Observations of Atmospheric Water Vapor Using Raman Lidar Techniques
Document ID: 97
Master's Thesis
The Pennsylvania State University
The Graduate School
Department of Electrical Engineering
Abstract
Raman lidar has become a well-established technique to obtain water vapor profiles. Measurements of the atmospheric distributions of water vapor have been made with the LAMP lidar (Laser Atmospheric Measurement Program) during the 1995 Case I measurement program on Wallops Island, VA The history of the development of methods used to obtain water vapor measurements is briefly reviewed. Scattering mechanisms used by LAMP lidar are summarized as a basis for obtaining atmospheric distributions of water vapor. A description of the LAMP lidar, its system parameters, and the analysis procedure used to determine water vapor profiles is presented. A correction applied to the water vapor measurements to account for the attenuation due to the wavelength dependence of molecular (Rayleigh) scattering is provided. A correction needed for the tropospheric ozone absorption in the Hartley band for the UV channels is also provided. Simultaneous measurements obtained from the vibrational Raman technique at night using visible and UV channels were compared to validate the Raman technique for the UV channel. A comparison between the visible and UV channels produced an overall correlation coefficient of 0.96. Nighttime profiles from the surface to 5 km and daytime vertical profiles from the surface to about 1 km are displayed to illustrate results from LAMP lidar. Useful daytime measurements are expected up to 2.5 km from the LAMP instrument. Suggestions for improvements in obtaining water vapor profiles are made for future experiments.
| Citation: | R. S. Harris, "Observations of Atmospheric Water Vapor Using Raman Lidar Techniques", The Pennsylvania State University, Master's Thesis, May 1996, 61 pages |