Precise multispecies agricultural gas flux determined using broadband open-path dual-comb spectroscopy.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33789900.
- Also identified by DOI 10.1126/sciadv.abe9765 and PMC identifier 8011971.
- Licence recorded as CC BY-NC.
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Abstract
Advances in spectroscopy have the potential to improve our understanding of agricultural processes and associated trace gas emissions. We implement field-deployed, open-path dual-comb spectroscopy (DCS) for precise multispecies emissions estimation from livestock. With broad atmospheric dual-comb spectra, we interrogate upwind and downwind paths from pens containing approximately 300 head of cattle, providing time-resolved concentration enhancements and fluxes of CH<sub>4</sub>, NH<sub>3</sub>, CO<sub>2</sub>, and H<sub>2</sub>O. The methane fluxes determined from DCS data and fluxes obtained with a colocated closed-path cavity ring-down spectroscopy gas analyzer agree to within 6%. The NH<sub>3</sub> concentration retrievals have sensitivity of 10 parts per billion and yield corresponding NH3 fluxes with a statistical precision of 8% and low systematic uncertainty. Open-path DCS offers accurate multispecies agricultural gas flux quantification without external calibration and is easily extended to larger agricultural systems where point-sampling-based approaches are insufficient, presenting opportunities for field-scale biogeochemical studies and ecological monitoring.