scholarly journals Precise multispecies agricultural gas flux determined using broadband open-path dual-comb spectroscopy

2021 ◽  
Vol 7 (14) ◽  
pp. eabe9765
Author(s):  
Daniel I. Herman ◽  
Chinthaka Weerasekara ◽  
Lindsay C. Hutcherson ◽  
Fabrizio R. Giorgetta ◽  
Kevin C. Cossel ◽  
...  
Keyword(s):  
Ecological Monitoring ◽  
Trace Gas ◽  
Gas Analyzer ◽  
Gas Flux ◽  
Time Resolved ◽  
Trace Gas Emissions ◽  
Open Path ◽  
Statistical Precision ◽  
Methane Fluxes ◽  
Flux Quantification

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 CH4, NH3, CO2, and H2O. 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 NH3 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.

scholarly journals Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency

2018 ◽  
Vol 18 (5) ◽  
pp. 3717-3735 ◽  
Author(s):  
Elise-Andrée Guérette ◽  
Clare Paton-Walsh ◽  
Maximilien Desservettaz ◽  
Thomas E. L. Smith ◽  
Liubov Volkova ◽  
...  
Keyword(s):  
Forest Fires ◽  
Temperate Forest ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Trace Gas ◽  
Ion Flow ◽  
Airborne Measurements ◽  
Trace Gas Emissions ◽  
Open Path ◽  
Modified Combustion Efficiency

Abstract. We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

scholarly journals Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency

2017 ◽  
Author(s):  
Elise-Andrée Guérette ◽  
Clare Paton-Walsh ◽  
Maximilien Desservettaz ◽  
Thomas E. L. Smith ◽  
Liubov Volkova ◽  
...  
Keyword(s):  
Forest Fires ◽  
Temperate Forest ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Trace Gas ◽  
Airborne Measurements ◽  
Trace Gas Emissions ◽  
Open Path ◽  
Modified Combustion Efficiency

Abstract. We characterised trace gas emissions from Australian temperate forest fires through a mixture of in situ open-path FTIR measurements spectroscopy and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR spectroscopy of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for fires in North American temperate ecosystems and for fires in Australian savanna and find that, although emission factors of some species agree within 20 %, others differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

scholarly journals Field intercomparison of four methane gas analyzers suitable for eddy covariance flux measurements

2013 ◽  
Vol 10 (6) ◽  
pp. 3749-3765 ◽  
Author(s):  
O. Peltola ◽  
I. Mammarella ◽  
S. Haapanala ◽  
G. Burba ◽  
T. Vesala
Keyword(s):  
Eddy Covariance ◽  
Power Spectra ◽  
High Flux ◽  
Random Errors ◽  
Gas Analyzer ◽  
Measurement Campaign ◽  
Methane Gas ◽  
Open Path ◽  
Short Period ◽  
Methane Fluxes

Abstract. Performances of four methane gas analyzers suitable for eddy covariance measurements are assessed. The assessment and comparison was performed by analyzing eddy covariance data obtained during summer 2010 (1 April to 26 October) at a pristine fen, Siikaneva, Southern Finland. High methane fluxes with pronounced seasonality have been measured at this fen. The four participating methane gas analyzers are commercially available closed-path units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research, USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit Prototype-7700 (LI-COR Biosciences, USA). The RMT-200 functioned most reliably throughout the measurement campaign, during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had the smallest random errors and the fluxes agree remarkably well throughout the measurement campaign. Cospectra and power spectra calculated from RMT-200 and G1301-f data agree well with corresponding temperature spectra during a high flux period. None of the gas analyzers showed statistically significant diurnal variation for methane flux. Prototype-7700 functioned only for a short period of time, over one month, in the beginning of the measurement campaign during low flux period, and thus, its overall accuracy and season-long performance were not assessed. The open-path gas analyzer is a practical choice for measurement sites in remote locations due to its low power demand, whereas for G1301-f methane measurements interference from water vapor is straightforward to correct since the instrument measures both gases simultaneously. In any case, if only the performance in this intercomparison is considered, RMT-200 performed the best and is the recommended choice if a new fast response methane gas analyzer is needed.

Stochastic Diffusion Model for Estimating Trace Gas Emissions with Static Chambers

2001 ◽  
Vol 65 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Asger R. Pedersen ◽  
Søren O. Petersen ◽  
Finn P. Vinther
Keyword(s):  
Diffusion Model ◽  
Trace Gas ◽  
Stochastic Diffusion ◽  
Gas Emissions ◽  
Trace Gas Emissions
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