Applications and Analysis of Raman Lidar Techniques for Measurements of Ozone and Water Vapor in the Troposphere
Document ID: 248
Master's Thesis
The Pennsylvania State University
The Graduate School
Department of Electrical Engineering
Abstract
The Lidar Atmospheric Profile Sensor (LAPS) instrument is capable of simultaneously measuring profiles of ozone, water vapor, temperature, and optical extinction. The measurements are range-resolved in 75 m increments and recorded in 1 minute time steps. The measured profiles are integrated, for user selected intervals, to calculate and display the real-time atmospheric profiles with their associated errors, +1σ standard deviation. Water vapor measurements are obtained by taking the ratio of the first Stokes Raman shifted radiation scattered by H2O and N2 molecules in the scattering volume. Profiles of ozone are obtained from a Differential Absorption Lidar (DIAL) analysis of the Raman shifted radiation scattered by N2 and O2 molecules from the transmitted 4th harmonic of the Nd:YAG laser at 266 nm. The LAPS instrument uses the "solar blind" portion of the ultraviolet spectrum to obtain measurements during daytime periods when large background limits visible measurements.
The approach used for analysis of data measured by the LAPS instrument is described with special emphasis on the recent measurements of ozone. Errors with the profile measurements of ozone are evaluated. The Raman lidar technique is shown to provide a new and unique capability to measure the ozone in the troposphere. Comparisons between the lidar profiles and point sensors on aircraft are used to verify the result.
| Citation: | S. T. Esposito, "Applications and Analysis of Raman Lidar Techniques for Measurements of Ozone and Water Vapor in the Troposphere", The Pennsylvania State University, Master's Thesis, May 1999, 92 pages |