Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.248 IF 3.248
  • IF 5-year value: 3.650 IF 5-year
    3.650
  • CiteScore value: 3.37 CiteScore
    3.37
  • SNIP value: 1.253 SNIP 1.253
  • SJR value: 1.869 SJR 1.869
  • IPP value: 3.29 IPP 3.29
  • h5-index value: 47 h5-index 47
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 60 Scimago H
    index 60
Discussion papers
https://doi.org/10.5194/amt-2018-373
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/amt-2018-373
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 07 Dec 2018

Research article | 07 Dec 2018

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Measurement Techniques (AMT).

Application of Open Path Fourier Transform Infrared Spectroscopy (OP-FTIR) to Measure Greenhouse Gas Concentrations from Agricultural Soils

Cheng-Hsien Lin1, Cliff T. Johnston1, Richard H. Grant1, and Albert J. Heber2 Cheng-Hsien Lin et al.
  • 1Department of Agronomy, Purdue University, West Lafayette, IN 47907, United States
  • 2Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, United States

Abstract. Open-path Fourier transform infrared spectroscopy (OP-FTIR) has often been used to measure hazardous or trace gases from the "hot" point sources (e.g., volcano, industrial or agricultural facilities) but seldom used in the field-scale source areas, such as soil emissions. OP-FTIR, the close-path mid-IR laser-based N2O, and the nondispersive-IR CO2 analyzers were used to measure the concentrations of greenhouse gases (e.g., N2O and CO2) emitted from agricultural soils over a period of 9−19 June in 2014. We developed a quantitative method of N2O/CO2 analysis that minimized the interferences from diurnal changes of humidity and temperature in order to measure N2O/CO2 concentrations accurately. Two chemometric multivariate models were developed, a classical least squares (CLS) and a partial least squares (PLS), respectively. This study evaluated different methods to generate the single beam background spectra, and different spectral regions to determine N2O/CO2 concentrations from OP-FTIR spectra. A standard extractive method was used to measure the "actual" path-averaged concentrations along an OP-FTIR optical path in situ, as a benchmark to assess the feasibilities of these quantitative methods. Within the absolute humidity of 5000−20 000 ppmv and the temperature of 10−35 °C, we found that the CLS model underestimated N2O concentrations (Bias = −4.9 ± 3.1 %) calculated from OP-FTIR spectra, and the PLS model improved the accuracy of the calculated N2O (Bias = 1.4 ± 2.3 %). The bias of the calculated CO2 was −1.0 ± 2.8 % using the CLS model. These methods suggested that the changed ambient factors potentially led to biases in N2O/CO2 estimations from OP-FTIR spectra, and may help the OP-FTIR user to escape from the dependency of extractive methods used to calibrate the concentration determined by OP-FTIR.

Cheng-Hsien Lin et al.
Interactive discussion
Status: open (extended)
Status: open (extended)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Cheng-Hsien Lin et al.
Cheng-Hsien Lin et al.
Viewed  
Total article views: 276 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
211 60 5 276 2 2
  • HTML: 211
  • PDF: 60
  • XML: 5
  • Total: 276
  • BibTeX: 2
  • EndNote: 2
Views and downloads (calculated since 07 Dec 2018)
Cumulative views and downloads (calculated since 07 Dec 2018)
Viewed (geographical distribution)  
Total article views: 198 (including HTML, PDF, and XML) Thereof 198 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 23 Mar 2019
Publications Copernicus
Download
Short summary
The open path FTIR (OP-FTIR) is often used to measure the atmospheric gas composition and concentrations. The OP-FTIR, however, is sensitive to the changed ambient factors, which likely led to quantitative biases. This study developed methods to minimize the effect of the ambient temperature and humidity on N2O/CO2 quantification. These methods can help the increased users who implement the OP-FTIR to estimate gas fluxes in the agroecosystem achieve more precise and accurate estimations.
The open path FTIR (OP-FTIR) is often used to measure the atmospheric gas composition and...
Citation