Electronic Thesis and Dissertation Repository


Master of Science




Dr. R.J. Sica


The Purple Crow Lidar (PCL) has recently participated in a water vapour validation cam- paign with the NASA/GSFC Atmospheric Laboratory for Validation/Interagency Collaboration and Education (ALVICE) Lidar. The purpose of this calibration campaign is to insure that PCL water vapour measurements are of sufficient quality for use in scientific investigations of atmo- spheric change, and to be included in the Network for the Detection of Atmospheric Climate Change (NDACC) data base. The detection of long term changes in water vapour concentra- tion, particularly in the upper troposphere and lower stratosphere (UTLS) is an issue of pressing scientific, ecological and societal concern. The field campaign took place at the University of Western Ontario Environmental Re- search Field Station, near London Ontario Canada, from May 23rd to June 10th 2012 and resulted in 57 hours of measurements taken over 12 clear nights. On each night a minimum of one RS92 radiosonde was launched. In addition 3 cryogenic frost-point hygrometer (CFH) sondes were launched on clear nights over the course of the campaign. Measurements were obtained from near the surface up to ∼20 km by both lidar systems, the radiosondes, and the CFH balloons. These measurements will be used to calibrate profiles of water vapour mixing ratio by the newly relocated PCL. Comparisons between measurements of water vapour mass mixing ratio taken by RS92 ra- diosondes, Cryogenic Frostpoint Hygometers, and the ALVICE and PCL lidars has resulted in the derivation of a system calibration factor of ξ sys = 0.7545. The application of this calibration factor to PCL retrievals has allowed for the validation of PCL water vapour mass mixing ratio profiles to within ±5% between the altitudes of 2 km and 9 km.