Supercontinuum LIDAR Measurements of Atmospheric Constituents
Document ID: 330
Brown, David M.1
Edwards, Perry S.1
Shi, Kebin1
Liu, Zhiwen Z.1
Philbrick, C. Russell
1 The Pennsylvania State University, Department of Electrical Engineering, University Park, PA, U.S.A.
Presented: 29th Review of Atmospheric Transmission Models Meeting
Museum of Our National Heritage, Lexington, Massachusetts, June 13 -14, 2007
Abstract
Optical transmission and radiance models such as MODTRANTM4 have provided the framework for the conceptual design of many remote sensing systems spanning the commercial, military, and academic arenas. Our application of MODTRANTM5 has allowed us to design and test a supercontinuum absorption lidar (SAL) system capable of measuring concentrations of various atmospheric constituents at background levels through a long path absorption. Our white light lidar systems utilize femtosecond or nanosecond supercontinuum lasers and free space or fiber optic coupling options for the transceiver systems. Prototype designs are currently being used to demonstrate the capability of these techniques to measure open path atmospheric concentrations of H2O, O2, and other species across the Penn State University Park campus. The purpose of this study is to demonstrate the capability of this technology to accurately quantify atmospheric species concentrations through broadband absorption of a supercontinuum source. By controlling the source of broadband radiation, the approach is able to remove uncertainties inherent in hyper-spectral remote sensing systems that use sunlight as a source. Analysis of Differential Absorption Spectroscopic (DAS) data collected through the SAL requires the use of various multi-wavelength algorithms to determine concentration path length. Even though these algorithmic approaches are still under development, preliminary trade studies and performance estimates are possible through the use of the MODTRANTM5 model. Preliminary examples are discussed.