High resolution photoacoustic spectroscopy of the oxygen a-band

Cich, Matthew J.

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https://hdl.handle.net/2142/91151 Copy

Description

Title

High resolution photoacoustic spectroscopy of the oxygen a-band

Author(s)

Cich, Matthew J.

Contributor(s)

• Okumura, Mitchio
• Hodges, Joseph T.
• Long, David A.
• Miller, Charles
• Drouin, Brian
• Crawford, Timothy J.
• Rupasinghe, Priyanka
• Hogan, Daniel
• Bray, Caitlin
• Bui, Thinh Quoc
• Stroscio, Gautam
• Lunny, Elizabeth M.

Issue Date

2016-06-22

Keyword(s)

Spectroscopy in Atmospheric Chemistry

Abstract

NASA’s Orbiting Carbon Observatory missions require spectroscopic parameterization of the Oxygen A-Band absorption (757-775 nm) with unprecedented detail to meet the objective of delivering space-based column CO2 measurements with an accuracy of better than 1 ppm, and spectroscopic parameters with accuracies at the 0.1\% level. To achieve this it is necessary for line shape models to include deviations from the Voigt line shape, including the collisional effects of speed-dependence, line mixing (LM), and collision-induced absorption (CIA). LM and CIA have been difficult to quantify in FTIR and CRDS spectra which have been limited to lower pressure measurements. A photoacoustic spectrometer has been designed to study the pressure- dependence of the spectral line shape up to pressures of 5 atm, where LM and CIA contribute significantly to the A-Band absorption. This spectrometer has a high signal-to-noise (S/N) of about 10,000 and frequency accuracy of 2 MHz. In addition, temperature-dependent effects on the line shape are studied using PID-controlled cooled nitrogen flow/ heater system. The latest acquired spectra and analysis are reported here.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

En

Permalink

http://hdl.handle.net/2142/91151

Copyright and License Information

Copyright 2016 by the authors

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