Trace-gas measurements with an infrared sun photometer

John E. Allen Jr.; R. N. Halthore; David Alan Glenar; Brian L. Markham

doi:10.1117/12.187598

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30 September 1994 Trace-gas measurements with an infrared sun photometer

John E. Allen Jr., R. N. Halthore, David Alan Glenar, Brian L. Markham

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Proceedings Volume 2266, Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research; (1994) https://doi.org/10.1117/12.187598
Event: SPIE's 1994 International Symposium on Optics, Imaging, and Instrumentation, 1994, San Diego, CA, United States

Abstract

Accurate assessment of the potential impact of greenhouse gases and aerosols on the Earth system can be enhanced by a global monitoring network and can be facilitated by the development of compact, portable optical instruments for field use. The more important of these gases, e.g., methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O), have strong absorptions at wavelengths between 2 and 5 micrometers ; however, this spectral region is heavily dominated by absorption by water (H₂O) which is itself an important contributor to radiative transfer at these wavelengths. To achieve the desired reduction in instrument size, it is often necessary to relax wavelength resolution requirements which in turn affects the accuracy and precision of the retrieved column abundances. To address these measurement problems, an infrared sun photometer has been constructed for application to trace-gas detection and analysis techniques are being developed to extract column abundances from the spectrally congested data. The current instrument design is based on a circular variable filter (CVF) with wavelength coverage from 1.2 to 5 micrometers . Preliminary measurements with this instrument are presented and electro-optical alternatives to the CVF as the tuning element are discussed.

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John E. Allen Jr., R. N. Halthore, David Alan Glenar, and Brian L. Markham "Trace-gas measurements with an infrared sun photometer", Proc. SPIE 2266, Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research, (30 September 1994); https://doi.org/10.1117/12.187598

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