the signal level in the near range and allows water vapor retrieval starting from 100 m. The water vapor mixing ratio is retrieved using the ratio of the water vapor and the nitrogen Raman signals. An additional detection channel for oxygen Raman signal is used for aerosol correction.