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

scholarly journals Intercomparison of atmospheric trace gas dispersion models: Barnett Shale case study

2019 ◽  
Vol 19 (4) ◽  
pp. 2561-2576 ◽  
Author(s):  
Anna Karion ◽  
Thomas Lauvaux ◽  
Israel Lopez Coto ◽  
Colm Sweeney ◽  
Kimberly Mueller ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Methane Emissions ◽  
Gas Production ◽  
Estimation Methods ◽  
Trace Gas ◽  
Barnett Shale ◽  
Dispersion Models ◽  
Data Set ◽  
Gas Dispersion ◽  
Tracer Dispersion

Abstract. Greenhouse gas emissions mitigation requires understanding the dominant processes controlling fluxes of these trace gases at increasingly finer spatial and temporal scales. Trace gas fluxes can be estimated using a variety of approaches that translate observed atmospheric species mole fractions into fluxes or emission rates, often identifying the spatial and temporal characteristics of the emission sources as well. Meteorological models are commonly combined with tracer dispersion models to estimate fluxes using an inverse approach that optimizes emissions to best fit the trace gas mole fraction observations. One way to evaluate the accuracy of atmospheric flux estimation methods is to compare results from independent methods, including approaches in which different meteorological and tracer dispersion models are used. In this work, we use a rich data set of atmospheric methane observations collected during an intensive airborne campaign to compare different methane emissions estimates from the Barnett Shale oil and natural gas production basin in Texas, USA. We estimate emissions based on a variety of different meteorological and dispersion models. Previous estimates of methane emissions from this region relied on a simple model (a mass balance analysis) as well as on ground-based measurements and statistical data analysis (an inventory). We find that in addition to meteorological model choice, the choice of tracer dispersion model also has a significant impact on the predicted downwind methane concentrations given the same emissions field. The dispersion models tested often underpredicted the observed methane enhancements with significant variability (up to a factor of 3) between different models and between different days. We examine possible causes for this result and find that the models differ in their simulation of vertical dispersion, indicating that additional work is needed to evaluate and improve vertical mixing in the tracer dispersion models commonly used in regional trace gas flux inversions.

scholarly journals Mobile Laboratory Observations of Methane Emissions in the Barnett Shale Region

2015 ◽  
Vol 49 (13) ◽  
pp. 7889-7895 ◽  
Author(s):  
Tara I. Yacovitch ◽  
Scott C. Herndon ◽  
Gabrielle Pétron ◽  
Jonathan Kofler ◽  
David Lyon ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Barnett Shale ◽  
Mobile Laboratory

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.

scholarly journals Integrating Source Apportionment Tracers into a Bottom-up Inventory of Methane Emissions in the Barnett Shale Hydraulic Fracturing Region

2015 ◽  
Vol 49 (13) ◽  
pp. 8175-8182 ◽  
Author(s):  
Amy Townsend-Small ◽  
Josette E. Marrero ◽  
David R. Lyon ◽  
Isobel J. Simpson ◽  
Simone Meinardi ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Source Apportionment ◽  
Methane Emissions ◽  
Barnett Shale ◽  
Bottom Up

Characterizing Fugitive Methane Emissions in the Barnett Shale Area Using a Mobile Laboratory

2015 ◽  
Vol 49 (13) ◽  
pp. 8139-8146 ◽  
Author(s):  
Xin Lan ◽  
Robert Talbot ◽  
Patrick Laine ◽  
Azucena Torres
Keyword(s):  
Methane Emissions ◽  
Barnett Shale ◽  
Mobile Laboratory

scholarly journals Airborne Ethane Observations in the Barnett Shale: Quantification of Ethane Flux and Attribution of Methane Emissions

2015 ◽  
Vol 49 (13) ◽  
pp. 8158-8166 ◽  
Author(s):  
Mackenzie L. Smith ◽  
Eric A. Kort ◽  
Anna Karion ◽  
Colm Sweeney ◽  
Scott C. Herndon ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Barnett Shale

scholarly journals Aircraft-Based Estimate of Total Methane Emissions from the Barnett Shale Region

2015 ◽  
Vol 49 (13) ◽  
pp. 8124-8131 ◽  
Author(s):  
Anna Karion ◽  
Colm Sweeney ◽  
Eric A. Kort ◽  
Paul B. Shepson ◽  
Alan Brewer ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Barnett Shale

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

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>

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