Differential absorption LIDAR (DIAL) with multiple wavelengths provides capabilities for separately identifying and quantifying chemicals in mixtures that are impossible for conventional two-line DIAL. It also permits several choices about how to convert individual laser pulse returns into estimates of gas concentrations. These choices concern both averaging techniques and procedures for fitting averaged data to library spectra of possible gases. The purpose of this paper is to compare several analysis options using real data taken with 8 or 10 mid-wave IR wavelengths in field test. The options fall naturally into two groups, as implied above. The first group comprises ways to combine data averaging with ratioing. The second group comprises various maximum-likelihood estimators and least-squares fits of the averaged data. Several options arise in the second group because data is taken at multiple wavelengths; for two-line DIAL there would be only a single option in this second group. This paper compares the result of field data analysis for these two groups of options. The properties of the data acquired by the multi-line DIAL system are first described. Then the three averaging/ratioing techniques are discussed. The various options for extracting concentration estimates from averaged data are compared. Finally, the implications for remote sensing data analysis are discussed.
[1]
P T Woods,et al.
Pulse averaging methods for a laser remote monitoring system using atmospheric backscatter.
,
1987,
Applied optics.
[2]
Jinxue Wang,et al.
History of one family of atmospheric radiative transfer codes
,
1994,
Remote Sensing.
[3]
J A Fox,et al.
Practical considerations for the design of CO(2) lidar systems.
,
1988,
Applied optics.
[4]
R E Warren,et al.
Detection and discrimination using multiple-wavelength differential absorption lidar.
,
1985,
Applied optics.
[5]
Mark R. Hermann,et al.
Frequency-agile OPO-based transmitters for multiwavelength DIAL
,
1996,
Optics & Photonics.