New mobile Raman lidar for measurement of tropospheric water vapor

Abstract

The content of water vapor in atmosphere is very little and the ratio of volume of moisture to air is about 0.1%–3%, but water vapor is the most active molecule in atmosphere. There are many absorption bands in infrared (IR) wavelength for water vapor, and water vapor is also an important factor in cloud formation and precipitation, therefore it takes a significant position in the global radiation budget and climatic changes. Because of the advantages of the high resolution, wide range, and highly automatic operation, the Raman lidar has become a new-style and useful tool to measure water vapor. In this paper, first, the new mobile Raman lidar’s structure and specifications were introduced. Second, the process method of lidar data was described. Finally, the practical and comparative experiments were made over Hefei City in China. The results of measurement show that this lidar has the ability to gain profiles of ratio of water vapor mixing ratio from surface to a height of about 8 km at night. Meanwhile, the measurement of water vapor in daytime has been taken, and the profiles of water vapor mixing ratio at ground level have been detected.

Keywords

optics, lidar, water vapor, aerosol, Raman