Methane Emissions from Grazing Cattle Using Point-Source Dispersion

2011 ◽  
Vol 40 (1) ◽  
pp. 22-27 ◽  
Author(s):  
S. M. McGinn ◽  
D. Turner ◽  
N. Tomkins ◽  
E. Charmley ◽  
G. Bishop-Hurley ◽  
...  
Keyword(s):  
Point Source ◽  
Methane Emissions ◽  
Grazing Cattle

Enteric Methane Emissions of Beef Cows Grazing Tallgrass Prairie Pasture on the Southern Great Plains

2019 ◽  
Vol 62 (6) ◽  
pp. 1455-1465
Author(s):  
Richard W. Todd ◽  
Corey Moffet ◽  
James P. S. Neel ◽  
Kenneth E. Turner ◽  
Jean L. Steiner ◽  
...  
Keyword(s):  
Point Source ◽  
Tallgrass Prairie ◽  
Beef Cows ◽  
Methane Emissions ◽  
Ratio Method ◽  
Beef Cow ◽  
Enteric Methane ◽  
Dormant Season ◽  
Methane Emission Rate ◽  
Enteric Methane Emissions

HighlightsEnteric methane (CH4) from beef cows on pasture was measured over three seasons using three methods.Methods yielded similar results during the summer grazing season but diverged in autumn and winter seasons.Emission averaged 0.34, 0.27, and 0.29 kg CH4 cow-1 during lactation, mid-gestation, and late gestation, respectively.Annualized enteric methane emission rate for a beef cow herd grazing tallgrass prairie was 0.32 kg d-1 cow-1.Abstract. Methane (CH4) is an important greenhouse gas, and about 20% of the carbon dioxide equivalent (CO2e) greenhouse gases emitted by U.S. agriculture are attributed to enteric CH4 produced by grazing beef cattle. Grazing cattle are mobile point sources of methane and present challenges to quantifying the enteric methane emission rate (MER). In this study, we applied three methods to measure herd-scale and individual-animal MER for a herd of beef cows grazing a native tallgrass prairie: a point source method that used forward-mode dispersion analysis and open-path lasers and cow locations, an open chamber breath analysis system (GreenFeed), and an eddy covariance ratio method that used the ratio of CH4 and CO2 mass fluxes. Three campaigns were conducted during the early season (July), late season (October), and dormant season (February). The point source and GreenFeed methods yielded similar MER (±SD) values during the early season campaign: 0.38 ±0.04 and 0.34 ±0.05 kg d-1 cow-1, respectively. However, the MER values from the two methods diverged in subsequent seasons. The GreenFeed MER decreased through the late and dormant seasons to 0.23 ±0.03 and 0.19 ±0.03 kg d-1 cow-1, respectively. In contrast, the point source MER stayed the same during the late season and increased during the dormant season to 0.41 ±0.07 kg d-1 cow-1. The CH4:CO2 ratio method, which was used only during the dormant season, yielded a MER of 0.29 ±0.05 kg d-1 cow-1. The point source and GreenFeed methods measured different MER (integrated herd-scale versus a subset of individual animals) and likely sampled methane emissions at different times during the day. We conclude that the point source method tended to overestimate emissions, and the GreenFeed method tended to underestimate emissions. Enteric methane emissions from beef cows over the three grazing seasons averaged 0.39 and 0.25 kg d-1 cow-1 as measured by the point source and GreenFeed methods, respectively. An annualized enteric MER for a beef cow herd grazing tallgrass prairie was 0.32 kg d-1 cow-1. Quantifying enteric methane emissions from grazing beef cows remains a challenge because of the mobile, often dispersed behavior of grazing cattle and the dynamic interactions of forage quality, dry matter intake, and changing physiological state of cows during the year. Keywords: Beef cows, Enteric methane, Forage quality, Grazing, Tallgrass prairie.

A multi-tiered methane analytic framework for constraining budgets, point source attribution, and anomalous event detection

2020 ◽  
Author(s):  
Daniel Cusworth ◽  
Riley Duren ◽  
Andrew Thorpe ◽  
Natasha Stavros ◽  
Brian Bue ◽  
...  
Keyword(s):  
Los Angeles ◽  
Point Source ◽  
Methane Flux ◽  
Global Scale ◽  
Methane Emissions ◽  
Point Sources ◽  
Analytic Framework ◽  
Source Attribution ◽  
Surface Measurements ◽  
New Generation

<p>Methane emissions monitoring is rapidly expanding with increasing coverage of surface, airborne, and satellite instruments. However, no single methane instrument or observing strategy can both close emission budgets and pinpoint point sources on regional to global scales. Instead, we present a multi-tiered data analytics system that synthesizes information across various instruments into a single analytic framework. We highlight an example in Los Angeles, where we combine surface measurements from the Los Angeles megacities project, mountaintop measurements from the CLARS-FTS instrument, airborne AVIRIS-NG point source emission estimates, and TROPOMI total column retrievals into a single analytic framework. Surface, mountaintop, and satellite measurements are assimilated into a methane flux inverse model to constrain basin-wide emissions and pinpoint sub-basin methane hotspots. We show an example of a large urban landfill, whose anomalous emissions were detected by the inverse system, and validated using AVIRIS-NG methane plume maps. This general approach of quantifying both methane area and point source emissions is an avenue not just for closing regional to global scale budgets, but also for understanding which emission sources dominate the budget (i.e., so called methane super-emitters). We finally show how this multi-tiered analytic framework can be improved with future satellite missions, and present examples of unexpectedly large methane emissions that were detected by a new generation of satellite imaging spectrometers.</p>

scholarly journals Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin

2015 ◽  
Vol 49 (13) ◽  
pp. 7904-7913 ◽  
Author(s):  
Tegan N. Lavoie ◽  
Paul B. Shepson ◽  
Maria O. L. Cambaliza ◽  
Brian H. Stirm ◽  
Anna Karion ◽  
...  
Keyword(s):  
Point Source ◽  
Methane Emissions ◽  
Barnett Shale

Applicability of Eddy Covariance to Estimate Methane Emissions from Grazing Cattle

2018 ◽  
Vol 47 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Trevor W. Coates ◽  
Marcelo A. Benvenutti ◽  
Thomas K. Flesch ◽  
Ed Charmley ◽  
Sean M. McGinn ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Methane Emissions ◽  
Grazing Cattle

Evaluating an eddy covariance technique to estimate point-source emissions and its potential application to grazing cattle

2017 ◽  
Vol 234-235 ◽  
pp. 164-171 ◽  
Author(s):  
Trevor W. Coates ◽  
Thomas K. Flesch ◽  
Sean M. McGinn ◽  
Ed Charmley ◽  
Deli Chen
Keyword(s):  
Point Source ◽  
Eddy Covariance ◽  
Potential Application ◽  
Eddy Covariance Technique ◽  
Grazing Cattle

Field-scale operation of methane biofiltration systems to mitigate point source methane emissions

2011 ◽  
Vol 159 (6) ◽  
pp. 1715-1720 ◽  
Author(s):  
Vijayamala C. Hettiarachchi ◽  
Patrick J. Hettiaratchi ◽  
Anil K. Mehrotra ◽  
Sunil Kumar
Keyword(s):  
Point Source ◽  
Methane Emissions ◽  
Field Scale

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

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