Comparison of Atmospheric Stability Methods for Calculating Ammonia and Methane Emission Rates with WindTrax

2013 ◽  
Vol 56 (2) ◽  
pp. 763-768 ◽  
Author(s):  
Anita C Koehn ◽  
April B. Leytem ◽  
David L. Bjorneberg
Keyword(s):  
Methane Emission ◽  
Atmospheric Stability ◽  
Emission Rates

scholarly journals Ruminal methane emission by dairy cattle in Southeast Brazil

2009 ◽  
Vol 66 (6) ◽  
pp. 742-750 ◽  
Author(s):  
Márcio dos Santos Pedreira ◽  
Odo Primavesi ◽  
Magda Aparecida Lima ◽  
Rosa Frighetto ◽  
Simone Gisele de Oliveira ◽  
...  
Keyword(s):  
Methane Emission ◽  
Farming Systems ◽  
Panicum Maximum ◽  
Emission Rates ◽  
Tracer Gas ◽  
Brachiaria Decumbens ◽  
Southeast Brazil ◽  
Lactating Cows ◽  
Tropical Conditions ◽  
Four Blocks

Ruminal gases, particularly methane, generated during the fermentative process in rumen, represent a partial loss of feed energy and are also pointed to as an important factors in greenhouse effect. This study aimed at quantifying methane (CH4) emission rates from lactating and dry cows and heifers, 24 month-old in average, on pasture under Southeast Brazil tropical conditions, using the tracer gas technique, sulphur hexafluoride (SF6), four animals per category, distributed in four blocks. Measurements were performed in February and June, 2002, with Holstein and Brazilian Dairy Crossbred (Holstein ¾ x Gir (Zebu) ¼), maintained on fertilized Tanzania-grass (Panicum maximum Jacq. cv. Tanzania) and fertilized Brachiaria-grass (Brachiaria decumbens cv. Basilisk) pastures. Heifers of both breeds were maintained on unfertilized Brachiaria-grass to simulate conditions of extensive cattle farming systems. CH4 and SF6 levels were measured with gas chromatography. Differences in CH4 emissions were measured (p < 0.05) for genetical groups. Holstein produced more methane (299.3 g day-1) than the Crossbred (264.2 g day-1). Lactating cows produced more methane (353.8 g day-1) than dry cows (268.8 g day-1) and heifers (222.6 g day-1). Holstein, with greater milk production potential, produced less CH4 (p < 0.05) per unit of dry matter intake (19.1 g kg-1) than the Crossbred (22.0 g kg-1). Methane emission by heifers grazing fertilized pasture (intensive system) was 222.6 g day-1, greater (p < 0.05) than that of heifers on unfertilized pasture (179.2 g day-1). Methane emission varied as function of animal category and management intensity of production system.

scholarly journals Comment on "Reduced efficacy of marine cloud brightening geoengineering due to in-plume aerosol coagulation: parameterization and global implications" by Stuart et al. (2013)

2015 ◽  
Vol 15 (2) ◽  
pp. 753-756 ◽  
Author(s):  
S. Anand ◽  
Y. S. Mayya
Keyword(s):  
Particle Number ◽  
Regional Scale ◽  
Atmospheric Stability ◽  
Emission Rates ◽  
Survival Fraction ◽  
Functional Forms ◽  
Coagulation Equation ◽  
Parameterized Model ◽  
Microphysical Processes ◽  
Air Pollution Models

Abstract. We examine the parameterized model of Stuart et al. (2013) vis-à-vis a diffusion-based model proposed by us earlier (Anand and Mayya, 2011) to estimate the fraction of aerosol particles surviving coagulation in a dispersing plume. While the Stuart et al. approach is based on the solutions to the coagulation problem in an expanding plume model, the diffusion-based approach solves the diffusion–coagulation equation for a steady-state standing plume to arrive at the survival fraction correlations. We discuss the differences in the functional forms of the survival fraction expressions obtained in the two approaches and compare the results for the case studies presented in Stuart et al. (2013) involving different particle emission rates and atmospheric stability categories. There appears to be a better agreement between the two models at higher survival fractions as compared to lower survival fractions; on the whole, the two models agree with each other within a difference of 10%. The diffusion-based expression involves a single exponent fit to a theoretically generated similarity variable combining the parameters of the problem with inbuilt exponents and hence avoids the multi-exponent parameterization exercise. It also possesses a wider range of applicability in respect of the source and atmospheric parameters as compared to that based on parameterization. However, in the diffusion model, the choice of a representative value for the coagulation coefficient is more prescriptive than rigorous, which has been addressed in a more satisfactory manner by the parameterization method. The present comparative exercise, although limited in scope, confirms the importance of aerosol microphysical processes envisaged by Stuart et al. for cloud brightening applications. In a larger context, it seems to suggest that either of the two forms of expressions might be suitable for incorporation into global-/regional-scale air pollution models for predicting the contribution of localized sources to the particle number loading in the atmosphere.

scholarly journals Influence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in rice ecosystem

2021 ◽  
Vol 13 (SI) ◽  
pp. 26-34
Author(s):  
S. K. Rajkishore ◽  
M. Maheswari ◽  
K. S. Subramanian ◽  
R. Prabhu ◽  
G. Vanitha
Keyword(s):  
Elevated Co2 ◽  
Methane Emission ◽  
Methane Flux ◽  
Methane Emissions ◽  
Soil Microflora ◽  
Mitigation Strategies ◽  
Emission Rates ◽  
Randomized Design ◽  
Dry Soil ◽  
Rice Ecosystem

The dynamics of methane emission and its associated soil microflora in rice ecosystem as a response to elevated CO2 concentrations were studied in open top chamber (OTC) conditions. The treatments consisted of three levels of CO2 (396, 550 and 750 µmol mol-1) and three levels of nitrogen (0, 150 and 200 kg ha-1) and replicated five times in a completely randomized design. The data showed that elevated [CO2] significantly (P ? 0.01) increased the DOC throughout the cropping period with the values ranging from 533 to 722 mg L-1 and 368 to 501 mg L-1 in C750 and Camb, respectively. Methane emission rates were monitored regularly during the experiment period and it was revealed that elevated [CO2] had increased the methane emissions regardless of stages of crop growth.  It was observed that methane emissions were significantly higher under [CO2] of 750 µmol mol-1 by 33 to 54 per cent over the ambient [CO2] of 396 µmol mol-1. Consistent with the observed increases in methane flux, the enumeration of methanogens showed a significant (P ? 0.01) increase under elevated [CO2] with the population ranging from 5.7 to 20.1 x 104 CFU g-1 of dry soil and 5.1 to 16.9 x 104 CFU g-1 of dry soil under C750 and Camb concentrations, respectively. Interestingly, even though higher methanotrophs population was recorded under elevated [CO2], it could not circumvent the methane emission. Overall, the results of OTC studies suggest that methane mitigation strategies need to be explored for the future high CO2 environments. 

scholarly journals Fire prediction for a non-sanitary landfill “Bubanj” in Serbia

2016 ◽  
Vol 20 (4) ◽  
pp. 1295-1305
Author(s):  
Emina Mihajlovic ◽  
Lidija Milosevic ◽  
Jasmina Radosavljevic ◽  
Amelija Djordjevic ◽  
Ivan Krstic
Keyword(s):  
Methane Emission ◽  
Landfill Gas ◽  
The State ◽  
Sanitary Landfill ◽  
Emission Rates ◽  
Gas Generation ◽  
Active Section ◽  
The Difference ◽  
One Year ◽  
The City

This paper reviews the state of the ?Bubanj? landfill near the City of Nis, Serbia, which has been used for 47 years and which is categorized as a non-sanitary landfill. We utilised the LandGEM 3.02 model, used for estimating landfill gas emission rates, to calculate the amount of landfill gases. Additionally, we measured the amount and composition of landfill gas in section S4 of the landfill from July 2014 to June 2015. We utilised the ALOHA software to estimate the fire-vulnerable zone. The results of our analysis show that the measured average methane emission is higher than the calculated emission. The difference between the measured average emission and calculated emission of methane is logical, as the measurements were performed in an active section, where methane emission higher than in inactive sections is to be expected. Based on the measured methane emissions during one year, we conclude that the methane emission drops as the ambient temperature drops. This paper showcases the state of the ?Bubanj? landfill, which is highly unsatisfactory in terms of environmental and fire protection because of landfill gas generation.

Development of Methods for Top-Down Methane Emission Measurements of Oil and Gas Facilities in an Offshore Environment Using a Miniature Methane Spectrometer and Long-Endurance UAS

2021 ◽  
Author(s):  
Brendan Smith ◽  
Stuart Buckingham ◽  
Daniel Touzel ◽  
Abigail Corbett ◽  
Charles Tavner
Keyword(s):  
Methane Emission ◽  
Methane Concentration ◽  
Oil And Gas ◽  
Detection Limits ◽  
Emission Rates ◽  
Concentration Data ◽  
Closed Cavity ◽  
Gaussian Plume ◽  
Facility Level ◽  
Long Endurance

Abstract With atmospheric methane concentrations rising, spurring increased social concern, there is a renewed focus in the oil and gas industry on methane emission monitoring and control. In 2019, a methane emission survey at a bp asset west of Shetland was conducted using a closed-cavity methane spectrometer mounted onboard a long-endurance fixed-wing unmanned aerial vehicle (UAV). This flight represents the first methane emissions survey of an offshore facility with a miniature methane spectrometer onboard a UAV with subsequent flights performed. The campaign entailed gathering high-density methane concentration data in a cylindrical flight pattern that circumnavigated the facility in close proximity. A small laser spectrometer was modified from an open-cavity system to a closed-cavity onboard the aircraft and yielded in-flight detection limits (3s) of 1065ppb methane above background for the 2019/2020 sensor version and 150ppb for the 2021 sensor versions. Through simulation, the sensors minimum detection limits in mass flow rate were determined to be 50 kg/h for the 2019/2020 campaign and 2.5kg/h for the 2021 campaigns; translating to an obtainable measurement for 23% and 82% of assets reporting higher than 1 kg/h according to the 2019 EEMS dataset, respectively. To operationalize the approach, a simulation tool for flight planning was developed utilizing a gaussian plume model and a scaled coefficient of variation to invoke expected methane concentration fluctuations at short time intervals. The simulation is additionally used for creation of synthetic datasets to test and validate algorithm development. Two methods were developed to calculate offshore facility level emission rates from the geolocated methane concentration data acquired during the emission surveys. Furthermore, a gaussian plume simulator was developed to predict plume behavior and aid in error analysis. These methods are under evaluation, but all allow for the rapid processing (&lt;24h) of results upon landing the aircraft. Additional flights were conducted in 2020 and 2021 with bp and several UK North Sea Operators through Net Zero Technology Centre (NZTC) funded project, resulting in a total of 18 methane emission survey flights to 11 offshore assets between 2019 and 2021. The 2019 flight, and subsequent 2020/21 flights, demonstrated the potential of the technology to derive facility level emission rates to verify industry emission performance and data.

A new approach to estimation of methane emission rates from landfills

2013 ◽  
Vol 33 (12) ◽  
pp. 2713-2719 ◽  
Author(s):  
Han Zhu ◽  
Marcus O. Letzel ◽  
Martin Reiser ◽  
Martin Kranert ◽  
Wolfgang Bächlin ◽  
...  
Keyword(s):  
Methane Emission ◽  
Emission Rates ◽  
New Approach
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