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Advances in Data Processing for Open-path Fourier Transform Infrared Spectrometry of Greenhouse Gases.

Shao, L. and Griffiths, P.R. and Leytem, A.B. (2010) Advances in Data Processing for Open-path Fourier Transform Infrared Spectrometry of Greenhouse Gases. ANALYTICAL CHEMISTRY. 82(19):8027-8033. 30 September 2010.

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Abstract

The automated quantification of three greenhouse gases, ammonia, methane and nitrous oxide, in the vicinity of a large dairy farm by open-path Fourier transform infrared (OP/FT-IR) spectrometry at intervals of 5 minutes is demonstrated. Spectral pretreatment, including the detection and correction of the effect of interrupting the infrared beam is by a moving object, and ways of correcting for the effect, and correction for the nonlinear detector response are applied to the measured interferograms. Two ways of obtaining quantitative data from OP/FT-IR data are described. The first, which is installed in commercial OP/FT-IR spectrometers, is based on classical least squares (CLS) regression and the second is based on partial least squares (PLS) regression. It is shown that CLS regression only gives accurate results if the absorption features of the analytes are located in very short regions where lines due to atmospheric water vapor are absent; of the three analytes examined, only ammonia fell into this category. On the other hand, PLS regression allowed what appeared to be accurate results to be obtained for all three analytes.

Item Type: Article
NWISRL Publication Number: 1392
Subjects: Air Quality > Air Emissions
Depositing User: Michelle Wayment
Date Deposited: 27 May 2011 16:58
Last Modified: 27 May 2011 16:59
Item ID: 1422
URI: https://eprints.nwisrl.ars.usda.gov/id/eprint/1422

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