Simultaneous Raman and Mie-Rayleigh lidar measurement in the lower troposphere

摘要

A lidar system capable of simultaneous measurement of Raman and Mie-Rayleigh scattering was constructed, and used for measurement of O_3, water vapor, and aerosols in the lower troposphere. O_3 concentration measurement was performed by differential absorption of N_2 and O_2 Raman scattering signals with the lidar transmitter operating at 280.0 nm, and also by differential absorption of Mie-Rayleigh scattering and of N_2 Raman scattering with the transmitter operating at 279.5 nm and 280.5 nm on alternate pulses. Water vapor profiles were obtained as the mix ing ratio relative to N_2 using the N_2 and H_2O Raman scattering signals with the lidar transmitter operating at 280.0 nm. Simultaneous measurement of H_2O Raman scattering and Mie scattering over a continuous period of about 13 hours showed that the lidar system can identify uncondensed water vapor and condensed water vapor by comparison of temporal and spatial variations of the water vapor mixing ratio and of the Mie backscattering coefficient.