Preliminary Statistical Study of subtropical water vapor profiles from Raman LIDAR at La Reunion (21°S, 55°E) over the period 2002-2005

Ground based lidars can provide continuous observations of tropospheric water vapor profiles using the Raman scattering by water vapor and nitrogen molecules. A Raman water vapor lidar was deployed at La Reunion over the period 2002-2005 in aim to perform a preliminary study of water vapor monitoring and evaluate the needs in view of a more specific lidar system to be implemented at the Observatory of Physique de l’Atmosphere de La Reunion (OPAR). A statistical study of the distribution of water vapor profiles is presented, and some investigations concerning the calibration have been evaluated. The data set having several long acquisition measurements during nighttime, an analysis of the diurnal cycle of water vapor has also been investigated. Based on these results, the characteristics and the design of a future lidar system to be implemented at the new observatory (2000 meters) for long-term water vapor monitoring are presented.