English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

. Open-path Fourier transform infrared spectroscopy(OP-FTIR) has often been used to measure hazardous or trace gases from hotpoint sources (e.g. volcano, industrial, or agricultural facilities) butseldom used to measure greenhouse gases (GHGs) from field-scale sources(e.g. agricultural soils). Closed-path mid-IR laser-based N2O ,nondispersive-IR CO2 analysers, and OP-FTIR were used to measureconcentrations of N2O and CO2 at a maize cropping system during9–19 June 2014. To measure N2O and CO2 concentrations accurately, wedeveloped a quantitative method of N2O∕CO2 analysis that minimizedinterferences from diurnal changes of humidity and temperature. Twochemometric multivariate models, classical least squares (CLS) and partialleast squares (PLS), were developed. This study evaluated various methods togenerate the single-beam background spectra and different spectral regionsfor determining N2O and CO2 concentrations from OP-FTIR spectra. Astandard extractive method was used to measure the actual path-averagedconcentrations along an OP-FTIR optical path in situ, as a benchmark toassess the feasibilities of these quantitative methods. Within an absolutehumidity range of 5000–20 000 ppmv and a temperature range of 10–35  ∘ C, we found that the CLS model underestimated N2O concentrations (bias  = - 4.9 ± 3.1  %) calculated from OP-FTIRspectra, and the PLS model improved the accuracy of calculated N2O concentrations (bias  = 1.4 ± 2.3  %). The bias of calculated CO2 concentrations was - 1.0 ± 2.8  % using the CLS model. Thesemethods suggested that environmental variables potentially lead to biases in N2O and CO2 estimations from OP-FTIR spectra and may help OP-FTIRusers avoid dependency on extractive methods of calibrations.

Application of open-path Fourier transform infrared spectroscopy (OP-FTIR) to measure greenhouse gas concentrations from agricultural fields