WorldWideScience

Sample records for methane emission control

  1. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Don Augenstein

    1999-01-11

    ''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

  2. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, Charlotte; Tagesson, Håkan Torbern;

    2013-01-01

    controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...... short-term control factors (temperature and water table). Our findings suggest the importance of multiyear studies with a continued focus on shoulder seasons in Arctic ecosystems....

  3. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with

  4. Revisiting factors controlling methane emissions from high-Arctic tundra

    Directory of Open Access Journals (Sweden)

    M. Mastepanov

    2013-07-01

    Full Text Available The northern latitudes are experiencing disproportionate warming relative to the mid-latitudes, and there is growing concern about feedbacks between this warming and methane production and release from high-latitude soils. Studies of methane emissions carried out in the Arctic, particularly those with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006–2010 of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods. The measurements show clear seasonal dynamics in methane emission. The start of the growing season and the increase in CH4 fluxes were strongly related to the date of snowmelt. Within each particular growing season, CH4 fluxes were highly correlated with the soil temperature (R2 > 0.75, which is probably explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010 despite large differences in climatic factors (temperature and water table. Late-season bursts of CH4 coinciding with soil freezing in the autumn were observed during at least three years. The cumulative emission during the freeze-in CH4 bursts was comparable in size with the growing season emission for the year 2007, and about one third of the growing season emissions for the years 2009 and 2010. In all three cases the CH4 burst was accompanied by a corresponding episodic increase in CO2 emission, which can compose a significant contribution to the annual CO2

  5. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, C.; Tagesson, T.;

    2013-01-01

    with measurements made outside the growing season, are underrepresented in the literature. Here we present results of 5 yr (2006-2010) of automatic chamber measurements at a high-Arctic location in Zackenberg, NE Greenland, covering both the growing seasons and two months of the following freeze-in periods...... explained by high seasonality of both variables, and weakly correlated with the water table. The greatest variability in fluxes between the study years was observed during the first part of the growing season. Somewhat surprisingly, this variability could not be explained by commonly known factors...... controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...

  6. Modelling global methane emissions from livestock: Biological and nutritional controls

    Science.gov (United States)

    Johnson, Donald E.

    1992-01-01

    The available observations of methane production from the literature have been compiled into a ruminant methane data base. This data base includes 400 treatment mean observations of methane losses from cattle and sheep, and minor numbers of measurements from other species. Methane loss varied from 2.0 to 11.6 percent of dietary gross energy. Measurements included describe the many different weights and physiological states of the animals fed and diets ranging from all forage to all concentrate diets or mixtures. An auxiliary spreadsheet lists approximately 1000 individual animal observations. Many important concepts have emerged from our query and analysis of this data set. The majority of the world's cattle, sheep, and goats under normal husbandry circumstances likely produce methane very close to 6 percent of their daily diets gross energy (2 percent of the diet by weight). Although individual animals or losses from specific dietary research circumstances can vary considerably, the average for the vast majority of groups of ruminant livestock are likely to fall between 5.5 to 6.5 percent. We must caution, however, that little experimental data is available for two-thirds of the world's ruminants in developing countries. Available evidence suggests similar percentage of emissions, but this supposition needs confirmation. More importantly, data is skimpy or unavailable to describe diet consumption, animal weight, and class distribution.

  7. Environmental factors controlling methane emissions from peatlands in northern Minnesota

    Science.gov (United States)

    Dise, Nancy B.; Gorham, Eville; Verry, Elon S.

    1993-01-01

    The environmental factors affecting the emission of methane from peatlands were investigated by correlating CH4 emission data for two years, obtained from five different peatland ecosystems in northern Minnesota, with peat temperature, water table position, and degree of peat humification. The relationship obtained between the CH4 flux and these factors was compared to results from a field manipulation experiment in which the water table was artificially raised in three experimental plots within the driest peatland. It was found that peat temperature, water table position, and degree of peat humification explained 91 percent of the variance in log CH4 flux, successfully predicted annual CH4 emission from individual wetlands, and predicted the change in flux due to the water table manipulation. Raising the water table in the bog corrals by an average of 6 cm in autumn 1989 and 10 cm in summer 1990 increased CH4 emission by 2.5 and 2.2 times, respectively.

  8. Global Health Benefits from Reductions in Background Tropospheric Ozone due to Methane Emission Controls

    Science.gov (United States)

    West, J. J.; Mauzerall, D. L.; Fiore, A. M.; Horowitz, L. W.

    2005-05-01

    Increases in background ozone throughout the troposphere are partially attributed to rising anthropogenic methane concentrations, which are projected to continue to increase in the future. Because methane is long-lived and affects background ozone, controls on methane emissions would reduce surface ozone concentrations fairly uniformly around the globe. Epidemiological research indicates that exposure to ozone increases incidence of respiratory ailments and premature mortality. In addition, exposure to ozone reduces agricultural yields and damages natural ecosystems. We use the MOZART-2 global atmospheric chemistry and transport model to estimate the effects on global surface ozone of perturbations in methane emissions. We consider a baseline scenario for 2000 and the 2030 A2 scenario (emissions from the IPCC AR-4 2030 atmospheric chemistry experiments), and examine the impact on ozone of decreasing anthropogenic methane emissions relative to this baseline by 20%. Using the simulated spatially-distributed decreases in surface ozone concentrations resulting from these reductions in methane emissions, we estimate the global benefits to human health in the methane emission reduction scenario. We focus on human mortality, and consider the sensitivity of our estimates to different assumptions of health effect thresholds at low ozone concentrations.

  9. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Don Augenstein

    2001-02-01

    The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

  10. Primary production control of methane emission from wetlands

    Science.gov (United States)

    Whiting, G. J.; Chanton, J. P.

    1993-01-01

    Based on simultaneous measurements of CO2 and CH4 exchange in wetlands extending from subarctic peatlands to subtropical marshes, a positive correlation between CH4 emission and net ecosystem production is reported. It is suggested that net ecosystem production is a master variable integrating many factors which control CH4 emission in vegetated wetlands. It is found that about 3 percent of the daily net ecosystem production is emitted back to the atmosphere as CH4. With projected stimulation of primary production and soil microbial activity in wetlands associated with elevated atmospheric CO2 concentration, the potential for increasing CH4 emission from inundated wetlands, further enhancing the greenhouse effect, is examined.

  11. Quantification of methane emissions from danish landfills

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Mønster, Jacob; Kjeldsen, Peter

    2013-01-01

    Whole-landfill methane emission was quantified using a tracer technique that combines controlled tracer gas release from the landfill with time-resolved concentration measurements downwind of the landfill using a mobile high-resolution analytical instrument. Methane emissions from 13 Danish...... landfills varied between 2.6 and 60.8 kg CH4 h–1. The highest methane emission was measured at the largest (in terms of disposed waste amounts) of the 13 landfills, whereas the lowest methane emissions (2.6-6.1 kgCH4 h–1) were measured at the older and smaller landfills. At two of the sites, which had gas...... collection, emission measurements showed that the gas collection systems only collected between 30-50% of the methane produced (assuming that the produced methane equalled the sum of the emitted methane and the collected methane). Significant methane emissions were observed from disposed shredder waste...

  12. Methane emissions from ruminants

    African Journals Online (AJOL)

    user

    2011-02-21

    Feb 21, 2011 ... Review. Livestock-environment interactions: Methane emissions from ruminants. Aluwong, T.1* ... perception of air quality by human neighbours.The three ... on the climate; the global warming potential of methane is. 21-times that of ... has serious impact on high atmosphere ozone formation. It is important ...

  13. Methane emissions from process equipment at natural gas production sites in the United States: pneumatic controllers.

    Science.gov (United States)

    Allen, David T; Pacsi, Adam P; Sullivan, David W; Zavala-Araiza, Daniel; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Sawyer, Robert F; Seinfeld, John H

    2015-01-06

    Emissions from 377 gas actuated (pneumatic) controllers were measured at natural gas production sites and a small number of oil production sites, throughout the United States. A small subset of the devices (19%), with whole gas emission rates in excess of 6 standard cubic feet per hour (scf/h), accounted for 95% of emissions. More than half of the controllers recorded emissions of 0.001 scf/h or less during 15 min of measurement. Pneumatic controllers in level control applications on separators and in compressor applications had higher emission rates than controllers in other types of applications. Regional differences in emissions were observed, with the lowest emissions measured in the Rocky Mountains and the highest emissions in the Gulf Coast. Average methane emissions per controller reported in this work are 17% higher than the average emissions per controller in the 2012 EPA greenhouse gas national emission inventory (2012 GHG NEI, released in 2014); the average of 2.7 controllers per well observed in this work is higher than the 1.0 controllers per well reported in the 2012 GHG NEI.

  14. Controls on tree species stem transport and emission of methane from tropical peatlands

    Science.gov (United States)

    Van Haren, J. L. M.; Cadillo-Quiroz, H.

    2016-12-01

    Methane emissions from wetlands dominate the global budget and are most likely responsible for the annual variability in emissions. Methane is produced and consumed by microbial activity and then transported to the atmosphere. Plants have been shown to facilitate the transport of methane to significant amounts, but broad surveys across multiple sites have been lacking. We present data collected from multiple peatland and wetland sites south of Iquitos Peru and varzea sites from Santarem Brazil and compare our results to the limited literature of tree stem fluxes. The survey suggests that methane stem emissions might be conserved at the genera level, but not the family level. Large emitters exist in the Aracaceae, Euphorbiaceae, and Sapotaceae, however, other genera within the same families do not emit any methane. Certain genera are consistent pan-tropical methane emitters. The methane emission from the stems decreases generally with height, suggesting a diffusion constrained stem flux. Further constraints on the methane emissions from tree stems involve soil methane concentration and wood density, which is likely an indicator for stem conductivity. Diurnal cycles, flooding level and tree leaves appear to have less of an influence on the tree methane emissions though flooding can lead to a translocation of emissions up the stem to above the flooding level. Methane emissions and the plant transport pathways appear to be constrained at the genera level within wetlands.

  15. A process-based mathematical model on methane production with emission indices for control.

    Science.gov (United States)

    Chakraborty, A; Bhattacharaya, D K

    2006-08-01

    In this paper, a process-based mathematical model is developed for the production of methane through biodegradation. It is a three-dimensional model given by ordinary differential equations. The results of the analysis of the model are interpreted through three emission indices, which are introduced for the first time. The estimation of either one or all of them can interpret the feasibility of the equilibrium and the long-term emission tendency of methane. The vulnerability of the methane production process with respect to soil temperature effects in methanogenic phase has been discussed and a feasible condition within a specified temperature range has defined for the nonvulnerability of the methane production process and also it has shown that under the same condition, zero-emission process of methane will be nonvulnerable with respect to the soil temperature effects in methanogenic phase. Lastly, condition for zero emission of methane is also obtained and it is interpreted through the emission indices.

  16. Methane Emissions from Upland Forests

    Science.gov (United States)

    Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

    2016-04-01

    Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

  17. Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls

    Science.gov (United States)

    Zhang, Bowen; Tian, Hanqin; Ren, Wei; Tao, Bo; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Pan, Shufen

    2016-09-01

    Given the importance of the potential positive feedback between methane (CH4) emissions and climate change, it is critical to accurately estimate the magnitude and spatiotemporal patterns of CH4 emissions from global rice fields and better understand the underlying determinants governing the emissions. Here we used a coupled biogeochemical model in combination with satellite-derived contemporary inundation area to quantify the magnitude and spatiotemporal variation of CH4 emissions from global rice fields and attribute the environmental controls of CH4 emissions during 1901-2010. Our study estimated that CH4 emissions from global rice fields varied from 18.3 ± 0.1 Tg CH4/yr (Avg. ±1 SD) under intermittent irrigation to 38.8 ± 1.0 Tg CH4/yr under continuous flooding in the 2000s, indicating that the magnitude of CH4 emissions from global rice fields is largely dependent on different water schemes. Over the past 110 years, our simulated results showed that global CH4 emissions from rice cultivation increased by 85%. The expansion of rice fields was the dominant factor for the increasing trends of CH4 emissions, followed by elevated CO2 concentration, and nitrogen fertilizer use. On the contrary, climate variability had reduced the cumulative CH4 emissions for most of the years over the study period. Our results imply that CH4 emissions from global rice fields could be reduced through optimizing irrigation practices. Therefore, the future magnitude of CH4 emissions from rice fields will be determined by the human demand for rice production as well as the implementation of optimized water management practices.

  18. Factors Affecting Methane Emission from Rice Paddies

    Institute of Scientific and Technical Information of China (English)

    于心科; 王卫东; 等

    1995-01-01

    A comparative study of rice paddies and the uncovered water field in Taoyuan(Hunan) showed that methane emission from rice-vegetated paddy fields in 1993 was different from that in 1992(I,e,lower in rates and irregular in pattern).Climate has obvious influence on methane emission .And ebullition made a considerable contribution to the total flux of methane emission from rice paddies (45%).This implies that the intensification of paddy cultivation of rice might not be,as was proposed,the main con-tributor to the observed gradual increasing of atmospheric methane.24-hour automatic measurements of atmospheric temperature,air temperature and methane concentration in the static sampling boxes revealed that temperature,in addition to fertilization and irrigation style,is one of the most important factors that control the emission of methane from rice paddies.

  19. Environmental and physical controls on northern terrestrial methane emissions across permafrost zones.

    Science.gov (United States)

    Olefeldt, David; Turetsky, Merritt R; Crill, Patrick M; McGuire, A David

    2013-02-01

    Methane (CH4 ) emissions from the northern high-latitude region represent potentially significant biogeochemical feedbacks to the climate system. We compiled a database of growing-season CH4 emissions from terrestrial ecosystems located across permafrost zones, including 303 sites described in 65 studies. Data on environmental and physical variables, including permafrost conditions, were used to assess controls on CH4 emissions. Water table position, soil temperature, and vegetation composition strongly influenced emissions and had interacting effects. Sites with a dense sedge cover had higher emissions than other sites at comparable water table positions, and this was an effect that was more pronounced at low soil temperatures. Sensitivity analysis suggested that CH4 emissions from ecosystems where the water table on average is at or above the soil surface (wet tundra, fen underlain by permafrost, and littoral ecosystems) are more sensitive to variability in soil temperature than drier ecosystems (palsa dry tundra, bog, and fen), whereas the latter ecosystems conversely are relatively more sensitive to changes of the water table position. Sites with near-surface permafrost had lower CH4 fluxes than sites without permafrost at comparable water table positions, a difference that was explained by lower soil temperatures. Neither the active layer depth nor the organic soil layer depth was related to CH4 emissions. Permafrost thaw in lowland regions is often associated with increased soil moisture, higher soil temperatures, and increased sedge cover. In our database, lowland thermokarst sites generally had higher emissions than adjacent sites with intact permafrost, but emissions from thermokarst sites were not statistically higher than emissions from permafrost-free sites with comparable environmental conditions. Overall, these results suggest that future changes to terrestrial high-latitude CH4 emissions will be more proximately related to changes in moisture, soil

  20. Valuing the Ozone-Related Health Benefits of Methane Emission Controls

    Energy Technology Data Exchange (ETDEWEB)

    Sarofim, Marcus C.; Waldhoff, Stephanie T.; Anenberg, Susan C.

    2015-06-29

    Methane is a greenhouse gas that oxidizes to form ground-level ozone, itself a greenhouse gas and a health-harmful air pollutant. Reducing methane emissions will both slow anthropogenic climate change and reduce ozone-related mortality. We estimate the benefits of reducing methane emissions anywhere in the world for ozone-related premature mortality globally and for eight geographic regions. Our methods are consistent with those used by the U.S. Government to estimate the Social Cost of Carbon (SCC). We find that the global short- and long-term premature mortality benefits due to reduced ozone production from methane mitigation are (2011)$790 and $1775 per tonne methane, respectively. These correspond to approximately 70% and 150% of the valuation of methane’s global climate impacts using the SCC after extrapolating from carbon dioxide to methane using Global Warming Potential (GWP) estimates. Results are most sensitive to the choice of VSL and increase for emission years further in the future. Regionally, most of the global mortality benefits accrue in Asia, but 10% accrue in the United States. This methodology can be used to assess the benefits of methane emission reductions anywhere in the world, including those achieved by national and multinational policies.

  1. Global health benefits of mitigating ozone pollution with methane emission controls

    Science.gov (United States)

    West, J. Jason; Fiore, Arlene M.; Horowitz, Larry W.; Mauzerall, Denise L.

    2006-03-01

    Methane (CH4) contributes to the growing global background concentration of tropospheric ozone (O3), an air pollutant associated with premature mortality. Methane and ozone are also important greenhouse gases. Reducing methane emissions therefore decreases surface ozone everywhere while slowing climate warming, but although methane mitigation has been considered to address climate change, it has not for air quality. Here we show that global decreases in surface ozone concentrations, due to methane mitigation, result in substantial and widespread decreases in premature human mortality. Reducing global anthropogenic methane emissions by 20% beginning in 2010 would decrease the average daily maximum 8-h surface ozone by 1 part per billion by volume globally. By using epidemiologic ozone-mortality relationships, this ozone reduction is estimated to prevent 30,000 premature all-cause mortalities globally in 2030, and 370,000 between 2010 and 2030. If only cardiovascular and respiratory mortalities are considered, 17,000 global mortalities can be avoided in 2030. The marginal cost-effectiveness of this 20% methane reduction is estimated to be 420,000 per avoided mortality. If avoided mortalities are valued at 1 million each, the benefit is 240 per tonne of CH4 (12 per tonne of CO2 equivalent), which exceeds the marginal cost of the methane reduction. These estimated air pollution ancillary benefits of climate-motivated methane emission reductions are comparable with those estimated previously for CO2. Methane mitigation offers a unique opportunity to improve air quality globally and can be a cost-effective component of international ozone management, bringing multiple benefits for air quality, public health, agriculture, climate, and energy. human health | mortality | tropospheric ozone | air quality

  2. Methane emissions from Carex rostrata

    Science.gov (United States)

    Yelverton, C. A.; Varner, R. K.; Roddy, S.; Noyce, G. L.

    2013-12-01

    Peatlands, especially in northern regions, are known for their contribution to the increase of methane (CH4) in the atmosphere. Methane emissions from peatlands are strongly correlated with water table, temperature, and species composition. Sedges, in particular, are a conduit for the release of CH4 directly to the atmosphere. This study examines the impact of clipping and sealing sedges (Carex rostrata) on CH4 emissions from a temperate peatland (Sallie's Fen, Barrington, NH, USA). Measurements of CH4 fluxes, dissolved CH4, and environmental conditions were made over a six-year period. Data from 2008 to 2013 show that the presence of Carex rostrata in this peatland increases CH4 emissions. Clipped plots have both lower seasonal and annual CH4 emissions, compared to control plots. By studying the type of environment associated with C. rostrata through measurements of water-table depth, pore water characteristics, and the peat, surface, and air temperature of each surrounding location, further studies will show how these factors affect the rate at which CH4 is emitted into the atmosphere.

  3. Wetland methane emissions during the Last Glacial Maximum estimated from PMIP2 simulations: Climate, vegetation, and geographic controls

    Science.gov (United States)

    Weber, S. L.; Drury, A. J.; Toonen, W. H. J.; van Weele, M.

    2010-03-01

    It is an open question to what extent wetlands contributed to the interglacial-glacial decrease in atmospheric methane concentration. Here we estimate methane emissions from glacial wetlands, using newly available PMIP2 simulations of the Last Glacial Maximum (LGM) climate from coupled atmosphere-ocean and atmosphere-ocean-vegetation models. These simulations apply improved boundary conditions resulting in better agreement with paleoclimatic data than earlier PMIP1 simulations. Emissions are computed from the dominant controls of water table depth, soil temperature, and plant productivity, and we analyze the relative role of each factor in the glacial decline. It is found that latitudinal changes in soil moisture, in combination with ice sheet expansion, cause boreal wetlands to shift southward in all simulations. This southward migration is instrumental in maintaining the boreal wetland source at a significant level. The mean emission temperature over boreal wetlands drops by only a few degrees, despite the strong overall cooling. The temperature effect on the glacial decline in the methane flux is therefore moderate, while reduced plant productivity contributes equally to the total reduction. Model results indicate a relatively small boreal and large tropical source during the LGM, with wetlands on the exposed continental shelves mainly contributing to the tropical source. This distribution in emissions is consistent with the low interpolar difference in glacial methane concentrations derived from ice core data.

  4. Variability in methane emissions from West Siberia's shallow boreal lakes on a regional scale and its environmental controls

    Science.gov (United States)

    Sabrekov, Aleksandr F.; Runkle, Benjamin R. K.; Glagolev, Mikhail V.; Terentieva, Irina E.; Stepanenko, Victor M.; Kotsyurbenko, Oleg R.; Maksyutov, Shamil S.; Pokrovsky, Oleg S.

    2017-08-01

    Small lakes represent an important source of atmospheric CH4 from northern wetlands. However, spatiotemporal variations in flux magnitudes and the lack of knowledge about their main environmental controls contribute large uncertainty into the global CH4 budget. In this study, we measured methane fluxes from small lakes using chambers and bubble traps. Field investigations were carried out in July-August 2014 within the West Siberian middle and southern taiga zones. The average and median of measured methane chamber fluxes were 0.32 and 0.30 mgCH4 m-2 h-1 for middle taiga lakes and 8.6 and 4.1 mgCH4 m-2 h-1 for southern taiga lakes, respectively. Pronounced flux variability was found during measurements on individual lakes, between individual lakes and between zones. To analyze these differences and the influences of environmental controls, we developed a new dynamic process-based model. It shows good performance with emission rates from the southern taiga lakes and poor performance for individual lakes in the middle taiga region. The model shows that, in addition to well-known controls such as temperature, pH and lake depth, there are significant variations in the maximal methane production potential between these climatic zones. In addition, the model shows that variations in gas-filled pore space in lake sediments are capable of controlling the total methane emissions from individual lakes. The CH4 emissions exhibited distinct zonal differences not only in absolute values but also in their probability density functions: the middle taiga lake fluxes were best described by a lognormal distribution while the southern taiga lakes followed a power-law distribution. The latter suggests applicability of self-organized criticality theory for methane emissions from the southern taiga zone, which could help to explain the strong variability within individual lakes.

  5. Management practices and controls on methane emissions from sub-tropical wetlands

    Science.gov (United States)

    DeLucia, Nicholas; Casa-Nova Gomez, Nuri; Bernacchi, Carl

    2015-04-01

    It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on any combination of climate conditions, natural and anthropogenic disturbances, or ecosystem perturbations. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are the main source for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. CH4 is one of the most damaging green house gases with current emission estimates ranging from 55 to 231 Tg CH4 yr-1. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04"N, 81o21'8.56"W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified

  6. Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy

    Directory of Open Access Journals (Sweden)

    A. Meijide

    2011-09-01

    Full Text Available Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4, the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem.

    For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd. was installed in an eddy-covariance field set-up in a rice paddy field in the Po Valley (Northern Italy. Methane fluxes were measured during the rice growing season, both with EC and with manually operated closed chambers. Methane fluxes were strongly influenced by the presence of the water table, with emissions peaking when it was above 10–12 cm. Further studies are required to evaluate if water table management could decrease CH4 emissions. The development of rice plants and soil temperature were also responsible of the seasonal variation on the fluxes. The EC measured showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between both measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.8 g CH4 m−2

  7. Methane emissions from grasslands.

    NARCIS (Netherlands)

    Pol-van Dasselaar, van den A.

    1998-01-01

    IntroductionMethane (CH 4 ) is an important greenhouse gas. The concentration of greenhouse gases in the atmosphere has been increasing since pre-industrial times, mainly due to human activities. This increase gives concern, because it may cause global warming due to an enhanced greenhous

  8. Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy

    Directory of Open Access Journals (Sweden)

    A. Meijide

    2011-12-01

    Full Text Available Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4, the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem.

    For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd. was installed in a rice paddy field in the Po Valley (Northern Italy. Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10–12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.7 g CH4 m−2 measured with chambers and EC respectively and even greater differences are found if shorter periods with high chamber sampling

  9. Can rapeseed lower methane emission from heifers?

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Sørensen, Martin Tang; Weisbjerg, Martin Riis

    2013-01-01

    Twelve heifers were assigned to either a control diet (CON) with 26 g fat per kg dry matter (DM) or a supplemented diet (FAT) with crushed rapeseed with 53 g fat per kg DM. Methane (CH4) emission was measured by open-circuit indirect calorimetry for four days when the heifers weighed approximately...

  10. Methane emission from wetland rice fields.

    NARCIS (Netherlands)

    Denier van der Gon, H.A.C.

    1996-01-01

    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic methane emission. Methane fluxes fro

  11. Cryptic Methane Emissions from Upland Forest Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Megonigal, Patrick [Smithsonian Institution, Washington, DC (United States); Pitz, Scott [Johns Hopkins Univ., Baltimore, MD (United States); Smithsonian Institution, Washington, DC (United States)

    2016-04-19

    This exploratory research on Cryptic Methane Emissions from Upland Forest Ecosystems was motivated by evidence that upland ecosystems emit 36% as much methane to the atmosphere as global wetlands, yet we knew almost nothing about this source. The long-term objective was to refine Earth system models by quantifying methane emissions from upland forests, and elucidate the biogeochemical processes that govern upland methane emissions. The immediate objectives of the grant were to: (i) test the emerging paradigm that upland trees unexpectedly transpire methane, (ii) test the basic biogeochemical assumptions of an existing global model of upland methane emissions, and (iii) develop the suite of biogeochemical approaches that will be needed to advance research on upland methane emissions. We instrumented a temperate forest system in order to explore the processes that govern upland methane emissions. We demonstrated that methane is emitted from the stems of dominant tree species in temperate upland forests. Tree emissions occurred throughout the growing season, while soils adjacent to the trees consumed methane simultaneously, challenging the concept that forests are uniform sinks of methane. High frequency measurements revealed diurnal cycling in the rate of methane emissions, pointing to soils as the methane source and transpiration as the most likely pathway for methane transport. We propose the forests are smaller methane sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements. The methods we used can be effectively implemented in order to determine if the phenomenon is widespread.

  12. Major factors controlling nitrous oxide emission and methane uptake from forest soil

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Soil samples were taken from depth of 0-12 cm in virgin broad-leaved Korean pine mixed forest in Changbai Mountain in July 2000. The effects of temperature, soil water content, pH, NH4+ and NO3- on N2O emission and CH4 uptake of a forest soil were studied in laboratory by the method of orthogonal design. It was observed under laboratory conditions in this study that there were significant correlations between N2O emission rate, CH4 oxidation rate, soil pH and temperature. Nevertheless, N2O emission rate also showed a significant positive correlation with CH4 oxidation rate. The results suggested that pH and tem-perature were important factors controlling N2O emission and CH4 oxidation under this experiment conditions.

  13. The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990–2030

    Directory of Open Access Journals (Sweden)

    F. Raes

    2004-12-01

    Full Text Available To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4, carbon monoxide (CO, non-methane volatile organic compounds (NMVOC and nitrogen oxides (NOx up to the year 2030 and implemented them in two global Chemistry Transport Models. The "Current Legislation" (CLE scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a "Maximum technically Feasible Reduction" (MFR scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios scenarios (Nakicenovic et al., 2000. With the TM3 and STOCHEM models we performed several long-term integrations (1990–2030 to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce realistically the observed trends in background ozone, CO, and CH4 concentrations from 1990 to 2002. For the "current legislation" case, both models indicate an increase of the annual average ozone levels in the Northern hemisphere by 5 ppbv, and up to 15 ppbv over the Indian

  14. Methane emission in the gas industry of Russia; Emissions de methane dans l'industrie gaziere de la Russie

    Energy Technology Data Exchange (ETDEWEB)

    Sedykh, A.D. [Join-Stock Company Gazprom (Russian Federation); Gritsenko, A.I.; Akopova, G.S. [VNIIGAZ (Russian Federation); Maksimov, V.M. [Oil and Gas Research Institute (Russian Federation)

    2000-07-01

    The paper presents the methodology of methane emission estimation and the strategy of the gas industry of Russia in the limitation of natural gas emission into the atmosphere. Special attention is paid to the problem of relationship between natural gas and climate change. The results of actual leakage and technological natural gas emission measurement, methods and control means are given. Design options on methane emission reduction under different processes, gas leakage and accidents. (authors)

  15. CYANOBACTERIA FOR MITIGATING METHANE EMISSION FROM SUBMERGED PADDY FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Upasana Mishra; Shalini Anand [Department of Environmental Studies, Inderprastha Engineering College, Sahibabad, Ghaziabad (India)

    2008-09-30

    Atmospheric methane, a potent greenhouse gas with high absorption potential for infrared radiation, is responsible for one forth of the total anticipated warming. It is forming a major part of green house gases, next after carbon dioxide. Its concentration has been increasing alarmingly on an average at the rate of one percent per year. Atmospheric methane, originating mainly from biogenic sources such as paddy fields, natural wetlands and landfills, accounts for 15-20% of the world's total anthropogenic methane emission. With intensification of rice cultivation in coming future, methane emissions from paddy fields are anticipated to increase. India's share in world's rice production is next after to China and likewise total methane emission from paddy fields also. Methane oxidation through planktophytes, particularly microalgae which are autotrophic and abundant in rice rhizospheres, hold promise in controlling methane emission from submerged paddy fields. The present study is focused on the role of nitrogen fixing, heterocystous cyanobacteria and Azolla (a water fern harboring a cyanobacterium Anabaena azollae) as biological sink for headspace concentration of methane in flooded soils. In this laboratory study, soil samples containing five potent nitrogen fixer cyanobacterial strains from paddy fields, were examined for their methane reducing potential. Soil sample without cyanobacterial strain was tested and taken as control. Anabaena sp. was found most effective in inhibiting methane concentration by 5-6 folds over the control. Moist soil cores treated with chemical nitrogen, urea, in combination with cyanobacteria mixture, Azolla microphylla or cyanobacteria mixture plus Azolla microphylla exhibited significance reduction in the headspace concentration of methane than the soil cores treated with urea alone. Contrary to other reports, this study also demonstrates that methane oxidation in soil core samples from paddy fields was stimulated by

  16. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    Science.gov (United States)

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  17. Methane emission from wetland rice fields.

    OpenAIRE

    H.A.C. Denier van der Gon

    1996-01-01

    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic methane emission. Methane fluxes from wetland rice fields in the Philippines were monitored with a closed chamber technique in close cooperation with the International Rice Research Institute (IRRI). The field studies were complemented by laboratory and greenhouse ex...

  18. Methane emission during municipal wastewater treatment.

    Science.gov (United States)

    Daelman, Matthijs R J; van Voorthuizen, Ellen M; van Dongen, Udo G J M; Volcke, Eveline I P; van Loosdrecht, Mark C M

    2012-07-01

    Municipal wastewater treatment plants emit methane. Since methane is a potent greenhouse gas that contributes to climate change, the abatement of the emission is necessary to achieve a more sustainable urban water management. This requires thorough knowledge of the amount of methane that is emitted from a plant, but also of the possible sources and sinks of methane on the plant. In this study, the methane emission from a full-scale municipal wastewater facility with sludge digestion was evaluated during one year. At this plant the contribution of methane emissions to the greenhouse gas footprint were slightly higher than the CO₂ emissions related to direct and indirect fossil fuel consumption for energy requirements. By setting up mass balances over the different unit processes, it could be established that three quarters of the total methane emission originated from the anaerobic digestion of primary and secondary sludge. This amount exceeded the carbon dioxide emission that was avoided by utilizing the biogas. About 80% of the methane entering the activated sludge reactor was biologically oxidized. This knowledge led to the identification of possible measures for the abatement of the methane emission.

  19. Greenhouse Gas Emissions: Quantifying Methane Emissions from Livestock

    OpenAIRE

    2012-01-01

    Problem statement: The rearing of animals for domestic consumption and export invariably lead to the production of methane as a product of digestion. This study investigated the emission of methane from Malaysian livestock between 1980 and 2008. Approach: Seven categories of animals identified were camel, buffalo, sheep, goats, horse, pigs and poultry. The estimation of methane was based on the IPCC Tier 1 and Tier 2 methods. Methane emission from cattle rose by 44% within the period from 45....

  20. Enteric methane emissions from German dairy cows

    DEFF Research Database (Denmark)

    Dammgen, U; Rosemann, C; Haenel, H D

    2012-01-01

    Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

  1. Enteric methane emissions from German dairy cows

    DEFF Research Database (Denmark)

    Dammgen, U; Rosemann, C; Haenel, H D

    2012-01-01

    Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

  2. Ebullitive methane emissions from oxygenated wetland streams.

    Science.gov (United States)

    Crawford, John T; Stanley, Emily H; Spawn, Seth A; Finlay, Jacques C; Loken, Luke C; Striegl, Robert G

    2014-11-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr(-1) ; over 6400 km(2) ) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  3. Ebullitive methane emissions from oxygenated wetland streams

    Science.gov (United States)

    Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

    2014-01-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  4. Methane emissions from floodplain trees of the Amazon basin

    Science.gov (United States)

    Pangala, Sunitha; Bastviken, David; Enrich-Prast, Alex; Gauci, Vincent

    2016-04-01

    Wetlands are the largest source of methane to the atmosphere, but emission estimates are highly uncertain leading to large discrepancies between emission inventories and much larger estimates of the Amazon methane source derived at larger scales. We examined methane emissions from all emission pathways including aquatic surfaces, emergent soils and herbaceous vegetation and more than 2000 trees from 13 locations across the central Amazon floodplain in 2014. Our data are the first measurements of stem emission from emergent portions of inundated trees in the Amazon and they demonstrate that regionally, tree stems are the dominant means of emissions for soil produced methane to the atmosphere. Emissions via the range of egress pathways varied substantially between sample locations and water-table exerted some control over emissions from ~2m below the soil surface upto 0.5-1m of inundation. Higher water (upto ~10m of inundation) exerted no further control over emissions. Applying our measurements to models of whole tree emission and scaling to the entire Amazon lowland basin demonstrates the significant contribution of trees to regional emissions that can close the Amazon basin methane budget.

  5. Capturing fugitive methane emissions from natural gas compressor buildings.

    Science.gov (United States)

    Litto, R; Hayes, R E; Liu, B

    2007-08-01

    Fugitive methane emissions account for about 50% of the greenhouse gas (GHG) emissions from the Canadian conventional oil and gas sector. Sources include leaks in natural gas transmission facilities such as pipelines and compressor stations. There are three sources of methane emissions in a compressor station. The first is emissions resulting from incomplete combustion in the engine; the second is leaks in valves, flanges and other equipment in the building; and the third results from instrument venting. Fugitive methane emissions may be in low concentration relative to air, and thus cannot be destroyed by conventional combustion (below flammability limits of about 5-16%). The present study investigates the feasibility of capturing methane emissions from a compressor station. Computer modelling of the flow patterns of lean methane emissions inside the building is used to show the influence of doors, vents and leak location. Simulations show that for a typical building most fugitive methane exits through the ridge vent provided that the main doors remain closed. When the extraction rate through the ridge vent is controlled, the methane concentration is at acceptable levels for destruction in a catalytic flow reverse reactor, that is, in the range of 0.1-1% by volume.

  6. The impact of air pollutant and methane emission controls on tropospheric ozone and radiative forcing: CTM calculations for the period 1990-2030

    Directory of Open Access Journals (Sweden)

    F. Dentener

    2005-01-01

    Full Text Available To explore the relationship between tropospheric ozone and radiative forcing with changing emissions, we compiled two sets of global scenarios for the emissions of the ozone precursors methane (CH4, carbon monoxide (CO, non-methane volatile organic compounds (NMVOC and nitrogen oxides (NOx up to the year 2030 and implemented them in two global Chemistry Transport Models. The 'Current Legislation' (CLE scenario reflects the current perspectives of individual countries on future economic development and takes the anticipated effects of presently decided emission control legislation in the individual countries into account. In addition, we developed a 'Maximum technically Feasible Reduction' (MFR scenario that outlines the scope for emission reductions offered by full implementation of the presently available emission control technologies, while maintaining the projected levels of anthropogenic activities. Whereas the resulting projections of methane emissions lie within the range suggested by other greenhouse gas projections, the recent pollution control legislation of many Asian countries, requiring introduction of catalytic converters for vehicles, leads to significantly lower growth in emissions of the air pollutants NOx, NMVOC and CO than was suggested by the widely used and more pessimistic IPCC (Intergovernmental Panel on Climate Change SRES (Special Report on Emission Scenarios scenarios (Nakicenovic et al., 2000, which made Business-as-Usual assumptions regarding emission control technology. With the TM3 and STOCHEM models we performed several long-term integrations (1990-2030 to assess global, hemispheric and regional changes in CH4, CO, hydroxyl radicals, ozone and the radiative climate forcings resulting from these two emission scenarios. Both models reproduce broadly the observed trends in CO, and CH4 concentrations from 1990 to 2002. For the 'current legislation' case, both models indicate an increase of the annual average ozone

  7. Greenhouse Gas Emissions: Quantifying Methane Emissions from Livestock

    Directory of Open Access Journals (Sweden)

    Rafiu O. Yusuf

    2012-01-01

    Full Text Available Problem statement: The rearing of animals for domestic consumption and export invariably lead to the production of methane as a product of digestion. This study investigated the emission of methane from Malaysian livestock between 1980 and 2008. Approach: Seven categories of animals identified were camel, buffalo, sheep, goats, horse, pigs and poultry. The estimation of methane was based on the IPCC Tier 1 and Tier 2 methods. Methane emission from cattle rose by 44% within the period from 45.61-65.57 Gg. Results: Buffalo recorded a drop in methane emission by 54% from 17.12-7.86 Gg while the methane emission from sheep initially rose by 350% in 1992 only to drop by another 56% by 2008. Goats emission only declined by 17% from 1.79 Gg in 1980-1.49 Gg by 2008. Methane emission from horse has been consistent at around 0.14 Gg. The decreasing stock of pigs has led to a drop in methane emission from these set of animals with most of the emission coming from manure management. Conclusion: The healthy export market for poultry has seen a rise in methane emission by 274% from 2.18 Gg in 1980-8.17 Gg by 2008. The overall increase in methane emission from all the livestock is 20% from 81.83 Gg in 1980-98.76 Gg in 2008. With the aggressive drive of government to boost cattle and goat production, there is the likelihood of an increase in methane emission in the future and mitigation options will have to be applied.

  8. Enteric methane emissions from German pigs

    DEFF Research Database (Denmark)

    Dämmgen, Ulrich; Schulz, Joachim; Klausing, Heinrich Kleine

    2012-01-01

    Methane emissions from enteric fermentation of pigs are object of emission reporting. Hitherto they were treated as part of the energy balance of pigs, in accordance with IPCC guidance documents. They were calculated from the gross energy intake rate and a constant methane conversion ratio....... Meanwhile numerous experimental data on methane emissions from enteric fermentation is available in Germany and abroad; the results are compiled in this work. These results also allow for a description of transformation processes in the hind gut and a subsequent establishment of models that relate emissions...... to feed and performance data. The model by Kirchgeßner et al. (1995) is based on German experimental data and reflects typical national diet compositions. It is used to quantify typical emissions and methane conversion ratios. The results agree with other experimental findings at home and abroad...

  9. Enteric methane emissions from German pigs

    DEFF Research Database (Denmark)

    Dämmgen, Ulrich; Schulz, Joachim; Klausing, Heinrich Kleine

    2012-01-01

    Methane emissions from enteric fermentation of pigs are object of emission reporting. Hitherto they were treated as part of the energy balance of pigs, in accordance with IPCC guidance documents. They were calculated from the gross energy intake rate and a constant methane conversion ratio....... Meanwhile numerous experimental data on methane emissions from enteric fermentation is available in Germany and abroad; the results are compiled in this work. These results also allow for a description of transformation processes in the hind gut and a subsequent establishment of models that relate emissions...... to feed and performance data. The model by Kirchgeßner et al. (1995) is based on German experimental data and reflects typical national diet compositions. It is used to quantify typical emissions and methane conversion ratios. The results agree with other experimental findings at home and abroad...

  10. The genome sequence of the rumen methanogen Methanobrevibacter ruminantium reveals new possibilities for controlling ruminant methane emissions.

    Directory of Open Access Journals (Sweden)

    Sinead C Leahy

    Full Text Available BACKGROUND: Methane (CH(4 is a potent greenhouse gas (GHG, having a global warming potential 21 times that of carbon dioxide (CO(2. Methane emissions from agriculture represent around 40% of the emissions produced by human-related activities, the single largest source being enteric fermentation, mainly in ruminant livestock. Technologies to reduce these emissions are lacking. Ruminant methane is formed by the action of methanogenic archaea typified by Methanobrevibacter ruminantium, which is present in ruminants fed a wide variety of diets worldwide. To gain more insight into the lifestyle of a rumen methanogen, and to identify genes and proteins that can be targeted to reduce methane production, we have sequenced the 2.93 Mb genome of M. ruminantium M1, the first rumen methanogen genome to be completed. METHODOLOGY/PRINCIPAL FINDINGS: The M1 genome was sequenced, annotated and subjected to comparative genomic and metabolic pathway analyses. Conserved and methanogen-specific gene sets suitable as targets for vaccine development or chemogenomic-based inhibition of rumen methanogens were identified. The feasibility of using a synthetic peptide-directed vaccinology approach to target epitopes of methanogen surface proteins was demonstrated. A prophage genome was described and its lytic enzyme, endoisopeptidase PeiR, was shown to lyse M1 cells in pure culture. A predicted stimulation of M1 growth by alcohols was demonstrated and microarray analyses indicated up-regulation of methanogenesis genes during co-culture with a hydrogen (H(2 producing rumen bacterium. We also report the discovery of non-ribosomal peptide synthetases in M. ruminantium M1, the first reported in archaeal species. CONCLUSIONS/SIGNIFICANCE: The M1 genome sequence provides new insights into the lifestyle and cellular processes of this important rumen methanogen. It also defines vaccine and chemogenomic targets for broad inhibition of rumen methanogens and represents a significant

  11. Towards Understanding Methane Emissions from Abandoned Wells

    Science.gov (United States)

    Reconciliation of large-scale top-down methane measurements and bottom-up inventories requires complete accounting of source types. Methane emissions from abandoned oil and gas wells is an area of uncertainty. This presentation reviews progress to characterize the potential inv...

  12. Controls on northern wetland methane emissions: insights from regional synthesis studies and the Alaska Peatland Experiment (APEX)

    Science.gov (United States)

    Turetsky, M. R.; Euskirchen, E. S.; Czimczik, C. I.; Waldrop, M. P.; Olefeldt, D.; Fan, Z.; Kane, E. S.; McGuire, A. D.; Harden, J. W.

    2014-12-01

    Wetlands are the largest natural source of atmospheric methane. Static chambers have been used to quantify variation in wetland CH4 flux for many decades. Regional to global scale synthesis studies of static chamber measurements show that relationships between temperature, water availability and CH4 emissions depend on wetland type (bog, fen, swamp), region (tropical, temperate, arctic) and disturbance. For example, while water table position and temperature serve as the dominant controls on bog and swamp CH4 flux, vegetation is an important control on emissions from fens. These studies highlight the fact that wetland types have distinct controls on CH4 emissions; however, it is unlikely that modeling of wetland CH4 flux will improve without a better mechanistic understanding of the processes underlying CH4 production, transport, and oxidation. At the Alaska Peatland Experiment, we are quantifying CH4 emission using static chambers, automated chambers, and towers. Our sites vary in permafrost regime, including groundwater fens without permafrost, forested peat plateaus with intact permafrost, and collapse scar bogs formed through permafrost thaw. Experimental studies that examine plant and microbial responses to altered water table position and soil temperature are complemented by a gradient approach, where we use a space-for-time substitutions to examine the consequences of thaw on time-scales of decades to centuries. Our results thus far have documented the importance of soil rewetting in governing large CH4 fluxes from northern wetland soils. Accounting for CH4, our collapse scar bog significantly contributed to the global warming potential of the landscape. A major objective of our work is to explore the role of permafrost C release in greenhouse gas fluxes from wetland soils, which we are assessing using radiocarbon as a natural tracer. We have shown, for example, that ebullition of CH4 is dominated by recently fixed C, but a significant fraction of CH4 in

  13. Superficial Methane Emissions from a Landfill in Merida, Yucatan, Mexico

    Directory of Open Access Journals (Sweden)

    Sauri-Riancho María Rosa

    2013-06-01

    Full Text Available On worldwide scale, one of the most important anthropogenic methane sources is landfill disposal for solid wastes. The main goal of this work was to quantify methane emissions at one landfill built in Merida, Mexico. This sit had venting wells by which a passive control for biogas movement was exerted. At the venting wells, methane concentrations were measured monthly during a 6 months period, Methane surface emission rate was estimated with the close chamber technique. Obtained results indicated that there are both spatial and seasonal variations in biogas composition. The average methane value during the monitoring period was 21.9% (12.7 to 32.5 V/V and the surface flow rate was in the range of 0 to 6,004 g CH4 m–2 d–1, with an average value of 1,480 g CH4 m–2 d–1, which is a high value in respect to these reported in publications.

  14. Global methane emissions from pit latrines.

    Science.gov (United States)

    Reid, Matthew C; Guan, Kaiyu; Wagner, Fabian; Mauzerall, Denise L

    2014-01-01

    Pit latrines are an important form of decentralized wastewater management, providing hygienic and low-cost sanitation for approximately one-quarter of the global population. Latrines are also major sources of the greenhouse gas methane (CH4) from the anaerobic decomposition of organic matter in pits. In this study, we develop a spatially explicit approach to account for local hydrological control over the anaerobic condition of latrines and use this analysis to derive a set of country-specific emissions factors and to estimate global pit latrine CH4 emissions. Between 2000 and 2015 we project global emissions to fall from 5.2 to 3.8 Tg y(-1), or from ∼ 2% to ∼ 1% of global anthropogenic CH4 emissions, due largely to urbanization in China. Two and a half billion people still lack improved sanitation services, however, and progress toward universal access to improved sanitation will likely drive future growth in pit latrine emissions. We discuss modeling results in the context of sustainable water, sanitation, and hygiene development and consider appropriate technologies to ensure hygienic sanitation while limiting CH4 emissions. We show that low-CH4 on-site alternatives like composting toilets may be price competitive with other CH4 mitigation measures in organic waste sectors, with marginal abatement costs ranging from 57 to 944 $/ton carbon dioxide equivalents (CO2e) in Africa and 46 to 97 $/ton CO2e in Asia.

  15. Microbial community composition controls the effects of climate change on methane emission from rice paddies.

    Science.gov (United States)

    Liu, Guang Cheng; Tokida, Takesi; Matsunami, Toshinori; Nakamura, Hirofumi; Okada, Masumi; Sameshima, Ryoji; Hasegawa, Toshihiro; Sugiyama, Shu-Ichi

    2012-12-01

    Rice paddies are one of the most important sources of CH4 emission from the terrestrial ecosystem. A Free-air CO2 Enrichment (FACE) experiment, which included a soil warming treatment, was conducted in a rice paddy at Shizukuishi, Japan. In this study, the changes in CH4 emission from a rice paddy, caused by global climate change, were explored in relation to the structural changes that have occurred in the methanogenic archaeal communities found in the soil and roots. The composition of the archaeal community was examined by terminal restriction fragment length polymorphism (T-RFLP) using the 16S rRNA gene, while its abundance was measured by real-time PCR using the methyl coenzyme M reductase (mcrA) gene. The archaeal community in the roots showed considerable change, characterized by the dominance of hydrogenotrophic methanogens and a corresponding decrease in acetoclastic methanogens. Seasonal changes in CH4 flux were closely related to the changes in methanogen abundance in the roots. Elevated CO2 caused an increase in root mass, which increased the abundance of methanogens leading to a rise in CH4 emissions. However, soil warming stimulated CH4 emissions by increasing CH4 production per individual methanogen. These results demonstrated that climate warming stimulates CH4 emission in a rice paddy by altering the abundance and activity of methanogenic archaea in the roots.

  16. Prediction of enteric methane emissions from cattle.

    Science.gov (United States)

    Moraes, Luis E; Strathe, Anders B; Fadel, James G; Casper, David P; Kebreab, Ermias

    2014-07-01

    Agriculture has a key role in food production worldwide and it is a major component of the gross domestic product of several countries. Livestock production is essential for the generation of high quality protein foods and the delivery of foods in regions where animal products are the main food source. Environmental impacts of livestock production have been examined for decades, but recently emission of methane from enteric fermentation has been targeted as a substantial greenhouse gas source. The quantification of methane emissions from livestock on a global scale relies on prediction models because measurements require specialized equipment and may be expensive. The predictive ability of current methane emission models remains poor. Moreover, the availability of information on livestock production systems has increased substantially over the years enabling the development of more detailed methane prediction models. In this study, we have developed and evaluated prediction models based on a large database of enteric methane emissions from North American dairy and beef cattle. Most probable models of various complexity levels were identified using a Bayesian model selection procedure and were fitted under a hierarchical setting. Energy intake, dietary fiber and lipid proportions, animal body weight and milk fat proportion were identified as key explanatory variables for predicting emissions. Models here developed substantially outperformed models currently used in national greenhouse gas inventories. Additionally, estimates of repeatability of methane emissions were lower than the ones from the literature and multicollinearity diagnostics suggested that prediction models are stable. In this context, we propose various enteric methane prediction models which require different levels of information availability and can be readily implemented in national greenhouse gas inventories of different complexity levels. The utilization of such models may reduce errors

  17. Methane emissions from a high arctic valley: findings and challenges

    DEFF Research Database (Denmark)

    Mastepanov, Mikhail; Sigsgaard, Charlotte; Ström, Lena

    2008-01-01

    Wet tundra ecosystems are well-known to be a significant source of atmospheric methane. With the predicted stronger effect of global climate change on arctic terrestrial ecosystems compared to lower-latitudes, there is a special obligation to study the natural diversity and the range of possible...... feedback effects on global climate that could arise from Arctic tundra ecosystems. One of the prime candidates for such a feedback mechanism is a potential change in the emissions of methane. Long-term datasets on methane emissions from high arctic sites are almost non-existing but badly needed...... for analyses of controls on interannual and seasonal variations in emissions. To help fill this gap we initiated a measurement program in a productive high arctic fen in the Zackenberg valley, NE Greenland. Methane flux measurements have been carried out at the same location since 1997. Compared...

  18. Diel methane emission patterns from Scirpus lacustris and Phragmites australis

    NARCIS (Netherlands)

    Van der Nat, J.W.A.; Middelburg, J.J.; Van Meteren, D.; Wielemaker, A.

    1998-01-01

    In mature Phragmites australis and Scirpus lacustris vegetated sediment methane was emitted almost exclusively by plant- mediated transport, whereas in unvegetated, but otherwise identical sediment, methane was emitted almost exclusively by ebullition. Diel variations in methane emission, with

  19. Diel methane emission patterns from Scirpus lacustris and Phragmites australis

    NARCIS (Netherlands)

    Van der Nat, J.W.A.; Middelburg, J.J.; Van Meteren, D.; Wielemaker, A.

    1998-01-01

    In mature Phragmites australis and Scirpus lacustris vegetated sediment methane was emitted almost exclusively by plant- mediated transport, whereas in unvegetated, but otherwise identical sediment, methane was emitted almost exclusively by ebullition. Diel variations in methane emission, with highe

  20. Microtopographic and Hydrological Controls over Respiratory Efflux and Late-Season Arctic Methane Emissions

    Science.gov (United States)

    Wilkman, E.; Zona, D.; Oechel, W. C.

    2014-12-01

    In recent years, Arctic peatlands have released approximately 35 Tg (3.5 x 1012g) of CH4 annually, corresponding to around 1/3 of the aggregate wetland CH4 fluxes and 16% of all natural emissions. As climate models increasingly suggest that current warming trends in the Arctic (4-8 °C higher annual surface air temperatures) will continue by century's end, carbon (C) cycling in these northern climes may be further amplified. Although much has been learned in recent decades, uncertainty remains in regard to the spatial and temporal extent of CO2 and CH4 emissions from these systems. Chamber based carbon flux measurements were gathered for three growing seasons from June 2007 to September 2013 in Barrow, Alaska to investigate the diurnal, weekly, and monthly patterns of CO2 and CH4 flux in the North American Arctic. For the 2007 and 2008 growing seasons, high temporal frequency auto-chambers (LI-8100A Automated Soil Flux System, LI-COR Biosciences) were used to gather over 18,000 individual flux measurements. From July to September 2013 an Ultraportable Greenhouse Gas Analyzer (Los Gatos Research Inc.) was deployed in concert with this soil flux system to gather high temporal frequency soil CO2 and CH4 fluxes. Nearby eddy covariance towers provided auxiliary meteorological and environmental data, while weekly transects amassed further surficial hydrological measures (pH, thaw depth, water table). For earlier periods of data, respiratory fluxes were partitioned into five microtopographic classes (polygon rims and troughs, low centered basins, high ridges, and flat mesic terrain). Conversely, for the later periods of data covered chamber fluxes were partitioned into three 'habitat' types (High, Medium, Wet) based on corresponding aboveground average water table extent. Marked dissimilarities were noted across habitat types and microtopographic classes. In general more mesic, waterlogged regions released greater quantities of CO2 across the growing season, while

  1. Methane emission by adult ostriches (Struthio camelus).

    Science.gov (United States)

    Frei, Samuel; Dittmann, Marie T; Reutlinger, Christoph; Ortmann, Sylvia; Hatt, Jean-Michel; Kreuzer, Michael; Clauss, Marcus

    2015-02-01

    Ostriches (Struthio camelus) are herbivorous birds with a digestive physiology that shares several similarities with that of herbivorous mammals. Previous reports, however, claimed a very low methane emission from ostriches, which would be clearly different from mammals. If this could be confirmed, ostrich meat would represent a very attractive alternative to ruminant-and generally mammalian-meat by representing a particularly low-emission agricultural form of production. We individually measured, by chamber respirometry, the amount of oxygen consumed as well as carbon dioxide and methane emitted from six adult ostriches (body mass 108.3±8.3 kg) during a 24-hour period when fed a pelleted lucerne diet. While oxygen consumption was in the range of values previously reported for ostriches, supporting the validity of our experimental setup, methane production was, at 17.5±3.2 L d(-1), much higher than previously reported for this species, and was of the magnitude expected for similar-sized, nonruminant mammalian herbivores. These results suggest that methane emission is similar between ostriches and nonruminant mammalian herbivores and that the environmental burden of these animals is comparable. The findings furthermore indicate that it appears justified to use currently available scaling equations for methane production of nonruminant mammals in paleo-reconstructions of methane production of herbivorous dinosaurs.

  2. Upscaling methane emission hotspots in boreal peatlands

    Directory of Open Access Journals (Sweden)

    F. Cresto Aleina

    2015-10-01

    Full Text Available Upscaling the properties and the effects of small-scale surface heterogeneities to larger scales is a challenging issue in land surface modeling. We developed a novel approach to upscale local methane emissions in a boreal peatland from the micro-topographic scale to the landscape-scale. We based this new parameterization on the analysis of the water table pattern generated by the Hummock–Hollow model, a micro-topography resolving model for peatland hydrology. We introduce this parameterization of methane hotspots in a global model-like version of the Hummock–Hollow model, that underestimates methane emissions. We tested the robustness of the parameterization by simulating methane emissions for the next century forcing the model with three different RCP scenarios. The Hotspot parameterization, despite being calibrated for the 1976–2005 climatology, mimics the output of the micro-topography resolving model for all the simulated scenarios. The new approach bridges the scale gap of methane emissions between this version of the model and the configuration explicitly resolving micro-topography.

  3. Aquatic herbivores facilitate the emission of methane from wetlands

    OpenAIRE

    Dingemans, B.J.J.; Bakker, E.S.; Bodelier, P. L. E.

    2011-01-01

    Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on shoots of wetland plants can modulate methane emission from wetlands. Diffusive methane emission was monitored inside and outside bird exclosures, using static flux chambers placed over whole vege...

  4. Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

    Science.gov (United States)

    Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

    2015-12-01

    Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

  5. Methane : its role in climate change and options for control

    OpenAIRE

    2012-01-01

    This study on CH4, (its role in climate change and options for control), aimed at a scenario analysis to assess future climate change under reduced methane emissions. At the same time improving the quality of CH4 emission inventories and estimating the costs of emission reductions between 2010 and 2100. In this thesis 28 major options to control or mitigate methane emissions from different sources were identified. The effectiveness and costs of these options were assessed. This resulted in a ...

  6. Methane emissions in Danish riparian wetlands

    DEFF Research Database (Denmark)

    Audet, Joachim; Johansen, Jan Ravn; Andersen, Peter Mejlhede

    2013-01-01

    The present study was conducted to (i) investigate parameters influencing the fluxes of the greenhouse gas methane (CH4) in Danish riparian wetlands with contrasting vegetation characteristics and (ii) develop models relating CH4 emissions to soil and/or vegetation parameters integrating the spat......The present study was conducted to (i) investigate parameters influencing the fluxes of the greenhouse gas methane (CH4) in Danish riparian wetlands with contrasting vegetation characteristics and (ii) develop models relating CH4 emissions to soil and/or vegetation parameters integrating...

  7. Evaluating Bay Area Methane Emission Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jeong, Seongeun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-03-01

    As a regulatory agency, evaluating and improving estimates of methane (CH4) emissions from the San Francisco Bay Area is an area of interest to the Bay Area Air Quality Management District (BAAQMD). Currently, regional, state, and federal agencies generally estimate methane emissions using bottom-up inventory methods that rely on a combination of activity data, emission factors, biogeochemical models and other information. Recent atmospheric top-down measurement estimates of methane emissions for the US as a whole (e.g., Miller et al., 2013) and in California (e.g., Jeong et al., 2013; Peischl et al., 2013) have shown inventories underestimate total methane emissions by ~ 50% in many areas of California, including the SF Bay Area (Fairley and Fischer, 2015). The goal of this research is to provide information to help improve methane emission estimates for the San Francisco Bay Area. The research effort builds upon our previous work that produced methane emission maps for each of the major source sectors as part of the California Greenhouse Gas Emissions Measurement (CALGEM) project (http://calgem.lbl.gov/prior_emission.html; Jeong et al., 2012; Jeong et al., 2013; Jeong et al., 2014). Working with BAAQMD, we evaluate the existing inventory in light of recently published literature and revise the CALGEM CH4 emission maps to provide better specificity for BAAQMD. We also suggest further research that will improve emission estimates. To accomplish the goals, we reviewed the current BAAQMD inventory, and compared its method with those from the state inventory from the California Air Resources Board (CARB), the CALGEM inventory, and recent published literature. We also updated activity data (e.g., livestock statistics) to reflect recent changes and to better represent spatial information. Then, we produced spatially explicit CH4 emission estimates on the 1-km modeling grid used by BAAQMD. We present the detailed activity data, methods and derived emission maps by sector

  8. Methane Gas Emissions - is Older Infrastructure Leakier?

    Science.gov (United States)

    Wendt, L. P.; Caulton, D.; Zondlo, M. A.; Lane, H.; Lu, J.; Golston, L.; Pan, D.

    2015-12-01

    Large gains in natural gas production from hydraulic fracturing is reinvigorating the US energy economy. It is a clean burning fuel with lower emissions than that of coal or oil. Studies show that methane (CH4) leaks from natural gas infrastructure vary widely. A broader question is whether leak rates of methane might offset the benefits of combustion of natural gas. Excess methane (CH4) is a major greenhouse gas with a radiative forcing constant of 25 times that of CO2 when projected over a 100-year period. An extensive field study of 250 wells in the Marcellus Shale conducted in July 2015 examined the emission rates of this region and identifed super-emitters. Spud production data will provide information as to whether older infrastructure is responsible for more of the emissions. Quantifying the emission rate was determined by extrapolating methane releases at a distance from private well pads using an inverse Gaussian plume model. Wells studied were selected by prevailing winds, distance from public roads, and topographical information using commercial (ARCGIS and Google Earth), non-profit (drillinginfo), and government (State of PA) databases. Data were collected from the mobile sensing lab (CH4, CO2 and H2O sensors), as well as from a stationary tower. Emission rates from well pads will be compared to their original production (spud dates) to evaluate whether infrastructure age and total production correlates with the observed leak rates. Very preliminary results show no statistical correlation between well pad production rates and observed leak rates.

  9. Methane emission from tidal freshwater marshes

    NARCIS (Netherlands)

    Van der Nat, F.J.; Middelburg, J.J.

    2000-01-01

    In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had

  10. Methane emission from tidal freshwater marshes

    NARCIS (Netherlands)

    Van der Nat, F.J.; Middelburg, J.J.

    2000-01-01

    In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had high

  11. Biochar effects on methane emissions from soils

    NARCIS (Netherlands)

    Jeffery, Simon; Verheijen, Frank G.A.; Kammann, Claudia; Abalos Rodriguez, Diego

    2016-01-01

    Methane (CH4) emissions have increased by more than 150% since 1750, with agriculture being the major source. Further increases are predicted as permafrost regions start thawing, and rice and ruminant animal production expand. Biochar is posited to increase crop productivity while miti

  12. Aquatic herbivores facilitate the emission of methane from wetlands.

    Science.gov (United States)

    Dingemans, Bas J J; Bakker, Elisabeth S; Bodelier, Paul L E

    2011-05-01

    Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on shoots of wetland plants can modulate methane emission from wetlands. Diffusive methane emission was monitored inside and outside bird exclosures, using static flux chambers placed over whole vegetation and over single shoots. Both methods showed significantly higher methane release from grazed vegetation. Surface-based diffusive methane emission from grazed plots was up to five times higher compared to exclosures. The absence of an effect on methane-cycling microbial processes indicated that this modulating effect acts on the gas transport by the plants. Modulation of methane emission by animal-plant-microbe interactions deserves further attention considering the increasing bird populations and changes in wetland vegetation as a consequence of changing land use and climate change.

  13. Terrestrial plant methane production and emission

    DEFF Research Database (Denmark)

    Bruhn, Dan; Møller, Ian M.; Mikkelsen, Teis Nørgaard

    2012-01-01

    In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce...... aerobic CH4 into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  14. Global Air Quality and Health Co-benefits of Mitigating Near-term Climate Change Through Methane and Black Carbon Emission Controls

    Science.gov (United States)

    Anenberg, Susan C.; Schwartz, Joel; Shindell, Drew Todd; Amann, Markus; Faluvegi, Gregory S.; Klimont, Zbigniew; Janssens-Maenhout, Greet; Pozzoli, Luca; Dingenen, Rita Van; Vignati, Elisabetta; Emberson, Lisa; Muller, Nicholas Z.; West, J. Jason; Williams, Martin; Demkine, Volodymyr; Hicks, W. Kevin; Kuylenstierna, Johan; Raes, Frank; Ramanathan, Veerabhadran

    2012-01-01

    Tropospheric ozone and black carbon (BC), a component of fine particulate matter (PM air quality and health benefits of 14 specific emission control measures targeting BC and methane, an ozone precursor, that were selected because of their potential to reduce the rate of climate change over the next 20-40 years. Methods: We simulated the impacts of mitigation measures on outdoor concentrations of PM2.5 and ozone using two composition-climate models, and calculated associated changes in premature PM2.5- and ozone-related deaths using epidemiologically derived concentration-response functions. Results: We estimated that, for PM2.5 and ozone, respectively, fully implementing these measures could reduce global population-weighted average surface concentrations by 23-34% and 7-17% and avoid 0.6-4.4 and 0.04-0.52 million annual premature deaths globally in 2030. More than 80% of the health benefits are estimated to occur in Asia. We estimated that BC mitigation measures would achieve approximately 98% of the deaths that would be avoided if all BC and methane mitigation measures were implemented, due to reduced BC and associated reductions of nonmethane ozone precursor and organic carbon emissions as well as stronger mortality relationships for PM2.5 relative to ozone. Although subject to large uncertainty, these estimates and conclusions are not strongly dependent on assumptions for the concentration-response function. Conclusions: In addition to climate benefits, our findings indicate that the methane and BC emission control measures would have substantial co-benefits for air quality and public health worldwide, potentially reversing trends of increasing air pollution concentrations and mortality in Africa and South, West, and Central Asia. These projected benefits are independent of carbon dioxide mitigation measures. Benefits of BC measures are underestimated because we did not account for benefits from reduced indoor exposures and because outdoor exposure estimates

  15. Estimating methane emissions from mangrove area in Ranong Province, Thailand

    Directory of Open Access Journals (Sweden)

    Suwanchai Nitisoravut

    2005-01-01

    Full Text Available This study aimed to estimate methane emissions from the mangrove area of Ranong Province andto explore the factors affecting the emissions, as part of an attempt to evaluate methane contribution to the global methane budget. Methane was measured by using a closed chamber technique and analyzed by a gas chromatograph equipped with a flame ionization detector (FID. The results showed that the annual estimated methane emission was released at approximately 157.32 mg/m2. The amount of methane emission from this mangrove area was lower than in other previously studied areas. Emission rates varied seasonally with the highest rate in the rainy season followed by summer and cold seasons, during which the values were 0.52, 0.27, and 0.19 mg/m2/day, respectively. Seasonal variations of methane emission was related to several factors depending upon field conditions such as water conductivity, soil temperature, and water level.

  16. Offsetting Ongoing Methane Emissions --- An Alternative to Emission Equivalence Metrics

    Science.gov (United States)

    Clisby, N.; Enting, I. G.; Lauder, A.; Carter, J.; Cowie, A.; Henry, B.; Raupach, M. R.

    2012-12-01

    The Global Warming Potential (GWP) has been widely adopted as a metric for comparing the climate impact of different greenhouse gases. As has been frequently noted, there are many problems with using GWPs to define emission equivalence in spite of the use of GWPs for this purpose in contexts such as the Kyoto Protocol. We propose that for methane, rather than define emission equivalence, the appropriate comparison is between ongoing emissions of 0.9 to 1.0 kg of CH4 per year and one-off emissions of 1 tonne of carbon. This approach represents an approximate solution to the inverse problem of defining a forcing equivalent index (FEI) that gives exact equivalence of radiative forcing over a range of timescales. In our approach, if ongoing methane emissions are offset by a one-off carbon removal that is built up with 40-year e-folding time, then the result is close to radiatively neutral over periods from years to centuries. In contrast, the GWP provides radiative equivalence (in integrated terms) only at a single time, with large discrepancies at other times. Our approach also follows from consideration of greenhouse gas stabilisation, since stabilising atmospheric CO2 requires an approximate cap on total emissions, while stabilising methane requires stabilisation of ongoing emissions. Our quantitative treatment recognises that, on time scales of centuries, removal of 1 tonne of carbon only lowers the atmospheric carbon content by 0.3 to 0.35 tonnes. We discuss the implications for rangeland grazing systems. In the absence of effective mitigation techniques for methane from rangeland systems, this approach may provide an attractive offset mechanism in spite of requiring that woody vegetation be established and maintained over about 15% of the landscape, or an equivalent amount of carbon storage in soil.

  17. A Survey of Methane Emissions from California's Natural Gas Infrastructure

    Science.gov (United States)

    Fischer, M. L.; Cui, X.; Jeong, S.; Conley, S. A.; Mehrotra, S.; Faloona, I. C.; Chen, T.; Blake, D. R.; Clements, C. B.; Lareau, N.; Lloyd, M.; Fairley, D.

    2015-12-01

    Methane emissions from natural gas infrastructure are estimated to contribute small but uncertain fractions of total natural gas consumed in California and of California's total GHG budget. Because natural gas (NG) methane is an energy resource, an economic commodity, a potential health hazard, and a potent greenhouse gas, it is important to identify and quantify and control both intentional venting, and un-intentional leakages. Here, we report results of an observational survey, measuring NG methane emissions across examples from subsectors of California's natural gas infrastructure, ranging from production and processing, to transmission and distribution, and notably including examples from the consumption subsector. At regional scales, a combination of tower and aircraft measurements are used to estimate emissions of NG methane for the San Francisco Bay Area. At facility scales, aircraft mass balance measurements are applied to estimate NG methane emissions from associated with individual petroleum production fields, NG storage facilities, and petroleum refineries. At local scales, ground-based roadway surveys are applied to place lower limits on NG emissions from aggregate leakage sources in selected urban and suburban areas, a sample of NG fueling stations, and a small number of capped gas wells. For a subset of the consumption subsector, mass balance and CH4:CO2 emission ratio measurements are used to estimate leakage from a sample of quiescent residential buildings and example operating gas appliances. In general, CH4 emissions are found to grow with the NG throughput in a given area or facility, though the observed ratio of leakage to throughput varies by more than an order of magnitude for some cases (e.g., urban areas), presumably in response to varied infrastructure type, vintage, and maintenance. Taken in sum, preliminary results of this initial survey are consistent with the commonly held assumption that total NG methane emissions from California NG

  18. [Spectroscopy technique and ruminant methane emissions accurate inspecting].

    Science.gov (United States)

    Shang, Zhan-Huan; Guo, Xu-Sheng; Long, Rui-Jun

    2009-03-01

    The increase in atmospheric CH4 concentration, on the one hand through the radiation process, will directly cause climate change, and on the other hand, cause a lot of changes in atmospheric chemical processes, indirectly causing climate change. The rapid growth of atmospheric methane has gained attention of governments and scientists. All countries in the world now deal with global climate change as an important task of reducing emissions of greenhouse gases, but the need for monitoring the concentration of methane gas, in particular precision monitoring, can be scientifically formulated to provide a scientific basis for emission reduction measures. So far, CH4 gas emissions of different animal production systems have received extensive research. The methane emission by ruminant reported in the literature is only estimation. This is due to the various factors that affect the methane production in ruminant, there are various variables associated with the techniques for measuring methane production, the techniques currently developed to measure methane are unable to accurately determine the dynamics of methane emission by ruminant, and therefore there is an urgent need to develop an accurate method for this purpose. Currently, spectroscopy technique has been used and is relatively a more accurate and reliable method. Various spectroscopy techniques such as modified infrared spectroscopy methane measuring system, laser and near-infrared sensory system are able to achieve the objective of determining the dynamic methane emission by both domestic and grazing ruminant. Therefore spectroscopy technique is an important methane measuring technique, and contributes to proposing reduction methods of methane.

  19. Methane : its role in climate change and options for control

    NARCIS (Netherlands)

    Amstel, van A.R.

    2012-01-01

    This study on CH4, (its role in climate change and options for control), aimed at a scenario analysis to assess future climate change under reduced methane emissions. At the same time improving the quality of CH4 emission inventories and estimating the costs of emission reducti

  20. Methane Emissions from Leak and Loss Audits of Natural Gas Compressor Stations and Storage Facilities.

    Science.gov (United States)

    Johnson, Derek R; Covington, April N; Clark, Nigel N

    2015-07-07

    As part of the Environmental Defense Fund's Barnett Coordinated Campaign, researchers completed leak and loss audits for methane emissions at three natural gas compressor stations and two natural gas storage facilities. Researchers employed microdilution high-volume sampling systems in conjunction with in situ methane analyzers, bag samples, and Fourier transform infrared analyzers for emissions rate quantification. All sites had a combined total methane emissions rate of 94.2 kg/h, yet only 12% of the emissions total resulted from leaks. Methane slip from exhausts represented 44% of the total emissions. Remaining methane emissions were attributed to losses from pneumatic actuators and controls, engine crankcases, compressor packing vents, wet seal vents, and slop tanks. Measured values were compared with those reported in literature. Exhaust methane emissions were lower than emissions factor estimates for engine exhausts, but when combined with crankcase emissions, measured values were 11.4% lower than predicted by AP-42 as applicable to emissions factors for four-stroke, lean-burn engines. Average measured wet seal emissions were 3.5 times higher than GRI values but 14 times lower than those reported by Allen et al. Reciprocating compressor packing vent emissions were 39 times higher than values reported by GRI, but about half of values reported by Allen et al. Though the data set was small, researchers have suggested a method to estimate site-wide emissions factors for those powered by four-stroke, lean-burn engines based on fuel consumption and site throughput.

  1. Terrestrial plant methane production and emission.

    Science.gov (United States)

    Bruhn, Dan; Møller, Ian M; Mikkelsen, Teis N; Ambus, Per

    2012-03-01

    In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH(4) ) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH(4) production, i.e. cutting injuries, increasing temperature, ultraviolet radiation and reactive oxygen species. Further, we analyze rates of measured emission of aerobically produced CH(4) in pectin and in plant tissues from different studies and argue that pectin is very far from the sole contributing precursor. In consequence, scaling up of aerobic CH(4) emission needs to take into consideration other potential sources than pectin. Due to the large uncertainties related to effects of stimulating factors, genotypic responses and type of precursors, we conclude that current attempts for upscaling aerobic CH(4) into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH(4) precursors in plant material.

  2. Mobile mapping of methane emissions and isoscapes

    Science.gov (United States)

    Takriti, Mounir; Ward, Sue; Wynn, Peter; Elias, Dafydd; McNamara, Niall

    2017-04-01

    Methane (CH4) is a potent greenhouse gas emitted from a variety of natural and anthropogenic sources. It is crucial to accurately and efficiently detect CH4 emissions and identify their sources to improve our understanding of changing emission patterns as well as to identify ways to curtail their release into the atmosphere. However, using established methods this can be challenging as well as time and resource intensive due to the temporal and spatial heterogeneity of many sources. To address this problem, we have developed a vehicle mounted mobile system that combines high precision CH4 measurements with isotopic mapping and dual isotope source characterisation. We here present details of the development and testing of a unique system for the detection and isotopic analysis of CH4 plumes built around a Picarro isotopic (13C/12C) gas analyser and a high precision Los Gatos greenhouse gas analyser. Combined with micrometeorological measurements and a mechanism for collecting discrete samples for high precision dual isotope (13C/12C, 2H/1H) analysis the system enables mapping of concentrations as well as directional and isotope based source verification. We then present findings from our mobile methane surveys around the North West of England. This area includes a variety of natural and anthropogenic methane sources within a relatively small geographical area, including livestock farming, urban and industrial gas infrastructure, landfills and waste water treatment facilities, and wetlands. We show that the system was successfully able to locate leaks from natural gas infrastructure and emissions from agricultural activities and to distinguish isotope signatures from these sources.

  3. Aquatic herbivores facilitate the emission of methane from wetlands

    NARCIS (Netherlands)

    Dingemans, B.J.J.; Bakker, E.S.; Bodelier, P.L.E.

    2011-01-01

    Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on

  4. Aquatic herbivores facilitate the emission of methane from wetlands

    NARCIS (Netherlands)

    Dingemans, B.J.J.; Bakker, E.S.; Bodelier, P.L.E.

    2011-01-01

    Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on

  5. Effect of phosphogypsum on respiration and methane emissions in sediment.

    Science.gov (United States)

    DeLaune, R D; Porthouse, J D; Patrick, W H

    2006-05-01

    The impact of adding phosphogypsum (PG) to freshwater wetland areas, and potential effect on methane production and respiration in sediment was studied in the laboratory. Two organic matter levels (native and enriched with 0.5% by weight ground dry plant material) were studied using five sediment treatments each: (1) no PG added, (2) 4% PG by dry weight (homogenized), (3) 20% PG by dry weight (homogenized), (4) 2000 kg ha(-1) (surface applied), and (5) 5000 kg ha (surface applied), and the experiment was run in triplicate. There was a net flux of methane into sediment for all treatments that were maintained at the native organic matter level, indicating net methane oxidation. In the organic-enriched cores, both of the homogenized treatments exhibited no methane emissions, while the surface applied treatments retained the potential for high emissions. Soil respiration was depressed in all treatments when compared to controls, especially in the organic-enriched cores. The results conclude that it may be possible to add PG to non-vegetated areas with few observable effects on sediment respiration, but organic matter content and method of application are critical concerns.

  6. 控制灌溉稻田的甲烷减排效果%Mitigation of methane emissions from paddy fields under controlled irrigation

    Institute of Scientific and Technical Information of China (English)

    彭世彰; 和玉璞; 杨士红; 徐俊增; 侯会静

    2013-01-01

    In order to explore the influence of soil moisture regulation on methane (CH4) emissions under water-saving irrigation and look for an irrigation mode for rice that would save water while simultaneously limiting CH4 emissions, the regularity of CH4 emissions from paddy fields under controlled irrigation was analyzed based on 5 years’of field experiment data. Two different irrigation managements were conducted as follows with the same rice variety, cultivation practices and plant protection measures:controlled irrigation (CI) and irrigated intermittently flooded single aeration irrigation (FI). Rice was cultivated in a 150 m2 (20 m×7.5 m) plot between 2006 and 2007, each plot was separated by brick concrete with a height of 30 cm and width of 30 cm. Plastic anti-seepage films were inserted into soil plough layer to a depth of 50cm to isolate water exchange between the plots. For exploring the influence of rainfall on CH4 emissions from irrigated paddy fields and controlling soil moisture accurately, experiments were conducted in lysimeter with mobile canopy between 2009 and 2011, and each plot area was 5 m2(2.5 m×2 m). Gas samples were collected using manual static chamber and were analyzed by a gas chromatograph (ShimadzuGC-14B) with a flame ionization detector (FID) for CH4 concentration. The results showed that the total CH4 emissions from CI paddy fields were 1.07±0.17g/m2, which was significantly reduced by 83.5%compared with FI paddy fields (6.49±0.17 g/m2). Total seasonal and annual CH4 emissions from CI and FI paddy fields located in Southeast China were lower than the reported values. Meanwhile, the total annual CH4 emissions from controlled irrigation paddy fields was lower than that of paddy filed in most parts of the World. When compared to irrigated intermittently flooded multiple aeration, irrigated intermittently flooded single aeration and irrigated continuously flooded paddy fields, seasonal CH4 emissions from CI paddy fields decreased 94

  7. Methane emissions from oceans, coasts, and freshwater habitats: New perspectives and feedbacks on climate

    Science.gov (United States)

    Hamdan, Leila J.; Wickland, Kimberly P.

    2016-01-01

    Methane is a powerful greenhouse gas, and atmospheric concentrations have risen 2.5 times since the beginning of the Industrial age. While much of this increase is attributed to anthropogenic sources, natural sources, which contribute between 35% and 50% of global methane emissions, are thought to have a role in the atmospheric methane increase, in part due to human influences. Methane emissions from many natural sources are sensitive to climate, and positive feedbacks from climate change and cultural eutrophication may promote increased emissions to the atmosphere. These natural sources include aquatic environments such as wetlands, freshwater lakes, streams and rivers, and estuarine, coastal, and marine systems. Furthermore, there are significant marine sediment stores of methane in the form of clathrates that are vulnerable to mobilization and release to the atmosphere from climate feedbacks, and subsurface thermogenic gas which in exceptional cases may be released following accidents and disasters (North Sea blowout and Deepwater Horizon Spill respectively). Understanding of natural sources, key processes, and controls on emission is continually evolving as new measurement and modeling capabilities develop, and different sources and processes are revealed. This special issue of Limnology and Oceanography gathers together diverse studies on methane production, consumption, and emissions from freshwater, estuarine, and marine systems, and provides a broad view of the current science on methane dynamics of aquatic ecosystems. Here, we provide a general overview of aquatic methane sources, their contribution to the global methane budget, and key uncertainties. We then briefly summarize the contributions to and highlights of this special issue.

  8. Measurement and prediction of enteric methane emission

    Science.gov (United States)

    Sejian, Veerasamy; Lal, Rattan; Lakritz, Jeffrey; Ezeji, Thaddeus

    2011-01-01

    The greenhouse gas (GHG) emissions from the agricultural sector account for about 25.5% of total global anthropogenic emission. While CO2 receives the most attention as a factor relative to global warming, CH4, N2O and chlorofluorocarbons (CFCs) also cause significant radiative forcing. With the relative global warming potential of 25 compared with CO2, CH4 is one of the most important GHGs. This article reviews the prediction models, estimation methodology and strategies for reducing enteric CH4 emissions. Emission of CH4 in ruminants differs among developed and developing countries, depending on factors like animal species, breed, pH of rumen fluid, ratio of acetate:propionate, methanogen population, composition of diet and amount of concentrate fed. Among the ruminant animals, cattle contribute the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. The estimated CH4 emission rate per cattle, buffaloe, sheep and goat in developed countries are 150.7, 137, 21.9 and 13.7 (g/animal/day) respectively. However, the estimated rates in developing countries are significantly lower at 95.9 and 13.7 (g/animal/day) per cattle and sheep, respectively. There exists a strong interest in developing new and improving the existing CH4 prediction models to identify mitigation strategies for reducing the overall CH4 emissions. A synthesis of the available literature suggests that the mechanistic models are superior to empirical models in accurately predicting the CH4 emission from dairy farms. The latest development in prediction model is the integrated farm system model which is a process-based whole-farm simulation technique. Several techniques are used to quantify enteric CH4 emissions starting from whole animal chambers to sulfur hexafluoride (SF6) tracer techniques. The latest technology developed to estimate CH4 more accurately is the micrometeorological mass difference technique. Because the conditions under which

  9. Sediment trapping by dams creates methane emission hot spots

    DEFF Research Database (Denmark)

    Maeck, A.; Delsontro, T.; McGinnis, Daniel F.

    2013-01-01

    Inland waters transport and transform substantial amounts of carbon and account for similar to 18% of global methane emissions. Large reservoirs with higher areal methane release rates than natural waters contribute significantly to freshwater emissions. However, there are millions of small dams...... worldwide that receive and trap high loads of organic carbon and can therefore potentially emit significant amounts of methane to the atmosphere. We evaluated the effect of damming on methane emissions in a central European impounded river. Direct comparison of riverine and reservoir reaches, where...... sedimentation in the latter is increased due to trapping by dams, revealed that the reservoir reaches are the major source of methane emissions (similar to 0.23 mmol CH4 m(-2) d(-1) vs similar to 19.7 mmol CH4 m(-2) d(-1), respectively) and that areal emission rates far exceed previous estimates for temperate...

  10. Methane emissions from grazing cattle using point-source dispersion.

    Science.gov (United States)

    McGinn, S M; Turner, D; Tomkins, N; Charmley, E; Bishop-Hurley, G; Chen, D

    2011-01-01

    The ability to accurately measure greenhouse gas (GHG) emissions is essential to gauge our ability to reduce these emissions. Enteric methane from ruminants is an important but often difficult source to quantify since it depends on the amount and type of feed intake. Unfortunately, many of the available measurement techniques for estimating enteric methane emissions can impose a change in feed intake. Our study evaluates a nonintrusive technique that uses a novel approach (point-source dispersion with multiple open-path concentrations) to calculate enteric methane emissions from grazing cattle, reported as the major source of GHG in many countries, particularly Australia. A scanner with a mounted open-path laser was used to measure methane concentration across five paths above a paddock containing 18 grazing cattle over 16 d. These data were used along with wind statistics in a dispersion model (WindTrax) to estimate an average herd methane emission rate over 10-mm intervals. Enteric methane emissions from the herd grazing a combination of Rhodes grass (Chlotis gayana Kunth) and Leucaena [Leucaena leucocephala (Lam.)] averaged (+/- SD) 141 (+/- 147) g animal(-1) d(-1). In a release-recovery experiment, the technique accounted for 77% of the released methane at a single point. Our study shows the technique generates more reliable methane emissions during daytime (unstable stratification).

  11. Methane emissions in India: Sub-regional and sectoral trends

    Science.gov (United States)

    Garg, Amit; Kankal, Bhushan; Shukla, P. R.

    2011-09-01

    This paper uses the 2006 IPCC Guidelines and latest country specific emission factors to estimate Indian methane emissions at sectoral and district level for the years 1990, 1995, 2005 and 2008. The estimates show that while methane emissions have increased steadily over past two decades, their share in India's aggregate GHG emissions has declined from 31% in 1985 to 27% in 2008 mainly due to relatively higher growth CO 2 emissions from the fossil fuels. The estimates for the year 2008 show that: i) agriculture sector, which employed two-thirds of India's population and contributed 17% of GDP, accounted for 23% of India's GHG emissions ii) 83% of country's methane emissions are contributed by enteric fermentation, manure use and rice production, and iii) methane emissions from urban solid waste are steadily rising over the past two decades; their share in aggregate methane emissions has reached 8%. Resting on the disaggregated emissions estimates, the paper argues for using geographical and sectoral flexibilities to develop a roadmap for mitigation of methane emissions for India.

  12. Evidence of species specific vascular plant functions as regulators of methane emissions from northern peatlands

    Science.gov (United States)

    Oquist, M. G.

    2001-05-01

    Peatlands play an indisputable role in the global carbon cycle by their net accumulation of atmospheric carbon dioxide and storage of carbon in the form of peat. They are also intimately tied into the fundamental processes of the atmospheric greenhouse gas balance through their production and concomitant emission of methane. During the last decade several studies have emphasized the function of vegetation as an important regulator of methane emissions from wetland ecosystems, including northern peatlands. Vascular plants can affect methane emissions either by facilitating transportation of methane over the soil/atmosphere interface, or by supplying the microbial soil communities with readily degradable organic substrates through root activity, stimulating biogeochemical transformation rates including methanogenesis. We found evidence of both these types of vegetation-based interactions in a sub-arctic peatland ecosystem and also indications that the two different processes of vegetation induced stimulation of methane emission rates are species specific with respect to the vascular plant communities. By reducing incoming PAR through shading manipulations and comparing these to ambient light control plots we created an intra-habitat gradient of vascular plant photosynthesis at two contrasting sites, one ombrotrophic (dominated by Eriophorum vaginatum/Carex rotundata) and one minerotrophic (dominated by Eriophorum angustifolium). The position of the water table was found to be the dominating environmental factor controlling methane emission rates in both habitat types. At the ombrotrophic site the photosynthetic rate was the second most important factor, especially during peak vascular plant activity (late June- early August) when this variable could explain ca 15% of the variations in methane flux rates. Furthermore, the photosynthetic rates in the shaded plots were reduced by ca 25% and was accompanied by a significant 20% (P=0.01) reduction in methane emission

  13. Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues

    Science.gov (United States)

    Douglas, P. M. J.; Stolper, D. A.; Smith, D. A.; Walter Anthony, K. M.; Paull, C. K.; Dallimore, S.; Wik, M.; Crill, P. M.; Winterdahl, M.; Eiler, J. M.; Sessions, A. L.

    2016-09-01

    Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Δ18 values spanning a range of more than 5‰.

  14. Correlation of methane emissions with cattle population in Argentine Pampas

    Science.gov (United States)

    Huarte, A.; Cifuentes, V.; Gratton, R.; Clausse, A.

    2010-07-01

    Satellite cartography of atmospheric methane concentrations during 2003-2004 is applied to a systematic top-down methodology to quantify large scale sources and sinks of this important greenhouse gas. Patterns of methane anomalies over South America below latitude 22 S and an assessment of the emissions from the Buenos Aires Province of Argentina are reported. The latter contains the main cattle livestock of the country together with a variety of surface conditions, both natural and man-modified, influencing methane emissions. It was found that anomalies in methane concentrations may be correlated to emission rates by a simple box accumulation-sweeping model validated by recurrent weather conditions. The model shows that the methane emission rates of the Buenos Aires Province are positively correlated with the cattle livestock corresponding to values of (190 ± 40) g d -1 per cattle head.

  15. Determination of methane emission rates on a biogas plant using data from laser absorption spectrometry.

    Science.gov (United States)

    Groth, Angela; Maurer, Claudia; Reiser, Martin; Kranert, Martin

    2015-02-01

    The aim of the work was to establish a method for emission control of biogas plants especially the observation of fugitive methane emissions. The used method is in a developmental stage but the topic is crucial to environmental and economic issues. A remote sensing measurement method was adopted to determine methane emission rates of a biogas plant in Rhineland-Palatinate, Germany. An inverse dispersion model was used to deduce emission rates. This technique required one concentration measurement with an open path tunable diode laser absorption spectrometer (TDLAS) downwind and upwind the source and basic wind information, like wind speed and direction. Different operating conditions of the biogas plant occurring on the measuring day (December 2013) could be represented roughly in the results. During undisturbed operational modes the methane emission rate averaged 2.8 g/s, which corresponds to 4% of the methane gas production rate of the biogas plant.

  16. Forecast of absolute methane emissions of mining areas

    Energy Technology Data Exchange (ETDEWEB)

    Krause, E.; Lukowicz, K.; Cybulski, K. [Central Mining Institute (GIG), Katowice (Poland)

    2001-07-01

    Within the space of the last years, in case of forecasting of methane emissions to mining areas, serious errors occur between the predicted and real methane emissions, exceeding the tolerance limits. The developed in the 1970s forecasting methods relating to methane emissions to mining areas admitted in their assumptions modular output from longwalls amounting to 500 Mg/day or 750 Mg/day. The progressing restructuring processes in the Polish mining industry, including the growth of output concentration, contributed to a radical increase of methane emissions to workings of the environment of longwalls being under operation. Taking into consideration the significant increase of the amount of methane emissions to mining areas, the problem of methane emission forecasting acquired special importance in the course of extraction planning in gassy mines. At the Experimental Mine 'Barbara' of the Central Mining Institute in the period 1998-1999 a forecasting method has been developed, called the dynamic forecast of longwall absolute methane emissions, issued in 2000 in the form of a technical guide. The method has been verified in six hard coal mines. The paper presents the assumptions and in general the forecasting method. 8 refs., 3 figs.

  17. Non-microbial methane emissions from soils

    Science.gov (United States)

    Wang, Bin; Hou, Longyu; Liu, Wei; Wang, Zhiping

    2013-12-01

    Traditionally, methane (CH4) is anaerobically formed by methanogenic archaea. However, non-microbial CH4 can also be produced from geologic processes, biomass burning, animals, plants, and recently identified soils. Recognition of non-microbial CH4 emissions from soils remains inadequate. To better understand this phenomenon, a series of laboratory incubations were conducted to examine effects of temperature, water, and hydrogen peroxide (H2O2) on CH4 emissions under both aerobic and anaerobic conditions using autoclaved (30 min, 121 °C) soils and aggregates (>2000 μm, A1; 2000-250 μm, A2; 250-53 μm, M1; and A2 > A1 > M2 and C-based emission an order of M2 > M1 > A1 > A2, demonstrating that both organic carbon quantity and property are responsible for CH4 emissions from soils at the scale of aggregate. Whole soil-based order of A2 > A1 > M1 > M2 suggests that non-microbial CH4 release from forest soils is majorly contributed by macro-aggregates (i.e., >250 μm). The underlying mechanism is that organic matter through thermal treatment, photolysis, or reactions with free radicals produce CH4, which, in essence, is identical with mechanisms of other non-microbial sources, indicating that non-microbial CH4 production may be a widespread phenomenon in nature. This work further elucidates the importance of non-microbial CH4 formation which should be distinguished from the well-known microbial CH4 formation in order to define both roles in the atmospheric CH4 global budget.

  18. Enhanced Methane Emissions during Amazonian Drought by Biomass Burning

    OpenAIRE

    Saito, Makoto; Kim, Heon-Sook; Ito, Akihiko; Yokota, Tatsuya; Maksyutov, Shamil

    2016-01-01

    The Amazon is a significant source of atmospheric methane, but little is known about the source response to increasing drought severity and frequency. We investigated satellite observations of atmospheric column-averaged methane for the 2010 drought and subsequent 2011 wet year in the Amazon using an atmospheric inversion scheme. Our analysis indicates an increase in atmospheric methane over the southern Amazon region during the drought, representing an increase in annual emissions relative t...

  19. Biofiltration for Mitigation of Methane Emission from Animal Husbandry

    NARCIS (Netherlands)

    Melse, R.W.; Werf, van der A.W.

    2005-01-01

    Removal of methane from exhaust air of animal houses and manure storage has a large potential for the reduction of greenhouse gas emissions from animal husbandry. The aim of this study was to design a biofilter for methane removal at a full-scale livestock production facility. Air from the headspace

  20. Potential for reduction of methane emissions from dairy cows

    DEFF Research Database (Denmark)

    Johannes, Maike; Hellwing, Anne Louise Frydendahl; Lund, Peter

    2010-01-01

    , while fibre and sugar enhance methane emissions. Fat can be regarded as the most promising feed additive at the moment. At AU, respiration chambers have been installed to enable methane measurements from dairy cows combined with digestibility trials, and at present studies are being conducted concerning...

  1. Biofiltration for Mitigation of Methane Emission from Animal Husbandry

    NARCIS (Netherlands)

    Melse, R.W.; Werf, van der A.W.

    2005-01-01

    Removal of methane from exhaust air of animal houses and manure storage has a large potential for the reduction of greenhouse gas emissions from animal husbandry. The aim of this study was to design a biofilter for methane removal at a full-scale livestock production facility. Air from the headspace

  2. Controlling Methane Emissions in the Natural Gas Sector. A Review of Federal and State Regulatory Frameworks Governing Production, Gathering, Processing, Transmission, and Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Paranhos, Elizabeth [Energy Innovation Partners, Seoul (South Korea); Kozak, Tracy G. [Energy Innovation Partners, Seoul (South Korea); Boyd, William [Univ. of Colorado, Boulder, CO (United States); Bradbury, James [U.S. Department of Energy, Washington, DC (United States); Steinberg, D. C. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Arent, D. J. [Joint Inst. for Strategic Energy Alaysis, Washington, DC (United States)

    2015-04-23

    This report provides an overview of the regulatory frameworks governing natural gas supply chain infrastructure siting, construction, operation, and maintenance. Information was drawn from a number of sources, including published analyses, government reports, in addition to relevant statutes, court decisions and regulatory language, as needed. The scope includes all onshore facilities that contribute to methane emissions from the natural gas sector, focusing on three areas of state and federal regulations: (1) natural gas pipeline infrastructure siting and transportation service (including gathering, transmission, and distribution pipelines), (2) natural gas pipeline safety, and (3) air emissions associated with the natural gas supply chain. In addition, the report identifies the incentives under current regulatory frameworks to invest in measures to reduce leakage, as well as the barriers facing investment in infrastructure improvement to reduce leakage. Policy recommendations regarding how federal or state authorities could regulate methane emissions are not provided; rather, existing frameworks are identified and some of the options for modifying existing regulations or adopting new regulations to reduce methane leakage are discussed.

  3. Effects of Fe and Mn in Paddy Soils Derived from Different Parent Materials on Methane Production and Emission

    Institute of Scientific and Technical Information of China (English)

    LIU Ke-Xing; LIAO Zong-Wen; WANG Sheng-Chun; YOU Zhi-Lin

    2003-01-01

    Three types of paddy soils, derived from granite, Quaternary red clay and basalt, respectively, were selected to study the effects of Fe and Mn in paddy soils on methane production and emission through pot and incubation experiments. The results indicated that the difference of Fe and Mn in paddy soils was one of the important factors causing obvious differences in methane emission from different soil types. Soil Fe and Mn affecting methane emission from the paddy soils was likely through affecting soil Eh and forming Fe and Mn plaques on rice roots. Different rates and valences of added Fe and Mn significantly affected methane production from paddy soils. Therefore, this study enhanced understanding of processes controlling methane emission from paddy soils and may help to improve modeling and estimating regional and global methane emission from paddy soils.

  4. Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

    Science.gov (United States)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

    2015-12-01

    Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

  5. Oxidative mitigation of aquatic methane emissions in large Amazonian rivers.

    Science.gov (United States)

    Sawakuchi, Henrique O; Bastviken, David; Sawakuchi, André O; Ward, Nicholas D; Borges, Clovis D; Tsai, Siu M; Richey, Jeffrey E; Ballester, Maria Victoria R; Krusche, Alex V

    2016-03-01

    The flux of methane (CH4 ) from inland waters to the atmosphere has a profound impact on global atmospheric greenhouse gas (GHG) levels, and yet, strikingly little is known about the dynamics controlling sources and sinks of CH4 in the aquatic setting. Here, we examine the cycling and flux of CH4 in six large rivers in the Amazon basin, including the Amazon River. Based on stable isotopic mass balances of CH4 , inputs and outputs to the water column were estimated. We determined that ecosystem methane oxidation (MOX) reduced the diffusive flux of CH4 by approximately 28-96% and varied depending on hydrologic regime and general geochemical characteristics of tributaries of the Amazon River. For example, the relative amount of MOX was maximal during high water in black and white water rivers and minimal in clear water rivers during low water. The abundance of genetic markers for methane-oxidizing bacteria (pmoA) was positively correlated with enhanced signals of oxidation, providing independent support for the detected MOX patterns. The results indicate that MOX in large Amazonian rivers can consume from 0.45 to 2.07 Tg CH4 yr(-1) , representing up to 7% of the estimated global soil sink. Nevertheless, climate change and changes in hydrology, for example, due to construction of dams, can alter this balance, influencing CH4 emissions to atmosphere.

  6. Ecosystem and physiological controls over methane production in northern wetlands

    Science.gov (United States)

    Valentine, David W.; Holland, Elisabeth A.; Schimel, David S.

    1994-01-01

    Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C: N and lignin: N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH4 production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin: N and C: N ratios (delta CH4/delta EtOH = 0.9-2.3 mg/g) and weakly in the acidic bogs with wide C: N and lignin: N ratios (delta CH4/delta EtOH = -0.04-0.02 mg/g). Observed Q(sub 10) values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry.

  7. Methane emission from wetland rice fields

    NARCIS (Netherlands)

    Denier van der Gon, H.A.C.

    1996-01-01


    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic

  8. Factors Affecting Mitigation of Methane Emission from Ruminants: Management Strategies

    Directory of Open Access Journals (Sweden)

    Afshar Mirzaei-Aghsaghali

    2015-06-01

    Full Text Available Nowadays, greenhouse gas emission which results in elevating global temperature is an important subject of worldwide ecological and environmental concern. Among greenhouse gases, methane is considered a potent greenhouse gas with 21 times more global warming potential than carbon dioxide. Worldwide, ruminant livestock produce about 80 million metric tons of methane each year, accounting for about 28% of global emissions from human related activities. Therefore it is impelling animal scientists to finding solutions to mitigate methane emission from ruminants. It seems that solutions can be discussed in four topics including: nutrition (feeding, biotechnology, microbiology and management strategies. We have already published the first review article on feeding strategies. In the current review, management strategies such as emphasizing on animals - type and individual variability, reducing livestock numbers, improving animal productivity and longevity as well as pasture management; that can be leads to decreasing methane production from ruminant animal production are discussed.

  9. Opportunities to reduce methane emissions in the natural gas industry

    Energy Technology Data Exchange (ETDEWEB)

    Cowgill, R.M. [Radian Corporation, Austin, TX (United States)

    1995-12-31

    The U.S. Environmental Protection Agency (EPA) and the Gas Research Institute (GRI) cofunded a project to quantify methane (CH{sub 4}) emissions from the U.S. natural gas industry. Methane, the major constituent of natural gas, is a potent greenhouse gas that is believed to increase the effect of global warming when released to the atmosphere. Reducing emissions from natural gas systems would lessen the greenhouse gas effect attributable to atmospheric CH{sub 4}. Further, mitigation methods to reduce emissions of natural gas, a marketable resource, could save money and increase energy efficiency. This presentation summarizes the major sources and quantity of methane being emitted to the atmosphere for all segments of the U.S. gas industry: production; processing; storage; transmission; and distribution. A description of how those emissions were determined is included here, as well as a discussion of which sources are potential candidates for reducing emissions. (author)

  10. Methane emissions from feedlot cattle fed barley or corn diets.

    Science.gov (United States)

    Beauchemin, K A; McGinn, S M

    2005-03-01

    Methane emitted from the livestock sector contributes to greenhouse gas emissions worldwide. Understanding the variability in enteric methane production related to diet is essential to decreasing uncertainty in greenhouse gas emission inventories and to identifying viable greenhouse gas reduction strategies. Our study focused on measuring methane in growing beef cattle fed corn- or barley-based diets typical of those fed to cattle in North American feedlots. The experiment was designed as a randomized complete block (group) design with two treatments, barley and corn. Angus heifer calves (initial BW = 328 kg) were allocated to two groups (eight per group), with four cattle in each group fed a corn or barley diet. The experiment was conducted over a 42-d backgrounding phase, a 35-d transition phase and a 32-d finishing phase. Backgrounding diets consisted of 70% barley silage or corn silage and 30% concentrate containing steam-rolled barley or dry-rolled corn (DM basis). Finishing diets consisted of 9% barley silage and 91% concentrate containing barley or corn (DM basis). All diets contained monensin (33 mg/kg of DM). Cattle were placed into four large environmental chambers (two heifers per chamber) during each phase to measure enteric methane production for 3 d. During the backgrounding phase, DMI was greater by cattle fed corn than for those fed barley (10.2 vs. 7.6 kg/d, P cattle were in the chambers; thus, methane emissions (g/d) reported may underestimate those of the feedlot industry. Methane emissions per kilogram of DMI and as a percentage of GE intake were not affected by grain source during the backgrounding phase (24.6 g/kg of DMI; 7.42% of GE), but were less (P methane emissions of cattle fed high-forage backgrounding diets and barley-based finishing diets. Mitigating methane losses from cattle will have long-term environmental benefits by decreasing agriculture's contribution to greenhouse gas emissions.

  11. Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets.

    Science.gov (United States)

    Hulshof, R B A; Berndt, A; Gerrits, W J J; Dijkstra, J; van Zijderveld, S M; Newbold, J R; Perdok, H B

    2012-07-01

    The objective of this study was to determine the effect of dietary nitrate on methane emission and rumen fermentation parameters in Nellore × Guzera (Bos indicus) beef cattle fed a sugarcane based diet. The experiment was conducted with 16 steers weighing 283 ± 49 kg (mean ± SD), 6 rumen cannulated and 10 intact steers, in a cross-over design. The animals were blocked according to BW and presence or absence of rumen cannula and randomly allocated to either the nitrate diet (22 g nitrate/kg DM) or the control diet made isonitrogenous by the addition of urea. The diets consisted of freshly chopped sugarcane and concentrate (60:40 on DM basis), fed as a mixed ration. A 16-d adaptation period was used to allow the rumen microbes to adapt to dietary nitrate. Methane emission was measured using the sulfur hexafluoride tracer technique. Dry matter intake (P = 0.09) tended to be less when nitrate was present in the diet compared with the control, 6.60 and 7.05 kg/d DMI, respectively. The daily methane production was reduced (P Methane emission per kilogram DMI was 27% less (P methane/kg DMI) than on the control diet (18.2 g methane/kg DMI). Methane losses as a fraction of gross energy intake (GEI) were less (P methane production by 87% of the theoretical potential. The rumen fluid ammonia-nitrogen (NH(3)-N()) concentration was significantly greater (P methane emission in beef cattle fed sugarcane based diet.

  12. Seasonal Production and Emission of Methane from Rice Fields, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, M. Aslam K.; Rasmussen,Reinhold A.

    2002-12-03

    B 139 - Methane (CH4) is a greenhouse gas regarded second only to carbon dioxide in its ability to cause global warming. Methane is important because of its relatively fast increase, and also because it is, per molecule, some 60 times more effective than carbon dioxide in causing global warming. The largest present anthropogenic sources of methane are rice fields, cattle and biomass burning. The global emissions from these sources are still not well known. In the middle 1980s there were few available data on methane emissions from rice fields leading to estimates of a global source between 100-280 Tg/yr. Extensive worldwide research during the last decade has shown that the global emissions from rice fields are more likely to be in the range of 30-80Tg/yr. While this work has led to a substantial reduction in the estimated emissions, the uncertainty is still quite large, and seriously affects our ability to include methane in integrated assessments for future climate change and environmental management.China dominated estimates of methane emissions from rice fields because it was, and is, the largest producer of rice, and major increases in rice production had taken place in the country over the last several decades. This report summarizes the work in Sichuan Province, China, in each of the following areas: the design of the experiment; the main results on methane emissions from rice fields, delineating the factors controlling emissions; production of methane in the soil; a survey of water management practices in sample of counties in Sichuan province; and results of ambient measurements including data from the background continental site. B139

  13. Methane Emissions from Tropical Coastal Lagoons, Yucatan, Mexico

    Science.gov (United States)

    Young, M.; Paytan, A.; Herrera-Silveira, J.

    2003-12-01

    Tropical and sub-tropical wetlands are thought to be the dominant natural source of methane to the atmosphere, and the majority of tropical methane flux research has been carried out in freshwater environments. In order to obtain better estimates of methane emissions from tropical coastal environments, we are currently conducting a multi-year study of methane cycling and flux in three tropical coastal lagoons and associated mangrove ecosystems located on the Yucatan Peninsula in Mexico. Previous studies have shown that methane emissions from tropical coastal ecosystems are widely variable, and that these emissions can be quite high despite the presence of moderate to marine salinities. We measured surface water methane concentrations in two lagoons (Celestun and Chelem) during different seasons, as well as in a third, heavily polluted lagoon (Terminos), during the rainy season. Celestun lagoon has a distinct year-round salinity gradient (7-35 ppt) due to groundwater input, Terminos lagoon ranges from fresh water at the river entrances to marine in most of the lagoon area, and Chelem has a salinity range from marine to slightly hyper-saline (30-40 ppt). Diffusive methane flux to the atmosphere was calculated from surface water methane concentrations, using both sample-specific and average area wind speed measurements. Additionally, flux chambers were used to measure methane emissions from each of the lagoons during the rainy season. Calculated diffusive fluxes ranged from less than 1 mg CH4/m2/day up to 100 mg CH4/m2/day in all three lagoons, with the highest fluxes occurring in both areas of lower salinity and areas with known waste water discharge. However, measurements of bubble flux made using flux chambers were between 20 and 150 times greater than the diffusive flux calculated for the same locations. During the course of this study, it appears that the most significant bubble flux occurs in these lagoons during the rainy season. Observations and flux chamber

  14. Quantifying methane emissions and sources in the Colorado Front Range

    Science.gov (United States)

    Hughes, S.; Townsend-Small, A.; Schroeder, J.; Blake, N. J.; Blake, D. R.

    2016-12-01

    Methane is a powerful greenhouse gas and is relatively constant throughout the atmosphere, at 1.8 ppmv. This value, however, is increasing primarily due to anthropogenic sources, including agriculture and natural gas extraction. Here we present atmospheric methane fluxes measured during the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) in July - August 2014 in the Colorado Front Range on the NCAR C-130. During this campaign 775 advanced whole air samples (AWAS) were collected onboard the aircraft and 248 samples were collected on the ground in order to quantify and evaluate air pollution sources. Methane concentrations were measured continuously aboard the aircraft using cavity ringdown spectroscopy. Major sources of methane in this region are oil and natural gas extraction and distribution, landfills, and cattle feed lots. In order to assess the impact of methane emissions on this area, methane flux was evaluated by comparing upwind and downwind concentrations where significant enhancements were observed downwind. We also present information from other hydrocarbons measured in canisters to attribute methane emissions to urban, agricultural, and oil and gas sources. The state of Colorado recently enacted legislation to reduce emissions of hydrocarbons from oil and gas facilities and our measurements will provide a preliminary estimate of whether these regulations are effective.

  15. Methane, a greenhouse gas: measures to reduce and valorize anthropogenic emissions; Le methane, un gaz a effet de serre: mesures de reduction et de valorisation des emissions anthropiques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-03-15

    This report first presents the greenhouse effect properties of methane (one of the six gases the emissions of which must be reduced according to the Kyoto protocol), comments the available data on methane emission assessment in the World, in Europe and in France, and outlines the possibilities of improvement of data and indicators on a short and middle term. It describes how methane can be captured and valorized, indicates the concerned quantities. Notably, it discussed the management of methane generating and spreading practices (from waste water treatment, from domestic wastes), how to reduce methane emissions in agriculture. It finally proposes elements aimed at elaborating a national and international policy regarding methane emission reductions

  16. Mobile monitoring of fugitive methane emissions from natural gas consumer industries

    Science.gov (United States)

    Zhou, X.; Albertson, J. D.; Gaylord, A.; von Fischer, J.; Rudek, J.; Thoma, E. D.

    2015-12-01

    Natural gas is used as a feedstock for major industrial processes, such as ammonia and fertilizer production. However, fugitive methane emissions from many major end-use sectors of the natural gas supply chain have not been quantified yet. This presentation introduces new tools for estimating emission rates from mobile methane measurements, and examines results from recent field measurements conducted downwind of several industrial plants using a specialized vehicle equipped with fast response methane sensor. Using these data along with local meteorological data measured by a 3-D sonic anemometer, a Bayesian approach is applied to probabilistically infer methane emission rates based on a modified Gaussian dispersion model. Source rates are updated recursively with repeated traversals of the downwind methane plume when the vehicle was circling around the targeted facilities. Data from controlled tracer release experiments are presented and used to validate the approach. With access via public roads, this mobile monitoring method is able to quickly assess the emission strength of facilities along the sensor path. This work is developing the capacity for efficient regional coverage of potential methane emission rates in support of leak detection and mitigation efforts.

  17. Quantification of Methane Emissions From Street Level Data

    Science.gov (United States)

    Prasad, K.; Cambaliza, M. L.; Lavoie, T. N.; Salmon, O. E.; Shepson, P. B.; Lauvaux, T.; Davis, K. J.; Whetstone, J. R.

    2013-12-01

    The problem of identifying, attributing, and quantifying methane emissions from urban sources such as landfills, waste-water treatment facilities and natural gas distribution systems is an active area of research. This interest is fueled, in part, by recent measurements indicating that urban emissions are a significant source of methane (CH4, a potent greenhouse gas) and in fact may be substantially higher than current inventory estimates. As a result, developing methods for locating and quantifying emissions from urban methane sources is of great interest to industries such as landfill owners, and governmental agencies. In an attempt to identify major methane source locations and emissions in the city of Indianapolis, systematic measurements of CH4 concentrations and meteorology data were made at street level using multiple vehicles equipped with cavity ring-down spectrometers. A number of discrete sources were detected at methane molar ratios in excess of 15 times background levels. The street level data is analyzed with plume inversion models including Weather Research and Forecasting (WRF) software, Fire Dynamics Simulator (FDS) and backward Lagrangian Simulations (bLS) to identify source location and emission rates. The methodology for analyzing the street level data and our estimates of CH4 emissions from various sources in the city of Indianapolis will be presented.

  18. Pump-to-Wheels Methane Emissions from the Heavy-Duty Transportation Sector.

    Science.gov (United States)

    Clark, Nigel N; McKain, David L; Johnson, Derek R; Wayne, W Scott; Li, Hailin; Akkerman, Vyacheslav; Sandoval, Cesar; Covington, April N; Mongold, Ronald A; Hailer, John T; Ugarte, Orlando J

    2017-01-17

    Pump-to-wheels (PTW) methane emissions from the heavy-duty (HD) transportation sector, which have climate change implications, are poorly documented. In this study, methane emissions from HD natural gas fueled vehicles and the compressed natural gas (CNG) and liquefied natural gas (LNG) fueling stations that serve them were characterized. A novel measurement system was developed to quantify methane leaks and losses. Engine related emissions were characterized from twenty-two natural gas fueled transit buses, refuse trucks, and over-the-road (OTR) tractors. Losses from six LNG and eight CNG stations were characterized during compression, fuel delivery, storage, and from leaks. Cryogenic boil-off pressure rise and pressure control venting from LNG storage tanks were characterized using theoretical and empirical modeling. Field and laboratory observations of LNG storage tanks were used for model development and evaluation. PTW emissions were combined with a specific scenario to view emissions as a percent of throughput. Vehicle tailpipe and crankcase emissions were the highest sources of methane. Data from this research are being applied by the authors to develop models to forecast methane emissions from the future HD transportation sector.

  19. System for quantitative measurements of methane emission from dairy cattle in Denmark

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Lund, Peter; Johannes, Maike

    , USA), which can measure flow rates up to 3000 standard liters per minute. After the air has passed the flow meter an air sample is drawn. A manifold, drying system, oxygen sensor, carbon dioxide sensor, methane sensor, and data program for management were delivered by Columbus instruments (Ohio, USA......The methane emission from the digestive tract of cattle in Denmark accounts for 45% of the total methane emission based on the assumption that 6% of the gross energy is metabolized to methane. There is a lack of newer experimental data available for Danish cattle; therefore we have built a unit......, water bowl and draining of urine and faeces. The air flow out of the chambers can be controlled individually by a motor controller. The outlet is in the top of the chambers through a filter box to reduce the dust content before the flow meter (Teledyne Hastings, delivered by Columbus instruments, Ohio...

  20. Methane oxidation associated to submerged brown-mosses buffers methane emissions from Siberian polygonal peatlands

    Science.gov (United States)

    Liebner, Susanne; Zeyer, Josef; Knoblauch, Christian

    2010-05-01

    study gives first evidence for MAMO in submerged brown-mosses and in the oligotrophic polygonal peatlands of the Lena Delta. It shows that MAMO might effectively reduce methane fluxes to the atmosphere also in Arctic GHG emission hot spots. References: [1] Zhang, T., Barry, R.G., Knowles, K., Heginbottom, J.A., and Brown, J. (1999) Statistics and characteristics of permafrost and ground-ice distribution in the Northern Hemisphere. Polar Geography 23(2): 132-154 [2] Schuur, E.A.G., Bockheim, J., Candell, J.G., Euskirchen, E., Field, C.B., Goryachkin, S.V., Hagemann, S., Kuhry, P., Lafleur, P.M., Lee, H., Mazhitova, G., Nelson, F.E., Rinke, A., Romanovsky, V., Shiklomanov, N., Tarnocai, C., Venevsky, S., Vogel, J., and Zimov, S. (2008) Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle. BioScience 58 (8): 701-714 [3] Denman, K.L., Brasseur G., Chidthaisong A., Ciais, P., Cox, P.M., Dickinson, R.E., Hauglustaine, D., Heinze, C., Holland, E., Jacob, D., Lohmann, U., Ramachandran, S., da Silva Dias, P.L., Wofsy, S.C., and Zhang, X. (2007) Couplings Between Changes in the Climate System and Biogeochemistry. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA [4] Wuebbles, J., and Hayhoe, K. (2002) Atmospheric methane and global change. Earth-Science Reviews 57: 177-210 [5] Sachs, T., Wille, C., Boike, J., and Kutzbach, L. (2008) Environmental controls on ecosystem-scale CH4 emission from polygonal tundra in the Lena River Delta, Siberia. Journal of Geophysical Research 113: G00A03 [6] Wille, C., Kutzbach, L., Sachs, T., Wagner, D., and Pfeiffer, E.M. (2008) Methane emissions from Siberian arctic polygonal tundra: Eddy covariance measurements and

  1. Methane emissions from rice paddies : experiments and modelling

    NARCIS (Netherlands)

    Bodegom, van P.M.

    2000-01-01

    This thesis describes model development and experimentation on the comprehension and prediction of methane (CH 4 ) emissions from rice paddies. The large spatial and temporal variability in CH 4 emissions and the dynamic non-linear relationships

  2. Measurements of methane emissions from landfills using mobile plume method with trace gas and cavity ring-down spectroscopy

    Science.gov (United States)

    Mønster, J.; Kjeldsen, P.; Scheutz, C.

    2012-04-01

    Methane is emitted to the atmosphere from both anthropogenic and natural sources. One of the major anthropogenic sources is methane produced by bacteria in anaerobic environments such as rice pads and landfills. Land filling has for many years been the preferred waste disposal method, resulting in a large methane production with a large contribution to the global increase in atmospheric green house gas concentration. Several steps have been taken to reduce the emission of methane from landfills. In order to validate the effect of these steps, a measurement method is needed to quantify methane emissions with a large spatial variation. One method is to use a highly sensitive and fast analytical method, capable of measuring the atmospheric concentration methane downwind from emission areas. Combined with down-wind measurements of a trace gas, emitted at a controlled mass flow rate, the methane emission can be calculated. This method is called the mobile plume method, as the whole plume is measured by doing several transects. In the current study a methane/acetylene analyzer with cavity ring-down spectroscopy detection (Picarro, G2203) was used to estimate methane from a number of Danish landfills. We measured at both active and closed landfills and investigated the difference in methane emission. At landfills where the emissions could have more than one origin, the source strength of the different emission areas was determined by accurate trace gas positioning and choosing appropriate wind speed and measurement distance. To choose these factors, we addressed the uncertainties and limitations of the method with respect to the configuration of the trace gas bottles and the distance between the emission area and the measurement points. Composting of organic material in large piles was done at several of the investigated landfills and where possible, the methane emission from this partly anaerobic digestion was measured as a separate emission.

  3. Spatial and temporal dynamics of methane emissions from agricultural sources in China

    NARCIS (Netherlands)

    Verburg, P.H.; Denier van der Gon, H.A.C.

    2001-01-01

    Agricultural activities contribute significantly to the global methane budget. Agricultural sources of methane are influenced by land-use change, including changes in agricultural area, livestock keeping and agricultural management practices. A spatially explicit inventory of methane emissions from

  4. Studies on Methane Emissions from Pastoral Farming in New Zealand

    Institute of Scientific and Technical Information of China (English)

    LI Meng-meng; ZHANG Gui-guo; SUN Xue-zhao; DONG Shu-ting; Simone O. Hoskin

    2014-01-01

    The aim of this paper was to give a basic understanding of studies on methane emissions of New Zealand, as we know the agriculture of New Zealand is pastoral farming, most livestock animals are grazed in pasture, and quantities of methane were released from the digestive tract and animals excreta. In New Zealand some 50% greenhouse gases (GHG) sources are attributed to agriculture and one third is methane from livestock enteric formation. For many years, many researchers have been exploiting the techniques and methods to measure the emission of methane of New Zealand, further more studing the available options to alleviate the methane emissions. Their pioneering work and successful experiences including the determined methods and mitigation strategies are worth learning for scholars around the world. Some of their approaches were not only suitable for New Zealand grazed livestock, but for many other countries, even the animals are intensively bred in pen. The calorimeter/respiration chamber is the most exactly method in present, but it needs expensive equipments and skilled manipulators, so there are still some dififculty in applying this approach extensively in practice. Sulfur hexalfuoride (SF6) trace technique is much adopted for grazed livestock evaluating the methane emission, though its veracity was doubted by some researchers, it is still a good option in present for studying the GHG emissions for grazing animals. By measuring the rumen volatile fatty acid (VFA) concentration to estimate the methane emission is a relatively simple approach, it is just only a rough evaluation, and it is unsuitable for exact study, but this method may be used in China for extensively raised ruminant. In present China, the ruminants are fed in an extensively managed state, the diversities of roughage and animals varieties caused dififcult to exactly estimate the methane emission. So exploiting theavailable options is much important for constituting the exhaustive emission

  5. A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands.

    Science.gov (United States)

    Turetsky, Merritt R; Kotowska, Agnieszka; Bubier, Jill; Dise, Nancy B; Crill, Patrick; Hornibrook, Ed R C; Minkkinen, Kari; Moore, Tim R; Myers-Smith, Isla H; Nykänen, Hannu; Olefeldt, David; Rinne, Janne; Saarnio, Sanna; Shurpali, Narasinha; Tuittila, Eeva-Stiina; Waddington, J Michael; White, Jeffrey R; Wickland, Kimberly P; Wilmking, Martin

    2014-07-01

    Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30-day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30-day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release.

  6. Methods for measuring and estimating methane emission from ruminants

    OpenAIRE

    2012-01-01

    Simple Summary Knowledge about methods used in quantification of greenhouse gasses is currently needed due to international commitments to reduce the emissions. In the agricultural sector one important task is to reduce enteric methane emissions from ruminants. Different methods for quantifying these emissions are presently being used and others are under development, all with different conditions for application. For scientist and other persons working with the topic it is very important to ...

  7. Gridded National Inventory of U.S. Methane Emissions.

    Science.gov (United States)

    Maasakkers, Joannes D; Jacob, Daniel J; Sulprizio, Melissa P; Turner, Alexander J; Weitz, Melissa; Wirth, Tom; Hight, Cate; DeFigueiredo, Mark; Desai, Mausami; Schmeltz, Rachel; Hockstad, Leif; Bloom, Anthony A; Bowman, Kevin W; Jeong, Seongeun; Fischer, Marc L

    2016-12-06

    We present a gridded inventory of US anthropogenic methane emissions with 0.1° × 0.1° spatial resolution, monthly temporal resolution, and detailed scale-dependent error characterization. The inventory is designed to be consistent with the 2016 US Environmental Protection Agency (EPA) Inventory of US Greenhouse Gas Emissions and Sinks (GHGI) for 2012. The EPA inventory is available only as national totals for different source types. We use a wide range of databases at the state, county, local, and point source level to disaggregate the inventory and allocate the spatial and temporal distribution of emissions for individual source types. Results show large differences with the EDGAR v4.2 global gridded inventory commonly used as a priori estimate in inversions of atmospheric methane observations. We derive grid-dependent error statistics for individual source types from comparison with the Environmental Defense Fund (EDF) regional inventory for Northeast Texas. These error statistics are independently verified by comparison with the California Greenhouse Gas Emissions Measurement (CALGEM) grid-resolved emission inventory. Our gridded, time-resolved inventory provides an improved basis for inversion of atmospheric methane observations to estimate US methane emissions and interpret the results in terms of the underlying processes.

  8. Methane emissions from a dairy feedlot during the fall and winter seasons in Northern China.

    Science.gov (United States)

    Gao, Zhiling; Yuan, Huijun; Ma, Wenqi; Liu, Xuejun; Desjardins, R L

    2011-05-01

    Accurately determining methane emission factors of dairy herd in China is imperative because of China's large population of dairy cattle. An inverse dispersion technique in conjunction with open-path lasers was used to quantify methane emissions from a dairy feedlot during the fall and winter seasons in 2009-2010. The methane emissions had a significant diurnal pattern during both periods with three emission peaks corresponding to the feeding schedule. A 10% greater emission rate in the fall season was obtained most likely by the higher methane emission from manure during that period. An annual methane emission rate of 109±6.7 kg CH4 yr(-1) characterized with a methane emission intensity of 32.3±1.59 L CH4 L(-1) of milk and a methane conversion factor (Ym) of 7.3±0.38% for mature cattle was obtained, indicating the high methane emission intensity and low milk productivity in Northern China.

  9. Comparative use of different emission measurement approaches to determine methane emissions from a biogas plant.

    Science.gov (United States)

    Reinelt, Torsten; Delre, Antonio; Westerkamp, Tanja; Holmgren, Magnus A; Liebetrau, Jan; Scheutz, Charlotte

    2017-06-16

    A sustainable anaerobic biowaste treatment has to mitigate methane emissions from the entire biogas production chain, but the exact quantification of these emissions remains a challenge. This study presents a comparative measurement campaign carried out with on-site and ground-based remote sensing measurement approaches conducted by six measuring teams at a Swedish biowaste treatment plant. The measured emissions showed high variations, amongst others caused by different periods of measurement performance in connection with varying operational states of the plant. The overall methane emissions measured by ground-based remote sensing varied from 5 to 25kgh(-1) (corresponding to a methane loss of 0.6-3.0% of upgraded methane produced), depending on operating conditions and the measurement method applied. Overall methane emissions measured by the on-site measuring approaches varied between 5 and 17kgh(-1) (corresponding to a methane loss of 0.6 and 2.1%) from team to team, depending on the number of measured emission points, operational state during the measurements and the measurement method applied. Taking the operational conditions into account, the deviation between different approaches and teams could be explained, in that the two largest methane-emitting sources, contributing about 90% of the entire site's emissions, were found to be the open digestate storage tank and a pressure release valve on the compressor station. Copyright © 2017. Published by Elsevier Ltd.

  10. Environmental control on aerobic methane oxidation in coastal waters

    Science.gov (United States)

    Steinle, Lea; Maltby, Johanna; Engbersen, Nadine; Zopfi, Jakob; Bange, Hermann; Elvert, Marcus; Hinrichs, Kai-Uwe; Kock, Annette; Lehmann, Moritz; Treude, Tina; Niemann, Helge

    2016-04-01

    Large quantities of methane are produced in anoxic sediments of continental margins and may be liberated to the overlying water column, where some of it is consumed by aerobic methane oxidizing bacteria (MOB). Aerobic methane oxidation (MOx) in the water column is consequently the final sink for methane before its release to the atmosphere, where it acts as a potent greenhouse gas. In the context of the ocean's contribution to atmospheric methane, coastal seas are particularly important accounting >75% of global methane emission from marine systems. Coastal oceans are highly dynamic, in particular with regard to the variability of methane and oxygen concentrations as well as temperature and salinity, all of which are potential key environmental factors controlling MOx. To determine important environmental controls on the activity of MOBs in coastal seas, we conducted a two-year time-series study with measurements of physicochemical water column parameters, MOx activity and the composition of the MOB community in a coastal inlet in the Baltic Sea (Boknis Eck Time Series Station, Eckernförde Bay - E-Bay). In addition, we investigated the influence of temperature and oxygen on MOx during controlled laboratory experiments. In E-Bay, hypoxia developed in bottom waters towards the end of the stratification period. Constant methane liberation from sediments resulted in bottom water methane accumulations and supersaturation (with respect to the atmospheric equilibrium) in surface waters. Here, we will discuss the factors impacting MOx the most, which were (i) perturbations of the water column (ii) temperature and (iii) oxygen concentration. (i) Perturbations of the water column caused by storm events or seasonal mixing led to a decrease in MOx, probably caused by replacement of stagnant water with a high standing stock of MOB by 'new' waters with a lower abundance of methanotrophs. b) An increase in temperature generally led to higher MOx rates. c) Even though methane was

  11. Methane emission from tropical savanna Trachypogon sp. grasses

    Directory of Open Access Journals (Sweden)

    E. Sanhueza

    2006-01-01

    Full Text Available Methane flux measurements from the soil-grass system were made during the wet season in unperturbed plots and plots where standing dry and green Trachypogon sp. grasses were clipped to just above the soil surface. Results support the surprising discovery that vegetation emits methane. The results of this work allows to infer that the savanna dry/green mixture of grasses produce methane at a rate of ~10 ng m−2 s−1, which is in agreement with early published soil-grass system fluxes. An extrapolation of this flux to the global savanna produces an annual emission much lower than the CH4 production recently suggested in the literature. On the other hand, during the wet season savanna soil consume CH4 at a rate of ~4.7 ng m−2 s−1. Therefore, the tropical savanna soil-grass system would make a modest contribution to the global budget of methane.

  12. Methane emission by Nellore cattle subjected to different nutritional plans.

    Science.gov (United States)

    Cota, Olinta Leone; de Figueiredo, Darcilene Maria; Branco, Renata Helena; Magnani, Elaine; do Nascimento, Cleisy Ferreira; de Oliveira, Luiza Freitas; Mercadante, Maria Eugênia Zerlotti

    2014-10-01

    The objective was to evaluate the emission of enteric methane by Nellore cattle subjected to different nutritional plans, as well as the intake and digestibility of nutrients from the diets supplied. Forty-seven animals in a confinement system (feedlot) were fed a corn silage-based diet for 35 days. Afterwards, these animals were evaluated in a grazing system during the rainy periods, in Urochloa brizantha cv Marandu paddocks, for 44 days. Chromic oxide was used as external marker to estimate the fecal production of animals. Samples of feces, ingredients, and pasture were collected and sampled for subsequent chemical analyses. The SF6 tracer gas technique was adopted to quantify the methane gas emitted by the animals. The experimental design was completely randomized, using procedure GLM of software SAS (9.2), including the fixed effects of sex and nutritional plan and the linear effect of the co-variable weights. Means were analyzed by Tukey's test at 5 % probability. The intakes of total dry matter and organic matter were greater for the animals subjected to the feedlot diet (P Emission of CH4/day (104.01 g) by the animals fed the feedlot diet (P methane production (CH4/CEB) and methane emission per dry matter consumed were lower in relation to the grazing treatment (3.75 vs 4.23 % and 11.67 vs 15.71 g/kg). The better quality of the diet in the feedlot promoted lower energy losses as methane.

  13. One year of continuous measurements constraining methane emissions from the Baltic Sea to the atmosphere using a ship of opportunity

    Directory of Open Access Journals (Sweden)

    W. Gülzow

    2013-01-01

    Full Text Available Methane and carbon dioxide were measured with an autonomous and continuous running system on a ferry line crossing the Baltic Sea on a 2–3 day interval from the Mecklenburg Bight to the Gulf of Finland in 2010. Surface methane saturations show great seasonal differences in shallow regions like the Mecklenburg Bight (103–507% compared to deeper regions like the Gotland Basin (96–161%. The influence of controlling parameters like temperature, wind, mixing depth and processes like upwelling, mixing of the water column and sedimentary methane emissions on methane oversaturation and emission to the atmosphere are investigated. Upwelling was found to influence methane surface concentrations in the area of Gotland significantly during the summer period. In February 2010, an event of elevated methane concentrations in the surface water and water column of the Arkona Basin was observed, which could be linked to a wind-derived water level change as a potential triggering mechanism. The Baltic Sea is a source of methane to the atmosphere throughout the year, with highest fluxes occurring during the winter season. Stratification was found to promote the formation of a methane reservoir in deeper regions like Gulf of Finland or Bornholm Basin, which leads to long lasting elevated methane concentrations and enhanced methane fluxes, when mixed to the surface during mixed layer deepening in autumn and winter. Methane concentrations and fluxes from shallow regions like the Mecklenburg Bight are predominantly controlled by sedimentary production and consumption of methane, wind events and the change in temperature-dependent solubility of methane in the surface water. Methane fluxes vary significantly in shallow regions (e.g. Mecklenburg Bight and regions with a temporal stratification (e.g. Bornholm Basin, Gulf of Finland. On the contrary, areas with a permanent stratification like the Gotland Basin show only small seasonal fluctuations in methane fluxes.

  14. One year of continuous measurements constraining methane emissions from the Baltic Sea to the atmosphere using a ship of opportunity

    Directory of Open Access Journals (Sweden)

    W. Gülzow

    2012-08-01

    Full Text Available Methane and carbon dioxide were measured with an autonomous and continuous running system on a ferry line crossing the Baltic Sea on a 2–3 day interval from the Mecklenburg Bight to the Gulf of Finland in 2010. Surface methane saturations show great seasonal differences in shallow regions like the Mecklenburg Bight (103–507% compared to deeper regions like the Gotland Basin (96–161%. The influence of controlling parameters like temperature, wind, mixing depth and processes like upwelling, mixing of the water column and sedimentary methane emissions on methane oversaturation and emission to the atmosphere are investigated. Upwelling was found to influence methane surface concentrations in the area of Gotland significantly during the summer period. In February 2010, an event of elevated methane concentrations in the surface water and water column of the Arkona Basin was observed, which could be linked to a wind-derived water level change as a potential triggering mechanism. The Baltic Sea is a source of methane to the atmosphere throughout the year, with highest fluxes during the winter season. Stratification was found to intensify the formation of a methane reservoir in deeper regions like Gulf of Finland or Bornholm Basin, which leads to long lasting elevated methane concentrations and enhanced methane fluxes, when mixed to the surface during mixed layer deepening in autumn and winter. Methane concentrations and fluxes from shallow regions like the Mecklenburg Bight are rather controlled by sedimentary production and consumption of methane, wind events and the change in temperature-dependent solubility of methane in the surface water. Methane fluxes vary significantly in shallow regions (e.g. Mecklenburg Bight and regions with a temporal stratification (e.g. Bornholm Basin, Gulf of Finland. On the contrary, areas with a permanent stratification like the Gotland Basin show only small seasonal fluctuations in methane fluxes.

  15. Development of the Vista Methane Emissions Inventory for Southern California: A GIS-Based Approach for Mapping Methane Emissions

    Science.gov (United States)

    Carranza, V.; Frausto-Vicencio, I.; Rafiq, T.; Verhulst, K. R.; Hopkins, F. M.; Rao, P.; Duren, R. M.; Miller, C. E.

    2016-12-01

    Atmospheric methane (CH4) is the second most prevalent anthropogenic greenhouse gas. Improved estimates of CH4 emissions from cities is essential for carbon cycle science and climate mitigation efforts. Development of spatially-resolved carbon emissions data sets may offer significant advances in understanding and managing carbon emissions from cities. Urban CH4 emissions in particular require spatially resolved emission maps to help resolve uncertainties in the CH4 budget. This study presents a Geographic Information System (GIS)-based approach to mapping CH4 emissions using locations of infrastructure known to handle and emit methane. We constrain the spatial distribution of sources to the facility level for the major CH4 emitting sources in the South Coast Air Basin. GIS spatial modeling was combined with publicly available datasets to determine the distribution of potential CH4 sources. The datasets were processed and validated to ensure accuracy in the location of individual sources. This information was then used to develop the Vista emissions prior, which is a one-year long, spatially-resolved CH4 emissions estimate. Methane emissions were calculated and spatially allocated to produce 1 km x 1 km gridded CH4 emission map spanning the Los Angeles Basin. In future work, the Vista CH4 emissions prior will be compared with existing, coarser-resolution emissions estimates and will be evaluated in inverse modeling studies using atmospheric observations. The Vista CH4 emissions inventory presents the first detailed spatial maps of CH4 sources and emissions estimates in the Los Angeles Basin and is a critical step towards sectoral attribution of CH4 emissions at local to regional scales.

  16. Factors affecting mitigation of methane emission from ruminants: Microbiology and biotechnology strategies

    Directory of Open Access Journals (Sweden)

    Afshar Mirzaei

    2015-12-01

    Full Text Available Climate change is a subject of global environmental concern. Increased anthropogenic Greenhouse Gas (GHG emissions have increased the global temperature the last 100 to 200 years. Carbon dioxide and methane are the main greenhouse gases related to animal nutrition and methane has greater global warming potential than carbon dioxide. Among greenhouse gases, methane is considered a potent greenhouse gas with 21 times more global warming potential than carbon dioxide. Worldwide, ruminant livestock produce about 80 million metric tons of methane each year, accounting for about 28% of global emissions from human related activities. Therefore it is impelling animal scientists to finding solutions to mitigate methane emission from ruminants. It seems that solutions can be discussed in four topics including: nutrition (feeding, biotechnology, microbiology and management strategies. We have already published the first and second review articles on feeding strategies and management strategies. In the current review, Microbiology and biotechnology such as emphasizing on animal  breeding, genetic merit, bovine somatotropin (BST, unproductive animals, vaccination, immunisation and biological control (bacteriophage, acetogenesis reductive, chemical defaunation that can be leads to decreasing methane production from ruminant animal production are discussed.

  17. Abiotic emissions of methane and reduced organic compounds from organic matter

    Science.gov (United States)

    Roeckmann, T.; Keppler, F.; Vigano, I.; Derendorp, L.; Holzinger, R.

    2012-12-01

    Recent laboratory studies show that the important greenhouse gas methane, but also other reduced atmospheric trace gases, can be emitted by abiotic processes from organic matter, such as plants, pure organic compounds and soils. It is very difficult to distinguish abiotic from biotic emissions in field studies, but in laboratory experiments this is easier because it is possible to carefully prepare/sterilize samples, or to control external parameters. For example, the abiotic emissions always show a strong increase with temperature when temperatures are increased to 70C or higher, well above the temperature optimum for bacterial activity. UV radiation has also been clearly shown to lead to emission of methane and other reduced gases from organic matter. Interesting information on the production mechanism has been obtained from isotope studies, both at natural abundance and with isotope labeling. For example, the methoxyl groups of pectin were clearly identified to produce methane. However, analysis of the isotopic composition of methane from natural samples clearly indicates that there must be other molecular mechanisms that lead to methane production. Abiotic methane generation could be a ubiquitous process that occurs naturally at low rates from many different sources.

  18. Timelines for mitigating methane emissions from energy technologies

    CERN Document Server

    Roy, Mandira; Trancik, Jessika E

    2015-01-01

    Energy technologies emitting differing proportions of methane and carbon dioxide vary in their relative climate impacts over time, due to the different atmospheric lifetimes of the two gases. Standard technology comparisons using the global warming potential (GWP) emissions equivalency metric do not reveal these dynamic impacts, and may not provide the information needed to assess technologies and emissions mitigation opportunities in the context of broader climate policy goals. Here we formulate a portfolio optimization model that incorporates changes in technology impacts as a radiative forcing (RF) stabilization target is approached. An optimal portfolio, maximizing allowed energy consumption while meeting the RF target, is obtained by year-wise minimization of the marginal RF impact in an intended stabilization year. The optimal portfolio calls for using certain higher methane-emitting technologies prior to an optimal switching year, followed by methane-light technologies as the stabilization year approac...

  19. MEASUREMENT OF CATTLE METHANE EMISSIONS USING THE EDDY-COVARIANCE TECHNIQUE

    OpenAIRE

    2014-01-01

    Methane emissions account for 8% of the EU-15 GHG emissions and livestock generates approximately half of these emissions [1]. Recent technological advances in spectroscopy now permit methane flux measurement using eddy covariance. Methane fluxes exchanged by a pasture were measured continuously since June 2012 at the Dorinne Terrestrial Observatory in Belgium. During grazing periods, fluxes are dominated by enteric fermentation. Methane emissions were found strongly related to cattle sto...

  20. Methane Emissions from Point and Area Sources in California

    Science.gov (United States)

    Peischl, J.; Ryerson, T. B.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Neuman, J.; Nowak, J. B.; Pollack, I. B.; Roberts, J. M.; Trainer, M.; Parrish, D. D.

    2010-12-01

    Airborne measurements of methane (CH4), carbon monoxide (CO), sulfur dioxide, ammonia, and nitric oxides were made aboard the NOAA WP-3D during May and June 2010, during the CalNex (Research at the Nexus of Air Quality and Climate Change) field campaign based out of Ontario, California. Emission ratios of CH4 to these other trace gas species are calculated from observations downwind of point sources and compared to national emissions inventories. Further, background urban ratios of CH4 to CO are established, and enhancements from known area CH4 sources, such as rice paddies and cattle ranches, are analyzed. Finally, significant methane emissions from point sources not in emissions inventories are examined.

  1. Carbon dioxide and methane emission dynamics in central London (UK)

    Science.gov (United States)

    Helfter, Carole; Nemitz, Eiko; Barlow, Janet F.; Wood, Curtis R.

    2013-04-01

    London, with a population of 8.2 million, is the largest city in Europe. It is heavily built-up (typically 8% vegetation cover within the central boroughs) and boasts some of the busiest arteries in Europe despite efforts to reduce traffic in the city centre with the introduction of a congestion charging scheme in 2007. We report on two substantial pollution monitoring efforts in the heart of London between October 2006 and present. Fluxes of carbon dioxide (CO2) and water (H2O) were measured continuously by eddy-covariance in central London from October 2006 until May 2008 from a 190 m telecommunication tower (BT tower; 51° 31' 17.4'' N 0° 8' 20.04'' W). The eddy-covariance system consisted of a Gill R3-50 ultrasonic anemometer operated at 20 Hz and a LI-COR 6262 infrared gas analyser. Air was sampled 0.3 m below the sensor head of the ultrasonic anemometer - which was itself mounted on a 3 m mast to the top of a 15 m lattice tower situated on the roof of the tower (instrument head at 190 m above street level) - and pulled down 45 m of 12.7 mm OD Teflon tubing. In addition, meteorological variables (temperature, relative humidity, pressure, precipitation, wind speed and direction) were also measured with a multi-sensor (Weather Transmitter WXT510, Vaisala). Eddy-covariance measurements at the BT tower location were reinstated in July 2011 and include methane (CH4), CO2 and H2O concentrations measured by a Picarro fast methane analyser (G2301-f). CO2 emissions were found to be mainly controlled by fossil fuel combustion (e.g. traffic, commercial and domestic heating). Diurnal averages of CO2 fluxes were found to be highly correlated to traffic. However changes in heating-related natural gas consumption and, to a lesser extent, photosynthetic activity in two large city centre green spaces (Hyde Park and Regent's Park) explained the seasonal variability. Annual estimates of net exchange of CO2 obtained by eddy-covariance agreed well with up-scaled data from the UK

  2. Toward a statistical description of methane emissions from arctic wetlands

    DEFF Research Database (Denmark)

    Pirk, Norbert; Mastepanov, Mikhail; López-Blanco, Efrén

    2017-01-01

    Methane (CH4) emissions from arctic tundra typically follow relations with soil temperature and water table depth, but these process-based descriptions can be difficult to apply to areas where no measurements exist. We formulated a description of the broader temporal flux pattern in the growing s...

  3. Methane emissions to the atmosphere through aquatic plants

    Science.gov (United States)

    Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

    1985-01-01

    The movement of methane (CH4) from anaerobic sediments through the leaves, stems, and flowers of aquatic plants and into the atmosphere was found to provide a significant pathway for the emission of CH4 from the aquatic substrates of flooded wetlands. Methane concentrations well above the surrounding ambient air levels were found in the mesophyll of 16 varies of aquatic plants and are attributed to transpiration, diffusion, and pressure-induced flow of gaseous CH4 from the roots when they are embedded in CH4-saturated anaerobic sediments. Methane emissions from the emergent parts of aquatic plants were measured using floating chamber techniques and by enclosing the plants in polyethylene bags of known volume. Concentration changes were monitored in the trapped air using syringes and gas chromatographic techniques. Vertical profiles of dissolved CH4 in sediment pore water surrounding the aquatic plants' rhizomes were obtained using an interstitial sampling technique. Methane emissions from the aquatic plants studied varied from 14.8 mg CH4/d to levels too low to be detectable. Rooted and unrooted freshwater aquatic plants were studied as well as saltwater and brackish water plants. Included in the experiment is detailed set of measurements on CH4 emissions from the common cattail (Typha latifolia). This paper illustrates that aquatic plants play an important gas exchange role in the C cycle between wetlands and the atmosphere.

  4. Deconstructing methane emissions from a small Northern-European river: Hydrodynamics and temperature as key drivers

    OpenAIRE

    McGinnis, Daniel F.; Bilsley, Nicole; Schmidt, Mark; Fietzek, Peer; Bodmer, Pascal; Premke, Katrin; Lorke, Andreas; Flury, Sabine

    2016-01-01

    Methane (CH4) emissions from small rivers and streams, particularly via ebullition, are currently under-represented in the literature. Here, we quantify the methane effluxes and drivers in a small, Northern European river. Methane fluxes are comparable to those from tropical aquatic systems, with average emissions of 320 mg CH4 m-2 d-1. Two important drivers of methane flux variations were identified in the studied system: 1) temperature-driven sediment methane ebullition and 2) flow-dependen...

  5. Understanding the nature of methane emission from rice ecosystems as basis of mitigation strategies

    Energy Technology Data Exchange (ETDEWEB)

    Buendia, L.V.; Neue, H.U.; Wassmann, R. [International Rice Research Institute, Laguna (Philippines)] [and others

    1996-12-31

    Methane is considered as an important Greenhouse gas and rice fields are one of the major atmospheric methane sources. The paper aims to develop sampling strategies and formulate mitigation options based on diel (day and night) and seasonal pattern of methane emission. The study was conducted in 4 countries to measure methane flux using an automatic closed chamber system. A 24-hour bihourly methane emissions were continuously obtained during the whole growing season. Daily and seasonal pattern of methane fluxes from different rice ecosystems were evaluated. Diel pattern of methane emission from irrigated rice fields, in all sites, displayed similar pattern from planting to flowering. Fluxes at 0600, 1200, and 1800 h were important components of the total diel flux. A proposed sampling frequency to accurately estimate methane emission within the growing season was designed based on the magnitude of daily flux variation. Total methane emission from different ecosystems follow the order: deepwater rice > irrigated rice > rainfed rice. Application of pig manure increased total emission by 10 times of that without manure. Green manure application increased emission by 49% of that applied only with inorganic fertilizer. Removal of floodwater at 10 DAP and 35 DAP, within a period of 4 days, inhibited production and emission of methane. The level of variation in daily methane emission and seasonal emission pattern provides useful information for accurate determination of methane fluxes. Characterization of seasonal emission pattern as to ecologies, fertilizer amendments, and water management gives an idea of where to focus mitigation strategies for sustainable rice production.

  6. Comparative use of different emission measurement approaches to determine methane emissions from a biogas plant

    DEFF Research Database (Denmark)

    Reinelt, Torsten; Delre, Antonio; Westerkamp, Tanja

    2017-01-01

    A sustainable anaerobic biowaste treatment has to mitigate methane emissions from the entire biogas production chain, but the exact quantification of these emissions remains a challenge. This study presents a comparative measurement campaign carried out with on-site and ground-based remote sensing...... measurement approaches conducted by six measuring teams at a Swedish biowaste treatment plant. The measured emissions showed high variations, amongst others caused by different periods of measurement performance in connection with varying operational states of the plant. The overall methane emissions measured...

  7. Methane emission to the atmosphere through emergent cattail (Typha latifolia L.) plants

    OpenAIRE

    Yavitt, J. B.; A. K. Knapp

    2011-01-01

    Methane (CH4) produced microbially in sediments of marshes is emitted to the atmosphere primarily by flowing through and out of emergent aquatic plants. The magnitude of such emission rates and factors controlling those rates are not well understood. We evaluated CH4 emission from the widely distributed aquatic emergent plant cattail (Typha latifolia L.) in several wetlands in the United States using a field gas-exchange system that concurrently estimated stomatal aperture (i.e., conductance)...

  8. New Result on Methane Emissions from the East Siberian Arctic Shelf

    Science.gov (United States)

    Shakhova, N. E.; Semiletov, I. P.; Sergienko, V.; Lobkovsky, L. I.; Dmitrevsky, N.; Salyuk, A.; Yusupov, V.; Salomatin, A.; Karnaukh, V.; Chernykh, D.; Kosmach, D.; Ananiev, R.; Meluzov, A.; Nicolsky, D.; Panteleev, G.

    2013-12-01

    Methane release from thawing Arctic permafrost is one of the few carbon-climate mechanisms that could change projected climate forcing substantially in this century. Venting of methane to the atmosphere in the East Siberian Arctic Shelf, the world's largest yet shallowest shelf, was recently shown to be ubiquitous. Here we report results of multi-year investigations performed in the coastal East Siberian Arctic Shelf (ESAS), where invasion of relatively warm seawater occurred most recently. Observational data and simulation of the warming effect of seawater on subsea permafrost suggest that disintegrating subsea permafrost allows formation of migration pathways for methane bubbles released from the sea floor. Sonar data collected in the coastal area and in the mid-outer shelf area together with data, obtained using high-resolution high-speed video camera, enabled area-weighted methane fluxes to be estimated. New factors controlling spatial and temporal variability of methane fluxes on the ESAS were found. In the outer shelf, it was shown that methane releases from the seabed via strong flare-like ebullition that produces fluxes much greater than on the shallow shelf, where largely frozen sediments restrict fluxes. The coastward progression of thawing subsea permafrost in a warming Arctic could potentially result in a significant increase in methane emissions from the East Siberian Arctic Shelf.

  9. Methane Oxidation to Methanol without CO2 Emission: Catalysis by Atomic Negative Ions

    CERN Document Server

    Tesfamichael, Aron; Felfli, Zineb; Msezane, Alfred Z

    2014-01-01

    The catalytic activities of the atomic Y-, Ru-, At-, In-, Pd-, Ag-, Pt-, and Os- ions have been investigated theoretically using the atomic Au- ion as the benchmark for the selective partial oxidation of methane to methanol without CO2 emission. Dispersion-corrected density-functional theory has been used for the investigation. From the energy barrier calculations and the thermodynamics of the reactions, we conclude that the catalytic effect of the atomic Ag-, At-, Ru-, and Os- ions is higher than that of the atomic Au- ion catalysis of CH4 conversion to methanol. By controlling the temperature around 290K (Os-), 300K (Ag-), 310K (At-), 320K (Ru-) and 325K (Au-) methane can be completely oxidized to methanol without the emission of CO2. We conclude by recommending the investigation of the catalytic activities of combinations of the above negative ions for significant enhancement of the selective partial oxidation of methane to methanol.

  10. Estimation of methane and nitrous oxide emissions from Indian livestock.

    Science.gov (United States)

    Patra, Amlan K

    2012-10-26

    Greenhouse gas (GHG; methane and nitrous oxide) emissions from enteric fermentation and manure management of Indian livestock were estimated from the last two Indian livestock census datasets (2003 and 2007) using IPCC Tier 2 (2006) guidelines. The total annual GHG emissions from Indian livestock increased in 2007 compared to the year 2003 with an annual growth rate of 1.52% over this period. The contributions of GHG by dairy cattle, non-dairy cattle, buffaloes, goats, sheep and other animals (yak, mithun, horse, donkeys, pigs and poultry) were 30.52, 24.0, 37.7, 4.34, 2.09 and 3.52%, respectively, in 2007. Enteric fermentation was the major source of methane, accounting for 89.2% of the total GHG emissions, followed by manure methane (9.49%). Nitrous oxide emissions accounted for 1.34%. GHG emissions (CO(2)-eq. per kg of fat and protein corrected milk (FPCM)) by female animals were considerably lower for crossbred cows (1161 g), followed by buffaloes (1332 g) and goats (2699 g), and were the highest for indigenous cattle (3261 g) in 2007. There was a decreasing trend in GHG emissions (-1.82% annual growth rate) in relation to milk production from 2003 to 2007 (1818 g and 1689 g CO(2)-eq. per kg FPCM in 2003 and 2007, respectively). This study revealed that GHG emissions (total as well as per unit of products) from dairy and other categories of livestock populations could be reduced substantially through proper dairy herd management without compromising animal production. In conclusion, although the total GHG emissions from Indian livestock increased in 2007, there was a decreasing trend in GHG production per kg of milk production or animal products.

  11. High rates of methane emissions from south taiga wetland ponds.

    Science.gov (United States)

    Glagolev, M.; Kleptsova, I.; Maksyutov, S.

    2012-04-01

    Since wetland ponds are often assumed to be insignificant sources of methane, there is a limited data about its fluxes. In this study, we found surprisingly high rates of methane emission at several shallow ponds in the south taiga zone of West Siberia. Wetland ponds within the Great Vasyugan Mire ridge-hollow-pool patterned bog system were investigated. 22 and 24 flux measurements from ponds and surrounded mires, respectively, were simultaneously made by a static chamber method in July, 2011. In contrast to previous measurements, fluxes were measured using the small boat with floated chamber to avoid disturbance to the water volume. Since the ebullition is most important emission pathway, minimization of physical disturbance provoking gas bubbling significantly increases the data accuracy. Air temperature varied from 15 to 22° C during the measurements, and pH at different pond depths - from 4.4 to 5. As it was found, background emission from surrounding ridges and hollows was 1.7/2.6/3.3 mgC·m-2·h1 (1st/2nd/3rd quartiles). These rates are in a perfect correspondence with the typical methane emission fluxes from other south taiga bogs. Methane emission from wetland ponds turned out to be by order of magnitude higher (9.3/11.3/15.6 mgC·m-2·h1). Comparing to other measurements in West Siberia, many times higher emissions (70.9/111.6/152.3 mgC·m-2·h1) were found in forest-steppe and subtaiga fen ponds. On the contrary, West Siberian tundra lakes emit methane insignificantly, with the flux rate close to surrounding wetlands (about 0.2-0.3 mgC·m-2·h1). Apparently, there is a naturally determined distribution of ponds with different flux rates over different West Siberia climate-vegetation zones. Further investigations aiming at revelation of the zones with different fluxes would be helpful for total flux revision purposes. With respect to other studies, high emission rates were already detected, for instance, in Baltic ponds (Dzyuban, 2002) and U.K. lakes

  12. Methods for Measuring and Estimating Methane Emission from Ruminants

    Directory of Open Access Journals (Sweden)

    Jørgen Madsen

    2012-04-01

    Full Text Available This paper is a brief introduction to the different methods used to quantify the enteric methane emission from ruminants. A thorough knowledge of the advantages and disadvantages of these methods is very important in order to plan experiments, understand and interpret experimental results, and compare them with other studies. The aim of the paper is to describe the principles, advantages and disadvantages of different methods used to quantify the enteric methane emission from ruminants. The best-known methods: Chambers/respiration chambers, SF6 technique and in vitro gas production technique and the newer CO2 methods are described. Model estimations, which are used to calculate national budget and single cow enteric emission from intake and diet composition, are also discussed. Other methods under development such as the micrometeorological technique, combined feeder and CH4 analyzer and proxy methods are briefly mentioned. Methods of choice for estimating enteric methane emission depend on aim, equipment, knowledge, time and money available, but interpretation of results obtained with a given method can be improved if knowledge about the disadvantages and advantages are used in the planning of experiments.

  13. Evaluation of modelled methane emissions over northern peatland sites

    Science.gov (United States)

    Gao, Yao; Burke, Eleanor; Chadburn, Sarah; Raivonen, Maarit; Susiluoto, Jouni; Vesala, Timo; Aurela, Mika; Lohila, Annalea; Aalto, Tuula

    2017-04-01

    Methane (CH4) is a powerful greenhouse gas, with approximately 34 times the global warming potential of carbon dioxide (CO2) over a century time horizon (IPCC, 2013). The strong sensitivity of methane emissions to environmental factors has led to concerns about potential positive feedbacks to climate change. Evaluation of the ability of the process-based land surface models of earth system models (ESMs) in simulating CH4 emission over peatland is needed for more precise future predictions. In this study, two peatland sites of poor and rich soil nutrient conditions, in southern and northern Finland respectively, are adopted. The measured CH4 fluxes at the two sites are used to evaluate the CH4 emissions simulated by the land surface model (JULES) of the UK Earth System model and by the Helsinki peatland methane emission model (HIMMELI), which is developed at Finnish Meteorological Institute and Helsinki University. In JULES, CH4 flux is simply related to soil temperature, wetland fraction and effective substrate availability. However, HIMMELI has detailed descriptions of microbial and transport processes for simulating CH4 flux. The seasonal dynamics of CH4 fluxes at the two sites are relatively well captured by both models, but model biases exist. Simulated CH4 flux is sensitive to water table depth (WTD) at both models. However, the simulated WTD is limited to be below ground in JULES. It is also important to have the annual cycle of LAI correct when coupling JULES with HIMMELI.

  14. Enhanced Emission Performance and Fuel Efficiency for HD Methane Engines. Literature Study. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Broman, R.; Staalhammar, P.; Erlandsson, L.

    2010-05-15

    A literature survey has been conducted in order to define state-of-the-art for methane fuelled engines to be used in heavy duty vehicles. Use of methane can be favourable to increase security of supply and mitigate CO2 emissions, especially when the methane origins from biomass. Furthermore, methane used as a fuel in heavy duty engines has a potential to reduce toxic exhaust emissions. Historically, use of methane in heavy duty engines has often been hampered by poor efficiency, i.e. high fuel consumption when using the Otto-cycle. However, current generation technology engines might be within 5-10 % of the efficiency of Diesel engine technology. In this context it is worth mentioning that compliance-driven changes for meeting future emission regulations for Diesel engines may have a negative impact on fuel efficiency, thereby narrowing the gap. This may present an opportunity for heavy methane fuelled engines. The reliability and durability of the exhaust aftertreatment devices for methane fuelled engines has also given rise to some concerns. Some concepts are performing acceptable while others do not meet expectations. This is partly due to difficulties in handling methane in the aftertreatment device and partly to issues in the design of the ignition system. Methane is a fuel used worldwide and has a potential to be an important complement to Diesel oil. There are two categories of HD methane engines available to end-users: Retrofitted engines, which often include computer controlled retrofit systems developed as 'bolt-on' technologies that can be removed if necessary, to resell the vehicle with a normal diesel engine, and those developed specifically for and in conjunction with engine manufacturers and delivered to customers as factory-built engines or vehicles (OEM). Additionally, both these categories can include engines that use the Otto- or Diesel combustion cycles. When adapting a HD Diesel engine to run on methane there are two options, either

  15. Methane fugitive emissions quantification using the novel 'plume camera' (spatial correlation) method

    Science.gov (United States)

    Crosson, E.; Rella, C.

    2012-12-01

    measurement of the emission rate. One example of this method is shown in Fig. 1. This method is simple to deploy, does not require an accurate model of atmospheric transport or knowledge of the distance to the emission source or its spatial distribution. Accurate measurements of the emissions can be made with just a few minutes of data collection. Results of controlled release methane experiments are presented, and the strengths and limitations of the methodology are discussed. REFERENCES R. Howarth, R. Santoro, and A. Ingraffea (2011): "Methane and the greenhouse-gas footprint of natural gas from shale formations," Climatic Change 106, 679 - 690. Fig 1: Spatial correlation analysis for two measurement points (or pixels) distributed vertically (A and B) or horizontally (A and C), for measurements at a distance of 21 meters from a methane point source of 650 sccm. The emission rate recovered from this analysis was 496 ± 160 sccm of CH4. The total measurement time was 30 minutes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hettiarachchi, Vijayamala C. [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Hettiaratchi, Patrick J., E-mail: jhettiar@ucalgary.ca [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Mehrotra, Anil K. [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada); Kumar, Sunil, E-mail: sunil_neeri@yahoo.co.in [Centre for Environmental Engineering Research and Education (CEERE), Schulich School of Engineering, University of Calgary, Calgary, AB, T2N 1N4 (Canada)

    2011-06-15

    Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH{sub 4}). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH{sub 4} to carbon dioxide (CO{sub 2}) and water (H{sub 2}O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH{sub 4} emissions using an MBF at a natural gas monitoring station. A new comprehensive three-dimensional numerical model was developed incorporating advection-diffusive flow of gas, biological reactions and heat and moisture flow. The one-dimensional version of this model was used as a guiding tool for designing and operating the MBF. The long-term monitoring results of the field MBF are also presented. The field MBF operated with no control of precipitation, evaporation, and temperature, provided more than 80% of CH{sub 4} oxidation throughout spring, summer, and fall seasons. The numerical model was able to predict the CH{sub 4} oxidation behavior of the field MBF with high accuracy. The numerical model simulations are presented for estimating CH{sub 4} oxidation efficiencies under various operating conditions, including different filter bed depths and CH{sub 4} flux rates. The field observations as well as numerical model simulations indicated that the long-term performance of MBFs is strongly dependent on environmental factors, such as ambient temperature and precipitation. - Highlights: > One-dimensional version of the model was used as a guiding tool for designing and operating the MBF. > Mathematical model predicted CH{sub 4} oxidation behaviors of the field MBF with high accuracy i.e. (> 80 %). > Performance of MBF is dependent on ambient temperature and precipitation. - The developed numerical model simulations and field observations for estimating CH{sub 4} oxidation efficiencies under various operating conditions indicate that

  17. Methane from the Tropospheric Emission Spectrometer (TES)

    Science.gov (United States)

    Payne, Vivienne; Worden, John; Kulawik, Susan; Frankenberg, Christian; Bowman, Kevin; Wecht, Kevin

    2012-01-01

    TES V5 CH4 captures latitudinal gradients, regional variability and interannual variation in the free troposphere. V5 joint retrievals offer improved sensitivity to lower troposphere. Time series extends from 2004 to present. V5 reprocessing in progress. Upper tropospheric bias. Mitigated by N2O correction. Appears largely spatially uniform, so can be corrected. How to relate free-tropospheric values to surface emissions.

  18. Upward revision of global fossil fuel methane emissions based on isotope database.

    Science.gov (United States)

    Schwietzke, Stefan; Sherwood, Owen A; Bruhwiler, Lori M P; Miller, John B; Etiope, Giuseppe; Dlugokencky, Edward J; Michel, Sylvia Englund; Arling, Victoria A; Vaughn, Bruce H; White, James W C; Tans, Pieter P

    2016-10-06

    Methane has the second-largest global radiative forcing impact of anthropogenic greenhouse gases after carbon dioxide, but our understanding of the global atmospheric methane budget is incomplete. The global fossil fuel industry (production and usage of natural gas, oil and coal) is thought to contribute 15 to 22 per cent of methane emissions to the total atmospheric methane budget. However, questions remain regarding methane emission trends as a result of fossil fuel industrial activity and the contribution to total methane emissions of sources from the fossil fuel industry and from natural geological seepage, which are often co-located. Here we re-evaluate the global methane budget and the contribution of the fossil fuel industry to methane emissions based on long-term global methane and methane carbon isotope records. We compile the largest isotopic methane source signature database so far, including fossil fuel, microbial and biomass-burning methane emission sources. We find that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are not increasing over time, but are 60 to 110 per cent greater than current estimates owing to large revisions in isotope source signatures. We show that this is consistent with the observed global latitudinal methane gradient. After accounting for natural geological methane seepage, we find that methane emissions from natural gas, oil and coal production and their usage are 20 to 60 per cent greater than inventories. Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 per cent to approximately 2 per cent over the past three decades.

  19. Upward revision of global fossil fuel methane emissions based on isotope database

    Science.gov (United States)

    Schwietzke, Stefan; Sherwood, Owen A.; Bruhwiler, Lori M. P.; Miller, John B.; Etiope, Giuseppe; Dlugokencky, Edward J.; Michel, Sylvia Englund; Arling, Victoria A.; Vaughn, Bruce H.; White, James W. C.; Tans, Pieter P.

    2016-10-01

    Methane has the second-largest global radiative forcing impact of anthropogenic greenhouse gases after carbon dioxide, but our understanding of the global atmospheric methane budget is incomplete. The global fossil fuel industry (production and usage of natural gas, oil and coal) is thought to contribute 15 to 22 per cent of methane emissions to the total atmospheric methane budget. However, questions remain regarding methane emission trends as a result of fossil fuel industrial activity and the contribution to total methane emissions of sources from the fossil fuel industry and from natural geological seepage, which are often co-located. Here we re-evaluate the global methane budget and the contribution of the fossil fuel industry to methane emissions based on long-term global methane and methane carbon isotope records. We compile the largest isotopic methane source signature database so far, including fossil fuel, microbial and biomass-burning methane emission sources. We find that total fossil fuel methane emissions (fossil fuel industry plus natural geological seepage) are not increasing over time, but are 60 to 110 per cent greater than current estimates owing to large revisions in isotope source signatures. We show that this is consistent with the observed global latitudinal methane gradient. After accounting for natural geological methane seepage, we find that methane emissions from natural gas, oil and coal production and their usage are 20 to 60 per cent greater than inventories. Our findings imply a greater potential for the fossil fuel industry to mitigate anthropogenic climate forcing, but we also find that methane emissions from natural gas as a fraction of production have declined from approximately 8 per cent to approximately 2 per cent over the past three decades.

  20. Estimation of Methane Emissions from Municipal Solid Waste Landfills in China Based on Point Emission Sources

    Directory of Open Access Journals (Sweden)

    Cai Bo-Feng

    2014-01-01

    Citation: Cai, B.-F., Liu, J.-G., Gao, Q.-X., et al., 2014. Estimation of methane emissions from municipal solid waste landfills in China based on point emission sources. Adv. Clim. Change Res. 5(2, doi: 10.3724/SP.J.1248.2014.081.

  1. Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Kjeldsen, Peter; Bogner, J.E.;

    2009-01-01

    utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used...... to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed.......Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials...

  2. The contribution of an overlooked transport process to a wetland's methane emissions

    Science.gov (United States)

    Poindexter, Cristina M.; Baldocchi, Dennis D.; Matthes, Jaclyn Hatala; Knox, Sara Helen; Variano, Evan A.

    2016-06-01

    Wetland methane transport processes affect what portion of methane produced in wetlands reaches the atmosphere. We model what has been perceived to be the least important of these transport processes: hydrodynamic transport of methane through wetland surface water and show that its contribution to total methane emissions from a temperate freshwater marsh is surprisingly large. In our 1 year study, hydrodynamic transport comprised more than half of nighttime methane fluxes and was driven primarily by water column thermal convection occurring overnight as the water surface cooled. Overall, hydrodynamic transport was responsible for 32% of annual methane emissions. Many methane models have overlooked this process, but our results show that wetland methane fluxes cannot always be accurately described using only other transport processes (plant-mediated transport and ebullition). Modifying models to include hydrodynamic transport and the mechanisms that drive it, particularly convection, could help improve predictions of future wetland methane emissions.

  3. Differential Absorption Lidar (DIAL) Measurements of Landfill Methane Emissions

    Science.gov (United States)

    Innocenti, Fabrizio; Robinson, Rod; Gardiner, Tom; Finlayson, Andrew; Connor, Andy

    2017-04-01

    DIFFERENTIAL ABSORPTION LIDAR (DIAL) MEASURMENTS OF LANDFILL METHANE EMISSIONS F. INNOCENTI *, R.A. ROBINSON *, T.D. GARDINER, A. FINLAYSON *, A. CONNOR* * National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom Methane is one of the most important gaseous hydrocarbon species for both industrial and environmental reasons. Understanding and quantifying methane emissions to atmosphere is an important element of climate change research. Range-resolved infrared Differential Absorption Lidar (DIAL) measurements provide the means to map and quantify a wide range of different methane sources. DIAL is a powerful technique that can be used to track and quantify plumes emitted from area emission sources such as landfill sites, waste water treatment plants and petrochemical plants. By using lidar (light detection and ranging), the DIAL technique is able to make remote range-resolved single-ended measurements of the actual distribution of target gases in the atmosphere, with no disruption to normal site operational activities. DIAL provides 3D mapping of emission concentrations and quantification of emission rates for a wide range of target gases such as methane. The NPL DIAL laser source is operated alternately at two similar wavelengths. One of these, termed the "on-resonant wavelength", is chosen to be at a wavelength which is absorbed by the target species. The other, the "off-resonant wavelength", is chosen to be at a nearby wavelength which is not absorbed significantly by the target species. The two wavelengths are chosen to be close, so that the atmospheric scattering properties are the same for both wavelengths. They are also chosen so that any differential absorption due to other atmospheric species are minimised. Any measured difference in the returned signals is therefore due to absorption by the target gas. In the typical DIAL measurement configuration the mobile DIAL facility is positioned downwind of the area being

  4. Measurements of methane emissions at natural gas production sites in the United States

    OpenAIRE

    Allen, David T.; Torres, Vincent M.; Thomas, James; Sullivan, David W.; Harrison, Matthew; Hendler, Al; Herndon, Scott C.; Kolb, Charles E.; Fraser, Matthew P.; Hill, A. Daniel; Lamb, Brian K.; Miskimins, Jennifer; Sawyer, Robert F.; Seinfeld, John H.

    2013-01-01

    Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confiden...

  5. Methane Emissions from the Arctic Ocean to the Atmosphere

    Science.gov (United States)

    Platt, Stephen; Hermansen, Ova; Schmidbauer, Norbert; Pisso, Ignacio; Silyakova, Anna; Ferré, Benedicte; Lowry, Dave; Percival, Carl; Mienert, Jürgen; Myhre, Cathrine Lund

    2015-04-01

    The release of methane (CH4) presently stored in vast hydrate deposits under the seafloor is a potential climate tipping point and a major uncertainty in the global methane budget. Significant methane hydrate deposits are located in shallow waters in the Arctic where they may destabilise, releasing methane to the atmosphere due to ocean warming. To address this issue the Methane Emissions from Arctic Ocean to Atmosphere (MOCA, http://moca.nilu.no/) project was established in cooperation with the CAGE Centre of Excellence (http:cage.uit.no/). State-of-the-art oceanographic and atmospheric measurement techniques were applied over a large area of the Arctic including northern Norway, the Barents Sea, and areas of shallow water around Svalbard during summer 2014. Oceanographic measurements included the deployment of 63 measurement stations (temperature, salinity, density, oxygen, fluorescence, turbidity, etc.), water column sampling (CH4, nitrate, phosphate, silicates), and echo sounding (revealing locations where streams of gas bubbles are vented). Atmospheric on-line measurements were performed aboard the research vessel Helmer Hanssen (CH4, CO2, CO, meteorological parameters) and during a flight campaign (CH4, etc.). Air samples were collected for isotopic analysis (13C, 2H) and quantification of other hydrocarbons (ethane, propane, etc.). Finally, atmospheric measurements are compared with long term data sets from the nearby Zeppelin Mountain monitoring station (Ny Ålesund, Svalbard). Back-trajectory analysis and FLEXPART modelling are used to rule out non-local sources. Here we present an overview of all of these activities and the first results from MOCA in cooperation with CAGE - Centre for Arctic Gas Hydrate, and Climate at UiT, The Arctic University of Norway. We demonstrate that there are hotspots of activity where hydrocarbons are being emitted from the ocean, while in some areas emissions are surprisingly well contained by local biological and hydrological

  6. Emissions of methane from northern peatlands: a review of management impacts and future implications

    Science.gov (United States)

    Abdalla, Mohamed; Hastings, Astley; Mander, Ulo; Smith, Pete; Nilsson, Mats

    2016-04-01

    Northern peatlands constitute a significant source of atmospheric methane (CH4). However, management of undisturbed peatlands, as well as restoration of disturbed peatlands, will alter the exchange of methane with the atmosphere. The aim of this literature review and meta-analysis was to collate and analyse recent literature to improve our understanding of the impacts of management on CH4 emissions from northern peatlands i.e. latitude 40 to 70o N. Results show that CH4 emissions from natural northern peatlands range from 0 to 154 g C m-2 yr-1 and the overall annual average (mean ± standard deviation) is 11.7 ± 21 g C m-2 yr-1 with the highest emissions from fen ecosystems. Drainage significantly (pMethane emissions are mainly controlled by water table (WT) depth, plant community composition and soil pH. Although temperature is not a good predictor of CH4 emissions by itself, the interaction between temperatures, plant community cover, WT depth and soil pH is important. According to short-term forecasts of climate change, these complex interactions will be the main determinant of increased CH4 emissions from northern peatlands. However, to fully evaluate the net effect of management practice on high latitude peatlands both net ecosystem exchange (NEE) and carbon exports needs to be considered.

  7. Methane and Carbon Dioxide Emissions from Different Composting Periods

    Directory of Open Access Journals (Sweden)

    Cheng-Hsiung Chang

    2009-01-01

    Full Text Available To investigate green house gas emissions from compost preparations, methane and carbon dioxide concentrations and emission rates at different accumulative times and composting periods were determined. While the accumulative time was less than 10 min with a closed acrylic chamber, meth ane and carbon dioxide emissions in creased slightly but with high fluntuation in the sampling e ror, and these values decreased significantly when the accumulative time was more than 20 min. During the 8 weeks of composting, the methane emission rate reaches its peak near the end of the second week and the carbon dioxide emission rate does the same near the end of third week. Meth ane and carbon dioxide emissions had high val ues at the first stage of com post ing and then de creased grad u ally for the ma tu rity of com post. Carbon dioxide emission (y was significantly related to temperature (x1, moisture content (x2, and total or ganiccarbon (x3; and there gression equation is: y = 3.11907x1 + 6.19236x2 - 6.63081x3 - 50.62498. The re gres sion equa tion be tween meth ane emis sion (y? and mois ture con tent (x2, pH (x4, C/N ra tio (x5, and ash con tent (x6 is: y?= 0.13225x2 - 0.97046x4 - 1.10599x5 - 0.55220x6 + 50.77057 in the ini tial com post ing stage (weeks 1 to 3; while, the equa tion is: y?= 0.02824x2 - 0.0037x4 - 0.1499x5 - 0.07013x6 + 4.13589 in the later compost ing stage (weeks 4 to 8. Dif ferent stage composts have significant variation of properties and greenhouse gas emissions. Moreover, the emissions may be reduced by manipulating the proper factors.

  8. Potential Cost-Effective Opportunities for Methane Emission Abatement

    Energy Technology Data Exchange (ETDEWEB)

    Warner, Ethan [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Steinberg, Daniel [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States); Hodson, Elke [U.S. Department of Energy, Washington, DC (United States); Heath, Garvin [Joint Inst. for Strategic Energy Analysis, Golden, CO (United States)

    2015-08-01

    The energy sector was responsible for approximately 84% of carbon dioxide equivalent (CO2e) greenhouse gas (GHG) emissions in the U.S. in 2012 (EPA 2014a). Methane is the second most important GHG, contributing 9% of total U.S. CO2e emissions. A large portion of those methane emissions result from energy production and use; the natural gas, coal, and oil industries produce approximately 39% of anthropogenic methane emissions in the U.S. As a result, fossil-fuel systems have been consistently identified as high priority sectors to contribute to U.S. GHG reduction goals (White House 2015). Only two studies have recently attempted to quantify the abatement potential and cost associated with the breadth of opportunities to reduce GHG emissions within natural gas, oil, and coal supply chains in the United States, namely the U.S. Environmental Protection Agency (EPA) (2013a) and ICF (2014). EPA, in its 2013 analysis, estimated the marginal cost of abatement for non-CO2 GHG emissions from the natural gas, oil, and coal supply chains for multiple regions globally, including the United States. Building on this work, ICF International (ICF) (2014) provided an update and re-analysis of the potential opportunities in U.S. natural gas and oil systems. In this report we synthesize these previously published estimates as well as incorporate additional data provided by ICF to provide a comprehensive national analysis of methane abatement opportunities and their associated costs across the natural gas, oil, and coal supply chains. Results are presented as a suite of marginal abatement cost curves (MACCs), which depict the total potential and cost of reducing emissions through different abatement measures. We report results by sector (natural gas, oil, and coal) and by supply chain segment - production, gathering and boosting, processing, transmission and storage, or distribution - to facilitate identification of which sectors and supply chain

  9. Monitoring fugitive methane and natural gas emissions, validation of measurement techniques.

    Science.gov (United States)

    Robinson, Rod; Innocenti, Fabrizio; Gardiner, Tom; Helmore, Jon; Finlayson, Andrew; Connor, Andy

    2017-04-01

    The detection and quantification of fugitive and diffuse methane emissions has become an increasing priority in recent years. As the requirements for routine measurement to support industry initiatives increase there is a growing requirement to assess and validate the performance of fugitive emission measurement technologies. For reported emissions traceability and comparability of measurements is important. This talk will present recent work addressing these needs. Differential Absorption Lidar (DIAL) is a laser based remote sensing technology, able to map the concentration of gases in the atmosphere and determine emission fluxes for fugitive emissions. A description of the technique and its application for determining fugitive emissions of methane from oil and gas operations and waste management sites will be given. As DIAL has gained acceptance as a powerful tool for the measurement and quantification of fugitive emissions, and given the rich data it produces, it is being increasingly used to assess and validate other measurement approaches. In addition, to support the validation of technologies, we have developed a portable controlled release facility able to simulate the emissions from area sources. This has been used to assess and validate techniques which are used to monitor emissions. The development and capabilities of the controlled release facility will be described. This talk will report on recent studies using DIAL and the controlled release facility to validate fugitive emission measurement techniques. This includes side by side comparisons of two DIAL systems, the application of both the DIAL technique and the controlled release facility in a major study carried out in 2015 by South Coast Air Quality Management District (SCAQMD) in which a number of optical techniques were assessed and the development of a prototype method validation approach for techniques used to measure methane emissions from shale gas sites. In conclusion the talk will provide an

  10. Seasonal and inter-annual variation in ecosystem scale methane emission from a boreal fen

    Science.gov (United States)

    Rinne, Janne; Li, Xuefei; Raivonen, Maarit; Peltola, Olli; Sallantaus, Tapani; Haapanala, Sami; Smolander, Sampo; Alekseychik, Pavel; Aurela, Mika; Korrensalo, Aino; Mammarella, Ivan; Tuittila, Eeva-Stiina; Vesala, Timo

    2016-04-01

    Northern wetlands are one of the major sources of atmospheric methane. We have measured ecosystem scale methane emissions from a boreal fen continuously since 2005. The site is an oligotrophic fen in boreal vegetation zone situated in Siikaneva wetland complex in Southern Finland. The mean annual temperature in the area is 3.3°C and total annual precipitation 710 mm. We have conducted the methane emission measurements by the eddy covariance method. Additionally we have measured fluxes of carbon dioxide, water vapor, and sensible heat together with a suite of other environmental parameters. We have analyzed this data alongside with a model run with University of Helsinki methane model. The measured fluxes show generally highest methane emission in late summers coinciding with the highest temperatures in saturated peat zone. During winters the fluxes show small but detectable emission despite the snow and ice cover on the fen. More than 90% of the annual methane emission occurs in snow-free period. The methane emission and peat temperature are connected in exponential manner in seasonal scales, but methane emission does not show the expected behavior with water table. The lack of water table position dependence also contrasts with the spatial variation across microtopography. There is no systematic variation in sub-diurnal time scale. The general seasonal cycle in methane emission is captured well with the methane model. We will show how well the model reproduces the temperature and water table position dependencies observed. The annual methane emission is typically around 10 gC m-2. This is a significant part of the total carbon exchange between the fen and the atmosphere and about twice the estimated carbon loss by leaching from the fen area. The inter-annual variability in the methane emission is modest. The June-September methane emissions from different years, comprising most of the annual emission, correlates positively with peat temperature, but not with

  11. Modeling methane emissions from arctic lakes: Model development and site-level study

    Science.gov (United States)

    Tan, Zeli; Zhuang, Qianlai; Walter Anthony, Katey

    2015-06-01

    To date, methane emissions from lakes in the pan-arctic region are poorly quantified. In order to investigate the response of methane emissions from this region to global warming, a process-based climate-sensitive lake biogeochemical model was developed. The processes of methane production, oxidation, and transport were modeled within a one-dimensional sediment and water column. The sizes of 14C-enriched and 14C-depleted carbon pools were explicitly parameterized. The model was validated using observational data from five lakes located in Siberia and Alaska, representing a large variety of environmental conditions in the arctic. The model simulations agreed well with the measured water temperature and dissolved CH4 concentration (mean error less than 1°C and 0.2 μM, respectively). The modeled CH4 fluxes were consistent with observations in these lakes. We found that bubbling-rate-controlling nitrogen (N2) stripping was the most important factor in determining CH4 fraction in bubbles. Lake depth and ice cover thickness in shallow waters were also controlling factors. This study demonstrated that the thawing of Pleistocene-aged organic-rich yedoma can fuel sediment methanogenesis by supplying a large quantity of labile organic carbon. Observations and modeling results both confirmed that methane emission rate at thermokarst margins of yedoma lakes was much larger (up to 538 mg CH4 m-2 d-1) than that at nonthermokarst zones in the same lakes and a nonyedoma, nonthermokarst lake (less than 42 mg CH4 m-2 d-1). The seasonal variability of methane emissions can be explained primarily by energy input and organic carbon availability.

  12. Estimating fugitive methane emissions from oil sands mining using extractive core samples

    Science.gov (United States)

    Johnson, Matthew R.; Crosland, Brian M.; McEwen, James D.; Hager, Darcy B.; Armitage, Joshua R.; Karimi-Golpayegani, Mojgan; Picard, David J.

    2016-11-01

    Fugitive methane emissions from oil sands mining activities are a potentially important source of greenhouse gas emissions for which there are significant uncertainties and a lack of open data. This paper investigates the potential of a control-system approach to estimating fugitive methane emissions by analyzing releasable gas volumes in core samples extracted from undeveloped mine regions. Field experiments were performed by leveraging routine winter drilling activities that are a component of normal mine planning and development, and working in conjunction with an on-site drill crew using existing equipment. Core samples were extracted from two test holes, sealed at the surface, and transported for off-site lab analysis. Despite the challenges of the on-site sample collection and the limitations of the available drilling technology, notable quantities of residual methane (mean of 23.8 mgCH4/kg-core-sample (+41%/-35%) or 779 mgCH4/kg-bitumen (+69%/-34%) at 95% confidence) were measured in the collected core samples. If these factors are applied to the volumes of bitumen mined in Alberta in 2015, they imply fugitive methane emissions equivalent to 2.1 MtCO2e (as correlated with bitumen content) or 1.4 MtCO2e (as correlated with total mined material) evaluated on a 100-year time horizon. An additional ∼0.2 Mt of fugitive CO2 emissions could also be expected. Although additional measurements at a larger number of locations are warranted to determine whether these emissions should be considered as additive to, or inclusive of, current estimates based on flux chamber measurements at the mine face, these first-of-their-kind results demonstrate an intriguing alternate method for quantifying fugitive emissions from oil sands mining and extraction.

  13. Impact of ruminal pH on enteric methane emissions.

    Science.gov (United States)

    Hünerberg, M; McGinn, S M; Beauchemin, K A; Entz, T; Okine, E K; Harstad, O M; McAllister, T A

    2015-04-01

    The objective of this study was to determine the impact of ruminal pH on methane (CH4) emission from beef cattle. Ruminal pH and CH4 data were generated in 2 experiments using 16 beef heifers offered high-forage (55% barley silage) or high-grain (92% concentrate; DM basis) diets. Both experiments were designed as a replicated 4 × 4 Latin square with 4 periods and 4 dietary treatments. Methane was measured over 4 consecutive days using open-circuit respiratory chambers with each chamber housing 2 heifers. The ruminal pH of individual heifers was measured using indwelling pH loggers. The mean ruminal pH and CH4 emission (g/h) of 2 heifers in every chamber were summarized in 30-min blocks. Even though rumen methanogens have been described to be inhibited by a pH 0.05). Daily mean CH4 emission (g/d) and ruminal pH were only mildly correlated (r2 = 0.27; P emissions from cattle fed high-grain as compared to high-forage diets. Lowering ruminal pH alone is, therefore, not an effective CH4-mitigation strategy. Mechanisms permitting methanogens to survive episodes of low-ruminal pH might include changes in community structure toward more pH-tolerant strains or sequestration into microenvironments within biofilms or protozoa where methanogens are protected from low pH.

  14. NUMERICAL SIMULATION OF METHANE EMISSIONS FROM RICE PADDY FIELDS IN THE YANGTZE DELTA OF CHINA

    Institute of Scientific and Technical Information of China (English)

    刘建栋; 周秀骥; 张宇

    2001-01-01

    A numerical simulation model is presented in this paper, which comprises the processes of crop growth, soil organic carbon decomposition, and methane emissions in agroecosystems.Simulation results show that the model can simulate the main process of methane emissions well,and the correlation coefficient between the simulated values and observed data is 0. 79 with 239 samples, which passed a significance test of 0. 01. The average error of methane emission simulation in whole growth period is about 15%. Numerical analysis of the model indicates that the average temperature during rice growth period has much impacts on methane emissions, and the basic trend of interannual methane emissions is similar to that of average temperature. The amount of methane emissions reduces about 34. 93%, when the fertilizer is used instead of manure in single rice paddy.

  15. Climate versus emission drivers of methane lifetime from 1860-2100

    Science.gov (United States)

    John, J. G.; Fiore, A. M.; Naik, V.; Horowitz, L. W.; Dunne, J. P.

    2012-07-01

    With a more-than-doubling in the atmospheric abundance of the potent greenhouse gas methane (CH4) since preindustrial times, and indications of renewed growth following a leveling off in recent years, questions arise as to future trends and resulting climate and public health impacts from continued growth without mitigation. Changes in atmospheric methane lifetime are determined by factors which regulate the abundance of OH, the primary methane removal mechanism, including changes in CH4 itself. We investigate the role of emissions of short-lived species and climate in determining the evolution of tropospheric methane lifetime in a suite of historical (1860-2005) and Representative Concentration Pathway (RCP) simulations (2006-2100), conducted with the Geophysical Fluid Dynamics Laboratory (GFDL) fully coupled chemistry-climate model (CM3). From preindustrial to present, CM3 simulates an overall 5% increase in CH4 lifetime due to a doubling of the methane burden which offsets coincident increases in nitrogen oxide (NOx) emissions. Over the last two decades, however, the methane lifetime declines steadily, coinciding with the most rapid climate warming and observed slow-down in CH4 growth rates, reflecting a possible negative feedback through the CH4 sink. The aerosol indirect effect plays a significant role in the CM3 climate and thus in the future evolution of the methane lifetime, due to the rapid projected decline of aerosols under all four RCPs. In all scenarios, the methane lifetime decreases (by 5-13%) except for the most extreme warming case (RCP8.5), where it increases by 4% due to the near-doubling of the CH4 abundance, reflecting a positive feedback on the climate system. In the RCP4.5 scenario changes in short-lived climate forcing agents reinforce climate warming and enhance OH, leading to a more-than-doubling of the decrease in methane lifetime from 2006 to 2100 relative to a simulation in which only well-mixed greenhouse gases are allowed to change

  16. Climate versus emission drivers of methane lifetime from 1860–2100

    Directory of Open Access Journals (Sweden)

    V. Naik

    2012-07-01

    Full Text Available With a more-than-doubling in the atmospheric abundance of the potent greenhouse gas methane (CH4 since preindustrial times, and indications of renewed growth following a leveling off in recent years, questions arise as to future trends and resulting climate and public health impacts from continued growth without mitigation. Changes in atmospheric methane lifetime are determined by factors which regulate the abundance of OH, the primary methane removal mechanism, including changes in CH4 itself. We investigate the role of emissions of short-lived species and climate in determining the evolution of tropospheric methane lifetime in a suite of historical (1860–2005 and Representative Concentration Pathway (RCP simulations (2006–2100, conducted with the Geophysical Fluid Dynamics Laboratory (GFDL fully coupled chemistry-climate model (CM3. From preindustrial to present, CM3 simulates an overall 5% increase in CH4 lifetime due to a doubling of the methane burden which offsets coincident increases in nitrogen oxide (NOx emissions. Over the last two decades, however, the methane lifetime declines steadily, coinciding with the most rapid climate warming and observed slow-down in CH4 growth rates, reflecting a possible negative feedback through the CH4 sink. The aerosol indirect effect plays a significant role in the CM3 climate and thus in the future evolution of the methane lifetime, due to the rapid projected decline of aerosols under all four RCPs. In all scenarios, the methane lifetime decreases (by 5–13% except for the most extreme warming case (RCP8.5, where it increases by 4% due to the near-doubling of the CH4 abundance, reflecting a positive feedback on the climate system. In the RCP4.5 scenario changes in short-lived climate forcing agents reinforce climate warming and enhance OH, leading to a more-than-doubling of the decrease in methane lifetime from 2006 to 2100 relative to a simulation in which only well-mixed greenhouse gases are

  17. Quantification of methane emissions from 15 Danish landfills using the mobile tracer dispersion method

    DEFF Research Database (Denmark)

    Mønster, Jacob; Samuelsson, Jerker; Kjeldsen, Peter

    2015-01-01

    biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41-81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills...

  18. Attribution of changes in global wetland methane emissions from pre-industrial to present using CLM4.5-BGC

    Science.gov (United States)

    Paudel, Rajendra; Mahowald, Natalie M.; Hess, Peter G. M.; Meng, Lei; Riley, William J.

    2016-03-01

    An understanding of potential factors controlling methane emissions from natural wetlands is important to accurately project future atmospheric methane concentrations. Here, we examine the relative contributions of climatic and environmental factors, such as precipitation, temperature, atmospheric CO2 concentration, nitrogen deposition, wetland inundation extent, and land-use and land-cover change, on changes in wetland methane emissions from preindustrial to present day (i.e., 1850-2005). We apply a mechanistic methane biogeochemical model integrated in the Community Land Model version 4.5 (CLM4.5), the land component of the Community Earth System Model. The methane model explicitly simulates methane production, oxidation, ebullition, transport through aerenchyma of plants, and aqueous and gaseous diffusion. We conduct a suite of model simulations from 1850 to 2005, with all changes in environmental factors included, and sensitivity studies isolating each factor. Globally, we estimate that preindustrial methane emissions were higher by 10% than present-day emissions from natural wetlands, with emissions changes from preindustrial to the present of +15%, -41%, and -11% for the high latitudes, temperate regions, and tropics, respectively. The most important change is due to the estimated change in wetland extent, due to the conversion of wetland areas to drylands by humans. This effect alone leads to higher preindustrial global methane fluxes by 33% relative to the present, with the largest change in temperate regions (+80%). These increases were partially offset by lower preindustrial emissions due to lower CO2 levels (10%), shifts in precipitation (7%), lower nitrogen deposition (3%), and changes in land-use and land-cover (2%). Cooler temperatures in the preindustrial regions resulted in our simulations in an increase in global methane emissions of 6% relative to present day. Much of the sensitivity to these perturbations is mediated in the model by changes in

  19. Fluxes of methane between landfills and the atmosphere: Natural and engineered controls

    Energy Technology Data Exchange (ETDEWEB)

    Bogner, J. [Argonne National Lab., IL (United States); Meadows, M. [ETSU, Harwell, Oxfordshire (United Kingdom); Czepiel, P. [Harvard Univ., Cambridge, MA (United States)

    1997-08-01

    Field measurement of landfill methane emissions indicates natural variability spanning more than 2 seven orders of magnitude, from approximately 0.0004 to more than 4000 g m{sub -2} day{sup -1}. This wide range reflects net emissions resulting from production (methanogenesis), consumption (methanotrophic oxidation), and gaseous transport processes. The determination of an {open_quotes}average{close_quotes} emission rate for a given field site requires sampling designs and statistical techniques which consider spatial and temporal variability. Moreover, particularly at sites with pumped gas recovery systems, it is possible for methanotrophic microorganisms in aerated cover soils to oxidize all of the methane from landfill sources below and, additionally, to oxidize methane diffusing into cover soils from atmospheric sources above. In such cases, a reversed soil gas concentration gradient is observed in shallow cover soils, indicating bidirectional diffusional transport to the depth of optimum methane oxidation. Rates of landfill methane oxidation from field and laboratory incubation studies range up to 166 g m{sup -2} day{sup -1} among the highest for any natural setting, providing an effective natural control on net emissions. Estimates of worldwide landfill methane emissions to the atmosphere have ranged from 9 to 70 Tg yr{sup -1}, differing mainly in assumed methane yields from estimated quantities of landfilled refuse. At highly controlled landfill sites in developed countries, landfill methane is often collected via vertical wells or horizontal collectors. Recovery of landfill methane through engineered systems can provide both environmental and energy benefits by mitigating subsurface migration, reducing surface emissions, and providing an alternative energy resource for industrial boiler use, on-site electrical generation, or upgrading to a substitute natural gas.

  20. Underlying Ecosystem Methane Emissions Exceed Cattle-Derived Methane from Subtropical Lowland Pastures.

    Science.gov (United States)

    Chamberlain, S. D.; Sparks, J. P.

    2014-12-01

    Grazing cattle are a major methane (CH4) source from pasture ecosystems, however the underlying landscape is a potentially significant CH4 source that has received far less attention. Ecosystem surface emissions of CH4 are poorly quantified, vary widely across time and space, and are easily underestimated if emission hotspots or episodic fluxes are overlooked. We used static chambers, eddy covariance, and mobile cavity-ringdown spectrometry surveys to quantify spatially and temporally variable CH4 emissions from subtropical lowland pastures. We conclude emissions from soil and standing water are the dominant CH4 source, and cattle were responsible for only 13% of annual CH4emissions. The ecosystem emit 33.8 ± 2.2 g CH4 m-2 yr-1, however surface CH4 emissions were highly variable in both time and space. Seasonal flooding of pastures and low-lying landforms (canals, ditches, wetlands) drove high magnitude CH4 emissions. We observed large CH4 emissions from wetlands and, to a lesser extent, the entire landscape during the wet season. In contrast, during the dry season there was no appreciable CH4 accumulation in pastures when cattle were not present, and canals, which comprise 1.7% of the total land area, were responsible 97.7 % of dry season emissions. Ecosystem CH4 fluxes, measured by eddy covariance, varied seasonally and positively correlated to soil and air temperature, topsoil water content, and water table depth. Our work is the first to use mobile spectrometers to map biogenic CH4 emissions at the landscape scale, and demonstrates that soils and water are a strong pasture CH4 source that must be considered in addition to cattle emissions.

  1. Methylotrophic methanogenic Thermoplasmata implicated in reduced methane emissions from bovine rumen

    DEFF Research Database (Denmark)

    Poulsen, Morten; Schwab, Clarissa; Jensen, Bent Borg

    2013-01-01

    Rumen methanogens are major sources of anthropogenic methane emissions, and these archaea are targets in strategies aimed at reducing methane emissions. Here we show that the poorly characterised Thermoplasmata archaea in bovine rumen are methylotrophic methanogens and that they are reduced upon...... potential as target in future strategies to mitigate methane emissions from ruminant livestock. Our findings and the findings of others also indicate a wider distribution of methanogens than previously anticipated....

  2. Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain

    OpenAIRE

    2011-01-01

    In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP) were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern wi...

  3. Comparison of biogenic methane emissions from unmanaged estuaries, lakes, oceans, rivers and wetlands

    Science.gov (United States)

    Ortiz-Llorente, M. J.; Alvarez-Cobelas, M.

    2012-11-01

    A literature review of quantitative data was carried out to conduct a cross-system study on methane emissions relating peak emissions (PE) and annual emissions (AE) in five types of non-managed ecosystems: estuaries, lakes, oceans, streams and wetlands. PE spanned eight orders of magnitude (0.015 μg CH4 m-2 h-1-300 mg CH4 m-2 h-1) while AE spanned seven (0.078-19044 g CH4 m-2 yr-1). PE and AE were strongly related worldwide (r2 = 0.93). There was no relationship between AE and latitude, with highly variable PE across latitudes and climates. The coefficient of variation (CV) was greatest for emissions in oceans and estuaries, while the highest emission rate was recorded in wetlands and lakes. Efflux from coastal areas and estuaries was higher than that from upwelling areas and deep seas. Concerning wetland types, marshes showed the highest PE with the highest wetland emissions occurring in sites dominated by big helophytes. Non-stratifying- and eutrophic lakes displayed more emissions than other lake types, but there was no environmental variable that might predict methane emissions from lakes on a worldwide basis. Generally, most ecosystem types followed a seasonal pattern of emissions, with a maximum in summer, except in estuaries which did not show any distinct pattern. Regarding the importance of hot spots within most ecosystems, more spatial variability of CH4 emissions was observed in lakes than in wetlands and oceans; however, no relationship between emissions and spatial variability was found. A positive relationship, albeit weak, was found between methane flux and either temperature or irradiance in wetlands; a narrow range of both negative and positive values of the water table promoted CH4 emissions. Previously, little was known about the factors controlling efflux from river and marine environments. Our study suggests that local conditions are important in controlling CH4 emissions, because the variability explained by the more commonly studied abiotic

  4. Mitigation options for methane emissions from rice fields in the Philippines

    Energy Technology Data Exchange (ETDEWEB)

    Lantin, R.S.; Buendia, L.V.; Wassmann, R. [International Rice Research Institute, Laguna (Philippines)] [and others

    1996-12-31

    The contribution of Philippine rice production to global methane emission and breakthroughs in methane emission studies conducted in the country are presented in this paper. A significant impact in the reduction of GHG emissions from agriculture can be achieved if methane emissions from ricefields can be abated. This study presents the contribution of Philippine rice cultivation to global methane emission and breakthroughs in methane emission studies in the country which address the issue of mitigation. Using the derived emission factors from local measurements, rice cultivation contributes 566.6 Gg of methane emission in the Philippines. This value is 62% of the total methane emitted from the agriculture sector. The emission factors employed which are 78% of the IPCC value for irrigated rice and 95% for rainfed rice were derived from measurements with an automatic system taken during the growth duration in the respective ecosystems. Plots drained for 2 weeks at midtillering and before harvest gave a significant reduction in methane emission as opposed to continuously flooded plots and plots drained before harvest. The cultivar Magat reduced methane emission by 50% as compared to the check variety IR72. The application of ammonium sulfate instead of urea reduced methane emission by 10% to 34%. Addition of 6 t ha{sup {minus}1} phosphogypsum in combination with urea reduced emission by 74% as opposed to plots applied with urea alone. It is also from the results of such measurements that abatement strategies are based as regards to modifying treatments such as water management, fertilization, and choice of rice variety. It is not easy to identify and recommend mitigation strategies that will fit a particular cropping system. However, the identified mitigation options provide focus for the abatement of methane emission from ricefields.

  5. Dairy farm methane emissions using a dispersion model.

    Science.gov (United States)

    McGinn, S M; Beauchemin, K A

    2012-01-01

    There is a need to know whole-farm methane (CH(4)) emissions since confined animal facilities such as beef cattle feedlots and dairy farms are emission "hot spots" in the landscape. However, measurements of whole-farm CH(4) emissions can differ between farms because of differences in contributing sources such as manure handling, number of lactating and nonlactating cows, and diet. Such differences may limit the usefulness of whole-farm emissions for national inventories and mitigation purposes unless the variance between farms is taken into account or a large number of farms can be examined. Our study describes the application of a dispersion model used in conjunction with field measurements of CH(4) concentration and stability of the air to calculate whole-farm emissions of CH(4) from three dairy farms in Alberta, Canada, during three sequential campaigns conducted in November 2004 and May and July 2005. The dairy farms ranged in herd size from 208 to 351 cows (102 to 196 lactating cows) and had different manure handling operations. The results indicate that the average CH(4) emission per cow (mixture of lactating and nonlactating) from the three dairy farms was 336 g d(-1), which was reduced to 271 g d(-1) when the emission (estimated) from the manure storage was removed. Further separation of source strength yielded an average CH(4) (enteric) emission of 363 g d(-1) for a lactating cow. The estimated CH(4) emission intensities were approximately 15 g CH(4) kg(-1) dry matter intake and 16.7 L CH(4) L(-1) of milk produced. The approach of understanding the farm-to-farm differences in CH(4) emissions as affected by diet, animal type, and manure management is essential when utilizing whole-farm emission measurements for mitigation and inventory applications.

  6. Atmospheric Inverse Estimates of Methane Emissions from Central California

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton; Nehrkorn, Thomas; Fischer, Marc L.

    2008-11-21

    Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced for sub-regions near the tower site, yielding best estimates of flux from those regions consistent with 'source' analysis results. The uncertainty reductions for regions near the tower indicate that a regional network of measurements will be necessary to provide accurate estimates of surface CH{sub 4} emissions for multiple regions.

  7. Heritability for enteric methane emission from Danish Holstein cows using a non-invasive FTIR method

    DEFF Research Database (Denmark)

    Lassen, Jan; Løvendahl, Peter

    2013-01-01

    Enteric methane emission from ruminants contributes substantially to the greenhouse effect. Few studies have focused on the genetic variation in enteric methane emission from dairy cattle. One reason for that is the limited number of methods appropriate for large scale phenotyping to measure...... tools to reduce methane emission from dairy cattle. Another study (Wall et al ., 2010) has shown that selecting for correlated indicator traits such as productivity and efficiency would help lowering the methane emission from the cattle production. Furthermore, it is still important to have emphasis...

  8. Zero methane emission bogs: extreme rhizosphere oxygenation by cushion plants in Patagonia.

    Science.gov (United States)

    Fritz, Christian; Pancotto, Veronica A; Elzenga, Josephus T M; Visser, Eric J W; Grootjans, Ab P; Pol, Arjan; Iturraspe, Rodolfo; Roelofs, Jan G M; Smolders, Alfons J P

    2011-04-01

    • Vascular wetland plants may substantially increase methane emissions by producing root exudates and easily degradable litter, and by providing a low-resistance diffusion pathway via their aerenchyma. However, model studies have indicated that vascular plants can reduce methane emission when soil oxygen demand is exceeded by oxygen released from roots. Here, we tested whether these conditions occur in bogs dominated by cushion plants. • Root-methane interactions were studied by comparing methane emissions, stock and oxygen availability in depth profiles below lawns of either cushion plants or Sphagnum mosses in Patagonia. • Cushion plants, Astelia pumila and Donatia fascicularis, formed extensive root systems up to 120 cm in depth. The cold soil (microbial activity and oxygen consumption. In cushion plant lawns, high soil oxygen coincided with high root densities, but methane emissions were absent. In Sphagnum lawns, methane emissions were substantial. High methane concentrations were only found in soils without cushion plant roots. • This first methane study in Patagonian bog vegetation reveals lower emissions than expected. We conclude that cushion plants are capable of reducing methane emission on an ecosystem scale by thorough soil and methane oxidation. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  9. Methodology of Estimation of Methane Emissions from Coal Mines in Poland

    Science.gov (United States)

    Patyńska, Renata

    2014-03-01

    Based on a literature review concerning methane emissions in Poland, it was stated in 2009 that the National Greenhouse Inventory 2007 [13] was published. It was prepared firstly to meet Poland's obligations resulting from point 3.1 Decision no. 280/2004/WE of the European Parliament and of the Council of 11 February 2004, concerning a mechanism for monitoring community greenhouse gas emissions and for implementing the Kyoto Protocol and secondly, for the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol. The National Greenhouse Inventory states that there are no detailed data concerning methane emissions in collieries in the Polish mining industry. That is why the methane emission in the methane coal mines of Górnośląskie Zagłębie Węglowe - GZW (Upper Silesian Coal Basin - USCB) in Poland was meticulously studied and evaluated. The applied methodology for estimating methane emission from the GZW coal mining system was used for the four basic sources of its emission. Methane emission during the mining and post-mining process. Such an approach resulted from the IPCC guidelines of 2006 [10]. Updating the proposed methods (IPCC2006) of estimating the methane emissions of hard coal mines (active and abandoned ones) in Poland, assumes that the methane emission factor (EF) is calculated based on methane coal mine output and actual values of absolute methane content. The result of verifying the method of estimating methane emission during the mining process for Polish coal mines is the equation of methane emission factor EF.

  10. Effect of Land Use History on Methane Emission and Methanogeinc Flora in Flooded Soils

    Institute of Scientific and Technical Information of China (English)

    MINHANG; CHENMEICI; 等

    1996-01-01

    The characteristics of methane emission were compared among six types of upland and paddy soils developed from different materials with distinct physical and chemical properties after planting rice.The fluxes of methane emission in submerged soils from the upland were obviously lower than those from the paddy rice field.The flux of methane emission in the paddy soil developed from fluvo-aquic soil was the largest among all the types of soils.Planting of rice was heplful to emission of methane in soils.The amounts of various groups of methanogenic flora were conformed with the differences among the fluxes of methane emission in various types of soils.Methane formation was observed in each type of air-dried soils stored for a long time after addition of water and incubation at 35℃.

  11. Methane emissions from digestate at an agricultural biogas plant.

    Science.gov (United States)

    Baldé, Hambaliou; VanderZaag, Andrew C; Burtt, Stephen D; Wagner-Riddle, Claudia; Crolla, Anna; Desjardins, Raymond L; MacDonald, Douglas J

    2016-09-01

    Methane (CH4) emissions were measured over two years at an earthen storage containing digestate from a mesophilic biodigester in Ontario, Canada. The digester processed dairy manure and co-substrates from the food industry, and destroyed 62% of the influent volatile solids (VS). Annual average emissions were 19gCH4m(-3)d(-1) and 0.27gCH4kg(-1)VSd(-1). About 76% of annual emissions occurred from June to October. Annual cumulative emissions from digestate corresponded to 12% of the CH4 produced within the digester. A key contributor to CH4 emissions was the sludge layer in storage, which contained as much VS as the annual discharge from the digester. These findings suggest that digestate management provides an opportunity to further enhance the benefits of biogas (i.e. reducing CH4 emissions compared to undigested liquid manure, and producing renewable energy). Potential best practices for future study include complete storage emptying, solid-liquid separation, and storage covering.

  12. Modeling methane emissions by cattle production systems in Mexico

    Science.gov (United States)

    Castelan-Ortega, O. A.; Ku Vera, J.; Molina, L. T.

    2013-12-01

    Methane emissions from livestock is one of the largest sources of methane in Mexico. The purpose of the present paper is to provide a realistic estimate of the national inventory of methane produced by the enteric fermentation of cattle, based on an integrated simulation model, and to provide estimates of CH4 produced by cattle fed typical diets from the tropical and temperate climates of Mexico. The Mexican cattle population of 23.3 million heads was divided in two groups. The first group (7.8 million heads), represents cattle of the tropical climate regions. The second group (15.5 million heads), are the cattle in the temperate climate regions. This approach allows incorporating the effect of diet on CH4 production into the analysis because the quality of forages is lower in the tropics than in temperate regions. Cattle population in every group was subdivided into two categories: cows (COW) and other type of cattle (OTHE), which included calves, heifers, steers and bulls. The daily CH4 production by each category of animal along an average production cycle of 365 days was simulated, instead of using a default emission factor as in Tier 1 approach. Daily milk yield, live weight changes associated with the lactation, and dry matter intake, were simulated for the entire production cycle. The Moe and Tyrrell (1979) model was used to simulate CH4 production for the COW category, the linear model of Mills et al. (2003) for the OTHE category in temperate regions and the Kurihara et al. (1999) model for the OTHE category in the tropical regions as it has been developed for cattle fed tropical diets. All models were integrated with a cow submodel to form an Integrated Simulation Model (ISM). The AFRC (1993) equations and the lactation curve model of Morant and Gnanasakthy (1989) were used to construct the cow submodel. The ISM simulates on a daily basis the CH4 production, milk yield, live weight changes associated with lactation and dry matter intake. The total daily CH

  13. Enhanced Emission Performance and Fuel Efficiency for HD Methane Engines. Literature Study. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Broman, R.; Staalhammar, P.; Erlandsson, L.

    2010-05-15

    A literature survey has been conducted in order to define state-of-the-art for methane fuelled engines to be used in heavy duty vehicles. Use of methane can be favourable to increase security of supply and mitigate CO2 emissions, especially when the methane origins from biomass. Furthermore, methane used as a fuel in heavy duty engines has a potential to reduce toxic exhaust emissions. Historically, use of methane in heavy duty engines has often been hampered by poor efficiency, i.e. high fuel consumption when using the Otto-cycle. However, current generation technology engines might be within 5-10 % of the efficiency of Diesel engine technology. In this context it is worth mentioning that compliance-driven changes for meeting future emission regulations for Diesel engines may have a negative impact on fuel efficiency, thereby narrowing the gap. This may present an opportunity for heavy methane fuelled engines. The reliability and durability of the exhaust aftertreatment devices for methane fuelled engines has also given rise to some concerns. Some concepts are performing acceptable while others do not meet expectations. This is partly due to difficulties in handling methane in the aftertreatment device and partly to issues in the design of the ignition system. Methane is a fuel used worldwide and has a potential to be an important complement to Diesel oil. There are two categories of HD methane engines available to end-users: Retrofitted engines, which often include computer controlled retrofit systems developed as 'bolt-on' technologies that can be removed if necessary, to resell the vehicle with a normal diesel engine, and those developed specifically for and in conjunction with engine manufacturers and delivered to customers as factory-built engines or vehicles (OEM). Additionally, both these categories can include engines that use the Otto- or Diesel combustion cycles. When adapting a HD Diesel engine to run on methane there are two options, either

  14. Methane emissions during storage of different treatments from cattle manure in Tianjin

    Institute of Scientific and Technical Information of China (English)

    Jiajun Wang; Chiqing Duan; Yaqin Ji; Yichao Sun

    2010-01-01

    Many studies on methane emissions from animal manure have revealed that animal manure is a major source of methane emissions to the atmosphere that can have negative consequences for people,animals and environment.In general,the release of methane can be influenced by the type of feed taken by animals,temperature,manure characteristics and so on.This study aimed at quantifying and comparing methane release from dairy manure with different piling treatments.Four treatments were designed including manure piling height 30,45,60 cm and adding 6 cm manure every day until the piling height was 60 cm.Static chamber method and gas chromatography were adopted to measure the methane emissions from April to June in 2009.Methane emission rates of all four manure treatments were low in the first week and then increased sharply until reaching the peak values.Subsequently,all the methane emission rates decreased and fluctuated within the steady range till the end of the experiment.Wilcoxon nonparametric tests analysis indicated that methane emission rate was greatly influenced by manure piling height and manner.There were no significant relationships between methane emission rates and the temperatures of ambience and heap.However,regression analysis showed that the quadratic equations were found between emission rates of all treatments and the gas temperature in the barrels.

  15. Methane emissions during storage of different treatments from cattle manure in Tianjin.

    Science.gov (United States)

    Wang, Jiajun; Duan, Chiqing; Ji, Yaqin; Sun, Yichao

    2010-01-01

    Many studies on methane emissions from animal manure have revealed that animal manure is a major source of methane emissions to the atmosphere that can have negative consequences for people, animals and environment. In general, the release of methane can be influenced by the type of feed taken by animals, temperature, manure characteristics and so on. This study aimed at quantifying and comparing methane release from dairy manure with different piling treatments. Four treatments were designed including manure piling height 30, 45, 60 cm and adding 6 cm manure every day until the piling height was 60 cm. Static chamber method and gas chromatography were adopted to measure the methane emissions from April to June in 2009. Methane emission rates of all four manure treatments were low in the first week and then increased sharply until reaching the peak values. Subsequently, all the methane emission rates decreased and fluctuated within the steady range till the end of the experiment. Wilcoxon nonparametric tests analysis indicated that methane emission rate was greatly influenced by manure piling height and manner. There were no significant relationships between methane emission rates and the temperatures of ambience and heap. However, regression analysis showed that the quadratic equations were found between emission rates of all treatments and the gas temperature in the barrels.

  16. Drilling down on methane emissions in the US Four Corners region

    Science.gov (United States)

    Petron, G.

    2016-12-01

    Two years ago the Four Corners region became known as the largest methane hotspot in the US [Kort et al., 2014]. More specifically, satellite based methane columns over the San Juan Basin had the largest enhancements above the regional mean column and this feature pertained between 2003 and 2009. The methane "hotpsot" designation hides a more complex reality. The region is home to large scale coal, oil, coalbed methane and natural gas extraction and processing which all can emit methane. Portions of the Fruitland coal outcrop on the Colorado side also have been degassing methane for decades. Other minor methane sources in the area include landfills and a few animal operations. In April 2015, a large airborne and ground-based campaign investigated the Four Corners methane hotspot to further characterize methane emissions in the region. In this talk we will summarize what has been learned and which questions remain.

  17. Site specific diel methane emission mechanisms in landfills: A field validated process based on vegetation and climate factors.

    Science.gov (United States)

    Xin, Danhui; Hao, Yongxia; Shimaoka, Takayuki; Nakayama, Hirofumi; Chai, Xiaoli

    2016-11-01

    Diel methane emission fluxes from a landfill that was covered by vegetation were investigated to reveal the methane emission mechanisms based on the interaction of vegetation characteristics and climate factors. The methane emissions showed large variation between daytime and nighttime, and the trend of methane emissions exhibited clear bimodal patterns from both Setaria viridis- and Neyraudia reynaudiana-covered areas. Plants play an important role in methane transportation as well as methane oxidation. The notable decrease in methane emissions after plants were cut suggests that methane transportation via plants is the primary way of methane emissions in the vegetated areas of landfill. Within plants, the methane emission fluxes were enhanced due to a convection mechanism. Given that the methane emission flux is highly correlated with the solar radiation during daytime, the convection mechanism could be attributed to the increase in solar radiation. Whereas the methane emission flux is affected by a combined impact of the wind speed and pedosphere characteristics during nighttime. An improved understanding of the methane emission mechanisms in vegetated landfills is expected to develop a reliable model for landfill methane emissions and to attenuate greenhouse gas emissions from landfills.

  18. Modeling Modern Methane Emissions from Natural Wetlands. 2; Interannual Variations 1982-1993

    Science.gov (United States)

    Walter, Bernadette P.; Heimann, Martin; Mattews, Elaine; Hansen, James E. (Technical Monitor)

    2001-01-01

    A global run of a process-based methane model [Walter et al., this issue] is performed using high-frequency atmospheric forcing fields from ECMWF reanalyses of the period from 1982 to 1993. We calculate global annual methane emissions to be 260 Tg/ yr. 25% of methane emissions originate from wetlands north of 30 deg. N. Only 60% of the produced methane is emitted, while the rest is re-oxidized. A comparison of zonal integrals of simulated global wetland emissions and results obtained by an inverse modeling approach shows good agreement. In a test with data from two wetlands, the seasonality of simulated and observed methane emissions agrees well. The effects of sub-grid scale variations in model parameters and input data are examined. Modeled methane emissions show high regional, seasonal and interannual variability. Seasonal cycles of methane emissions are dominated by temperature in high latitude wetlands, and by changes in the water table in tropical wetlands. Sensitivity tests show that +/- 1 C changes in temperature lead to +/- 20 % changes in methane emissions from wetlands. Uniform changes of +/- 20% in precipitation alter methane emissions by about +/- 18%. Limitations in the model are analyzed. Simulated interannual variations in methane emissions from wetlands are compared to observed atmospheric growth rate anomalies. Our model simulation results suggest that contributions from other sources than wetlands and/or the sinks are more important in the tropics than north-of 30 deg. N. In higher northern latitudes, it seems that a large part, of the observed interannual variations can be explained by variations in wetland emissions. Our results also suggest that reduced wetland emissions played an important role in the observed negative methane growth rate anomaly in 1992.

  19. Methane emissions from terrestrial plants over China and their effects on methane concentrations in lower troposphere

    Institute of Scientific and Technical Information of China (English)

    XIE Min; LI Shu; JIANG Fei; WANG TiJian

    2009-01-01

    Methane (CH4) is the most important greenhouse gas and reactive trace gas in the atmosphere. Re-cently, it has been reported that terrestrial plants can emit CH4 under aerobic conditions, which may call for reevaluation of the inventory of CH4 emissions in China. In this paper, those emissions over China and their effects on CH4 concentrations in lower troposphere were investigated. Firstly, based on the work of Keppler et al., the aerobic plant CH4 emission model (PLANTCH4) for China was established.And by using the database of normalized difference vegetation index (NDVI) derived from NOAA/AVHRR, the distribution of net primary productivity (NPP) over China was simulated, and thereby, for the first time, the amount and distribution of the newly identified source in China were estimated.Secondly, with the aid of the three-dimensional atmospheric chemistry model system (MM5-CALGRiD),the effects of the emissions were studied. The results show that the annual aerobic plant CH4 emis-sions over China amount to 11.83 Tg, i.e. nearly 24% of Chinese total CH4 emissions. And the major fraction (about 43%) comes from forests. When those emissions are considered in modeling, computed countrywide mean surface concentration of CH4 is 29.9% higher than without them, with a maximum increase of 69.61 ug- m-3 in the south of Yunnan Province. In conclusion, to study CH4 emissions from terrestrial plants over China may have important implications for correctly estimating the contribution of China to global CH4 budget, and may call for a reconsideration of the role of CH4 in global and re-gional environment and climate change.

  20. Mapping methane emission sources over California based on airborne measurements

    Science.gov (United States)

    Karl, T.; Guha, A.; Peischl, J.; Misztal, P. K.; Jonsson, H.; Goldstein, A. H.; Ryerson, T. B.

    2011-12-01

    The California Global Warming Solutions Act of 2006 (AB 32) has created a need to accurately characterize the emission sources of various greenhouse gases (GHGs) and verify the existing state GHG inventory. Methane (CH4) is a major GHG with a global warming potential of 20 times that of CO2 and currently constitutes about 6% of the total statewide GHG emissions on a CO2 equivalent basis. Some of the major methane sources in the state are area sources where methane is biologically produced (e.g. dairies, landfills and waste treatment plants) making bottom-up estimation of emissions a complex process. Other potential sources include fugitive emissions from oil extraction processes and natural gas distribution network, emissions from which are not well-quantified. The lack of adequate field measurement data to verify the inventory and provide independently generated estimates further contributes to the overall uncertainty in the CH4 inventory. In order to gain a better perspective of spatial distribution of major CH4 sources in California, a real-time measurement instrument based on Cavity Ring Down Spectroscopy (CRDS) was installed in a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of airborne CH4 and CO2 measurements during eight unique flights which covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. The coincident VOC measurements, obtained through a high frequency proton transfer reaction mass spectrometer (PTRMS), aid in CH4 source identification. High mixing ratios of CH4 (> 2000 ppb) are observed consistently in all the flight transects above the Central Valley. These high levels of CH4 are accompanied by high levels of methanol which is an important

  1. Role of regional wetland emissions in atmospheric methane variability

    Science.gov (United States)

    McNorton, J.; Gloor, E.; Wilson, C.; Hayman, G. D.; Gedney, N.; Comyn-Platt, E.; Marthews, T.; Parker, R. J.; Boesch, H.; Chipperfield, M. P.

    2016-11-01

    Atmospheric methane (CH4) accounts for 20% of the total direct anthropogenic radiative forcing by long-lived greenhouse gases. Surface observations show a pause (1999-2006) followed by a resumption in CH4 growth, which remain largely unexplained. Using a land surface model, we estimate wetland CH4 emissions from 1993 to 2014 and study the regional contributions to changes in atmospheric CH4. Atmospheric model simulations using these emissions, together with other sources, compare well with surface and satellite CH4 data. Modeled global wetland emissions vary by ±3%/yr (σ = 4.8 Tg), mainly due to precipitation-induced changes in wetland area, but the integrated effect makes only a small contribution to the pause in CH4 growth from 1999 to 2006. Increasing temperature, which increases wetland area, drives a long-term trend in wetland CH4 emissions of +0.2%/yr (1999 to 2014). The increased growth post-2006 was partly caused by increased wetland emissions (+3%), mainly from Tropical Asia, Southern Africa, and Australia.

  2. Methane emission quantification from landfills using a double tracer approach

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Samuelsson, J.; Fredenslund, Anders Michael

    2007-01-01

    in the October respectively February measurement. The CH4 emission from the compost area was 0.5 kg CH4 h-1, whereas the carbon dioxide (CO2) flux and nitrous oxide (N2O) was quantified to be in the order of 332 kg CO2 h-1 and 0.06 kg N2O h-1 respectively. The sludge pit located west of the compost material......A tracer method was successfully used for quantification of the whole methane (CH4) emission from Fakse landfill. By using two different tracers the emission from different sections of the landfill could be quantified. Furthermore, is was possible to determine the emissions from local on site...... sources; a composting facility and a sewage sludge storage unit by scaling the tracer method down. Two field campaigns were performed; during October 11-12, 2006 and February 19-20, 2007. At both field campaigns an overall leak search showed that the CH4 emission from the old landfill section...

  3. Identification of Methanogens and Controls on Methane Production in Incubations of Natural Methane Seep Sediments

    Science.gov (United States)

    Kevorkian, R.; Lloyd, K. G.

    2014-12-01

    Methane, the most abundant hydrocarbon in Earth's atmosphere, is produced in large quantities in sediments underlying the world's oceans. Very little of this methane makes it to surface sediments as it is consumed by Anaerobic Methanotrophs (ANME's) in consortia with Sulfate Reducing Bacteria (SRB). Less is known about which organisms are responsible for methane production in marine sediments, and whether that production is under thermodynamic control based on hydrogen concentrations. Although ANMEs have been found to be active in methanogenic sediments and incubations, it is currently unknown whether they are able to grow in methanogenic conditions. We demonstrated with bottle incubations of methane seep sediment taken from Cape Lookout Bight, NC, that hydrogen controls methane production. While sulfate was present the hydrogen concentration was maintained at below 2 nM. Only after the depletion of sulfate allowed hydrogen concentrations to rise above 5 nM did we see production of methane. The same sediments when spiked with methane gas demonstrated its complete removal while sulfate reduction occurred. Quantitative PCR shows that ANME-2 and ANME-1 increase in 16S copy number as methane increases. Total direct cell counts demonstrate a decline in cells with the decrease of sulfate until a recovery corresponding with production of methane. Our results strongly suggest that hydrogen concentrations influence what metabolic processes can occur in marine sediments, and that ANME-1 and ANME-2 are able to grow on the energy provided from methane production.

  4. Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions.

    Science.gov (United States)

    Miller, Benjamin L; Arntzen, Evan V; Goldman, Amy E; Richmond, Marshall C

    2017-07-21

    The United States is home to 2198 dams actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change Paris Agreement, it is important to accurately quantify anthropogenic greenhouse gas emissions. Methane ebullition, or methane bubbles originating from river or lake sediments, has been shown to account for nearly all methane emissions from tropical hydropower reservoirs to the atmosphere. However, distinct ebullitive methane fluxes have been studied in comparatively few temperate hydropower reservoirs globally. This study measures ebullitive and diffusive methane fluxes from two eastern Washington reservoirs, and synthesizes existing studies of methane ebullition in temperate, boreal, and tropical hydropower reservoirs. Ebullition comprises nearly all methane emissions (>97%) from this study's two eastern Washington hydropower reservoirs to the atmosphere. Summer methane ebullition from these reservoirs was higher than ebullition in six southeastern U.S. hydropower reservoirs, however it was similar to temperate reservoirs in other parts of the world. Our literature synthesis suggests that methane ebullition from temperate hydropower reservoirs can be seasonally elevated compared to tropical climates, however annual emissions are likely to be higher within tropical climates, emphasizing the possible range of methane ebullition fluxes and the need for the further study of temperate reservoirs. Possible future changes to the Intergovernmental Panel on Climate Change and UNFCCC guidelines for national greenhouse gas inventories highlights the need for accurate assessment of reservoir emissions.

  5. Control of Methane Production and Exchange in Northern Peatlands

    Science.gov (United States)

    Crill, Patrick

    1997-01-01

    This proposal has successfully supported studies that have developed unique long ten-n datasets of methane (CH4) emissions and carbon dioxide (CO2) exchange in order to quantify the controls on CH4 production and exchange especially the linkages to the carbon cycle in northern peatlands. The primary research site has been a small fen in southeastern New Hampshire where a unique multi-year data baseline of CH4 flux measurements was begun (with NASA funding) in 1989. The fen has also been instrumented for continuous hydrological and meteorological observations and year-round porewater sampling. Multiyear datasets of methane flux are very valuable and very rare. Datasets using the same sampling techniques at the same sites are the only way to assess the effect of the integrated ecosystem response to climatological variability. The research has had two basic objectives: 1. To quantify the effect of seasonal and interannual variability on CH4flux. 2. To examine process level controls on methane dynamics.

  6. Quantifying methane emission from fugitive sources by combining tracer release and downwind measurements – A sensitivity analysis based on multiple field surveys

    DEFF Research Database (Denmark)

    Mønster, Jacob; Samuelsson, Jerker; Kjeldsen, Peter

    2014-01-01

    Using a dual species methane/acetylene instrument based on cavity ring down spectroscopy (CRDS), the dynamic plume tracer dispersion method for quantifying the emission rate of methane was successfully tested in four measurement campaigns: (1) controlled methane and trace gas release with different...... trace gas configurations, (2) landfill with unknown emission source locations, (3) landfill with closely located emission sources, and (4) comparing with an Fourier transform infrared spectroscopy (FTIR) instrument using multiple trace gasses for source separation. The new real-time, high precision...... instrument can measure methane plumes more than 1.2km away from small sources (about 5kgh−1) in urban areas with a measurement frequency allowing plume crossing at normal driving speed. The method can be used for quantification of total methane emissions from diffuse area sources down to 1kg per hour and can...

  7. Renewable energy and reduction of methane emission. Emission-low manure storage; Duurzame energie en vermindering methaanemissies. Emissiearme mestopslag

    Energy Technology Data Exchange (ETDEWEB)

    Hilhorst, M.A.; Monteny, G.J.; De Gijsel, P. [IMAG Wageningen-UR, Wageningen (Netherlands); Van Dooren, H.J.C.; Van Lent, A.J.H. [Praktijkonderzoek Rundvee, Schapen en Paarden PR, Lelystad (Netherlands)

    2001-03-01

    It is the target of the Dutch government to reduce the emissions of all non-CO2 greenhouse gases in The Netherlands by 8 Mton CO2-eq in 2010. Livestock contributes for about 40% (10 Mton CO2-eq) to the emissions of methane. Enteric fermentation is responsible for 32% (8 Mton CO2-eq) and slurry for 8% (2 Mton CO2-eq). In the Netherlands, slurry is the most common manure system. Low-cost and effective options to reduce methane emissions, without increasing emissions of ammonia and nitrous oxide, are covering the outdoor slurry storage, shortening the indoor storage time, lowering the storage temperature and filtration of the air from the livestock house and storage facility. Other less favourable options are aeration, acidification, feed adjustments and controlled anaerobic digestion. Covering of outdoor storages is mandatory in the Netherlands to reduce ammonia emissions. The methane emission reduction of a well covered outdoor storage with the slurry at rest is around 60%. In The Netherlands the average temperature of outdoor storage is less than 10.2C. Methane emissions will decrease by 66% if the slurry temperature is decreased from 20C to 10C. For pig farms the main source of methane is the slurry stored under the slatted floor. The slurry surface is nearly at indoor temperature (20C). It is most effective for pig slurry to reduce the indoor storage time. Also for ruminants some reduction may be expected from shortening the indoor storage time of slurry. In addition measurements showed a reduction of more than 50% methane emission for well covered storages with slurry at rest. Therefore, the methane emission from an outdoor storage may be neglected. Reduction of the indoor storage time can result in methane emission reduction from slurry by 50% or 1 Mton CO2-eq. Since most of the methane is produced in the livestock house, i.e. methane from enteric fermentation and from slurry, it is evident that filtering the methane from the ventilation air can be an effective

  8. Rising methane emissions from northern wetlands associated with sea ice decline

    DEFF Research Database (Denmark)

    Parmentier, Frans Jan W; Zhang, Wenxin; Mi, Yanjiao

    2015-01-01

    . Nonetheless, terrestrial and marine environments are seldom jointly analyzed. By comparing satellite observations of Arctic sea ice concentrations to methane emissions simulated by three process-based biogeochemical models, this study shows that rising wetland methane emissions are associated with sea ice...

  9. Zero methane emission bogs : extreme rhizosphere oxygenation by cushion plants in Patagonia

    NARCIS (Netherlands)

    Fritz, Christian; Pancotto, Veronica A.; Elzenga, Josephus T.M.; Visser, Eric J.W.; Grootjans, Ab P.; Pol, Arjan; Iturraspe, Rodolfo; Roelofs, Jan G.M.; Smolders, Alfons J.P.

    2011-01-01

    Vascular wetland plants may substantially increase methane emissions by producing root exudates and easily degradable litter, and by providing a low-resistance diffusion pathway via their aerenchyma. However, model studies have indicated that vascular plants can reduce methane emission when soil oxy

  10. Large methane emissions from a subarctic lake during spring thaw: Mechanisms and landscape significance

    Science.gov (United States)

    Jammet, Mathilde; Crill, Patrick; Dengel, Sigrid; Friborg, Thomas

    2015-11-01

    The ice-cover season and subsequent spring thaw are thought to be of particular importance for the biogeochemical cycle of northern lakes and wetlands. Yet the magnitude of their methane emissions during an entire cold season is uncertain due to scarce measurements. While wetlands are known to be the highest natural emitters of methane, emissions from northern lakes are an uncertain component of terrestrial carbon budgets. To evaluate the importance of methane emissions from a subarctic lake during winter and spring, surface methane fluxes were recorded with the eddy covariance method in a subarctic fen-type wetland and in an adjacent shallow lake, from freezeup to complete ice out. The fen was a steady emitter of methane throughout winter. While no detectable flux was observed from the ice-covered lake surface during winter, it was the largest methane source of the landscape in spring, with a cumulative release 1.7-fold higher than at the fen, accounting for 53% of annual lake emissions. The high temporal resolution of the measurements allowed making a direct link between breakdown of the temperature stratification after ice breakup and the highest release of methane from the lake surface. A sediment upwelling at the end of the thaw season likely contributed to these emissions. We suggest that, unlike wetlands, shallow seasonally ice-covered lakes can have their highest methane emission potential in the cold season, likely dominating the spring methane release of subarctic landscapes with high lake coverage.

  11. Satellite-derived methane emissions from inundation in Bangladesh

    Science.gov (United States)

    Peters, C. N.; Bennartz, R.; Hornberger, G. M.

    2017-05-01

    The uncertainty in methane (CH4) source strength of rice fields and wetlands is particularly high in South Asia CH4 budgets. We used satellite observations of CH4 column mixing ratios from Atmospheric Infrared Sounder (AIRS), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and Greenhouse Gases Observing Satellite (GOSAT) to estimate the contribution of Bangladesh emissions to atmospheric CH4 concentrations. Using satellite-derived inundation area as a proxy for source area, we developed a simple inverse advection model that estimates average annual CH4 surface fluxes to be 4, 9, and 19 mg CH4 m-2 h-1 in AIRS, SCIAMACHY, and GOSAT, respectively. Despite this variability, our flux estimates varied over a significantly narrower range than reported values for CH4 surface fluxes from a survey of 32 studies reporting ground-based observations between 0 and 260 mg CH4 m-2 h-1. Upscaling our satellite-derived surface flux estimates, we estimated total annual CH4 emissions for Bangladesh to be 1.3 ± 3.2, 1.8 ± 2.0, 3.1 ± 1.6 Tg yr-1, depending on the satellite. Our estimates of total emissions are in line with the median of total emission values for Bangladesh reported in earlier studies.

  12. Mechanistic modeling of microbial interactions at pore to profile scale resolve methane emission dynamics from permafrost soil

    Science.gov (United States)

    Ebrahimi, Ali; Or, Dani

    2017-05-01

    The sensitivity of polar regions to raising global temperatures is reflected in rapidly changing hydrological processes associated with pronounced seasonal thawing of permafrost soil and increased biological activity. Of particular concern is the potential release of large amounts of soil carbon and stimulation of other soil-borne greenhouse gas emissions such as methane. Soil methanotrophic and methanogenic microbial communities rapidly adjust their activity and spatial organization in response to permafrost thawing and other environmental factors. Soil structural elements such as aggregates and layering affect oxygen and nutrient diffusion processes thereby contributing to methanogenic activity within temporal anoxic niches (hot spots). We developed a mechanistic individual-based model to quantify microbial activity dynamics in soil pore networks considering transport processes and enzymatic activity associated with methane production in soil. The model was upscaled from single aggregates to the soil profile where freezing/thawing provides macroscopic boundary conditions for microbial activity at different soil depths. The model distinguishes microbial activity in aerate bulk soil from aggregates (or submerged profile) for resolving methane production and oxidation rates. Methane transport pathways by diffusion and ebullition of bubbles vary with hydration dynamics. The model links seasonal thermal and hydrologic dynamics with evolution of microbial community composition and function affecting net methane emissions in good agreement with experimental data. The mechanistic model enables systematic evaluation of key controlling factors in thawing permafrost and microbial response (e.g., nutrient availability and enzyme activity) on long-term methane emissions and carbon decomposition rates in the rapidly changing polar regions.

  13. Renewed methane increase (2007-2014): contribution of oil and natural gas emissions determined from methane and ethane column observations

    Science.gov (United States)

    Hausmann, Petra; Sussmann, Ralf; Smale, Dan

    2016-04-01

    Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47° N, 2964 m a.s.l.) and at Lauder (45° S, 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6.2 [5.6, 6.9] ppb yr-1 at the Zugspitze and 6.0 [5.3, 6.7] ppb yr-1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as tracer for thermogenic methane emissions. In 2007, after years of weak decline, the Zugspitze ethane time series shows the sudden onset of a significant positive trend (2.3 [1.8, 2.8] × 10-2 ppb yr-1 for 2007-2014), while a negative trend persists at Lauder after 2007 (-0.4 [-0.6, -0.1] × 10-2 ppb yr-1). Zugspitze methane and ethane time series are significantly correlated for the period 2007-2014 and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio of 10-21 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr-1 along with an overall methane emission increase of 24-45 Tg yr-1. Based on these results, the oil and natural gas emission contribution C to the renewed methane increase is deduced using three different emission scenarios with dedicated ranges of methane-to-ethane ratios (MER). Reference scenario 1 assumes an oil and gas emission combination with MER = 3.3-7.6, which results in a

  14. Recent Development in the Methane Production,Measurement and Emission Control in Ruminants%反刍动物甲烷的产生、测定及减排调控的研究

    Institute of Scientific and Technical Information of China (English)

    李恩凯; 杨在宾

    2014-01-01

    文章综述了反刍动物甲烷的产生机制和瘤胃内主要的产甲烷菌种类,并阐明了不同的产甲烷菌的甲烷合成底物及甲烷合成途径。文章还阐明了反刍动物甲烷产量的测定方法以及减排措施。%This paper reviewed the methane production mechanism,main mathanogen bacteria and methane synthesis pathway in the rumen of ruminant,also discussed the measurement methods and measures to reduce methane emission.

  15. Detecting Methane Emission Sources in California: a Case-Study of Scientist/Decision-Maker Interactions

    Science.gov (United States)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Kuwayama, T.; Hinojosa, L.

    2015-12-01

    Reducing anthropogenic methane emissions is a high priority for the state of California as a strategy to meet near-term greenhouse gas emissions targets. However, implementation of an effective, cost-efficient methane mitigation plan requires local-to-regional scale information on methane sources, and cooperation of diverse stakeholders. We hypothesize that methane "super-emitters," large point sources thought to contribute disproportionately to anthropogenic methane emissions, are logical mitigation targets. We outline a tiered observing strategy involving satellite, aircraft, and surface observations to identify these super-emitters and their contribution to regional methane emissions. We demonstrate this approach with field studies of agricultural and oil and gas sources in California's San Joaquin Valley with cooperation a multi-stakeholder team. This partnership between researchers, regulators, and methane emitting industry took advantage of data sharing, site access, and complementary measurement approaches to identify appropriate methane mitigation targets. This experience suggests that collaborative partnerships that leverage multiple observational methods will be required for identifying methane mitigation targets and crafting regionally appropriate methane mitigation policy.

  16. Carbon dioxide and methane emissions from the Yukon River system

    Science.gov (United States)

    Striegl, Rob; Dornblaser, Mark M.; McDonald, Cory P.; Rover, Jennifer R.; Stets, Edward G.

    2012-01-01

    Carbon dioxide (CO2) and methane (CH4) emissions are important, but poorly quantified, components of riverine carbon (C) budgets. This is largely because the data needed for gas flux calculations are sparse and are spatially and temporally variable. Additionally, the importance of C gas emissions relative to lateral C exports is not well known because gaseous and aqueous fluxes are not commonly measured on the same rivers. We couple measurements of aqueous CO2 and CH4 partial pressures (pCO2, pCH4) and flux across the water-air interface with gas transfer models to calculate subbasin distributions of gas flux density. We then combine those flux densities with remote and direct observations of stream and river water surface area and ice duration, to calculate C gas emissions from flowing waters throughout the Yukon River basin. CO2emissions were 7.68 Tg C yr−1 (95% CI: 5.84 −10.46), averaging 750 g C m−2 yr−1 normalized to water surface area, and 9.0 g C m−2 yr−1 normalized to river basin area. River CH4 emissions totaled 55 Gg C yr−1 or 0.7% of the total mass of C emitted as CO2 plus CH4 and ∼6.4% of their combined radiative forcing. When combined with lateral inorganic plus organic C exports to below head of tide, C gas emissions comprised 50% of total C exported by the Yukon River and its tributaries. River CO2 and CH4 derive from multiple sources, including groundwater, surface water runoff, carbonate equilibrium reactions, and benthic and water column microbial processing of organic C. The exact role of each of these processes is not yet quantified in the overall river C budget.

  17. Methane emission from rice: Stable isotopes, diurnal variations, and CO2 exchange

    Science.gov (United States)

    Chanton, J. P.; Whiting, G. J.; Blair, N. E.; Lindau, C. W.; Bollich, P. K.

    1997-03-01

    The importance of vegetation in supporting methane production and emission within flooded rice fields was demonstrated. Methane emission from Lousiana, United States, rice fields was correlated to the quantity of live aboveground biomass and the rate of CO2 exchange. The quantity of belowground methane was greater in vegetated plots relative to plots maintained free of vegetation. The diurnal maximum in the rate of methane emission was coincident with the release of the most 13C-enriched methane and a maximum in transpiration rate rather than stomatal conductance, suggesting that diurnal variations in methane emission rate are linked with transpiration, in addition to temperature. Results of isotopic measurements of belowground, lacunal, and emitted methane indicate that methane is transported from rice predominantly via molecular diffusion with a small component due to transpiration-induced bulk flow. Samples of methane collected from air-filled internal spaces within the rice culm were 13C-enriched (-53.1 ± 0.3‰) relative to emitted (-64.5 ± 1.0‰) and belowground methane (-59 ± 1.0‰) . Reproduction of these observed 13C values with a numerical model required isotopic fractionation effects associated with transport of methane into and from rice plants. The model could not conclusively confirm rhizospheric methane oxidation. However, 13C-enriched methane was observed in the floodwater overlying the flooded soil (-44.4 ± 2.2‰), consistent with the oxidation of substantial quantities of methane as it diffused across the soil-water interface.

  18. Open Path Tracer Measurements of Methane Emissions from Free Ranging Cattle

    Science.gov (United States)

    Griffith, D. W.; Tonini, M.; Bryant, G. R.; Eckard, R.; Grainger, C.; McGinn, S. M.

    2006-12-01

    This paper addresses the need for more accurate and representative measurements of methane emissions from cattle in their natural environments. Improved measurements are or will be required to quantify methane emissions for national greenhouse gas budgets and future carbon trading schemes, and to assess the effectiveness of proposed mitigation strategies. We describe measurements of methane emissions from free- ranging cattle grazing in their natural outdoor environments in Australia and New Zealand. We employ a novel tracer method in which nitrous oxide is released at a known rate from fenceline tubing or canisters attached to individual cows, and the mixing ratios of methane, nitrous oxide and carbon dioxide are measured continuously and simultaneously downwind by open path FTIR spectroscopy. Correlations between methane, nitrous oxide and carbon dioxide can be used to infer the herd-average methane flux directly. Measurements will be compared with the more conventional SF6 ruminal tracer technique.

  19. Detection of marine methane emissions with AVIRIS band ratios

    Science.gov (United States)

    Bradley, Eliza S.; Leifer, Ira; Roberts, Dar A.; Dennison, Philip E.; Washburn, Libe

    2011-05-01

    The relative source contributions of methane (CH4) have high uncertainty, creating a need for local-scale characterization in concert with global satellite measurements. However, efforts towards methane plume imaging have yet to provide convincing results for concentrated sources. Although atmospheric CH4 mapping did not motivate the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) design, recent studies suggest its potential for studying concentrated CH4 sources such as the Coal Oil Point (COP) seep field (˜0.015 Tg CH4 yr-1) offshore Santa Barbara, California. In this study, we developed a band ratio approach on high glint COP AVIRIS data and demonstrate the first successful local-scale remote sensing mapping of natural atmospheric CH4 plumes. Plume origins closely matched surface and sonar-derived seepage distributions, with plume characteristics consistent with wind advection. Imaging spectrometer data may also be useful for high spatial-resolution characterization of concentrated, globally-significant CH4 emissions from offshore platforms and cattle feedlots.

  20. Estimation of methane emissions from a wastewater treatment plant in Valence

    Science.gov (United States)

    Ars, Sébastien; Yver Kwok, Camille; Bousquet, Philippe; Broquet, Grégoire; Ciais, Philippe; Wu, Lin

    2014-05-01

    Methane is the second most important anthropogenic greenhouse gas emitted; its 20 year global-warming potential is about 56 to 72 depending on authors. One of its sources is the treatment of wastewaters and more particularly anaerobic digestion processes and sludge treatment. To reduce methane emissions from wastewater treatment plants, it is necessary to precisely quantify the amount emitted globally by the plant but also for each step of the process. Fixing the potential leaks and collecting the methane emitted by the different processes allows to reduce methane emissions and costs as methane can be sold or used on-site as an energy source. Moreover improve methods to estimate flow from atmospheric measurements of methane will reduce uncertainties in the inversion models. Several measurement campaigns have been realized in the wastewater treatment plant of Valence, France. This plant treats up to 2800 m3/h of polluted water through a biological treatment. To quantify methane emissions from this wastewater treatment plant, a dual tracer method had been used. It consists in releasing acetylene collocated with the methane source and in measuring both concentrations in the emitted plumes. In parallel, an atmospheric local scale model was used to compare with the experimental results. The higher concentration of methane's emissions was observed around the wastewater arrival. Plant's emissions are in the same range as estimations from the CITEPA French inventory. Measurements during the campaign are well correlated with the model results.

  1. A new method for top-down quantification of methane and pollutant emissions from natural gas production

    Science.gov (United States)

    Alden, C. B.; Prasad, K.; Ghosh, S.; Sweeney, C.; Karion, A.; Coburn, S.; Wright, R.; Coddington, I.; Truong, G. W.; Baumann, E.; Cossel, K.; Newbury, N.; Rieker, G. B.

    2016-12-01

    A need exists for low-cost, high-precision, and high-accuracy quantification of pollutant and greenhouse gas emissions. This need is particularly pressing as new international agreements and national- and state-level rules require monitoring, quantification and reduction of emissions. We present a novel atmospheric observing system that locates and sizes pollutant sources using long-range (0.1 to 2+ km) open-path measurement of atmospheric constituents with a dual-frequency comb spectrometer, coupled with high resolution atmospheric transport modeling and inversion methods. Planned field deployment of the spectrometer in eastern Colorado and concurrent modeling efforts will constitute the first time that a dual-frequency comb spectrometer has been used in the field for top-down constraint and quantification of emissions. The initial field deployment is designed for quantification of methane emissions at oil and gas production and storage sites. A unique strength of the coupled spectrometer and inverse modeling system is the ability to locate and size multiple point sources of methane across a large area (>12 km2), potentially encompassing 10s of wells, with one spectrometer. We present inversion modeling techniques and transport modeling developed to constrain bottom-up inventories with detailed spatial information, and to provide continuous and temporally resolved emissions estimates. Synthetic data simulations have demonstrated the ability of the system to accurately locate and size very small methane emissions (3.17E-5 kg/s) within a relatively short period of time (>18-days). A particularly important consideration for quantifying emissions is background inflow variability. We will present novel methods for constraint of background concentrations, as well as our observing system design configuration, inversion methodology, results of synthetic data testing, and preliminary data from a controlled methane release field test. We will present new system development

  2. Methane emissions measurements of natural gas components using a utility terrain vehicle and portable methane quantification system

    Science.gov (United States)

    Johnson, Derek; Heltzel, Robert

    2016-11-01

    Greenhouse Gas (GHG) emissions are a growing problem in the United States (US). Methane (CH4) is a potent GHG produced by several stages of the natural gas sector. Current scrutiny focuses on the natural gas boom associated with unconventional shale gas; however, focus should still be given to conventional wells and outdated equipment. In an attempt to quantify these emissions, researchers modified an off-road utility terrain vehicle (UTV) to include a Full Flow Sampling system (FFS) for methane quantification. GHG emissions were measured from non-producing and remote low throughput natural gas components in the Marcellus region. Site audits were conducted at eleven locations and leaks were identified and quantified at seven locations including at a low throughput conventional gas and oil well, two out-of-service gathering compressors, a conventional natural gas well, a coalbed methane well, and two conventional and operating gathering compressors. No leaks were detected at the four remaining sites, all of which were coal bed methane wells. The total methane emissions rate from all sources measured was 5.3 ± 0.23 kg/hr, at a minimum.

  3. Methane emission modeling with MCMC calibration for a boreal peatland

    Science.gov (United States)

    Raivonen, Maarit; Smolander, Sampo; Susiluoto, Jouni; Backman, Leif; Li, Xuefei; Markkanen, Tiina; Kleinen, Thomas; Makela, Jarmo; Aalto, Tuula; Rinne, Janne; Brovkin, Victor; Vesala, Timo

    2016-04-01

    Natural wetlands, particularly peatlands of the boreal latitudes, are a significant source of methane (CH4). At the moment, the emission estimates are highly uncertain. These natural emissions respond to climatic variability, so it is necessary to understand their dynamics, in order to be able to predict how they affect the greenhouse gas balance in the future. We have developed a model of CH4 production, oxidation and transport in boreal peatlands. It simulates production of CH4 as a proportion of anaerobic peat respiration, transport of CH4 and oxygen between the soil and the atmosphere via diffusion in aerenchymatous plants and in peat pores (water and air filled), ebullition and oxidation of CH4 by methanotrophic microbes. Ultimately, we aim to add the model functionality to global climate models such as the JSBACH (Reick et al., 2013), the land surface scheme of the MPI Earth System Model. We tested the model with measured methane fluxes (using eddy covariance technique) from the Siikaneva site, an oligotrophic boreal fen in southern Finland (61°49' N, 24°11' E), over years 2005-2011. To give the model estimates regional reliability, we calibrated the model using Markov chain Monte Carlo (MCMC) technique. Although the simulations and the research are still ongoing, preliminary results from the MCMC calibration can be described as very promising considering that the model is still at relatively early stage. We will present the model and its dynamics as well as results from the MCMC calibration and the comparison with Siikaneva flux data.

  4. Influence of different plant species on methane emissions from soil in a restored Swiss wetland.

    Directory of Open Access Journals (Sweden)

    Gurbir S Bhullar

    Full Text Available Plants are a major factor influencing methane emissions from wetlands, along with environmental parameters such as water table, temperature, pH, nutrients and soil carbon substrate. We conducted a field experiment to study how different plant species influence methane emissions from a wetland in Switzerland. The top 0.5 m of soil at this site had been removed five years earlier, leaving a substrate with very low methanogenic activity. We found a sixfold difference among plant species in their effect on methane emission rates: Molinia caerulea and Lysimachia vulgaris caused low emission rates, whereas Senecio paludosus, Carex flava, Juncus effusus and Typha latifolia caused relatively high rates. Centaurea jacea, Iris sibirica, and Carex davalliana caused intermediate rates. However, we found no effect of either plant biomass or plant functional groups--based on life form or productivity of the habitat--upon methane emission. Emissions were much lower than those usually reported in temperate wetlands, which we attribute to reduced concentrations of labile carbon following topsoil removal. Thus, unlike most wetland sites, methane production in this site was probably fuelled chiefly by root exudation from living plants and from root decay. We conclude that in most wetlands, where concentrations of labile carbon are much higher, these sources account for only a small proportion of the methane emitted. Our study confirms that plant species composition does influence methane emission from wetlands, and should be considered when developing measures to mitigate the greenhouse gas emissions.

  5. Quantifying Fugitive Methane Emissions at an Underground Coal Fire Using Cavity Ring-Down Spectroscopy Technology

    Science.gov (United States)

    Fleck, D.; Gannon, L.; Kim-Hak, D.; Ide, T.

    2016-12-01

    Understanding methane emissions is of utmost importance due to its greenhouse warming potential. Methane emissions can occur from a variety of natural and anthropogenic sources which include wetlands, landfills, oil/gas/coal extraction activities, underground coal fires, and natural gas distribution systems. Locating and containing these emissions are critical to minimizing their environmental impacts and economically beneficial when retrieving large fugitive amounts. In order to design a way to mitigate these methane emissions, they must first be accurately quantified. One such quantification method is to measure methane fluxes, which is a measurement technique that is calculated based on rate of gas accumulation in a known chamber volume over methane seepages. This allows for quantification of greenhouse gas emissions at a localized level (sub one meter) that can complement remote sensing and other largescale modeling techniques to further paint the picture of emission points. High performance analyzers are required to provide both sufficient temporal resolution and precise concentration measurements in order to make these measurements over only minutes. A method of measuring methane fluxes was developed using the latest portable, battery-powered Cavity Ring-Down Spectroscopy analyzer from Picarro (G4301). In combination with a mobile accumulation chamber, the instrument allows for rapid measurement of methane and carbon dioxide fluxes over wide areas. For this study, methane fluxes that were measured at an underground coal fire near the Four Corners region using the Picarro analyzer are presented. The flux rates collected demonstrate the ability for the analyzer to detect methane fluxes across many orders of magnitude. Measurements were accompanied by simultaneously geotagging the measurements with GPS to georeferenced the data. Methane flux data were instrumental in our ability to characterize the extent and the migration of the underground fire. In the future

  6. Emissions of non-methane hydrocarbons from cars in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This study investigated the exhaust emission of non-methane hydrocarbons(NMHCs) from cars in China at the Beijing driving cycle on the chassis dynamometer.The emission factor average of NMHCs was 0.9 g/km,which was over twice that from the Australian car fleet and 2-4 times that of the American car emission in the 1990s-2000s.The emission profile of Beijing cars showed higher fractions of aromatics and C4?C7 HCs,and lower percentages of C2?C3 HCs,compared with those of the US car fleet.The average ratio of benzene/toluene for cars tested was 0.5,the average benzene/toluene/ethyl benzene/xylenes(BTEX) ratios were 1/2.2/0.1/1.8,which were consistent with those of the Tanyugou tunnel located in the suburb of Beijing.α-pinene and β-pinene were detected from the exhaust gas on dynamometer for the first time,and had likely similar exhaust emission characteristics with C2?C3 HCs and styrene,giving an evidence that air pinenes may be related to human activities.Isoprene was also detected directly.These observations suggest that the procedure regarding pinenes and isoprene as coming from biologic sources of VOCs in the atmosphere should be applied with great care,especially in the core of the big city like Beijing.The specific reactivity of NMHCs was higher than that of cars of US,and the specific reactivity of volatile aromatic compounds was higher than that of the US SPECIATE database.

  7. Methane emissions from dairies in the Los Angeles Basin

    Science.gov (United States)

    Viatte, Camille; Lauvaux, Thomas; Hedelius, Jacob K.; Parker, Harrison; Chen, Jia; Jones, Taylor; Franklin, Jonathan E.; Deng, Aijun J.; Gaudet, Brian; Verhulst, Kristal; Duren, Riley; Wunch, Debra; Roehl, Coleen; Dubey, Manvendra K.; Wofsy, Steve; Wennberg, Paul O.

    2017-06-01

    We estimate the amount of methane (CH4) emitted by the largest dairies in the southern California region by combining measurements from four mobile solar-viewing ground-based spectrometers (EM27/SUN), in situ isotopic 13/12CH4 measurements from a CRDS analyzer (Picarro), and a high-resolution atmospheric transport simulation with a Weather Research and Forecasting model in large-eddy simulation mode (WRF-LES). The remote sensing spectrometers measure the total column-averaged dry-air mole fractions of CH4 and CO2 (XCH4 and XCO2) in the near infrared region, providing information on total emissions of the dairies at Chino. Differences measured between the four EM27/SUN ranged from 0.2 to 22 ppb (part per billion) and from 0.7 to 3 ppm (part per million) for XCH4 and XCO2, respectively. To assess the fluxes of the dairies, these differential measurements are used in conjunction with the local atmospheric dynamics from wind measurements at two local airports and from the WRF-LES simulations at 111 m resolution. Our top-down CH4 emissions derived using the Fourier transform spectrometers (FTS) observations of 1.4 to 4.8 ppt s-1 are in the low end of previous top-down estimates, consistent with reductions of the dairy farms and urbanization in the domain. However, the wide range of inferred fluxes points to the challenges posed by the heterogeneity of the sources and meteorology. Inverse modeling from WRF-LES is utilized to resolve the spatial distribution of CH4 emissions in the domain. Both the model and the measurements indicate heterogeneous emissions, with contributions from anthropogenic and biogenic sources at Chino. A Bayesian inversion and a Monte Carlo approach are used to provide the CH4 emissions of 2.2 to 3.5 ppt s-1 at Chino.

  8. Heritability estimates for methane emission in Holstein cows using breath measurements

    DEFF Research Database (Denmark)

    Lassen, Jan; Madsen, Jørgen; Løvendahl, Peter

    2012-01-01

    Enteric methane emission from ruminants contributes substantially to the greenhouse effect. Few studies have focused on the genetic variation in enteric methane emission from dairy cattle. The objective of this study was to estimate the heritability for enteric methane emission from Danish Holstein...... of economic importance in the breeding goal as well as the possibility to use methane as an indicator of feed efficiency. It is concluded that FTIR breath analysis is effective for measuring GHG emissions and may find further applications with a wider panel of gases including acetone and its relation...... model included fixed effects of herd, month, days in milk, lactation number, and random effects of animal and residual. Variance components were estimated in an animal model design using a pedigree containing 9661 animals. The heritability of the methane to carbon dioxide ratio was moderate (0...

  9. Constraining global methane emissions and uptake by ecosystems

    Directory of Open Access Journals (Sweden)

    R. Spahni

    2011-01-01

    Full Text Available Natural methane (CH4 emissions from wet ecosystems are an important part of today's global CH4 budget. Climate affects the exchange of CH4 between ecosystems and the atmosphere by influencing CH4 production, oxidation, and transport in the soil. The net CH4 exchange depends on ecosystem hydrology, soil and vegetation characteristics. Here, the LPJ-WHyMe global dynamical vegetation model is used to simulate global net CH4 emissions for different ecosystems: northern peatlands (45°–90° N, naturally inundated wetlands (60° S–45° N, rice agriculture and wet mineral soils. Mineral soils are a potential CH4 sink, but can also be a source with the direction of the net exchange depending on soil moisture content. The geographical and seasonal distributions are evaluated against multi-dimensional atmospheric inversions for 2003–2005, using two independent four-dimensional variational assimilation systems. The atmospheric inversions are constrained by the atmospheric CH4 observations of the SCIAMACHY satellite instrument and global surface networks. Compared to LPJ-WHyMe the inversions result in a significant reduction in the emissions from northern peatlands and suggest that LPJ-WHyMe maximum annual emissions peak about one month late. The inversions do not put strong constraints on the division of sources between inundated wetlands and wet mineral soils in the tropics. Based on the inversion results we adapt model parameters in LPJ-WHyMe and simulate the surface exchange of CH4 over the period 1990–2008. Over the whole period we infer an increase of global ecosystem CH4 emissions of +1.11 Tg CH4 yr−1, not considering potential additional changes in wetland extent. The increase in simulated CH4 emissions is attributed to enhanced soil respiration resulting from the observed rise in land temperature

  10. Constraining global methane emissions and uptake by ecosystems

    Directory of Open Access Journals (Sweden)

    R. Spahni

    2011-06-01

    Full Text Available Natural methane (CH4 emissions from wet ecosystems are an important part of today's global CH4 budget. Climate affects the exchange of CH4 between ecosystems and the atmosphere by influencing CH4 production, oxidation, and transport in the soil. The net CH4 exchange depends on ecosystem hydrology, soil and vegetation characteristics. Here, the LPJ-WHyMe global dynamical vegetation model is used to simulate global net CH4 emissions for different ecosystems: northern peatlands (45°–90° N, naturally inundated wetlands (60° S–45° N, rice agriculture and wet mineral soils. Mineral soils are a potential CH4 sink, but can also be a source with the direction of the net exchange depending on soil moisture content. The geographical and seasonal distributions are evaluated against multi-dimensional atmospheric inversions for 2003–2005, using two independent four-dimensional variational assimilation systems. The atmospheric inversions are constrained by the atmospheric CH4 observations of the SCIAMACHY satellite instrument and global surface networks. Compared to LPJ-WHyMe the inversions result in a~significant reduction in the emissions from northern peatlands and suggest that LPJ-WHyMe maximum annual emissions peak about one month late. The inversions do not put strong constraints on the division of sources between inundated wetlands and wet mineral soils in the tropics. Based on the inversion results we diagnose model parameters in LPJ-WHyMe and simulate the surface exchange of CH4 over the period 1990–2008. Over the whole period we infer an increase of global ecosystem CH4 emissions of +1.11 Tg CH4 yr−1, not considering potential additional changes in wetland extent. The increase in simulated CH4 emissions is attributed to enhanced soil respiration resulting from the observed rise in land

  11. Methane emissions from bald cypress tree trunks in a bottomland forest

    Science.gov (United States)

    Schile, L. M.; Pitz, S.; Megonigal, P.

    2013-12-01

    Studies on natural methane emissions predominantly have occurred on wetland soils with herbaceous plant species. Less attention, however, has been placed on the role of woody wetland plant species in the methane cycle. Recent studies on methane emissions from tree trunks document that they are a significant source of emissions that previously has been not accounted for. In this study, we examine methane emissions from trunks of mature bald cypress (Taxodium distichum), which is a dominant tree species in bottomland hardwood forests of the Southeastern United States. To date, little is known about soil methane emissions in these systems, and published tree emissions have been limited to a single study conducted on bald cypress knees. In May 2013, we established a plot in a monospecific bald cypress stand planted approximately 70 years ago on the Chesapeake Bay in Maryland and are monitoring methane emissions on 12 tree trunks, soil chambers, and pore-water over the course of a year. Custom-made 30 cm tall open face rectangular tree chambers were constructed out of white acrylic sheets and secured on each tree at a midpoint of 45 cm above the soil surface. Chambers were lined with neoprene along the tree surface and sealed with an epoxy. On three trees that varied in trunk diameter, chambers were placed at average heights of 95, 145, 195, and 345 cm from the soil surface in order to calculate a decay curve of methane emissions. Once a month, chambers were sealed with lids and head-space samples were collected over the course of an hour. Methane flux was calculated and compared to emissions from soil chambers. Average cypress trunk methane fluxes ranged from 17.7 μmole m-2 hr-1 in May to 49.5 and 116.5 μmole m-2 hr-1 in June and July, respectively. Soil fluxes averaged 28.5 μmole m-2 hr-1 in May and June, and decreased to 13.7 μmole m-2 hr-1 in July. Methane emissions decreased exponentially up the tree trunk, with fluxes of 2 μmole m-2 hr-1 and less calculated

  12. Extreme methane emissions from a Swiss hydropower reservoir: contribution from bubbling sediments.

    Science.gov (United States)

    Delsontro, Tonya; McGinnis, Daniel F; Sobek, Sebastian; Ostrovsky, Ilia; Wehrli, Bernhard

    2010-04-01

    Methane emission pathways and their importance were quantified during a yearlong survey of a temperate hydropower reservoir. Measurements using gas traps indicated very high ebullition rates, but due to the stochastic nature of ebullition a mass balance approach was crucial to deduce system-wide methane sources and losses. Methane diffusion from the sediment was generally low and seasonally stable and did not account for the high concentration of dissolved methane measured in the reservoir discharge. A strong positive correlation between water temperature and the observed dissolved methane concentration enabled us to quantify the dissolved methane addition from bubble dissolution using a system-wide mass balance. Finally, knowing the contribution due to bubble dissolution, we used a bubble model to estimate bubble emission directly to the atmosphere. Our results indicated that the total methane emission from Lake Wohlen was on average >150 mg CH(4) m(-2) d(-1), which is the highest ever documented for a midlatitude reservoir. The substantial temperature-dependent methane emissions discovered in this 90-year-old reservoir indicate that temperate water bodies can be an important but overlooked methane source.

  13. Quantification of methane emissions from 15 Danish landfills using the mobile tracer dispersion method

    Energy Technology Data Exchange (ETDEWEB)

    Mønster, Jacob [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark); Samuelsson, Jerker, E-mail: jerker.samuelsson@fluxsense.se [Chalmers University of Technology/FluxSense AB, SE-41296 Göteborg (Sweden); Kjeldsen, Peter [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark); Scheutz, Charlotte, E-mail: chas@env.dtu.dk [Department of Environmental Engineering, Technical University of Denmark, Miljøvej – Building 113, DK-2800 Lyngby (Denmark)

    2015-01-15

    Highlights: • Quantification of whole landfill site methane emission at 15 landfills. • Multiple on-site source identification and quantification. • Quantified methane emission from shredder waste and composting. • Large difference between measured and reported methane emissions. - Abstract: Whole-site methane emissions from 15 Danish landfills were assessed using a mobile tracer dispersion method with either Fourier transform infrared spectroscopy (FTIR), using nitrous oxide as a tracer gas, or cavity ring-down spectrometry (CRDS), using acetylene as a tracer gas. The landfills were chosen to represent the different stages of the lifetime of a landfill, including open, active, and closed covered landfills, as well as those with and without gas extraction for utilisation or flaring. Measurements also included landfills with biocover for oxidizing any fugitive methane. Methane emission rates ranged from 2.6 to 60.8 kg h{sup −1}, corresponding to 0.7–13.2 g m{sup −2} d{sup −1}, with the largest emission rates per area coming from landfills with malfunctioning gas extraction systems installed, and the smallest emission rates from landfills closed decades ago and landfills with an engineered biocover installed. Landfills with gas collection and recovery systems had a recovery efficiency of 41–81%. Landfills where shredder waste was deposited showed significant methane emissions, with the largest emission from newly deposited shredder waste. The average methane emission from the landfills was 154 tons y{sup −1}. This average was obtained from a few measurement campaigns conducted at each of the 15 landfills and extrapolating to annual emissions requires more measurements. Assuming that these landfills are representative of the average Danish landfill, the total emission from Danish landfills were calculated at 20,600 tons y{sup −1}, which is significantly lower than the 33,300 tons y{sup −1} estimated for the national greenhouse gas inventory for

  14. Glacial wetland distribution and methane emissions estimated from PMIP2 climate simulations

    Science.gov (United States)

    Weber, Nanne; Drury, Annajoy; Toonen, Willem; van Weele, Michiel

    2010-05-01

    It is an open question to what extent wetlands contributed to the interglacial-glacial decrease in atmospheric methane concentration. Here we estimate methane emissions from glacial wetlands, using newly available PMIP2 simulations of the Last Glacial Maximum (LGM) climate from coupled atmosphere-ocean and atmosphere-ocean-vegetation models. Emissions are computed from the dominant controls of water table depth, soil temperature and plant productivity and we analyse the relative role of each factor in the glacial decline. It is found that latitudinal changes in soil moisture, in combination with ice-sheet expansion, cause boreal wetlands to shift southward in all simulations. This southward migration is instrumental in maintaining the boreal wetland source at a significant level. The temperature effect is found to be moderate, while reduced plant productivity contributes equally to the total reduction. Model results indicate a relatively small boreal and large tropical source during the LGM, consistent with the low interpolar difference in glacial methane concentrations derived from ice-core data.

  15. Methane Lunar Surface Thermal Control Test

    Science.gov (United States)

    Plachta, David W.; Sutherlin, Steven G.; Johnson, Wesley L.; Feller, Jeffrey R.; Jurns, John M.

    2012-01-01

    NASA is considering propulsion system concepts for future missions including human return to the lunar surface. Studies have identified cryogenic methane (LCH4) and oxygen (LO2) as a desirable propellant combination for the lunar surface ascent propulsion system, and they point to a surface stay requirement of 180 days. To meet this requirement, a test article was prepared with state-of-the-art insulation and tested in simulated lunar mission environments at NASA GRC. The primary goals were to validate design and models of the key thermal control technologies to store unvented methane for long durations, with a low-density high-performing Multi-layer Insulation (MLI) system to protect the propellant tanks from the environmental heat of low Earth orbit (LEO), Earth to Moon transit, lunar surface, and with the LCH4 initially densified. The data and accompanying analysis shows this storage design would have fallen well short of the unvented 180 day storage requirement, due to the MLI density being much higher than intended, its substructure collapse, and blanket separation during depressurization. Despite the performance issue, insight into analytical models and MLI construction was gained. Such modeling is important for the effective design of flight vehicle concepts, such as in-space cryogenic depots or in-space cryogenic propulsion stages.

  16. Global Scale Methane Emissions from On-Site Wastewater Management

    Science.gov (United States)

    Reid, M. C.; Guan, K.; Mauzerall, D. L.

    2013-12-01

    Pit latrines and other on-site sanitation methods are important forms of wastewater management at the global scale, providing hygienic and low-cost sanitation for more than 1.7 billion people in developing and middle-income regions. Latrines have also been identified as major sources of the greenhouse gas methane (CH4) from the anaerobic decomposition of organic waste in pits. Understanding the greenhouse gas footprint of different wastewater systems is essential for sustainable water resource development and management. Despite this importance, CH4 emissions from decentralized wastewater treatment have received little attention in the scientific literature, and the rough calculations underlying government inventories and integrated assessment models do not accurately capture variations in emissions within and between countries. In this study, we improve upon earlier efforts and develop the first spatially explicit approach to quantifying latrine CH4 emissions, combining a high-resolution geospatial analysis of population, urbanization, and water table (as an indicator of anaerobic decomposition pathways) with CH4 emissions factors from the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Country-level health and sanitation surveys were used to determine latrine utilization in 2000 and predict usage in 2015. 18 representative countries in Asia, Africa, and Latin America were selected for this analysis to illustrate regional variations in CH4 emissions and to include the greatest emitting nations. Our analysis confirms that pit latrines are a globally significant anthropogenic CH4 source, emitting 4.7 Tg CH4 yr-1 in the countries considered here. This total is projected to decrease ~25% by 2015, however, driven largely by rapid urbanization in China and decreased reliance on latrines in favor of flush toilets. India has the greatest potential for large growth in emissions in the post-2015 period, since public health campaigns to end open defecation

  17. A Novel, Compact Optical Device for Estimating the Methane Emissions in Geological Environment

    CERN Document Server

    Roy, Sandipta; Duttagupta, Siddhartha P

    2016-01-01

    Quantifying spontaneous, fugitive and venting related methane emissions are often difficult and cumbersome. However, auditing the methane emissions due to conventional and un-conventional hydrocarbon exploitation techniques are becoming necessary. Present generation compact chemical sensors are slower, degrade very fast, and are sensitive broad-spectrum gases. On the other hand, optical sensors are very fast in detection of gases and more precise and can be easily employed in various environments like boreholes and soils. In this study, we report development of an optical sensor that is methane specific, fast for real time applications and has tremendous application potential in the exploration of coal bed methane and other hydrocarbon reserves with methane as a major constituent. The detection process is based on the principle of spectroscopic absorption of light. The detector, NiSi Schottky diode, was fabricated and characterized exclusively for the 1.65 um, narrow bandwidth methane absorption. The probe is...

  18. Estimation of Methane Emissions from Municipal Solid Waste Landfills in China Based on Point Emission Sources

    Institute of Scientific and Technical Information of China (English)

    CAI Bo-Feng; LIU Jian-Guo; GAO Qing-Xian; NIE Xiao-Qin; CAO Dong; LIU Lan-Cui; ZHOU Ying; ZHANG Zhan-Sheng

    2014-01-01

    The methane (CH4) emissions from municipal solid waste (MSW) landfills in China in 2007 were estimated based on database of the three-dimensional emission factors matrix and point sources, by an IPCC recommended FOD (first-order decay) model. The location, capacity and age of landfills constitute the three dimensions of the emission factors matrix, which were obtained by laboratory analysis and in situ investigation. Key parameters such as waste composition, degradable organic carbon ratio, CH4 correction factor, oxidation factor and recovery rate, were carefully analyzed in terms of these three dimensions. The point sources database consists of 2,107 MSW landfills in cities and towns of China in 2007. The results show that the CH4 emissions from MSW landfills were 1.186 Mt in 2007. Compared with the CH4 emissions of 2.20 Mt in 2005, the significant discrepancy mainly comes from statistical data of landfills, e.g., number of landfills and amount of waste disposed in landfills. CH4 emissions were lower than 700 t for most of the landfills, whereas there were 279 landfills with emissions larger than 1,000 t, and only 10 landfills with emissions larger than 10,000 t. Jiangsu province ranks the largest emitter with 98,700 t while Tibet is the smallest emitter with 2,100 t. In general, the emissions from eastern provinces, such as Jiangsu, Guangdong and Zhejiang, were larger than those from western provinces, such as Ningxia, Tibet and Qinghai.

  19. The importance of addressing methane emissions as part of a comprehensive greenhouse gas management strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bylin, Carey [U.S. Environmental Protection Agency (EPA), Washington, DC (United States); Robinson, Donald; Cacho, Mariella; Russo, Ignacio; Stricklin, Eric [ICF International, Fairfax, VA (United States); Rortveit, Geir Johan [Statoil, Stavanger (Norway); Chakraborty, A.B. [Oil and Natural Gas Corporation Ltda. (ONGC), Dehradun (India); Pontiff, Mike [Newfield, The Woodlands, TX, (United States); Smith, Reid [British Petroleum (BP), London (United Kingdom)

    2012-07-01

    Given the climate forcing properties of greenhouse gases (GHGs) and the current state of the global economy, it is imperative to mitigate emissions of GHGs cost-effectively. Typically, CO{sub 2} is the main focus of most companies' and governments' GHG emissions reductions strategies. However, when considering near-term goals, it becomes clear that emissions reductions of other GHGs must be pursued. One such GHG is methane, the primary component of natural gas. Reducing GHG emissions and generating profits are not necessarily a mutually exclusive endeavor as illustrated by the United States Environmental Protection Agency's (EPA) Natural Gas STAR Program. The Program is a worldwide voluntary, flexible partnership of oil and gas companies which promotes cost-effective technologies and practices to reduce methane emissions from oil and natural gas operations. In an effort to meet environmental goals without sacrificing profitability, Natural Gas STAR partner companies have identified over 60 cost-effective best practices to reduce their methane emissions, which they report to the EPA. This paper discusses: 1) the importance of reducing methane emissions and its economic impact, 2) a comparison of methane emission reduction projects relative to other greenhouse gas reduction projects in the oil and gas industry, 3) the value of source-specific methane emissions inventories, and 4) methane emission reduction opportunities from hydraulically fractured gas well completions and centrifugal compressor wet seals. From the analyses and examples in this paper, it can be concluded that methane emission reduction projects can be readily identified, profitable, and effective in mitigating global climate change. (author)

  20. Effects of Plant Extracts on Microbial Population, Methane Emission and Ruminal Fermentation Characteristics in

    Directory of Open Access Journals (Sweden)

    E. T. Kim

    2012-06-01

    Full Text Available This study was conducted to evaluate effects of plant extracts on methanogenesis and rumen microbial diversity in in vitro. Plant extracts (Artemisia princeps var. Orientalis; Wormwood, Allium sativum for. Pekinense; Garlic, Allium cepa; Onion, Zingiber officinale; Ginger, Citrus unshiu; Mandarin orange, Lonicera japonica; Honeysuckle were obtained from the Plant Extract Bank at Korea Research Institute of Bioscience and Biotechnology. The rumen fluid was collected before morning feeding from a fistulated Holstein cow fed timothy and commercial concentrate (TDN; 73.5%, crude protein; 19%, crude fat; 3%, crude fiber; 12%, crude ash; 10%, Ca; 0.8%, P; 1.2% in the ratio of 3 to 2. The 30 ml of mixture, comprising McDougall buffer and rumen liquor in the ratio of 4 to 1, was dispensed anaerobically into serum bottles containing 0.3 g of timothy substrate and plant extracts (1% of total volume, respectively filled with O2-free N2 gas and capped with a rubber stopper. The serum bottles were held in a shaking incubator at 39°C for 24 h. Total gas production in all plant extracts was higher (p<0.05 than that of the control, and total gas production of ginger extract was highest (p<0.05. The methane emission was highest (p<0.05 at control, but lowest (p<0.05 at garlic extract which was reduced to about 20% of methane emission (40.2 vs 32.5 ml/g DM. Other plant extracts also resulted in a decrease in methane emissions (wormwood; 8%, onion; 16%, ginger; 16.7%, mandarin orange; 12%, honeysuckle; 12.2%. Total VFAs concentration and pH were not influenced by the addition of plant extracts. Acetate to propionate ratios from garlic and ginger extracts addition samples were lower (p<0.05, 3.36 and 3.38 vs 3.53 than that of the control. Real-time PCR indicted that the ciliate-associated methanogen population in all added plant extracts decreased more than that of the control, while the fibrolytic bacteria population increased. In particular, the F. succinogens

  1. Rising methane emissions from northern wetlands associated with sea ice decline

    DEFF Research Database (Denmark)

    Parmentier, Frans-Jan; Zhang, Wenxin; Mi, Yanjiao;

    2015-01-01

    The Arctic is rapidly transitioning toward a seasonal sea ice-free state, perhaps one of the most apparent examples of climate change in the world. This dramatic change has numerous consequences, including a large increase in air temperatures, which in turn may affect terrestrial methane emissions....... Nonetheless, terrestrial and marine environments are seldom jointly analyzed. By comparing satellite observations of Arctic sea ice concentrations to methane emissions simulated by three process-based biogeochemical models, this study shows that rising wetland methane emissions are associated with sea ice...... retreat. Our analyses indicate that simulated high-latitude emissions for 2005–2010 were, on average, 1.7 Tg CH4 yr−1 higher compared to 1981–1990 due to a sea ice-induced, autumn-focused, warming. Since these results suggest a continued rise in methane emissions with future sea ice decline, observation...

  2. Importance of the autumn overturn and anoxic conditions in the hypolimnion for the annual methane emissions from a temperate lake.

    Science.gov (United States)

    Encinas Fernández, Jorge; Peeters, Frank; Hofmann, Hilmar

    2014-07-01

    Changes in the budget of dissolved methane measured in a small temperate lake over 1 year indicate that anoxic conditions in the hypolimnion and the autumn overturn period represent key factors for the overall annual methane emissions from lakes. During periods of stable stratification, large amounts of methane accumulate in anoxic deep waters. Approximately 46% of the stored methane was emitted during the autumn overturn, contributing ∼80% of the annual diffusive methane emissions to the atmosphere. After the overturn period, the entire water column was oxic, and only 1% of the original quantity of methane remained in the water column. Current estimates of global methane emissions assume that all of the stored methane is released, whereas several studies of individual lakes have suggested that a major fraction of the stored methane is oxidized during overturns. Our results provide evidence that not all of the stored methane is released to the atmosphere during the overturn period. However, the fraction of stored methane emitted to the atmosphere during overturn may be substantially larger and the fraction of stored methane oxidized may be smaller than in the previous studies suggesting high oxidation losses of methane. The development or change in the vertical extent and duration of the anoxic hypolimnion, which can represent the main source of annual methane emissions from small lakes, may be an important aspect to consider for impact assessments of climate warming on the methane emissions from lakes.

  3. Methane emission from rice fields in relation to management of irrigation water.

    Science.gov (United States)

    Khosa, Maninder Kaur; Sidhu, B S; Benbi, D K

    2011-03-01

    A field experiment was conducted for two years to find out best water management practice to mitigate methane emission from the rice-fields. Continuously flooded conditions yielded two major flushes of methane emission and on an average resulted in relatively higher rate of methane emission (2.20 and 1.30 mg m(-2) hr(-1), respectively in 2005 and 2006) during the kharif season. The methane flux was reduced to half (1.02 and 0.47 mg m(-2) hr(-1), respectively in 2005 and 2006) when rice fields were irrigated 2-3 days after infiltration of flood water into the soil. Irrigating the field at 0.15 bar matric potential reduced seasonal methane flux by 60% (0.99 and 0.41 mg m(-2) hr(-1), respectively in 2005 and 2006) as compared to completely flooded conditions, without any decline in grain yield (60 q ha(-1)).

  4. Baseline study of methane emission from anaerobic ponds of palm oil mill effluent treatment.

    Science.gov (United States)

    Yacob, Shahrakbah; Ali Hassan, Mohd; Shirai, Yoshihito; Wakisaka, Minato; Subash, Sunderaj

    2006-07-31

    The world currently obtains its energy from the fossil fuels such as oil, natural gas and coal. However, the international crisis in the Middle East, rapid depletion of fossil fuel reserves as well as climate change have driven the world towards renewable energy sources which are abundant, untapped and environmentally friendly. Malaysia has abundant biomass resources generated from the agricultural industry particularly the large commodity, palm oil. This paper will focus on palm oil mill effluent (POME) as the source of renewable energy from the generation of methane and establish the current methane emission from the anaerobic treatment facility. The emission was measured from two anaerobic ponds in Felda Serting Palm Oil Mill for 52 weeks. The results showed that the methane content was between 35.0% and 70.0% and biogas flow rate ranged between 0.5 and 2.4 L/min/m(2). Total methane emission per anaerobic pond was 1043.1 kg/day. The total methane emission calculated from the two equations derived from relationships between methane emission and total carbon removal and POME discharged were comparable with field measurement. This study also revealed that anaerobic pond system is more efficient than open digesting tank system for POME treatment. Two main factors affecting the methane emission were mill activities and oil palm seasonal cropping.

  5. Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain

    Directory of Open Access Journals (Sweden)

    Zhiling Gao

    2011-01-01

    Full Text Available In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern with three peaks corresponding to the schedule of feeding activities. On a per capita basis, daily methane emission rates of these four seasons were 0.28, 0.32, 0.33, and 0.30 kg head−1 d−1, respectively. In summary, annual methane emission rate was 112.4 kg head−1 yr−1 associated with methane emission intensity of 32.65 L CH4 L−1 of milk and potential methane conversion factor Ym of 6.66% of gross energy intake for mature dairy cows in North China Plain.

  6. Evaluation of methane emissions from Palermo municipal landfill: Comparison between field measurements and models.

    Science.gov (United States)

    Di Bella, Gaetano; Di Trapani, Daniele; Viviani, Gaspare

    2011-08-01

    Methane (CH(4)) diffuse emissions from Municipal Solid Waste (MSW) landfills represent one of the most important anthropogenic sources of greenhouse gas. CH(4) is produced by anaerobic biodegradation of organic matter in landfilled MSW and constitutes a major component of landfill gas (LFG). Gas recovery is a suitable method to effectively control CH(4) emissions from landfill sites and the quantification of CH(4) emissions represents a good tool to evaluate the effectiveness of a gas recovery system in reducing LFG emissions. In particular, LFG emissions can indirectly be evaluated from mass balance equations between LFG production, recovery and oxidation in the landfill, as well as by a direct approach based on LFG emission measurements from the landfill surface. However, up to now few direct measurements of landfill CH(4) diffuse emissions have been reported in the technical literature. In the present study, both modeling and direct emission measuring methodologies have been applied to the case study of Bellolampo landfill located in Palermo, Italy. The main aim of the present study was to evaluate CH(4) diffuse emissions, based on direct measurements carried out with the flux accumulation chamber (static, non-stationary) method, as well as to obtain the CH(4) contoured flux map of the landfill. Such emissions were compared with the estimate achieved by means of CH(4) mass balance equations. The results showed that the emissions obtained by applying the flux chamber method are in good agreement with the ones derived by the application of the mass balance equation, and that the evaluated contoured flux maps represent a reliable tool to locate areas with abnormal emissions in order to optimize the gas recovery system efficiency.

  7. Mitigation of methane emissions from rice fields: Possible adverse effects of incorporated rice straw

    Science.gov (United States)

    Sass, R. L.; Fisher, F. M.; Harcombe, P. A.; Turner, F. T.

    1991-09-01

    Increased world demand for rice production may lead to an increase in methane emission to the atmosphere and future global warming. One suggested way to reduce methane emission is to discourage the practice of incorporating previous crop residue prior to planting rice, since the residue may enhance methane emission from flooded rice fields. This concept is supported by data from a 2-year study of flooded rice fields on two different soil types in Texas. In 1990, rice stubble from 1989 was incorporated into both soils. Seasonal methane emission from a Lake Charles clay field increased from 15.9 g m-2 in 1989 to 31.0 g m-2 in 1990. In the Beaumont clay field, seasonal methane emission increased from 4.5 to 11.4 g m-2. While methane emission increased between 1989 and 1990, grain yield dropped by 2100 and 840 kg ha-1 in the Lake Charles and Beaumont fields, respectively. Visual inspection at harvest indicated that the 1990 rice yield decrease resulted from grain abortion, presumably caused by the rice cultivar's sensitivity to soil anaerobiosis. The calculated amount of organic carbon not translocated to grain was comparable to the estimated amount of organic carbon required for the increased methane emission. We hypothesize that labile carbon in straighthead susceptible rice cultivars can "leak" from roots damaged by excessively anaerobic soil and be metabolized to its equivalent in methane. These data suggest that minimizing incorporation of crop residue prior to planting can decrease methane emission from flooded rice and reduce the potential for yield loss, particularly with some cultivars and in soils with low rates of seepage and percolation.

  8. Temporal patterns of methane emissions from wetland rice fields treated by different modes of N application

    Science.gov (United States)

    Wassmann, R.; Neue, H. U.; Lantin, R. S.; Aduna, J. B.; Alberto, M. C. R.; Andales, M. J.; Tan, M. J.; van der Gon, H. A. C. Denier; Hoffmann, H.; Papen, H.; Rennenberg, H.; Seiler, W.

    1994-08-01

    Methane emission rates from wetland rice fields were determined in Los Baños (Philippines) using an automatic system that allows continuous measurements over time. Methane emission was monitored in an irrigated Aquandic Epiaqualf planted to rice cultivar IR72. Urea fertilizer was applied using four modes: (1) broadcast 10 days after transplanting, (2) broadcast at transplanting, (3) broadcast and incorporated at final harrowing, and (4) deep placement as sulfur-coated granules. The treatments were laid out in a randomized complete block design with four replicates. Measurements were done in the 1991 wet season, 1992 dry season (four treatments), and the 1992 wet season (only treatment 3). Methane emission rates from the experimental plots showed pronounced seasonal and diel variations. The diel pattern of methane emission rates followed a consistent pattern, with highest rates observed in the early afternoon and lowest rates in the early morning. Methane emission rate was generally highest at the ripening stage. The average methane emission rate during the 1992 dry season (190 mg CH4 m-2 d-1) exceeded the average flux rates of the 1992 wet season (79 mg CH4 m-2 d-1) by a factor of 2.4. The total methane emitted from these flooded rice fields amounted to 19 g CH4 m-2 in the dry season with rice yields of 5.2-6.3 t ha-1 and 7 g CH4 m-2 in the wet season with rice yields of 2.4-3.3 t ha-1 regardless of the mode of N application. Significant amounts corresponding to 20% of the methane released under waterlogged conditions were released when the soil was drained after harvest. Emission rates increased sharply when the floodwater receded and macropores started to drain. Emission of methane stopped only when the soil became fully aerated.

  9. Anthropogenic and natural methane emissions from a shale gas exploration area of Quebec, Canada.

    Science.gov (United States)

    Pinti, Daniele L; Gelinas, Yves; Moritz, Anja M; Larocque, Marie; Sano, Yuji

    2016-10-01

    The increasing number of studies on the determination of natural methane in groundwater of shale gas prospection areas offers a unique opportunity for refining the quantification of natural methane emissions. Here methane emissions, computed from four potential sources, are reported for an area of ca. 16,500km(2) of the St. Lawrence Lowlands, Quebec (Canada), where Utica shales are targeted by the petroleum industry. Methane emissions can be caused by 1) groundwater degassing as a result of groundwater abstraction for domestic and municipal uses; 2) groundwater discharge along rivers; 3) migration to the surface by (macro- and micro-) diffuse seepage; 4) degassing of hydraulic fracturing fluids during first phases of drilling. Methane emissions related to groundwater discharge to rivers (2.47×10(-4) to 9.35×10(-3)Tgyr(-1)) surpass those of diffuse seepage (4.13×10(-6) to 7.14×10(-5)Tgyr(-1)) and groundwater abstraction (6.35×10(-6) to 2.49×10(-4)Tgyr(-1)). The methane emission from the degassing of flowback waters during drilling of the Utica shale over a 10- to 20-year horizon is estimated from 2.55×10(-3) to 1.62×10(-2)Tgyr(-1). These emissions are from one third to sixty-six times the methane emissions from groundwater discharge to rivers. This study shows that different methane emission sources need to be considered in environmental assessments of methane exploitation projects to better understand their impacts.

  10. Linseed plus nitrate in the diet for fattening bulls: effects on methane emission, animal health and residues in offal.

    Science.gov (United States)

    Doreau, M; Arbre, M; Popova, M; Rochette, Y; Martin, C

    2017-08-15

    The combination of linseed and nitrate is known to decrease enteric methane emission in dairy cows but few studies have been carried out in fattening cattle for animal liveweight gain, enteric methane emission, animal health and presence of residues in beef products. To address this gap, 16 young bulls received a control (C) diet between weaning at 9 months and 14 months, then were split into two groups of eight balanced on feed intake, BW gain and methane emission to receive either the C diet or a diet moderately supplemented with extruded linseed and calcium nitrate (LN) for 2 months before being slaughtered. On a dry matter (DM) basis, the C diet contained 70% baled grass silage and 30% concentrate mainly made of maize, wheat and rapeseed meal. In the LN diet, rapeseed meal and a fraction of cereals were replaced by 35% extruded linseed and 6% calcium nitrate; linseed fatty acids and nitrate supply in the LN diet were 1.9% and 1.0%, respectively. Methane emission was measured continuously using the GreenFeed system. Methaemoglobin was determined every week in peripheral blood from bulls receiving the LN diet. Nitrate and nitrite concentrations were determined in rumen, liver and tongue sampled at slaughter. Dry matter intake tended to be lower for LN diet (P=0.10). Body weight gain was lower for LN diet (P=0.01; 1.60 and 1.26 kg/day for C and LN diet, respectively). Daily methane emission was 9% lower (Panimals and was always lower than 5.6%, suggesting an absence of risk to animal health. Nitrite and nitrate concentrations in offal did not differ between C and LN diets. In conclusion, a moderate supply of linseed and nitrate in bull feed failed to decrease enteric methane yield and impaired bull liveweight gain but without adverse effects for animal health and food safety.

  11. Development of a low-maintenance measurement approach to continuously estimate methane emissions: A case study.

    Science.gov (United States)

    Riddick, S N; Hancock, B R; Robinson, A D; Connors, S; Davies, S; Allen, G; Pitt, J; Harris, N R P

    2016-12-18

    The chemical breakdown of organic matter in landfills represents a significant source of methane gas (CH4). Current estimates suggest that landfills are responsible for between 3% and 19% of global anthropogenic emissions. The net CH4 emissions resulting from biogeochemical processes and their modulation by microbes in landfills are poorly constrained by imprecise knowledge of environmental constraints. The uncertainty in absolute CH4 emissions from landfills is therefore considerable. This study investigates a new method to estimate the temporal variability of CH4 emissions using meteorological and CH4 concentration measurements downwind of a landfill site in Suffolk, UK from July to September 2014, taking advantage of the statistics that such a measurement approach offers versus shorter-term, but more complex and instantaneously accurate, flux snapshots. Methane emissions were calculated from CH4 concentrations measured 700m from the perimeter of the landfill with observed concentrations ranging from background to 46.4ppm. Using an atmospheric dispersion model, we estimate a mean emission flux of 709μgm(-2)s(-1) over this period, with a maximum value of 6.21mgm(-2)s(-1), reflecting the wide natural variability in biogeochemical and other environmental controls on net site emission. The emissions calculated suggest that meteorological conditions have an influence on the magnitude of CH4 emissions. We also investigate the factors responsible for the large variability observed in the estimated CH4 emissions, and suggest that the largest component arises from uncertainty in the spatial distribution of CH4 emissions within the landfill area. The results determined using the low-maintenance approach discussed in this paper suggest that a network of cheaper, less precise CH4 sensors could be used to measure a continuous CH4 emission time series from a landfill site, something that is not practical using far-field approaches such as tracer release methods. Even though

  12. The complex relationships between methane emissions and water table at an ombrotrophic bog

    Science.gov (United States)

    Humphreys, Elyn; Roulet, Nigel; Moore, Tim

    2017-04-01

    Broad spatial and temporal variations in methane emissions from peatlands have been related to many variables including water table position, temperature and vegetation characteristics and functioning. In general, wetter peatlands tend to have greater methane emissions. However, over shorter periods of time and space, the relationship between water table and methane emissions can reverse, show hysteresis or be absent entirely. These relationships are investigated at the Mer Bleue Bog, a temperate ombrotrophic bog near Ottawa, Canada. Six years of concurrent growing season eddy covariance and automated chamber fluxes reveal the expected broad patterns. During the wettest growing season, the water table remained within 40 cm of the bog's hummock surfaces. Methane emissions were upwards of 20 to 45 mg C m-2 d-1 and exceeded the emission rates from two drier growing seasons which saw periods where the water table dropped to nearly 80 cm below the hummock surface. In those periods, methane emission rates declined to about 5 mg C m-2 d-1 or less. Lawn plots with aerenchymatous Eriophorum vegetation and high water tables had greatest emissions (exceeding 200 mg C m-2 d-1) compared to hummock plots vegetated by ericaceous shrubs, which had emissions rates similar to those measured by eddy covariance. However, within a growing season, hysteresis and inverse relationships between water table and methane emissions were observed at both ecosystem and chamber plot scales. These included periods between rainfall events where methane emissions increased while the water table deepened. The potential roles of methane production, consumption, storage and transport processes on these patterns will be discussed.

  13. Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options

    NARCIS (Netherlands)

    Hristov, A.N.; Oh, J.; Firkins, J.; Dijkstra, J.; Kebreab, E.; Waghorn, G.; Makkar, H.P.S.; Adesogan, A.T.; Yang, W.; Lee, C.; Gerber, P.J.; Henderson, B.L.; Tricarico, J.M.

    2013-01-01

    The goal of this review was to analyze published data related to mitigation of enteric methane (CH4) emissions from ruminant animals to document the most effective and sustainable strategies. Increasing forage digestibility and digestible forage intake was one of the major recommended CH4 mitigation

  14. Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options

    NARCIS (Netherlands)

    Hristov, A.N.; Oh, J.; Firkins, J.; Dijkstra, J.; Kebreab, E.; Waghorn, G.; Makkar, H.P.S.; Adesogan, A.T.; Yang, W.; Lee, C.; Gerber, P.J.; Henderson, B.L.; Tricarico, J.M.

    2013-01-01

    The goal of this review was to analyze published data related to mitigation of enteric methane (CH4) emissions from ruminant animals to document the most effective and sustainable strategies. Increasing forage digestibility and digestible forage intake was one of the major recommended CH4 mitigation

  15. A New IPCC Tier 4 Site-Specific Model for Landfill Methane Emissions Inclusive of Seasonal Methane Oxidation

    Science.gov (United States)

    This project was initiated in the U.S. by the California Energy Commission (CEC) in cooperation with the California Integrated Waste Management Board and the California Air Resources Board to develop improved methods for landfill methane emissions for the California greenhouse gas inventory. This 3-...

  16. Genetic aspects of enteric methane emission in ruminants livestock

    Directory of Open Access Journals (Sweden)

    Martino Cassandro

    2013-10-01

    Full Text Available This review summarizes the importance of enteric methane (CH4 emission in ruminants and relevant to the current on knowledge relevant to genetic aspects of enteric CH4 production, highlighting future research needs and directions. Global average temperature has increased by about 0.7°C in the last century. The Intergovernmental Panel on Climate Change (IPCC reported that anthropogenic greenhouse gases (GHG, including carbon dioxide (CO2, CH4, nitrous oxide (N2O and halocarbons, have been responsible for most of the observed temperature increase since the middle of the twentieth century. Agriculture, particularly livestock, is increasingly being recognized as both a contributor to the process and a potential victim of it. Policy interventions and technical solutions are required to address both the impact of livestock production on climate change and the effects of climate change on livestock production. Food and Agriculture Organization (FAO, declared that in the next 50 years, the world’s farmers will be called upon to produce more food than has been produced in the past 10,000 years, and to do so in environmentally sustainable ways. Therefore, the GHG reduction should be treated as a public good. The United States congress is prospecting to define a price on GHG emissions. Limiting the concentration of CO2 and other GHG in Earth’s atmosphere requires a technological and economic revolution. A cost-effective way could be the genetic improvement of livestock, which produces permanent and cumulative changes in performance. Animal variation in enteric CH4 emission has been reported in the literature, providing potential for improvement through genetic selection. 

  17. Massive marine methane emissions from near-shore shallow coastal areas

    Science.gov (United States)

    Borges, Alberto V.; Champenois, Willy; Gypens, Nathalie; Delille, Bruno; Harlay, Jérôme

    2016-06-01

    Methane is the second most important greenhouse gas contributing to climate warming. The open ocean is a minor source of methane to the atmosphere. We report intense methane emissions from the near-shore southern region of the North Sea characterized by the presence of extensive areas with gassy sediments. The average flux intensities (~130 μmol m-2 d-1) are one order of magnitude higher than values characteristic of continental shelves (~30 μmol m-2 d-1) and three orders of magnitude higher than values characteristic of the open ocean (~0.4 μmol m-2 d-1). The high methane concentrations (up to 1,128 nmol L-1) that sustain these fluxes are related to the shallow and well-mixed water column that allows an efficient transfer of methane from the seafloor to surface waters. This differs from deeper and stratified seep areas where there is a large decrease of methane between bottom and surface by microbial oxidation or physical transport. Shallow well-mixed continental shelves represent about 33% of the total continental shelf area, so that marine coastal methane emissions are probably under-estimated. Near-shore and shallow seep areas are hot spots of methane emission, and our data also suggest that emissions could increase in response to warming of surface waters.

  18. Massive marine methane emissions from near-shore shallow coastal areas.

    Science.gov (United States)

    Borges, Alberto V; Champenois, Willy; Gypens, Nathalie; Delille, Bruno; Harlay, Jérôme

    2016-01-01

    Methane is the second most important greenhouse gas contributing to climate warming. The open ocean is a minor source of methane to the atmosphere. We report intense methane emissions from the near-shore southern region of the North Sea characterized by the presence of extensive areas with gassy sediments. The average flux intensities (~130 μmol m(-2) d(-1)) are one order of magnitude higher than values characteristic of continental shelves (~30 μmol m(-2) d(-1)) and three orders of magnitude higher than values characteristic of the open ocean (~0.4 μmol m(-2) d(-1)). The high methane concentrations (up to 1,128 nmol L(-1)) that sustain these fluxes are related to the shallow and well-mixed water column that allows an efficient transfer of methane from the seafloor to surface waters. This differs from deeper and stratified seep areas where there is a large decrease of methane between bottom and surface by microbial oxidation or physical transport. Shallow well-mixed continental shelves represent about 33% of the total continental shelf area, so that marine coastal methane emissions are probably under-estimated. Near-shore and shallow seep areas are hot spots of methane emission, and our data also suggest that emissions could increase in response to warming of surface waters.

  19. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

    NARCIS (Netherlands)

    Locatelli, R.; Bousquet, P.; Chevallier, F.; Fortems-Cheney, A.; Szopa, S.; Saunois, M.; Agusti-Panareda, A.; Bergmann, D.; Bian, H.; Cameron-Smith, P.; Chipperfield, M.P.; Gloor, E.; Houweling, S.; Kawa, S.R.; Krol, M.C.; Patra, P.K.; Prinn, R.G.; Rigby, M.; Saito, R.; Wilson, C.

    2013-01-01

    A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, ar

  20. Quantification of Fugitive Methane Emissions with Spatially Correlated Measurements Collected with Novel Plume Camera

    Science.gov (United States)

    Tsai, Tracy; Rella, Chris; Crosson, Eric

    2013-04-01

    Quantification of fugitive methane emissions from unconventional natural gas (i.e. shale gas, tight sand gas, etc.) production, processing, and transport is essential for scientists, policy-makers, and the energy industry, because methane has a global warming potential of at least 21 times that of carbon dioxide over a span of 100 years [1]. Therefore, fugitive emissions reduce any environmental benefits to using natural gas instead of traditional fossil fuels [2]. Current measurement techniques involve first locating all the possible leaks and then measuring the emission of each leak. This technique is a painstaking and slow process that cannot be scaled up to the large size of the natural gas industry in which there are at least half a million natural gas wells in the United States alone [3]. An alternative method is to calculate the emission of a plume through dispersion modeling. This method is a scalable approach since all the individual leaks within a natural gas facility can be aggregated into a single plume measurement. However, plume dispersion modeling requires additional knowledge of the distance to the source, atmospheric turbulence, and local topography, and it is a mathematically intensive process. Therefore, there is a need for an instrument capable of simple, rapid, and accurate measurements of fugitive methane emissions on a per well head scale. We will present the "plume camera" instrument, which simultaneously measures methane at different spatial points or pixels. The spatial correlation between methane measurements provides spatial information of the plume, and in addition to the wind measurement collected with a sonic anemometer, the flux can be determined. Unlike the plume dispersion model, this approach does not require knowledge of the distance to the source and atmospheric conditions. Moreover, the instrument can fit inside a standard car such that emission measurements can be performed on a per well head basis. In a controlled experiment

  1. Methane emission from flooded soils - from microorganisms to the atmosphere

    Science.gov (United States)

    Conrad, Ralf

    2016-04-01

    Methane is an important greenhouse gas that is affected by anthropogenic activity. The annual budget of atmospheric methane, which is about 600 million tons, is by more than 75% produced by methanogenic archaea. These archaea are the end-members of a microbial community that degrades organic matter under anaerobic conditions. Flooded rice fields constitute a major source (about 10%) of atmospheric methane. After flooding of soil, anaerobic processes are initiated, finally resulting in the disproportionation of organic matter to carbon dioxide and methane. This process occurs in the bulk soil, on decaying organic debris and in the rhizosphere. The produced methane is mostly ventilated through the plant vascular system into the atmosphere. This system also allows the diffusion of oxygen into the rizosphere, where part of the produced methane is oxidized by aerobic methanotrophic bacteria. More than 50% of the methane production is derived from plant photosynthetic products and is formed on the root surface. Methanocellales are an important group of methanogenic archaea colonizing rice roots. Soils lacking this group seem to result in reduced root colonization and methane production. In rice soil methane is produced by two major paths of methanogenesis, the hydrogenotrophic one reducing carbon dioxide to methane, and the aceticlastic one disproportionating acetate to methane and carbon dioxide. Theoretically, at least two third of the methane should be produced by aceticlastic and the rest by hydrogenotrophic methanogenesis. In nature, however, the exact contribution of the two paths can vary from zero to 100%. Several environmental factors, such as temperature and quality of organic matter affect the path of methane production. The impact of these factors on the composition and activity of the environmental methanogenic microbial community will be discussed.

  2. Data for "Estimates of reservoir methane emissions based on a spatially balanced probabilistic-survey"

    Data.gov (United States)

    U.S. Environmental Protection Agency — Measured diffusive and ebullitive methane emission rates from 115 sites in William H Harsha Lake. File also contains fields required for GRTS analysis. This dataset...

  3. Modeling methane emissions and methane inventories for cattle production systems in Mexico

    OpenAIRE

    2014-01-01

    Anaerobic fermentation of structural carbohydrates in the rumen of bovines produces waste products such as volatile fatty acids, fermentation heat, carbon dioxide and methane gas. Methane is a greenhouse gas having several times the global warming potential of CO 2 . The purpose of the present paper is to provide a realistic estimate of the national inventory of methane produced by the enteric fermentation of cattle, based on a simulation model and to provide estimates of CH 4 produced by cat...

  4. Enhanced winter soil frost reduces methane emission during the subsequent growing season in a boreal peatland.

    Science.gov (United States)

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2016-02-01

    Winter climate change may result in reduced snow cover and could, consequently, alter the soil frost regime and biogeochemical processes underlying the exchange of methane (CH4 ) in boreal peatlands. In this study, we investigated the short-term (1-3 years) vs. long-term (11 years) effects of intensified winter soil frost (induced by experimental snow exclusion) on CH4 exchange during the following growing season in a boreal peatland. In the first 3 years (2004-2006), lower CH4 emissions in the treatment plots relative to the control coincided with delayed soil temperature increase in the treatment plots at the beginning of the growing season (May). After 11 treatment years (in 2014), CH4 emissions were lower in the treatment plots relative to the control over the entire growing season, resulting in a reduction in total growing season CH4 emission by 27%. From May to July 2014, reduced sedge leaf area coincided with lower CH4 emissions in the treatment plots compared to the control. From July to August, lower dissolved organic carbon concentrations in the pore water of the treatment plots explained 72% of the differences in CH4 emission between control and treatment. In addition, greater Sphagnum moss growth in the treatment plots resulted in a larger distance between the moss surface and the water table (i.e., increasing the oxic layer) which may have enhanced the CH4 oxidation potential in the treatment plots relative to the control in 2014. The differences in vegetation might also explain the lower temperature sensitivity of CH4 emission observed in the treatment plots relative to the control. Overall, this study suggests that greater soil frost, associated with future winter climate change, might substantially reduce the growing season CH4 emission in boreal peatlands through altering vegetation dynamics and subsequently causing vegetation-mediated effects on CH4 exchange.

  5. Is Optical Gas Imaging Effective for Detecting Fugitive Methane Emissions? - A Technological and Policy Perspective

    Science.gov (United States)

    Ravikumar, A. P.; Wang, J.; Brandt, A. R.

    2016-12-01

    Mitigating fugitive methane emissions from the oil and gas industry has become an important concern for both businesses and regulators. While recent studies have improved our understanding of emissions from all sectors of the natural gas supply chain, cost-effectively identifying leaks over expansive natural gas infrastructure remains a significant challenge. Recently, the Environmental Protection Agency (EPA) has recommended the use of optical gas imaging (OGI) technologies to be used in industry-wide leak detection and repair (LDAR) programs. However, there has been little to no systematic study of the effectiveness of infrared-camera-based OGI technology for leak detection applications. Here, we develop a physics-based model that simulates a passive infrared camera imaging a methane leak against varying background and ambient conditions. We verify the simulation tool through a series of large-volume controlled release field experiments wherein known quantities of methane were released and imaged from a range of distances. After simulator verification, we analyze the effects of environmental conditions like temperature, wind, and imaging background on the amount of methane detected from a statistically representative survey program. We also examine the effects of LDAR design parameters like imaging distance, leak size distribution, and gas composition. We show that imaging distance strongly affects leak detection - EPA's expectation of a 60% reduction in fugitive emissions based on a semi-annual LDAR survey will be realized only if leaks are imaged at a distance less than 10 m from the source under ideal environmental conditions. Local wind speed is also shown to be important. We show that minimum detection limits are 3 to 4 times higher for wet-gas compositions that contain a significant fraction of ethane and propane, resulting a significantly large leakage rate. We also explore the importance of `super-emitters' on the performance of an OGI-based leak

  6. Relationship between residual feed intake and enteric methane emission in Nellore cattle.

    OpenAIRE

    2015-01-01

    Feed intake and average daily gain (ADG) in Nellore cattle were determined to calculate residual feed intake in two performance tests: first during the growth phase (RFIgrowth) and then during a measurement of the methane emission phase (RFImet). During the RFIgrowth test, 62 males and 56 females were classified as low-, medium-, and high-RFI. Enteric methane emission was measured in 46 animals; 23 males used for RFImet measurement plus 23 females (22 low-RFIgrowth and 24 high-RFIgrowth). Die...

  7. Mitigation of methane emissions from constructed farm wetlands.

    Science.gov (United States)

    Pangala, Sunitha R; Reay, David S; Heal, Kate V

    2010-01-01

    Constructed wetlands are increasingly used for water pollution treatment but may also be sources of the greenhouse gas CH(4). The effect of addition of two potential inhibitors of methanogenesis - iron ochre and gypsum - on net CH(4) emissions was investigated in a constructed wetland treating farm runoff in Scotland, UK. CH(4) fluxes from three 15-m(2) wetland plots were measured between January and July 2008 in large static chambers incorporating a tunable diode laser, with application of 5tonha(-1) ochre and gypsum in May. CH(4) fluxes were also measured from control and ochre- and gypsum-treated wetland sediment cores incubated at constant and varying temperature in the laboratory. Ochre addition suppressed CH(4) emissions by 64+/-13% in the field plot and >90% in laboratory incubations compared to controls. Gypsum application of 5tonha(-1) in the field and laboratory experiments had no effect on CH(4) emissions, but application of 10tonha(-1) to a sediment core reduced CH(4) emissions by 28%. Suppression of CH(4) emissions by ochre application to sediment cores also increased with temperature; the reduction relative to the control increased from 50% at 17.5 degrees C to >90% at 27.5 degrees C. No significant changes in N removal or pH and potentially-toxic metal content of sediments as the result of inhibitor application were detected in the wetland during the study.

  8. Methane emissions of beef cattle on forages: efficiency of grazing management systems.

    Science.gov (United States)

    DeRamus, H Alan; Clement, Terry C; Giampola, Dean D; Dickison, Peter C

    2003-01-01

    Fermentation in the rumen of cattle produces methane (CH4). Methane may play a role in global warming scenarios. The linking of grazing management strategies to more efficient beef production while reducing the CH4 emitted by beef cattle is important. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of best management practices (BMP) grazing compared with continuous grazing on CH4 production in several Louisiana forages during 1996-1998. Cows and heifers (Bos taurus) grazed common bermudagrass [Cynodon dactylon (L.) Pers.], bahiagrass (Paspalum notatum Flugge), and ryegrass (Lolium multiflorum Lam.) pastures and were wintered on bahiagrass hay with supplements of protein molasses blocks (PMB), cottonseed meal and corn (CSMC), urea and corn (URC), or limited ryegrass grazing (LRG). Daily CH4 emissions were between 89 and 180 g d(-1) for young growing heifers and 165 to 294 g d(-1) for mature Simbrah cows. Heifers on "ad lib" ryegrass in March and April produced only one-tenth the CH4 per kg of gain as heifers on LRG of 1 h. Using BMP significantly reduced the emission of CH4 per unit of animal weight gain. Management-intensive grazing (MIG) is a BMP that offers the potential for more efficient utilization of grazed forage crops via controlled rotational grazing and more efficient conversion of forage into meat and milk. Projected CH4 annual emissions in cows reflect a 22% reduction from BMP when compared with continuous grazing in this study. With the BMP application of MIG, less methane was produced per kilogram of beef gain.

  9. Methane Ebullition in Temperate Hydropower Reservoirs and Implications for US Policy on Greenhouse Gas Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Benjamin L.; Arntzen, Evan V.; Goldman, Amy E.; Richmond, Marshall C.

    2017-07-21

    The United States is home to more than 87,000 dams, 2,198 of which are actively used for hydropower production. With the December 2015 consensus adoption of the United Nations Framework Convention on Climate Change’s Paris Agreement, it is imperative for the U.S. to accurately quantify greenhouse gas fluxes from its hydropower reservoirs. Methane ebullition, or methane bubbles originating from river or lake sediments, can account for nearly all of a reservoir’s methane emissions to the atmosphere. However, methane ebullition in hydropower reservoirs has been studied in only three temperate locations, none of which are in the United States. This study measures high ebullitive methane fluxes from two hydropower reservoirs in eastern Washington, synthesizes the known information about methane ebullition from tropical, boreal, and temperate hydropower reservoirs, and investigates the implications for U.S. hydropower management and growth.

  10. The case for refining bottom-up methane emission inventories using top-down measurements

    Science.gov (United States)

    Kelly, Bryce F. J.; Iverach, Charlotte P.; Ginty, Elisa; Bashir, Safdar; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.

    2017-04-01

    Bottom-up global methane emission estimates are important for guiding policy development and mitigation strategies. Such inventories enable rapid and consistent proportioning of emissions by industrial sectors and land use at various scales from city to country to global. There has been limited use of top-down measurements to guide refining emission inventories. Here we compare the EDGAR gridmap data version 4.2 with over 5000 km of daytime ground level mobile atmospheric methane surveys in eastern Australia. The landscapes and industries surveyed include: urban environments, dryland farming, intensive livestock farming (both beef and lamb), irrigation agriculture, open cut and underground coal mining, and coal seam gas production. Daytime mobile methane surveys over a 2-year period show that at the landscape scale there is a high level of repeatability for the mole fraction of methane measured in the ground level atmosphere. Such consistency in the mole fraction of methane indicates that these data can be used as a proxy for flux. A scatter plot of the EDGAR emission gridmap Log[ton substance / 0.1 degree x 0.1 degree / year] versus the median mole fraction of methane / 0.1 degree x 0.1 degree in the ground level atmosphere highlights that the extent of elevated methane emissions associated with coal mining in the Hunter coalfields, which covers an area of 56 km by 24 km, has been under-represented in the EDGAR input data. Our results also show that methane emissions from country towns (population inventory. This is possibly due to poor information on the extent of urban gas leaks. Given the uncertainties associated with the base land use and industry data for each country, we generalise the Australian observations to the global inventory with caution. The extensive comparison of top-down measurements versus the EDGAR version 4.2 methane gridmaps highlights the need for adjustments to the base resource data and/or the emission factors applied for coal mining

  11. [Effect of Aeration Strategies on Emissions of Nitrogenous Gases and Methane During Sludge Bio-Drying].

    Science.gov (United States)

    Qi, Lu; Wei, Yuan-song; Zhang, Jun-ya; Zhao, Chen-yang; Cai, Xing; Zhang, Yuan-li; Shao, Chun-yan; Li, Hong-mei

    2016-01-15

    The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other was set as the test in which the aeration was used for oxygen supply, pile temperature control, and moisture removal in the start-up, middle and final stages, respectively. The results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11) , but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg x m(-3) and 219.8 mg x m(-3), respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg x t(-1) was observed than that of the control (3.73 kg x t(-1) dry weight) , the cumulative emission of NO in the test at 1.9 g x m(-2) was 15. 9% higher than that of the control (1.6 g x m(-2)).

  12. Evaluation of methane emissions of some rice cultivars of Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Namaratne, S.Y.; Alwis, H.P.W. de [Institute of Fundamental Studies, Kandy (Sri Lanka)

    1996-12-31

    A field experiment on three local rice cultivars, namely BG 300, BG 304 and AT 303, showed no statistically significant difference (p<0.05) among them with-respect to the methane flux emitted. The methane flux profiles of all three varieties indicated a more or less constant emission during the vegetative and reproductive periods, a peak emission during late flowering/early ripening stage and a dramatic increase in the flux during the late ripening period. The seasonal methane flux of BG 300, BG 304 and AT 303 were 200 {+-} 48, 156 {+-} 52 and 129 {+-} 40 g m{sup {minus}2}, respectively for a 92 day cropping period.

  13. Evaluation of the laser methane detector to estimate methane emissions from ewes and steers.

    Science.gov (United States)

    Ricci, P; Chagunda, M G G; Rooke, J; M Houdijk, J G; Duthie, C-A; Hyslop, J; Roehe, R; Waterhouse, A

    2014-11-01

    The laser methane detector (LMD) has been proposed as a method to characterize enteric methane (CH4) emissions from animals in a natural environment. To validate LMD use, its CH4 outputs (LMD-CH4), were compared against CH4 measured with respiration chambers (chamber-CH4). The LMD was used to measure CH4 concentration (µL/L) in the exhaled air of 24 lactating ewes and 72 finishing steers. In ewes, LMD was used on 1 d for each ewe, for 2-min periods at 5 hourly observation periods (P1 to P5, respectively) after feeding. In steers fed either low- or high-concentrate diets, LMD was used once daily for a 4-min period for 3 d. The week after LMD-CH4 measurement, ewes or steers entered respiration chambers to quantify daily CH4 output (g/d). The LMD outputs consisted of periodic events of high CH4 concentrations superimposed on a background of oscillating lower CH4 concentrations. The high CH4 events were attributed to eructation and the lower background CH4 to respiration. After fitting a double normal distribution to the data set, a threshold of 99% of probability of the lower distribution was used to separate respiration from eructation events. The correlation between mean LMD-CH4 and chamber-CH4 was not high, and only improved correlations were observed after data were separated in 2 levels. In ewes, a model with LMD and DMI (adjusted R(2) = 0.92) improved the relationship between DMI and chamber-CH4 alone (adjusted R(2) = 0.79) and between LMD and chamber-CH4 alone (adjusted R(2) = 0.86). In both experiments, chamber-CH4 was best explained by models with length of eructation events (time) and maximum values of CH4 concentration during respiration events (µL/L; P LMD were observed from 3 to 5 h after feeding. Given the short time and ease of use of LMD, there is potential for its commercial application and field-based studies. Although good indicators of quantity of CH4 were obtained with respiration and eructation CH4, the method needed to separate the data into

  14. Carbon dioxide and methane emissions from the scale model of open dairy lots.

    Science.gov (United States)

    Ding, Luyu; Cao, Wei; Shi, Zhengxiang; Li, Baoming; Wang, Chaoyuan; Zhang, Guoqiang; Kristensen, Simon

    2016-07-01

    To investigate the impacts of major factors on carbon loss via gaseous emissions, carbon dioxide (CO2) and methane (CH4) emissions from the ground of open dairy lots were tested by a scale model experiment at various air temperatures (15, 25, and 35 °C), surface velocities (0.4, 0.7, 1.0, and 1.2 m sec(-1)), and floor types (unpaved soil floor and brick-paved floor) in controlled laboratory conditions using the wind tunnel method. Generally, CO2 and CH4 emissions were significantly enhanced with the increase of air temperature and velocity (P 0.05). For CO2, similar emissions were found from the soil and brick floors at 15 and 25 °C, whereas higher rates were detected from the brick floor at 35 °C (P climate, floor systems, and management practices, which are quite different from those indoors. This study assessed the effects of floor types and air velocities on CO2 and CH4 emissions from the open dairy lots at various temperatures by a wind tunnel. It provided some valuable information for decision-making and further studies on gaseous emissions from open lots.

  15. Effect of industrial by-products containing electron acceptors on mitigating methane emission during rice cultivation.

    Science.gov (United States)

    Ali, Muhammad Aslam; Lee, Chang Hoon; Kim, Sang Yoon; Kim, Pil Joo

    2009-10-01

    Three industrial by-products (fly ash, phosphogypsum and blast furnace slag), were evaluated for their potential re-use as soil amendments to reduce methane (CH(4)) emission resulting from rice cultivation. In laboratory incubations, CH(4) production rates from anoxic soil slurries were significantly reduced at amendment levels of 0.5%, 1%, 2% and 5% (wt wt(-1)), while observed CO(2) production rates were enhanced. The level of suppression in methane production was the highest for phosphogypsum, followed by blast slag and then fly ash. In the greenhouse experiment, CH(4) emission rates from the rice planted potted soils significantly decreased with the increasing levels (2-20 Mg ha(-1)) of the selected amendments applied, while rice yield simultaneously increased compared to the control treatment. At 10 Mg ha(-1) application level of the amendments, total seasonal CH(4) emissions were reduced by 20%, 27% and 25%, while rice grain yields were increased by 17%, 15% and 23% over the control with fly ash, phosphogypsum, and blast slag amendments, respectively. The suppression of CH(4) production rates as well as total seasonal CH(4) flux could be due to the increased concentrations of active iron, free iron, manganese oxides, and sulfate in the amended soil, which acted as electron acceptors and controlled methanogens' activity by limiting substrates availability. Among the amendments, blast furnace slag and fly ash contributed mainly to improve the soil nutrients balance and increased the soil pH level towards neutral point, but soil acidity was developed with phosphogypsum application. Conclusively, blast slag among the selected amendments would be a suitable soil amendment for reducing CH(4) emissions as well as sustaining rice productivity.

  16. Effect of Different Level of Psyllium Supplementation to Horse Diet on in vitro Fermentation Parameters and Methane Emission

    Directory of Open Access Journals (Sweden)

    Kanber KARA

    2017-01-01

    Full Text Available The purpose of this study was to determine the effect of psyllium addition to horse diets on methane emissions and digestion parameters by in vitro digestion technique using horse feces as inoculum. The effect of 0 (control group, 5, 10, 20 and 40 g/kg DM (Dry matter (treatment groups psyllium (Psyllium Husk, Solgar, UK supplementations to horse diet were determined on in vitro total gas and methane production, metabolisable energy (ME, organic matter digestion (OMD, ammonia nitrogen (NH3-N, short chain fatty acids (SCFA and pH value. In vitro digestibility technique was performed with using glass syringes of 100 ml volumes (Model Fortuna, Germany at 39.0±0.2°C for 24 hour incubation. In the study, in vitro total gas production was linearly decreased in treatment groups (up to 130 ml/g DM compared to control group (181 ml/g DM (P0.05. Consequently, it was demonstrated that psyllium, which use commonly in constipated horses because of laxative efficacy, reduced methane emission as another positive effect in horses. Although psyllium reduced methane emission, it had adverse effects on in vitro digestibility of horse ration. However, it was considered that further investigations are necessary to understand the effects deeply by doing the in vitro or in vivo digestion trials with lower doses or psyllium is not suitable to use in healthy horses for a long time.

  17. Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH4 ice core records

    Science.gov (United States)

    Bock, Michael; Schmitt, Jochen; Beck, Jonas; Seth, Barbara; Chappellaz, Jérôme; Fischer, Hubertus

    2017-07-01

    Atmospheric methane (CH4) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [δ13CH4 and δD(CH4)] from four Antarctic ice cores, which provide improved constraints on past changes in natural methane sources. Our isotope data show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima. The changes in these sources are steered by variations in temperature, precipitation, and the water table as modulated by insolation, (local) sea level, and monsoon intensity. Based on our δD(CH4) constraint, it seems that geologic emissions of methane may play a steady but only minor role in atmospheric CH4 changes and that the glacial budget is not dominated by these sources. Superimposed on the glacial/interglacial variations is a marked difference in both isotope records, with systematically higher values during the last 25,000 y compared with older time periods. This shift cannot be explained by climatic changes. Rather, our isotopic methane budget points to a marked increase in fire activity, possibly caused by biome changes and accumulation of fuel related to the late Pleistocene megafauna extinction, which took place in the course of the last glacial.

  18. Controlling spontaneous emission

    DEFF Research Database (Denmark)

    Lodahl, Peter

    dots (QDs) embedded in 3D photonic crystals consisting of air spheres in titanium dioxide. Performing time-resolved experiments, we show that the photonic crystals control the emission decay rate of excitons confined in the QDs1,2. By varying the lattice parameter of the photonic crystals, we...

  19. Fugitive emissions of methane from abandoned, decommissioned oil and gas wells

    Science.gov (United States)

    Worrall, Fred; boothroyd, Ian; Almond, Sam; Davies, Richard

    2015-04-01

    The aim of this study was to consider the potential legacy of increased onshore, unconventional gas production by examining the integrity of decommissioned, onshore, oil and gas wells in the UK. In the absence of a history of unconventional hydrocarbon exploitation in the UK, conventional onshore sites were considered and an examination of pollution incidents records had suggested that only a small fraction of onshore wells could show integrity failures. In this study the fugitive emissions of methane from former oil and gas production wells onshore in the UK were considered as a measure of well integrity. The survey considered 49 decommissioned (abandoned) wells from 4 different basins that were between 8 and 78 years old; all but one of these wells would be considered as having been decommissioned properly, i.e. wells cut, sealed and buried by soil cover to the extent that the well sites were being used for agriculture. For each well site the soil gas methane was analysed multiple times and assessed relative to a nearby control site of similar land-use and soil type. The results will be expressed in terms of the proportion and extent of well integrity failure, or success, over time since decommissioning and relative to local control sites. The probability of failure and the emissions factor for decommissioned wells will be presented.

  20. Sensitivity of detection of fugitive methane emissions from coal seam gas fields

    Science.gov (United States)

    Feitz, A. J.; Berko, H.; Wilson, P.; Jenkins, C.; Loh, Z. M.; Etheridge, D.

    2013-12-01

    There is increasing recognition that minimising methane emissions from the oil and gas sector is a key step in reducing global greenhouse gas emissions in the near term. Atmospheric monitoring techniques are likely to play an important future role in measuring the extent of existing emissions and verifying emission reductions. They can be very suitable for monitoring gas fields as they are continuous and integrate emissions from a number of potential point and diffuse sources that may vary in time. Geoscience Australia and CSIRO Marine & Atmospheric Research have collected three years of continuous methane and carbon dioxide measurements at their atmospheric composition monitoring station ('Arcturus') in the Bowen Basin, Australia. Methane signals in the Bowen Basin are likely to be influenced by cattle production, landfill, coal production, and conventional and coal seam gas (CSG) production. Australian CSG is typically 'dry' and is characterised by a mixed thermogenic-biogenic methane source with an absence of C3-C6+ alkanes. The range of δ13C isotopic signatures of the CSG is similar to methane from landfill gas and cattle emissions. The absence of standard in-situ tracers for CSG fugitive emissions suggests that having a comprehensive baseline will be critical for successful measurement of fugitive emissions using atmospheric techniques. In this paper we report on the sensitivity of atmospheric techniques for the detection of fugitive emissions from a simulated new CSG field against a three year baseline signal. Simulation of emissions was performed for a 1-year period using the coupled prognostic meteorological and air pollution model TAPM at different fugitive emission rates (i.e. estimates of <1% to up to 10% of production lost) and distances (i.e. 10 - 50 km) from the station. Emissions from the simulated CSG field are based on well density, production volumes, and field size typical of CSG fields in Australia. The distributions of the perturbed and

  1. Methane emissions from terrestrial plants under aerobic conditions

    NARCIS (Netherlands)

    Keppler, F.; Hamilton, J.T.G.; Brass, M.; Röckmann, T.

    2006-01-01

    Methane is an important greenhouse gas and its atmospheric concentration has almost tripled since pre-industrial times1,2. It plays a central role in atmospheric oxidation chemistry and affects stratospheric ozone and water vapour levels. Most of the methane from natural sources in Earth’s atmospher

  2. Methane emissions from terrestrial plants under aerobic conditions

    NARCIS (Netherlands)

    Keppler, F.; Hamilton, J.T.G.; Brass, M.|info:eu-repo/dai/nl/304823600; Röckmann, T.|info:eu-repo/dai/nl/304838233

    2006-01-01

    Methane is an important greenhouse gas and its atmospheric concentration has almost tripled since pre-industrial times1,2. It plays a central role in atmospheric oxidation chemistry and affects stratospheric ozone and water vapour levels. Most of the methane from natural sources in Earth’s

  3. Methane emissions from terrestrial plants under aerobic conditions

    NARCIS (Netherlands)

    Keppler, F.; Hamilton, J.T.G.; Brass, M.|info:eu-repo/dai/nl/304823600; Röckmann, T.|info:eu-repo/dai/nl/304838233

    2006-01-01

    Methane is an important greenhouse gas and its atmospheric concentration has almost tripled since pre-industrial times1,2. It plays a central role in atmospheric oxidation chemistry and affects stratospheric ozone and water vapour levels. Most of the methane from natural sources in Earth’s atmospher

  4. Effects of organic nitrification inhibitors on methane and nitrous oxide emission from tropical rice paddy

    Science.gov (United States)

    Datta, A.; Adhya, T. K.

    2014-08-01

    We have studied the effects of application of different nitrification inhibitors on methane (CH4) and nitrous oxide (N2O) emissions from rice paddy and associated soil chemical and biological dynamics during wet and dry seasons of rice crop in a tropical climate of eastern India. The experiment consisted of four treatments viz. (i) Prilled urea amended control (ii) urea + Dicyandiamide (DCD), (iii) urea + Nimin and (iv) urea + Karanjin. CH4 emission was significantly higher from the DCD (372.36 kg ha-1) and Karanjin (153.07 kg ha-1) applied plots during the wet and dry season, respectively. N2O emission was significantly inhibited in the Nimin applied plots during both seasons (69% and 85% over control during wet season and dry season respectively). CH4 and N2O emissions per Mg of rice grain yield were lowest from the Nimin applied plots during both seasons. Global warming potential (GWP) of the plot treated with DCD (13.93) was significantly higher during the experimental period. CH4 production potential was significantly higher from the nitrification inhibitor applied plots compared to control. While, CH4 oxidation potential followed the order; urea + Nimin > urea + Karanjin > urea + DCD > control. Application of Nimin significantly increased the methanotrophic bacterial population in the soil during the maximum tillering to flowering stage and may be attributed to low CH4 emission from the plots. Denitrification enzyme activity (DEA) of the soil was significantly low from the Nimin and Karanjin applied plots. Results suggest that apart from being potent nitrification inhibitors, Nimin and Karanjin also have the potential to reduce the denitrification activity in the soil. This in turn, would reduce N2O emission from flooded paddy where both nitrification and denitrification processes causes N2O emission.

  5. Influence of rumen protozoa on methane emission in ruminants: a meta-analysis approach.

    Science.gov (United States)

    Guyader, J; Eugène, M; Nozière, P; Morgavi, D P; Doreau, M; Martin, C

    2014-11-01

    A meta-analysis was conducted to evaluate the effects of protozoa concentration on methane emission from ruminants. A database was built from 59 publications reporting data from 76 in vivo experiments. The experiments included in the database recorded methane production and rumen protozoa concentration measured on the same groups of animals. Quantitative data such as diet chemical composition, rumen fermentation and microbial parameters, and qualitative information such as methane mitigation strategies were also collected. In the database, 31% of the experiments reported a concomitant reduction of both protozoa concentration and methane emission (g/kg dry matter intake). Nearly all of these experiments tested lipids as methane mitigation strategies. By contrast, 21% of the experiments reported a variation in methane emission without changes in protozoa numbers, indicating that methanogenesis is also regulated by other mechanisms not involving protozoa. Experiments that used chemical compounds as an antimethanogenic treatment belonged to this group. The relationship between methane emission and protozoa concentration was studied with a variance-covariance model, with experiment as a fixed effect. The experiments included in the analysis had a within-experiment variation of protozoa concentration higher than 5.3 log10 cells/ml corresponding to the average s.e.m. of the database for this variable. To detect potential interfering factors for the relationship, the influence of several qualitative and quantitative secondary factors was tested. This meta-analysis showed a significant linear relationship between methane emission and protozoa concentration: methane (g/kg dry matter intake)=-30.7+8.14×protozoa (log10 cells/ml) with 28 experiments (91 treatments), residual mean square error=1.94 and adjusted R 2=0.90. The proportion of butyrate in the rumen positively influenced the least square means of this relationship.

  6. Methane Emission Quantification at the Farm Scale Using Boundary-Layer Volume Budgets

    Science.gov (United States)

    Stieger, J.; Eugster, W.; Siegwolf, R. T.; Buchmann, N. C.

    2012-12-01

    Agriculture plays an important role in the global greenhouse gas budget. Especially emissions of CH4 from livestock and manure management are of key importance. In Switzerland, roughly 80% of all national methane emissions originate from the agricultural sector. However, methane emissions in Switzerland so far were not measured but were estimated via emission factors for enteric fermentation of livestock and for manure management. This results in high uncertainties associated with emission estimates (up to 55%). Our study aims at quantifying methane emissions at the farm scale. We explored whether boundary-layer budget quantifications of methane can be used for the validation of emission estimates, and hence for the reduction of associated uncertainties in national inventory reports under the Kyoto Protocol. We will present methane emission budgets based on concentration profiles obtained from tethered balloon measurements from several campaigns carried out over two consecutive years (2011 and 2012). We will show how CH4 emissions at the farm scale (0.5 - 5 km2) were quantified using this boundary-layer budgeting approach. Clear diurnal courses of CH4 fluxes showed, that the temporal and spatial variability of emissions and atmospheric processes played an important role for source strength estimation. As an effect of these processes, budget quantifications differed up to 45% compared to the national inventory estimates. While the major determinants of methane emission budgets are still unclear, we will show that the δ13C ratios in CH4 concentrations did provide additional information about the processes responsible for the CH4 fluxes obtained.

  7. A new methane control and prediction software suite for longwall mines

    Science.gov (United States)

    Dougherty, Heather N.; Özgen Karacan, C.

    2011-09-01

    This paper presents technical and application aspects of a new software suite, MCP (Methane Control and Prediction), developed for addressing some of the methane and methane control issues in longwall coal mines. The software suite consists of dynamic link library (DLL) extensions to MS-Access TM, written in C++. In order to create the DLLs, various statistical, mathematical approaches, prediction and classification artificial neural network (ANN) methods were used. The current version of MCP suite (version 1.3) discussed in this paper has four separate modules that (a) predict the dynamic elastic properties of coal-measure rocks, (b) predict ventilation emissions from longwall mines, (c) determine the type of degasification system that needs to be utilized for given situations and (d) assess the production performance of gob gas ventholes that are used to extract methane from longwall gobs. These modules can be used with the data from basic logs, mining, longwall panel, productivity, and coal bed characteristics. The applications of these modules separately or in combination for methane capture and control related problems will help improve the safety of mines. The software suite's version 1.3 is discussed in this paper. Currently, it's new version 2.0 is available and can be downloaded from http://www.cdc.gov/niosh/mining/products/product180.htm free of charge. The models discussed in this paper can be found under "ancillary models" and under "methane prediction models" for specific U.S. conditions in the new version.

  8. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    Science.gov (United States)

    Wang, Zi-han; Wang, Chun-mei; Tang, Hua-xin; Zuo, Cheng-ji; Xu, Hong-ming

    2009-06-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  9. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    Institute of Scientific and Technical Information of China (English)

    Zi-han Wang; Chun-mei Wang; Hua-xin Tang; Cheng-ji Zuo; Hong-ming Xu

    2009-01-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition tim-ing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its appli-cation, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NO while decreasing HC and CO emissions. Exhaust gas recir-culation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NO is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  10. Invading Phragmites australis stimulates methane emissions from North American tidal marshes

    Science.gov (United States)

    Mueller, Peter; Meschter, Justin E.; Hager, Rachel N.; Mozdzer, Thomas J.; Jensen, Kai; Langley, J. Adam; Baldwin, Andrew; Megonigal, J. Patrick

    2015-04-01

    Most studies concerned with invasive plant species focus on effects on biodiversity, while only few have investigated how the greenhouse gas balance of an ecosystem or, in particular, how methane emissions are affected by invasion driven shifts in plant species composition. In this study, conducted in brackish marsh sites of the Chesapeake Bay, United States, we investigated the effect of the none-native grass Phragmites australis invading native shortgrass communities on methane emissions. In situ gas flux measurements using static chambers were used to quantify methane emissions along transects of progressive invasion by Phragmites. Methane emissions were several fold higher in Phragmites stands than in adjacent native communities and increased with progressive invasion of Phragmites. Results of a mesocosm experiment support our field observations and show consistently higher methane emissions from mesocoms planted with Phragmites even at different hydrological conditions. Because tidal marshes, as blue carbon ecosystems, sequester soil carbon rapidly and emit methane slowly compared to other wetland ecosystems, they are increasingly recognized as having a high carbon value. Our results indicate that the replacement of native marsh communities by Phragmites may considerably change the green house gas balance of these ecosystems and thus lower their carbon sequestration value.

  11. Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions

    Science.gov (United States)

    Isaksen, Ivar S.A.; Gauss, Michael; Myhre, Gunnar; Walter Anthony, Katey M.; Ruppel, Carolyn

    2011-01-01

    The magnitude and feedbacks of future methane release from the Arctic region are unknown. Despite limited documentation of potential future releases associated with thawing permafrost and degassing methane hydrates, the large potential for future methane releases calls for improved understanding of the interaction of a changing climate with processes in the Arctic and chemical feedbacks in the atmosphere. Here we apply a “state of the art” atmospheric chemistry transport model to show that large emissions of CH4 would likely have an unexpectedly large impact on the chemical composition of the atmosphere and on radiative forcing (RF). The indirect contribution to RF of additional methane emission is particularly important. It is shown that if global methane emissions were to increase by factors of 2.5 and 5.2 above current emissions, the indirect contributions to RF would be about 250% and 400%, respectively, of the RF that can be attributed to directly emitted methane alone. Assuming several hypothetical scenarios of CH4 release associated with permafrost thaw, shallow marine hydrate degassing, and submarine landslides, we find a strong positive feedback on RF through atmospheric chemistry. In particular, the impact of CH4 is enhanced through increase of its lifetime, and of atmospheric abundances of ozone, stratospheric water vapor, and CO2 as a result of atmospheric chemical processes. Despite uncertainties in emission scenarios, our results provide a better understanding of the feedbacks in the atmospheric chemistry that would amplify climate warming.

  12. Methane emissions of rice increased by elevated carbon dioxide and temperature.

    Science.gov (United States)

    Allen, Leon H; Albrecht, Stephan L; Colón-Guasp, Wilfredo; Covell, Stephen A; Baker, Jeffrey T; Pan, Deyun; Boote, Kenneth J

    2003-01-01

    Methane (CH4) effluxes by paddy-culture rice (Oryza sativa L.) contribute about 16% of the total anthropogenic emissions. Since radiative forcing of CH4 at current atmospheric concentrations is 21 times greater on a per mole basis than that of carbon dioxide (CO2), it is imperative that the impact of global change on rice CH4 emissions be evaluated. Rice (cv. IR72) was planted in sunlit, closed-circulation, controlled-environment chambers in which CH4 efflux densities were measured daily. The CO2 concentration was maintained at either 330 or 660 micromol mol(-1). Air temperatures were controlled to daily maxima and minima of 32/23, 35/26, and 38/29 degrees C at each CO2 treatment. Emissions of CH4 each day were determined during a 4-h period after venting and resealing the chambers at 0800 h. Diurnal CH4 effluxes on 77, 98, and 119 d after planting (DAP) were obtained similarly at 4-h intervals. Emissions over four-plant hills and over flooded bare soil were measured at 53, 63, and 100 DAP. Emissions were negligible before 40 DAP. Thereafter, emissions were observed first in high-CO2, high-temperature treatments and reached a sustained maximum efflux density of about 7 mg m(-2) h(-1) (0.17 g m(-2) d(-1)) near the end of the growing season. Total seasonal CH4 emission was fourfold greater for high-CO2, high-temperature treatments than for the low-CO2, low-temperature treatment, probably due to more root sloughing or exudates, since about sixfold more acetate was found in the soil at 71 DAP. Both rising CO2 and increasing temperatures could lead to a positive feedback on global warming by increasing the emissions of CH4 from rice.

  13. Qualitative assessment of methane emission inventory from municipal solid waste disposal sites: a case study

    Science.gov (United States)

    Kumar, Sunil; Mondal, A. N.; Gaikwad, S. A.; Devotta, Sukumar; Singh, R. N.

    2004-09-01

    In developing countries like India, urban solid waste (SW) generation is increasing enormously and most of the SWs are disposed off by land filling in low-lying areas, resulting into generation of large quantities of biogas. Methane, the major constituent gas is known to cause global warming due to green house gas (GHG) effect. There is a need to study the ever-increasing contribution of SW to the global GHG effect. To assess the impacts, estimation of GHG emission is must and to avoid misguidance by these emission-data, qualitative assessment of the estimated GHG is a must. In this paper, methane emission is estimated for a particular landfill site, using default methodology and modified triangular methodology. Total methane generation is same for both theoretical methodologies, but the modified triangular method has an upper hand as it provides a time-dependent emission profile that reflects the true pattern of the degradation process. To check the quality of calculated emission-data, extensive sampling is carried out for different seasons in a year. Field results show a different trend as compared to theoretical results, this compels for logical thinking. Each methane emission-data is backed up by the uncertainty associated with it, this further strengthens the quality check of these data. Uncertainty calculation is done using Monte Carlo simulation technique, recommended in IPCC Guideline. In the due course of qualitative assessment of methane emission-data, many site-specific sensitive parameters are discovered and are briefly discussed in this paper.

  14. Nonmicrobial aerobic methane emission from poplar shoot cultures under low-light conditions.

    Science.gov (United States)

    Brüggemann, Nicolas; Meier, Rudolf; Steigner, Dominik; Zimmer, Ina; Louis, Sandrine; Schnitzler, Jörg-Peter

    2009-06-01

    The aerobic formation of methane in plants has been reported previously, but has been questioned by a number of researchers. Recently, isotopic evidence demonstrated that ultraviolet irradiation and heating lead to photochemical or thermal aerobic methane formation mainly from plant pectin in the absence of microbial methane production. However, the origin of aerobic methane formation from plant material observed under low temperature and low-light/dark conditions is still unclear. Here we show that Grey poplar (Populus × canescens, syn. Populus tremula × Populus alba) plants derived from cell cultures under sterile conditions released 13C-labeled methane under low-light conditions after feeding the plants with 13CO2. Molecular biological analysis proved the absence of any microbial contamination with known methanogenic microorganisms and ruled out the possibility that methane emission from our poplar shoot cultures under aerobic low-light/dark and ambient temperature conditions could be of microbial origin. The CH4 release rates in our experiment were in the range of 0.16-0.7 ng g-1 DW h-1, adding evidence to the growing opinion that the quantitative role of aerobic methane emissions from plants in the global methane budget, at least from cold temperate or boreal regions, is only of minor importance.

  15. 2004 Methane and Nitrous Oxide Emissions from Manure Management in South Africa

    Directory of Open Access Journals (Sweden)

    Mokhele Edmond Moeletsi

    2015-03-01

    Full Text Available Manure management in livestock makes a significant contribution towards greenhouse gas emissions in the Agriculture; Forestry and Other Land Use category in South Africa. Methane and nitrous oxide emissions are prevalent in contrasting manure management systems; promoting anaerobic and aerobic conditions respectively. In this paper; both Tier 1 and modified Tier 2 approaches of the IPCC guidelines are utilized to estimate the emissions from South African livestock manure management. Activity data (animal population, animal weights, manure management systems, etc. were sourced from various resources for estimation of both emissions factors and emissions of methane and nitrous oxide. The results show relatively high methane emissions factors from manure management for mature female dairy cattle (40.98 kg/year/animal, sows (25.23 kg/year/animal and boars (25.23 kg/year/animal. Hence, contributions for pig farming and dairy cattle are the highest at 54.50 Gg and 32.01 Gg respectively, with total emissions of 134.97 Gg (3104 Gg CO2 Equivalent. Total nitrous oxide emissions are estimated at 7.10 Gg (2272 Gg CO2 Equivalent and the three main contributors are commercial beef cattle; poultry and small-scale beef farming at 1.80 Gg; 1.72 Gg and 1.69 Gg respectively. Mitigation options from manure management must be taken with care due to divergent conducive requirements of methane and nitrous oxide emissions requirements.

  16. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

    Directory of Open Access Journals (Sweden)

    R. Locatelli

    2013-04-01

    Full Text Available A modelling experiment has been conceived to assess the impact of transport model errors on the methane emissions estimated by an atmospheric inversion system. Synthetic methane observations, given by 10 different model outputs from the international TransCom-CH4 model exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the PYVAR-LMDZ-SACS inverse system to produce 10 different methane emission estimates at the global scale for the year 2005. The same set-up has been used to produce the synthetic observations and to compute flux estimates by inverse modelling, which means that only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg CH4 per year at the global scale, representing 5% of the total methane emissions. At continental and yearly scales, transport model errors have bigger impacts depending on the region, ranging from 36 Tg CH4 in north America to 7 Tg CH4 in Boreal Eurasian (from 23% to 48%. At the model gridbox scale, the spread of inverse estimates can even reach 150% of the prior flux. Thus, transport model errors contribute to significant uncertainties on the methane estimates by inverse modelling, especially when small spatial scales are invoked. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher resolution models. The analysis of methane estimated fluxes in these different configurations questions the consistency of transport model errors in current inverse systems. For future methane inversions, an improvement in the modelling of the atmospheric transport would make the estimations more accurate. Likewise, errors of the observation covariance matrix should be more consistently prescribed in future inversions in order to limit the impact of transport model errors on estimated methane

  17. Sensitivity of wetland methane emissions to model assumptions: application and model testing against site observations

    Directory of Open Access Journals (Sweden)

    L. Meng

    2012-07-01

    Full Text Available Methane emissions from natural wetlands and rice paddies constitute a large proportion of atmospheric methane, but the magnitude and year-to-year variation of these methane sources are still unpredictable. Here we describe and evaluate the integration of a methane biogeochemical model (CLM4Me; Riley et al., 2011 into the Community Land Model 4.0 (CLM4CN in order to better explain spatial and temporal variations in methane emissions. We test new functions for soil pH and redox potential that impact microbial methane production in soils. We also constrain aerenchyma in plants in always-inundated areas in order to better represent wetland vegetation. Satellite inundated fraction is explicitly prescribed in the model, because there are large differences between simulated fractional inundation and satellite observations, and thus we do not use CLM4-simulated hydrology to predict inundated areas. A rice paddy module is also incorporated into the model, where the fraction of land used for rice production is explicitly prescribed. The model is evaluated at the site level with vegetation cover and water table prescribed from measurements. Explicit site level evaluations of simulated methane emissions are quite different than evaluating the grid-cell averaged emissions against available measurements. Using a baseline set of parameter values, our model-estimated average global wetland emissions for the period 1993–2004 were 256 Tg CH4 yr−1 (including the soil sink and rice paddy emissions in the year 2000 were 42 Tg CH4 yr−1. Tropical wetlands contributed 201 Tg CH4 yr−1, or 78% of the global wetland flux. Northern latitude (>50 N systems contributed 12 Tg CH4 yr−1. However, sensitivity studies show a large range (150–346 Tg CH4 yr−1 in predicted global methane emissions (excluding emissions from rice paddies. The large range is

  18. Reduction of methane emission from landfills using bio-mitigation systems – from lab tests to full scale implementation

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Scheutz, Charlotte

    , or open or closed bed biofilter systems. The objective of this paper is to describe the relationship between research on process understanding of the oxidation of landfill gas contained methane and the up-scale to full bio-mitigation systems implemented at landfills. The oxidation of methane is controlled...... due to self-heating processes. Bio-mitigation can be used as a stand-alone technology or combined with active or passive gas collection. When implementing bio-mitigation systems focus should be on additional fugitive methane emissions or the presence of uncontrolled point releases. A protocol...... for implementing a bio-mitigation system is presented, and the reported landfill-implemented bio-mitigation systems either established as full-scale or pilot-scale systems are reviewed. It is concluded that bio-mitigation systems have a large potential for providing cost-efficient mitigation options for reducing...

  19. Methane emissions from a Californian landfill, determined from airborne remote sensing and in situ measurements

    Science.gov (United States)

    Krautwurst, Sven; Gerilowski, Konstantin; Jonsson, Haflidi H.; Thompson, David R.; Kolyer, Richard W.; Iraci, Laura T.; Thorpe, Andrew K.; Horstjann, Markus; Eastwood, Michael; Leifer, Ira; Vigil, Samuel A.; Krings, Thomas; Borchardt, Jakob; Buchwitz, Michael; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

    2017-09-01

    Fugitive emissions from waste disposal sites are important anthropogenic sources of the greenhouse gas methane (CH4). As a result of the growing world population and the recognition of the need to control greenhouse gas emissions, this anthropogenic source of CH4 has received much recent attention. However, the accurate assessment of the CH4 emissions from landfills by modeling and existing measurement techniques is challenging. This is because of inaccurate knowledge of the model parameters and the extent of and limited accessibility to landfill sites. This results in a large uncertainty in our knowledge of the emissions of CH4 from landfills and waste management. In this study, we present results derived from data collected during the research campaign COMEX (CO2 and MEthane eXperiment) in late summer 2014 in the Los Angeles (LA) Basin. One objective of COMEX, which comprised aircraft observations of methane by the remote sensing Methane Airborne MAPper (MAMAP) instrument and a Picarro greenhouse gas in situ analyzer, was the quantitative investigation of CH4 emissions. Enhanced CH4 concentrations or CH4 plumes were detected downwind of landfills by remote sensing aircraft surveys. Subsequent to each remote sensing survey, the detected plume was sampled within the atmospheric boundary layer by in situ measurements of atmospheric parameters such as wind information and dry gas mixing ratios of CH4 and carbon dioxide (CO2) from the same aircraft. This was undertaken to facilitate the independent estimation of the surface fluxes for the validation of the remote sensing estimates. During the COMEX campaign, four landfills in the LA Basin were surveyed. One landfill repeatedly showed a clear emission plume. This landfill, the Olinda Alpha Landfill, was investigated on 4 days during the last week of August and first days of September 2014. Emissions were estimated for all days using a mass balance approach. The derived emissions vary between 11.6 and 17.8 kt CH4 yr-1

  20. The Application Of Biofilter System For Reduction Of Methane Emissions From Modern Sanitary Landfills

    Science.gov (United States)

    Sung, K.; Park, S.

    2007-12-01

    Increased atmospheric concentrations of greenhouse gases (GHG) caused by anthropogenic activities has been related to global climate change. Methane, the second most important GHG after CO2, is 21 times more effective at trapping heat than CO2. Therefore, methane emission control is of utmost importance for global warming reduction. To minimize leachate production and protect groundwater resources, modern sanitary landfills are equipped with composite covers and gas collection systems. Methane from modern sanitary landfills is vented directly to the atmosphere, except for some of the largest landfills where it is recovered as energy and burned at the site. However, the efficiency of energy recovery systems in larger landfills is reduced as the amount of CH4 generated from landfill begins to decrease. In this study, the performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills by conducting batch and column experiments using landfill cover soil amended with earthworm cast as the filter bed medium. From the batch experiments to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10-15% by weight and 25-35°C, respectively. The column experiment was conducted to measure the influence of inlet CH4 concentration and CH4 loading rate on CH4 removal capacity of a biofilter system. As the inlet CH4 concentration decreased, the percentage of CH4 oxidized increased. Up to a CH4 loading rate of 2785 g CH4 m3 h- 1 (EBRT = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Based on the results of the study, the installation of a properly managed biofilter system should be capable of achieving a reduction in atmospheric CH4 emissions from modern sanitary landfills at low CH4 generation stage.

  1. Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows.

    Science.gov (United States)

    Olijhoek, D W; Hellwing, A L F; Brask, M; Weisbjerg, M R; Højberg, O; Larsen, M K; Dijkstra, J; Erlandsen, E J; Lund, P

    2016-08-01

    Nitrate may lower methane production in ruminants by competing with methanogenesis for available hydrogen in the rumen. This study evaluated the effect of 4 levels of dietary nitrate addition on enteric methane production, hydrogen emission, feed intake, rumen fermentation, nutrient digestibility, microbial protein synthesis, and blood methemoglobin. In a 4×4 Latin square design 4 lactating Danish Holstein dairy cows fitted with rumen, duodenal, and ileal cannulas were assigned to 4 calcium ammonium nitrate addition levels: control, low, medium, and high [0, 5.3, 13.6, and 21.1g of nitrate/kg of dry matter (DM), respectively]. Diets were made isonitrogenous by replacing urea. Cows were fed ad libitum and, after a 6-d period of gradual introduction of nitrate, adapted to the corn-silage-based total mixed ration (forage:concentrate ratio 50:50 on DM basis) for 16d before sampling. Digesta content from duodenum, ileum, and feces, and rumen liquid were collected, after which methane production and hydrogen emissions were measured in respiration chambers. Methane production [L/kg of dry matter intake (DMI)] linearly decreased with increasing nitrate concentrations compared with the control, corresponding to a reduction of 6, 13, and 23% for the low, medium, and high diets, respectively. Methane production was lowered with apparent efficiencies (measured methane reduction relative to potential methane reduction) of 82.3, 71.9, and 79.4% for the low, medium, and high diets, respectively. Addition of nitrate increased hydrogen emissions (L/kg of DMI) quadratically by a factor of 2.5, 3.4, and 3.0 (as L/kg of DMI) for the low, medium, and high diets, respectively, compared with the control. Blood methemoglobin levels and nitrate concentrations in milk and urine increased with increasing nitrate intake, but did not constitute a threat for animal health and human food safety. Microbial crude protein synthesis and efficiency were unaffected. Total volatile fatty acid

  2. Rising methane emissions from northern wetlands associated with sea ice decline

    Science.gov (United States)

    Parmentier, Frans-Jan W.; Zhang, Wenxin; Zhu, Xudong; van Huissteden, Jacobus; Hayes, Daniel J.; Zhuang, Qianlai; Christensen, Torben R.; McGuire, Anthony

    2015-01-01

    The Arctic is rapidly transitioning toward a seasonal sea ice-free state, perhaps one of the most apparent examples of climate change in the world. This dramatic change has numerous consequences, including a large increase in air temperatures, which in turn may affect terrestrial methane emissions. Nonetheless, terrestrial and marine environments are seldom jointly analyzed. By comparing satellite observations of Arctic sea ice concentrations to methane emissions simulated by three process-based biogeochemical models, this study shows that rising wetland methane emissions are associated with sea ice retreat. Our analyses indicate that simulated high-latitude emissions for 2005–2010 were, on average, 1.7 Tg CH4 yr−1 higher compared to 1981–1990 due to a sea ice-induced, autumn-focused, warming. Since these results suggest a continued rise in methane emissions with future sea ice decline, observation programs need to include measurements during the autumn to further investigate the impact of this spatial connection on terrestrial methane emissions.

  3. Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment

    DEFF Research Database (Denmark)

    Flury, Sabine; McGinnis, Daniel Frank; Gessner, Mark O.

    2010-01-01

    We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel ...... to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.  ......We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel...... traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because...

  4. Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment

    DEFF Research Database (Denmark)

    Flury, Sabine; McGinnis, Daniel Frank; Gessner, Mark O.

    2010-01-01

    We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel ...... to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.  ......We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel...... traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because...

  5. Effects of Acidifying Pig Diets on Emissions of Ammonia, Methane, and Sulfur from Slurry during Storage.

    Science.gov (United States)

    Eriksen, Jørgen; Nørgaard, Jan V; Poulsen, Hanne D; Poulsen, Henrik V; Jensen, Bent B; Petersen, Søren O

    2014-11-01

    Ammonia (NH) volatilization from intensive livestock production is a threat to natural ecosystems. This study investigated pig diet manipulation by 1% (w/w) benzoic acid (BA) amendment and lowering of dietary electrolyte balance through substituting 1.4% (w/w) CaCO with 2.0% (w/w) CaCl. Urine and feces were collected separately from 24 pigs fed one of four diets (Control, +BA, +CaCl, +BA+CaCl) in metabolic cages and mixed as slurry. During 103 d of storage, all acidifying diets consistently reduced pH in the slurry by 0.4 to 0.6 units. There was a strong relationship between slurry pH and NH emissions, which were considerably reduced by the three acidifying diets. The +BA diet decreased NH emission by 28%, the +CaCl diet by 37%, and the combined +BA and +CaCl diet by 40%. Acidifying diets had no effect on S cycling or emission of volatile S compounds under the prevailing conditions of restricted S feeding. Methane (CH) emissions were increased by 73% in diets with CaCl. An initial delay in CH emissions was investigated in a separate experiment with manipulation of pH (5.4, 6.7, or 8.8) and inoculation with adapted pig slurry (0, 4, 11, or 19%), which showed that methanogenic potential, rather than inhibitory effects of the chemical environment, caused the delay. In conclusion, NH emissions from slurry could be reduced by addition of BA to pig diets or by controlling the dietary electrolyte balance, but there was no additive effect of combining the two strategies. However, CH emissions from slurry may increase with acidifying diets. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily

    Energy Technology Data Exchange (ETDEWEB)

    Helene Hilger; James Oliver; Jean Bogner; David Jones

    2009-03-31

    Methane and carbon dioxide are formed in landfills as wastes degrade. Molecule-for-molecule, methane is about 20 times more potent than carbon dioxide at trapping heat in the earth's atmosphere, and thus, it is the methane emissions from landfills that are scrutinized. For example, if emissions composed of 60% methane and 40% carbon dioxide were changed to a mix that was 40% methane and 60% carbon dioxide, a 30% reduction in the landfill's global warming potential would result. A 10% methane, 90% carbon dioxide ratio will result in a 75% reduction in global warming potential compared to the baseline. Gas collection from a closed landfill can reduce emissions, and it is sometimes combined with a biocover, an engineered system where methane oxidizing bacteria living in a medium such as compost, convert landfill methane to carbon dioxide and water. Although methane oxidizing bacteria merely convert one greenhouse gas (methane) to another (carbon dioxide), this conversion can offer significant reductions in the overall greenhouse gas contribution, or global warming potential, associated with the landfill. What has not been addressed to date is the fact that methane can also escape from a landfill when the active cell is being filled with waste. Federal regulations require that newly deposited solid waste to be covered daily with a 6 in layer of soil or an alternative daily cover (ADC), such as a canvas tarp. The aim of this study was to assess the feasibility of immobilizing methane oxidizing bacteria into a tarp-like matrix that could be used for alternative daily cover at open landfill cells to prevent methane emissions. A unique method of isolating methanotrophs from landfill cover soil was used to create a liquid culture of mixed methanotrophs. A variety of prospective immobilization techniques were used to affix the bacteria in a tarp-like matrix. Both gel encapsulation of methanotrophs and gels with liquid cores containing methanotrophs were readily

  7. Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

    Science.gov (United States)

    Gentner, D. R.; Ford, T. B.; Guha, A.; Boulanger, K.; Brioude, J.; Angevine, W. M.; de Gouw, J. A.; Warneke, C.; Gilman, J. B.; Ryerson, T. B.; Peischl, J.; Meinardi, S.; Blake, D. R.; Atlas, E.; Lonneman, W. A.; Kleindienst, T. E.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; VandenBoer, T. C.; Markovic, M. Z.; Murphy, J. G.; Harley, R. A.; Goldstein, A. H.

    2014-05-01

    Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. It is essential to understand the emissions and air quality impacts of these relatively understudied sources, especially for oil/gas operations in light of increasing US production. Ground site measurements in Bakersfield and regional aircraft measurements of reactive gas-phase organic compounds and methane were part of the CalNex (California Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions, and provide average source profiles. To examine the spatial distribution of emissions in the San Joaquin Valley, we developed a statistical modeling method using ground-based data and the FLEXPART-WRF transport and meteorological model. We present evidence for large sources of paraffinic hydrocarbons from petroleum operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes, most of which have limited previous in situ measurements or characterization in petroleum operation emissions. Observed dairy emissions were dominated by ethanol, methanol, acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The petroleum operations source profile was developed using the composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil. The observed source profile is

  8. Emission of Methane From Enteric Fermentation: National Contribution and Factors Affecting it in Livestock

    Directory of Open Access Journals (Sweden)

    Budi Haryanto

    2009-12-01

    Full Text Available Changing in atmosphere condition is affected by the quantity of gases produced from all activities on the earth. Gases that have effects on global warming are CO2, N2O, H2O, and CH4 (methane. Among other sources of methane are enteric fermentation of organic material from ruminants and feces decomposition. Methane production from ruminants is affected by several factors such as breed/type of animal, feed quality, environmental temperature and physiological status of the animal. Energy as methane in ruminants may reach 2 to 15% of the total energy consumption. To reduce the emission of methane from ruminants, it is necessary to apply a strategic feeding system for more efficient utilization of feed.

  9. Stable isotopes provide revised global limits of aerobic methane emissions from plants

    Directory of Open Access Journals (Sweden)

    D. F. Ferretti

    2007-01-01

    Full Text Available Recently Keppler et al. (2006 discovered a surprising new source of methane – terrestrial plants under aerobic conditions, with an estimated global production of 62–236 Tg yr−1 by an unknown mechanism. This is ~10–40% of the annual total of methane entering the modern atmosphere and ~30–100% of annual methane entering the pre-industrial (0 to 1700 AD atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4 and stable carbon isotope ratios (δ13CH4 over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006 during the last 2000 years and are likely to lie in the range 0–46 Tg yr−1 and 0–176 Tg yr−1 during the pre-industrial and modern eras, respectively.

  10. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 15: GAS-ASSISTED GLYCOL PUMPS

    Science.gov (United States)

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

  11. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 13: CHEMICAL INJECTION PUMPS

    Science.gov (United States)

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

  12. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 12: PNEUMATIC DEVICES

    Science.gov (United States)

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

  13. Determinants of spatial variability of methane emissions from wet grasslands on peat soil

    NARCIS (Netherlands)

    Pol-Van Dasselaar, van den A.; Beusichem, van M.L.; Oenema, O.

    1999-01-01

    Methane (CH4) emissions from soils, representing the consequence of CH4 production, CH4 consumption and CH4 transport, are poorly characterised and show a large spatial variability. This study aimed to assess the determinants of field-scale spatial variability of CH4 emissions from wet grasslands on

  14. Lateral gas transport in soil adjacent to an old landfill: factors governing emissions and methane oxidation

    DEFF Research Database (Denmark)

    Christophersen, Mette; Kjeldsen, Peter; Holst, Helle

    2001-01-01

    Field investigations of lateral gas transport and subsequent emissions in soil adjacent to an old landfill in Denmark have been conducted during a one-year period. A significant seasonal variation in the emissions with high carbon dioxide and low methane fluxes in the summer (May to October...

  15. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 11: COMPRESSOR DRIVER EXHAUST

    Science.gov (United States)

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

  16. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 7: BLOW AND PURGE ACTIVITIES

    Science.gov (United States)

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...

  17. Eddy covariance observations of methane and nitrous oxide emissions: Towards more accurate estimates from ecosystems

    NARCIS (Netherlands)

    Kroon-van Loon, P.S.

    2010-01-01

    About 30% of the increased greenhouse gas (GHG) emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are related to land use changes and agricultural activities. In order to select effective measures, knowledge is required about GHG emissions from these ecosystems and how these e

  18. Genetic parameters for predicted methane production and potential for reducing enteric emissions through genomic selection

    NARCIS (Netherlands)

    Haas, de Y.; Windig, J.J.; Calus, M.P.L.; Dijkstra, J.; Haan, de M.H.A.; Bannink, A.; Veerkamp, R.F.

    2011-01-01

    Mitigation of enteric methane (CH4) emission in ruminants has become an important area of research because accumulation of CH4 is linked to global warming. Nutritional and microbial opportunities to reduce CH4 emissions have been extensively researched, but little is known about using natural

  19. Evidence for a hydrogen-sink mechanism of (+)catechin-mediated emission reduction of the ruminant greenhouse gas methane

    NARCIS (Netherlands)

    Becker, P.M.; Wikselaar, van P.G.; Franssen, M.C.R.; Vos, de C.H.; Hall, R.D.; Beekwilder, M.J.

    2014-01-01

    Methane formation in the rumen is a major cause of greenhouse gas emission. Plant secondary compounds in ruminant diets, such as essential oils, saponins and tannins, are known to affect methane production. However, their methane-lowering properties have generally been associated with undesired side

  20. Methane emission from animals: A Global High-Resolution Data Base

    Science.gov (United States)

    Lerner, Jean; Matthews, Elaine; Fung, Inez

    1988-06-01

    We present a high-resolution global data base of animal population densities and associated methane emission. Statistics on animal populations from the Food and Agriculture Organization and other sources have been compiled. Animals were distributed using a 1° resolution data base of countries of the world and a 1° resolution data base of land use. The animals included are cattle and dairy cows, water buffalo, sheep, goats, camels, pigs, horses and caribou. Published estimates of methane production from each type of animal have been applied to the animal populations to yield a global distribution of annual methane emission by animals. There is large spatial variability in the distribution of animal populations and their methane emissions. Emission rates greater than 5000 kg CH4 km-2 yr-1 are found in small regions such as Bangladesh, the Benelux countries, parts of northern India, and New Zealand. Of the global annual emission of 75.8 Tg CH4 for 1984, about 55% is concentrated between 25°N and 55°N, a significant contribution to the observed north-south gradient of atmospheric methane concentration. A magnetic tape of the global data bases is available from the authors.

  1. Recent decreases in fossil-fuel emissions of ethane and methane derived from firn air.

    Science.gov (United States)

    Aydin, Murat; Verhulst, Kristal R; Saltzman, Eric S; Battle, Mark O; Montzka, Stephen A; Blake, Donald R; Tang, Qi; Prather, Michael J

    2011-08-10

    Methane and ethane are the most abundant hydrocarbons in the atmosphere and they affect both atmospheric chemistry and climate. Both gases are emitted from fossil fuels and biomass burning, whereas methane (CH(4)) alone has large sources from wetlands, agriculture, landfills and waste water. Here we use measurements in firn (perennial snowpack) air from Greenland and Antarctica to reconstruct the atmospheric variability of ethane (C(2)H(6)) during the twentieth century. Ethane levels rose from early in the century until the 1980s, when the trend reversed, with a period of decline over the next 20 years. We find that this variability was primarily driven by changes in ethane emissions from fossil fuels; these emissions peaked in the 1960s and 1970s at 14-16 teragrams per year (1 Tg = 10(12) g) and dropped to 8-10 Tg  yr(-1) by the turn of the century. The reduction in fossil-fuel sources is probably related to changes in light hydrocarbon emissions associated with petroleum production and use. The ethane-based fossil-fuel emission history is strikingly different from bottom-up estimates of methane emissions from fossil-fuel use, and implies that the fossil-fuel source of methane started to decline in the 1980s and probably caused the late twentieth century slow-down in the growth rate of atmospheric methane.

  2. Development of coal mine methane concentration technology for reduction of greenhouse gas emissions

    Institute of Scientific and Technical Information of China (English)

    Takahisa; UTAKI

    2010-01-01

    In coal mines in such countries as China and Russia,most of the coal mine methane(CMM) generated during mining is emitted to the atmosphere without any effective usage,because the methane concentration of CMM is relatively low and not allowed to be used as fuel for safety reasons.Methane is one of the greenhouse gases.Therefore,if it becomes possible to concentrate CMM to an acceptable level for use as fuel,this will greatly contribute to reduction of greenhouse gas emissions.With the aim of gaining approval as a greenhouse gas emission reduction of the clean development mechanism(CDM) or joint implementation(JI) project,we developed a CMM concentration system to apply the vacuum pressure swing adsorption(VPSA) technology using a high methane-selective adsorbent by Osaka Gas Co.,Ltd.The pilot-scale plant of a CMM concentration system was installed in a coal mine in Fuxin City in the northeastern China and a demonstration test was commenced in December 2008.As the result,the pilot-scale plant successfully concentrated the raw material gas with a methane concentration of 21% and a flow rate of 1000 Nm3/h to 48%,which exceeded the target of the methane concentration performance(a 25% increase).The methane recovery rate reached 93%.

  3. Landfill methane emission mitigation – How to construct and document a full‐scale biocover system

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Scheutz, Charlotte

    2014-01-01

    Landfills receiving organic wastes produce biogas (landfill gas – LFG) containing methane (CH4). Landfills are significant sources of methane, which contributes to climate change. As an alternative to gas utilization systems or as a follow‐on technology when a gas utilization system gets non...... rate can be obtained in soils, compost and other materials, high enough to significant reduce the methane emission from landfills. The process has been scaled up by DTU Environment to a full‐scale implemented technology at two Danish landfills. Now the Danish government has decided to establish bio...

  4. Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

    Directory of Open Access Journals (Sweden)

    D. R. Gentner

    2013-10-01

    Full Text Available Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. Ground site measurements in Bakersfield and aircraft measurements of reactive gas-phase organic compounds were made in this region as part of the CalNex (California Research at the Nexus of Air Quality and Climate Change project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions from these prominent sources that are relatively understudied compared to motor vehicles We also developed a statistical modeling method with the FLEXPART-WRF transport and meteorological model using ground-based data to assess the spatial distribution of emissions in the San Joaquin Valley. We present evidence for large sources of paraffinic hydrocarbons from petroleum extraction/processing operations and oxygenated compounds from dairy (and other cattle operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes that have limited previous in situ measurements or characterization in emissions from petroleum operations. Observed dairy emissions were dominated by ethanol, methanol, and acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well-correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The good agreement of the observed petroleum operations source profile with the measured composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil suggests a fugitive emissions pathway during petroleum extraction, storage, or processing with

  5. Mitigating methane emission from paddy soil with rice-straw biochar amendment under projected climate change

    Science.gov (United States)

    Han, Xingguo; Sun, Xue; Wang, Cheng; Wu, Mengxiong; Dong, Da; Zhong, Ting; Thies, Janice E.; Wu, Weixiang

    2016-04-01

    Elevated global temperatures and increased concentrations of carbon dioxide (CO2) in the atmosphere associated with climate change will exert profound effects on rice cropping systems, particularly on their greenhouse gas emitting potential. Incorporating biochar into paddy soil has been shown previously to reduce methane (CH4) emission from paddy rice under ambient temperature and CO2. We examined the ability of rice straw-derived biochar to reduce CH4 emission from paddy soil under elevated temperature and CO2 concentrations expected in the future. Adding biochar to paddy soil reduced CH4 emission under ambient conditions and significantly reduced emissions by 39.5% (ranging from 185.4 mg kg‑1 dry weight soil, dws season‑1 to 112.2 mg kg‑1 dws season‑1) under simultaneously elevated temperature and CO2. Reduced CH4 release was mainly attributable to the decreased activity of methanogens along with the increased CH4 oxidation activity and pmoA gene abundance of methanotrophs. Our findings highlight the valuable services of biochar amendment for CH4 control from paddy soil in a future that will be shaped by climate change.

  6. Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions.

    Science.gov (United States)

    Johnson, Derek R; Covington, April N; Clark, Nigel N

    2016-06-12

    The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas industry faces continued scrutiny for methane emissions from across the supply chain, due to methane's relatively high global warming potential (25-84x that of carbon dioxide, according to the Energy Information Administration). Currently, a variety of techniques of varied uncertainties exists to measure or estimate methane emissions from components or facilities. Currently, only one commercial system is available for quantification of component level emissions and recent reports have highlighted its weaknesses. In order to improve accuracy and increase measurement flexibility, we have designed, developed, and implemented a novel full flow sampling system (FFS) for quantification of methane emissions and greenhouse gases based on transportation emissions measurement principles. The FFS is a modular system that consists of an explosive-proof blower(s), mass airflow sensor(s) (MAF), thermocouple, sample probe, constant volume sampling pump, laser based greenhouse gas sensor, data acquisition device, and analysis software. Dependent upon the blower and hose configuration employed, the current FFS is able to achieve a flow rate ranging from 40 to 1,500 standard cubic feet per minute (SCFM). Utilization of laser-based sensors mitigates interference from higher hydrocarbons (C2+). Co-measurement of water vapor allows for humidity correction. The system is portable, with multiple configurations for a variety of applications ranging from being carried by a person to being mounted in a hand drawn cart, on-road vehicle bed, or from the bed of utility terrain vehicles (UTVs). The FFS is able to quantify methane emission rates with a relative uncertainty of ± 4.4%. The FFS has proven, real world operation for the quantification of methane emissions occurring in conventional and remote facilities.

  7. Methane emissions and microbial communities as influenced by dual cropping of Azolla along with early Rice

    DEFF Research Database (Denmark)

    Liu, Jingna; Xu, Heshui; Jiang, Ying

    2017-01-01

    Azolla caroliniana Willd. is widely used as a green manure accompanying rice, but its ecological importance remains unclear, except for its ability to fix nitrogen in association with cyanobacteria. To investigate the impacts of Azolla cultivation on methane emissions and environmental variables...... in paddy fields, we performed this study on the plain of Dongting Lake, China, in 2014. The results showed that the dual cropping of Azolla significantly suppressed the methane emissions from paddies, likely due to the increase in redox potential in the root region and dissolved oxygen concentration...... at the soil-water interface. Furthermore, the floodwater pH decreased in association with Azolla cultivation, which is also a factor significantly correlated with the decrease in methane emissions. An increase in methanotrophic bacteria population (pmoA gene copies) and a reduction in methanogenic archaea (16...

  8. Effect of feeding garlic leaves on rumen fermentation, methane emission, plasma glucose kinetics, and nitrogen utilization in sheep.

    Science.gov (United States)

    Panthee, Arvinda; Matsuno, Ayana; Al-Mamun, Mohammad; Sano, Hiroaki

    2017-01-01

    Garlic and its constituents are reported to have been effective in reducing methane emission and also influence glucose metabolism in body; however, studies in ruminants using garlic leaves are scarce. Garlic leaves contain similar compounds as garlic bulbs, but are discarded in field after garlic bulb harvest. We speculate that feeding garlic leaves might show similar effect as garlic constituents in sheep and could be potential animal feed supplement. Thus, we examined the effect of freeze dried garlic leaves (FDGL) on rumen fermentation, methane emission, plasma glucose kinetics and nitrogen utilization in sheep. Six sheep were fed Control diet (mixed hay and concentrate (60:40)) or FDGL diet (Control diet supplemented with FDGL at 2.5 g/kg BW(0.75) of sheep) using a crossover design. Methane gas emission was measured using open-circuit respiratory chamber. Plasma glucose turnover rate was measured using isotope dilution technique of [U-(13)C]glucose. Rumen fluid, feces and urine were collected to measure rumen fermentation characteristics and nitrogen utilization. No significant difference in rumen fermentation parameters was noticed except for rumen ammonia tended to be higher (0.05 glucose concentration was similar between diets and plasma glucose turnover rate tended to be higher in FDGL diet (0.05 glucose turnover rate and microbial nitrogen supply, further studies at higher dose would be necessary to conclude the merit of FDGL as supplement in ruminant feedstuff.

  9. Trends of non-methane hydrocarbons (NMHC emissions in Beijing during 2002–2013

    Directory of Open Access Journals (Sweden)

    M. Wang

    2014-07-01

    Full Text Available Non-methane hydrocarbons (NMHCs play a critical role in the photochemical production of ozone (O3 and organic aerosols. Obtaining an accurate understanding on NMHC emission trends is essential for predicting air quality changes and evaluating the effectiveness of current control measures. In this study, we evaluated temporal trends in NMHC emissions in Beijing based on ambient measurements during the summer at an urban site in Beijing from 2002 to 2013. In contrast to the results of the most recent inventory (Multi-resolution Emission Inventory for China, MEIC, which reported that total NMHC emissions increased at a rate of ~4% yr−1, mixing ratios of NMHCs measured at this urban site displayed an obvious decrease (~30% during the last decade. A Positive Matrix Factorization (PMF model was applied to the NMHC measurements for source apportionment, and the results showed a decrease in the concentrations contributed by transportation-related sources to total NMHC emissions by 66% during 2004–2012, which was comparable to the relative decline of 65% reported by the MEIC inventory. This finding indicates that the implementation of stricter emissions standards and control measures has been effective for reducing transportation-related NMHC emissions. In addition, the PMF results suggested that there were no significant temporal changes in NMHC concentrations from paint and solvent use during 2004–2012, in contrast with the rapid rate of increase (27.5% yr−1 reported by the MEIC inventory. To re-evaluate the NMHC emissions trends for paint and solvent use, annual variations in NMHC / NOx ratios were compared between ambient measurements and the MEIC inventory. In contrast to the significant rise in NMHC / NOx ratios from the inventory, the measured ratios declined by 14% during 2005–2012. However, the inferred NMHC / NOx ratios based on PMF results exhibited a comparable decline of 11% to measurements. These results indicate that the increase

  10. Natural emissions of methane from geothermal and volcanic sources in Europe

    Science.gov (United States)

    Etiope, G.; Fridriksson, T.; Italiano, F.; Winiwarter, W.; Theloke, J.

    2007-08-01

    It has recently been demonstrated that methane emission from lithosphere degassing is an important component of the natural greenhouse-gas atmospheric budget. Globally, the geological sources are mainly due to seepage from hydrocarbon-prone sedimentary basins, and subordinately from geothermal/volcanic fluxes. This work provides a first estimate of methane emission from the geothermal/volcanic component at European level. In Europe, 28 countries have geothermal systems and at least 10 countries host surface geothermal manifestations (hot springs, mofettes, gas vents). Even if direct methane flux measurements are available only for a few small areas in Italy, a fair number of data on CO 2, CH 4 and steam composition and flux from geothermal manifestations are today available for 6 countries (Czech Republic, Germany, Greece, Iceland, Italy, Spain). Following the emission factor and area-based approach, the available data have been analyzed and have led to an early and conservative estimate of methane emission into the atmosphere around 10,000 ton/yr (4000-16,000 ton/yr), basically from an area smaller than 4000 km 2, with a speculative upper limit in the order of 10 5 ton/yr. Only 4-18% of the conservative estimate (about 720 ton/yr) is due to 12 European volcanoes, where methane concentration in volcanic gases is generally in the order of a few tens of ppmv. Volcanoes are thus not a significant methane source. While the largest emission is due to geothermal areas, which may be situated next to volcanoes or independent. Here inorganic synthesis, thermometamorphism and thermal breakdown of organic matter are substantial. Methane flux can reach hundreds of ton/yr from small individual vents. Geothermal methane is mainly released in three countries located in the main high heat flow regions: Italy, Greece, and Iceland. Turkey is likely a fourth important contributor but the absolute lack of data prevents any emission estimate. Therefore, the actual European geothermal

  11. Sensitivity of wetland methane emissions to model assumptions: application and model testing against site observations

    Directory of Open Access Journals (Sweden)

    L. Meng

    2011-06-01

    Full Text Available Methane emissions from natural wetlands and rice paddies constitute a large proportion of atmospheric methane, but the magnitude and year-to-year variation of these methane sources is still unpredictable. Here we describe and evaluate the integration of a methane biogeochemical model (CLM4Me; Riley et al., 2011 into the Community Land Model 4.0 (CLM4CN in order to better explain spatial and temporal variations in methane emissions. We test new functions for soil pH and redox potential that impact microbial methane production in soils. We also constrain aerenchyma in plants in always-inundated areas in order to better represent wetland vegetation. Satellite inundated fraction is explicitly prescribed in the model because there are large differences between simulated fractional inundation and satellite observations. A rice paddy module is also incorporated into the model, where the fraction of land used for rice production is explicitly prescribed. The model is evaluated at the site level with vegetation cover and water table prescribed from measurements. Explicit site level evaluations of simulated methane emissions are quite different than evaluating the grid cell averaged emissions against available measurements. Using a baseline set of parameter values, our model-estimated average global wetland emissions for the period 1993–2004 were 256 Tg CH4 yr−1, and rice paddy emissions in the year 2000 were 42 Tg CH4 yr−1. Tropical wetlands contributed 201 Tg CH4 yr−1, or 78 % of the global wetland flux. Northern latitude (>50 N systems contributed 12 Tg CH4 yr−1. We expect this latter number may be an underestimate due to the low high-latitude inundated area captured by satellites and unrealistically low high-latitude productivity and soil carbon predicted by CLM4. Sensitivity analysis showed a large range (150–346 Tg CH4 yr−1 in

  12. Methane emission by termites: Impacts on the self-cleansing mechanisms of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mugedo, J.Z.A. [Maseno Univ. College (Kenya)

    1996-12-31

    Termites are reported to emit large quantities of methane, carbon dioxide, carbon monoxide, hydrogen and dimethyl sulfide. The emission of other trace gases, namely C{sub 2} to C{sub 10} hydrocarbons, is also documented. We have carried out, both in the field and in the laboratory, measurements of methane emissions by Macrotermes subhyalinus (Macrotermitinae), Trinervitermes bettonianus (Termitinae), and unidentified Cubitermes and Microcerotermes species. Measured CH{sub 4} field flux rates ranged from 3.66 to 98.25g per m{sup 2} of termite mound per year. Laboratory measurements gave emission rates that ranged from 14.61 to 165.05 mg CH{sub 4} per termite per year. Gaseous production in all species sampled varied both within species and from species to species. Recalculated global emission of methane from termites was found to be 14.0 x 10{sup 12} g CH{sub 4}, per year. From our study, termites contribution to atmospheric methane content is between 1.11% and 4.25% per year. This study discusses the greenhouse effects as well as photochemical disposal of methane in the lower atmosphere in the tropics and the impacts on the chemistry of HO{sub x} systems and CL{sub x} cycles.

  13. A new approach to estimation of methane emission rates from landfills.

    Science.gov (United States)

    Zhu, Han; Letzel, Marcus O; Reiser, Martin; Kranert, Martin; Bächlin, Wolfgang; Flassak, Thomas

    2013-12-01

    Methane emission monitoring has become increasingly essential for diffusive area sources, especially for landfills, which contribute to a significant fraction of the total anthropogenic methane emission globally. Statutorily, methane emission rate from landfills in Germany shall be examined on a semiannual basis; however, an appropriate approach has yet to be developed and adopted for general use. In this study, a new method is proposed based on experimental results, which utilizes a TDLAS (Tunable Diode Laser Absorption Spectroscopy) instrument - GasFinder2.0 system and a dispersion model LASAT (Lagrangian Simulation of Aerosol Transport) as the measurement device and calculation model, respectively. Between April 2010 and December 2011, a research project was conducted at a pilot scale landfill in the south of Germany. Drawing on the extensive research into this pilot project, an effective strategy of measurement setup was determined. Methane concentration was measured with GasFinder2.0 system in the upstream and downstream sections of the project site, while wind and turbulence data were measured simultaneously by an ultrasonic anemometer. The average methane emission rate from the source can be calculated by using the results as input data in the dispersion model. With this method, site-specific measurement approaches can be designed for not only landfills, but also different diffusive area sources with less workload and lower cost compared to conventional FID (Flame Ionization Detector) method. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Archaeal abundance in post-mortem ruminal digesta may help predict methane emissions from beef cattle

    Science.gov (United States)

    Wallace, R. John; Rooke, John A.; Duthie, Carol-Anne; Hyslop, Jimmy J.; Ross, David W.; McKain, Nest; de Souza, Shirley Motta; Snelling, Timothy J.; Waterhouse, Anthony; Roehe, Rainer

    2014-07-01

    Methane produced from 35 Aberdeen-Angus and 33 Limousin cross steers was measured in respiration chambers. Each group was split to receive either a medium- or high-concentrate diet. Ruminal digesta samples were subsequently removed to investigate correlations between methane emissions and the rumen microbial community, as measured by qPCR of 16S or 18S rRNA genes. Diet had the greatest influence on methane emissions. The high-concentrate diet resulted in lower methane emissions (P Methane was correlated, irrespective of breed, with the abundance of archaea (R = 0.39), bacteria (-0.47), protozoa (0.45), Bacteroidetes (-0.37) and Clostridium Cluster XIVa (-0.35). The archaea:bacteria ratio provided a stronger correlation (0.49). A similar correlation was found with digesta samples taken 2-3 weeks later at slaughter. This finding could help enable greenhouse gas emissions of large animal cohorts to be predicted from samples taken conveniently in the abattoir.

  15. Estimating methane gas generation from Devil's swamp landfill using greenhouse gas emission models

    Science.gov (United States)

    Adeyemi, Ayodeji Thompson

    Greenhouse gas (GHG) has been a key issue in the study, design, and management of landfills. Landfill gas (LFG) is considered either as a significant source of renewable energy (if extracted and processed accordingly) or significant source of pollution and risk (if not mitigated or processed). A municipal solid waste (MSW) landfill emits a significant amount of methane, a potent GHG. Thus, quantification and mitigation of GHG emissions is an important area of study in engineering and other sciences related to landfill technology and management. The present study will focus on estimating methane generation from Devils swamp landfill (DSLF), a closed landfill in Baton Rouge, LA. The landfill operated for 53 years (1940-1993) and contains both industrial and municipal waste products. Since the Clean Air Act of 1963, landfills are now classified as New Source Performance Standard (NSPS) waste (i.e., waste that will decompose to generate LFG). Currently, the DSLF is being used as source of renewable energy through the "Waste to Energy" program. For this study, to estimate the methane potential in the DSLF, it is important to determine the characteristics and classification of the landfill's wastes. The study uses and compares different GHG modeling tools---LandGEM, a multiphase model, and a simple first-order model---to estimate methane gas emission and compare results with the actual emissions from the DSLF. The sensitivity of the methane generation rate was analyzed by the methane generation models to assess the effects of variables such as initial conditions, specific growth rate, and reaction rate constants. The study concludes that methane (L0) and initial organic concentration in waste (k) are the most important parameters when estimating methane generation using the models.

  16. Magnitude and Seasonality of Wetland Methane Emissions from the Hudson Bay Lowlands (Canada)

    Science.gov (United States)

    Pickett-Heaps, C. A.; Jacob, D. J.; Wecht, K. J.; Kort, E. A.; Wofsy, S. C.; Diskin, G. S.; Worthy, D. E. J.; Kaplan, J. O.; Bey, I.; Drevet, J.

    2011-01-01

    The Hudson Bay Lowlands (HBL) is the second largest boreal wetland ecosystem in the world and an important natural source of global atmospheric methane. We quantify the HBL methane emissions by using the GEOS-Chem chemical transport model to simulate aircraft measurements over the HBL from the ARCTAS and pre-HIPPO campaigns in May-July 2008, together with continuous 2004-2008 surface observations at Fraserdale (southern edge of HBL) and Alert (Arctic background). The difference in methane concentrations between Fraserdale and Alert is shown to be a good indicator of HBL emissions, and implies a sharp seasonal onset of emissions in late May (consistent with the aircraft data), a peak in July-August, and a seasonal shut-off in September. The model, in which seasonal variation of emission is mainly driven by surface temperature, reproduces well the observations in summer but its seasonal shoulders are too broad. We suggest that this reflects the suppression of emissions by snow cover and greatly improve the model simulation by accounting for this effect. Our resulting best estimate for HBL methane emissions is 2.3 Tg/a, several-fold higher than previous estimates (Roulet et al., 1994; Worthy et al., 2000).

  17. Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts.

    Science.gov (United States)

    McKain, Kathryn; Down, Adrian; Raciti, Steve M; Budney, John; Hutyra, Lucy R; Floerchinger, Cody; Herndon, Scott C; Nehrkorn, Thomas; Zahniser, Mark S; Jackson, Robert B; Phillips, Nathan; Wofsy, Steven C

    2015-02-17

    Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas emission rates for 1 y in the urban region of Boston, using a comprehensive atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission flux, 18.5 ± 3.7 (95% confidence interval) g CH4 ⋅ m(-2) ⋅ y(-1). Simultaneous observations of atmospheric ethane, compared with the ethane-to-methane ratio in the pipeline gas delivered to the region, demonstrate that natural gas accounted for ∼ 60-100% of methane emissions, depending on season. Using government statistics and geospatial data on natural gas use, we find the average fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end use, was 2.7 ± 0.6% in the Boston urban region, with little seasonal variability. This fraction is notably higher than the 1.1% implied by the most closely comparable emission inventory.

  18. Magnitude and seasonality of wetland methane emissions from the Hudson Bay Lowlands (Canada

    Directory of Open Access Journals (Sweden)

    C. A. Pickett-Heaps

    2011-04-01

    Full Text Available The Hudson Bay Lowlands (HBL is the second largest boreal wetland ecosystem in the world and an important natural source of global atmospheric methane. We quantify the HBL methane emissions by using the GEOS-Chem chemical transport model to simulate aircraft measurements over the HBL from the ARCTAS and pre-HIPPO campaigns in May–July 2008, together with continuous 2004–2008 surface observations at Fraserdale (southern edge of HBL and Alert (Arctic background. The difference in methane concentrations between Fraserdale and Alert is shown to be a good indicator of HBL emissions, and implies a sharp seasonal onset of emissions in late May (consistent with the aircraft data, a peak in July–August, and a seasonal shut-off in September. The model, in which seasonal variation of emission is mainly driven by surface temperature, reproduces well the observations in summer but its seasonal shoulders are too broad. We suggest that this reflects the suppression of emissions by snow cover and greatly improve the model simulation by accounting for this effect. Our resulting best estimate for HBL methane emissions is 2.3 Tg a−1, several-fold higher than previous estimates (Roulet et al., 1994; Worthy et al., 2000.

  19. Emissions of sulfur-containing odorants, ammonia, and methane from pig slurry: effects of dietary methionine and benzoic acid.

    Science.gov (United States)

    Eriksen, Jørgen; Adamsen, Anders Peter S; Nørgaard, Jan V; Poulsen, Hanne D; Jensen, Bent Borg; Petersen, Søren O

    2010-01-01

    Supplementation of benzoic acid to pig diets reduces the pH of urine and may thereby affect emissions of ammonia and other gases from slurry, including sulfur-containing compounds that are expected to play a role in odor emission. Over a period of 112 d, we investigated hydrogen sulfide (H(2)S), methanethiol (MT), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS), as well as ammonia and methane emissions from stored pig slurry. The slurry was derived from a feeding experiment with four pig diets in a factorial design with 2% (w/w) benzoic acid and 1% (w/w) methionine supplementation as treatments. Benzoic acid reduced slurry pH by 1 to 1.5 units and ammonia emissions by 60 to 70% for up to 2 mo of storage, and a considerable, but transitory reduction of methane emissions was also observed after 4 to 5 wk. All five volatile sulfur (S) compounds were identified in gas emitted from the slurry of the control treatment, which came from pigs fed according to Danish recommendations for amino acids and minerals. The emission patterns of volatile S compounds suggested an intense cycling between pools of organic S in the slurries, with urinary sulfate as the main source. Diet supplementation with methionine significantly increased all S emissions. Diet supplementation with benzoic acid reduced emissions of H(2)S and DMTS compared with the control slurry and moderately increased the concentrations of MT. Sulfur gas emissions were influenced by a strong interaction between methionine and benzoic acid treatments, which caused a significant increase in emissions of especially MT, but also of DMDS. In conclusion, addition of 2% benzoic acid to pig diets effectively reduced ammonia volatilization, but interactions with dietary S may increase odor problems.

  20. Effects of organic matter application on methane emission from paddy fields adopting organic farming system

    Directory of Open Access Journals (Sweden)

    P Nungkat

    2015-01-01

    Full Text Available A study that was aimed to determine the effect of the use of organic manure and azolla on methane emission on paddy field of organic systems was conducted on paddy fields in the Gempol Village, Sambirejo District of Sragen Regency, Indonesia. The experimental design performed for this study was a completely randomized block design consisting of three factors; the factor I was rice cultivars (Mira-1; Mentik Wangi; Merah Putih; factor II was dose of organic manure (0 t/ha and 10 t/ha and factor III was Azolla inoculums dose (0 t/ha and 2 t/ha. Gas sampling was conducted 3 times in one growing season when the rice plants reached ages of 38, 66 and 90 days after planting. The results showed that there was no correlation between the uses of organic fertilizers for rice production on methane emission. The increase of methane emission was very much influenced by the redox potential. Methane emission from Mira-1 field was higher than that from Mentik Wangi and Merah Putih fields. Emission of methane gas from Mira-1 field ranged from -509.82 to 791.34 kg CH4/ha; that from Wangi ranged from -756.77 to d 547.50 kg CH4/ha and that from Merah Putih ranged from -399.63 to 459.94 kg CH4/ha. Application of 10 t organic manure /ha and 2 t azolla/ha in Mentik Wangi reduced methane emissions with a high rice production compared to Merah Putih and Mira-1.

  1. METHANE EMISSION FROM DIRECT SEEDED RICE UNDER THE INFLUENCES OF RICE STRAW AND NITRIFICATION INHIBITOR

    Directory of Open Access Journals (Sweden)

    A. Wihardjaka

    2013-04-01

    Full Text Available Incorporation of rice straw into soil is a common practice to improve soil productivity and increase inorganic fertilizer availability. However, this practice could contribute to methane (CH4 emission; one of the greenhouse gases that causes global warming. Nitrification inhibitors such as neem cake and carbofuran may reduce methane emission following application of rice straw. The study aimed to evaluate the application of rice straw and nitrification inhibitor to methane emission in rainfed lowland rice system. A factorial randomized block design was used with three replications. The first factor was rice straw incorporation (5 t ha-1 fresh straw, 5 t ha-1 composted straw, and the second factor was nitrification inhibitor application (20 kg ha-1 neem cake, 20 kg ha-1 carbofuran. The experiment was conducted at rainfed lowland in Pati, Central Java, during 2009/2010 wet season. Ciherang variety was planted as direct seeded rice with spacing of 20 cm x 20 cm in each plot of 4 m x 5 m. The rice straw was treated together with soil tillage, whereas nitrification inhibitor was applied together with urea application. Parameters observed were methane flux, plant height, plant biomass, grain yield, organic C content, and bacterial population in soil. The methane flux and soil organic C were measured at 25, 45, 60, 75, and 95 days after emergence. The results showed that composted rice straw incorporation significantly emitted methane lower (73.2 ± 6.6 kg CH4 ha-1 season-1 compared to the fresh rice straw (93.5 ± 4.0 CH4 ha-1 season-1. Application of nitrification inhibitors neem cake and carbofuran reduced methane emission as much as 20.7 and 15.4 kg CH4 ha-1 season-1, respectively. Under direct seeded rice system, methane flux level correlated with plant biomass as shown by linear regression of Y = 0.0015 X + 0.0575 (R2 = 0.2305, n = 27. This means that higher plant biomass produced more methane flux. The study indicates that application of

  2. Methane emissions and uptake in temperate and tropical forest trees on free-draining soils.

    Science.gov (United States)

    Welch, Bertie; Sayer, Emma; Siegenthaler, Andy; Gauci, Vincent

    2016-04-01

    Forests play an important role in the exchange of radiatively important gases with the atmosphere. Previous studies have shown that in both temperate and tropical wetland forests tree stems are significant sources of methane (CH4), yet little is known about trace greenhouse gas dynamics in free-draining soils that dominate global forested areas. We examined trace gas (CH4 and N2O) fluxes from both soils and tree stems in a lowland tropical forest on free-draining soils in Panama, Central America and from a deciduous woodland in the United Kingdom. The tropical field site was a long-term experimental litter manipulation experiment in the Barro Colorado Nature Monument within the Panama Canal Zone, fluxes were sampled over the dry to wet season transition (March-August) in 2014 and November 2015. Temperate fluxes were sampled at Wytham Woods, Oxfordshire, over 12 months from February 2015 to January 2016. Tree stem samples were collected via syringe from temporary chambers strapped to the trees (as per Siegenthaler et al. (2015)) and the soil fluxes were sampled from permanently installed collars inserted to a 3cm depth. We found that seasonality (precipitation) is a significant driver of changing soil exchange from methane uptake to emission at the Panama sites. Experimental changes to litter quantity only become significant when coupled with seasonal change. Seasonal variability is an important control of the fluxes at out temperate forest site with changes in temperature and soil water content leading to changes in soil and tree stem trace gas fluxes from Wytham Woods. Siegenthaler, A., Welch, B., Pangala, S. R., Peacock, M., and Gauci, V.: Technical Note: Semi-rigid chambers for methane gas flux measurements on tree-stems, Biogeosciences Discuss., 12, 16019-16048, doi:10.5194/bgd-12-16019-2015, 2015.

  3. Quantifying Fugitive Methane Emissions from Natural Gas Production with Mobile Technology

    Science.gov (United States)

    Tsai, T.; Rella, C.; Crosson, E.

    2013-12-01

    Quantification of fugitive methane (CH4) emissions to determine the environmental impact of natural gas production is challenging with current methods. We present a new mobile method known as the Plume Scanner that can quickly quantify CH4 emissions of point sources. The Plume Scanner is a direct measurement technique which utilizes a mobile Picarro cavity ring-down spectrometer and a gas sampling system based on AirCore technology [1]. As the Plume Scanner vehicle drives through the plume, the air is simultaneously sampled at four different heights, and therefore, the spatial CH4 distribution can be captured (Fig. 1). The flux of the plume is then determined by multiplying the spatial CH4 distribution data with the anemometer measurements. In this way, fugitive emission rates of highly localized sources such as natural gas production pads can be made quickly (~7 min). Verification with controlled CH4 releases demonstrate that under stable atmospheric conditions (Pasquill stability class is C or greater), the Plume Scanner measurements have an error of 2% and a repeatability of 15% [2]. Under unstable atmospheric conditions (Class A or B), the error is 6%, and the repeatability increases to 70% due to the variability of wind conditions. Over two weeks, 275 facilities in the Barnett Shale were surveyed from public roads by sampling the air for elevations in CH4 concentration, and 77% were found leaking. Emissions from 52 sites have been quantified with the Plume Scanner (Fig. 2), and the total emission is 4,900 liters per min (lpm) or 39,000 metric tons/yr CO2e. 1. Karion, A., C. Sweeney, P. Tans, and T. Newberger (2010), AirCore: An innovative atmospheric sampling system, J. Atmos. Oceanic Tech, 27, 1839-1853. 2. F. Pasquill (1961), The estimation of the dispersion of wind borne material, Meterol. Mag., 90(1063), 33-49 Figure 1. Plume Scanner Cartoon Figure 2. Distribution of methane fugitive emissions with error bars associated with the Pasquill stability classes

  4. Effect of technical cashew nut shell liquid on rumen methane emission and lactation performance of dairy cows.

    Science.gov (United States)

    Branco, A F; Giallongo, F; Frederick, T; Weeks, H; Oh, J; Hristov, A N

    2015-06-01

    Technical-grade cashew nut shell liquid (TCNSL) is a by-product of the cashew nut industry in tropical countries, and is known to exhibit a wide range of biological activities, including inhibitory effect against gram-positive bacteria. This study was conducted to investigate the effects of TCNSL (73.3% cardanol, 16.4% cardol, and 3.0% methylcardol) on rumen methane emission, nutrient digestibility, dry matter intake, and milk yield and composition in dairy cows. Eight multiparous Holstein cows were used in a crossover design trial with two 21-d experimental periods. The diet was based on corn silage and alfalfa haylage and was formulated to meet or exceed the energy and metabolizable protein requirements of the cows. Treatments were control (no TCNSL supplementation) or 30 g/cow per day of TCNSL. Rumen carbon dioxide emission was not affected by TCNSL. Treatment had no effect on methane emission (542 vs. 511±35.3 g/cow per day, respectively) and methane emission intensity (15.0 vs. 13.9±0.58 g/kg of energy-corrected milk, respectively) and tended to decrease methane emission per kilogram of dry matter intake (20.2 vs. 18.6±1.04 g/kg, respectively). Dry matter intake (average 26.9±1.00 kg/d), milk yield (40.0±1.73 kg/d), and milk composition were not different between treatments. The TCNSL had no effect on N losses in urine and feces and total-tract apparent digestibility of nutrients, except digestibility of neutral detergent fiber tended to be increased compared with the control. Plasma urea and glucose concentrations were not affected by TCNSL. Concentration of milk C18:0 tended to be decreased (17%) by TCNSL compared with the control. In this study, TCNSL did not alter absolute methane emission in the rumen, but tended to decrease it by 8% per kilogram of dry matter intake. The TCNSL had no effect on milk yield and composition in dairy cows.

  5. Assessment of methane generation, oxidation, and emission in a subtropical landfill test cell.

    Science.gov (United States)

    Moreira, João M L; Candiani, Giovano

    2016-08-01

    This paper presents results of a methane balance assessment in a test cell built in a region with a subtropical climate near São Paulo, Brazil. Measurements and calculations were carried out to obtain the total methane emission to the atmosphere, the methane oxidation rate in the cover, and the total methane generation rate in the test cell. The oxidation rate was obtained through a calculation scheme based on a vertical one-dimensional methane transport in the cover region. The measured maximum and mean methane fluxes to the atmosphere were 124.4 and 15.87 g m(-2) d(-1), respectively. The total methane generation rate obtained for the test cell was 0.0380 ± 0.0075 mol s(-1). The results yielded that 69 % of the emitted methane occurred through the central well and 31 % through the cover interface with the atmosphere. The evaluations of the methane oxidation fraction for localized conditions in the lateral embankment of the test cell yielded 0.36 ± 0.11, while for the whole test cell yielded 0.15 ± 0.10. These results conciliate localized and overall evaluations reported in the literature. The specific methane generation rate obtained for the municipal solid waste with an age of 410 days was 317 ± 62 mol year(-1) ton(-1). This result from the subtropical São Paulo region is lower than reported figures for tropical climates and higher than reported figures for temperate climates.

  6. The Role of Sedges in Methane Production and Emission From a Temperate Fen

    Science.gov (United States)

    Noyce, G. L.; Szarkowski, E. R.; Bubier, J. L.; Varner, R. K.

    2008-12-01

    Northern peatlands are the largest single natural source of atmospheric methane (CH4) and thus any changes in these fluxes could have global consequences. Positive correlations have been observed between sedge biomass and high CH4 emissions from peatlands. We examined the effect that Carex rostrata has on methane production and transport in Sallie's Fen, Barrington, NH. During the summer of 2008, CH4 fluxes, pore-water CH4 concentrations, and C. rostrata biomass, along with temperature, net ecosystem CO2 exchange (NEE), and water table depth, were measured from both clipped and unclipped plots. In clipped plots, all C. rostrata were clipped below the peat surface and then sealed with petroleum jelly and plastic bags. Unclipped plots were left undisturbed. We observed a strong positive correlation between C. rostrata biomass and CH4 fluxes. Initial findings suggest that sedges have a strong effect on gas transport. The average 18 cm (C. rostrata rooting depth) pore water CH4 concentrations in the clipped plots (6141 ppm CH4) were significantly higher (p<0.001) than in the unclipped plots (3912 ppm CH4). The past 20 years of data at Sallie's Fen also show that plots with more C. rostrata have higher mid-season CH4 fluxes, on average, than shrub-dominated plots. Depth to water table, however, may be a stronger control on CH4 fluxes than vegetation.

  7. A Mobile Sensing Approach for Regional Surveillance of Fugitive Methane Emissions in Oil and Gas Production.

    Science.gov (United States)

    Albertson, John D; Harvey, Tierney; Foderaro, Greg; Zhu, Pingping; Zhou, Xiaochi; Ferrari, Silvia; Amin, M Shahrooz; Modrak, Mark; Brantley, Halley; Thoma, Eben D

    2016-03-01

    This paper addresses the need for surveillance of fugitive methane emissions over broad geographical regions. Most existing techniques suffer from being either extensive (but qualitative) or quantitative (but intensive with poor scalability). A total of two novel advancements are made here. First, a recursive Bayesian method is presented for probabilistically characterizing fugitive point-sources from mobile sensor data. This approach is made possible by a new cross-plume integrated dispersion formulation that overcomes much of the need for time-averaging concentration data. The method is tested here against a limited data set of controlled methane release and shown to perform well. We then present an information-theoretic approach to plan the paths of the sensor-equipped vehicle, where the path is chosen so as to maximize expected reduction in integrated target source rate uncertainty in the region, subject to given starting and ending positions and prevailing meteorological conditions. The information-driven sensor path planning algorithm is tested and shown to provide robust results across a wide range of conditions. An overall system concept is presented for optionally piggybacking of these techniques onto normal industry maintenance operations using sensor-equipped work trucks.

  8. Model for estimating enteric methane emissions from United States dairy and feedlot cattle.

    Science.gov (United States)

    Kebreab, E; Johnson, K A; Archibeque, S L; Pape, D; Wirth, T

    2008-10-01

    Methane production from enteric fermentation in cattle is one of the major sources of anthropogenic greenhouse gas emission in the United States and worldwide. National estimates of methane emissions rely on mathematical models such as the one recommended by the Intergovernmental Panel for Climate Change (IPCC). Models used for prediction of methane emissions from cattle range from empirical to mechanistic with varying input requirements. Two empirical and 2 mechanistic models (COWPOLL and MOLLY) were evaluated for their prediction ability using individual cattle measurements. Model selection was based on mean square prediction error (MSPE), concordance correlation coefficient, and residuals vs. predicted values analyses. In dairy cattle, COWPOLL had the lowest root MSPE and greatest accuracy and precision of predicting methane emissions (correlation coefficient estimate = 0.75). The model simulated differences in diet more accurately than the other models, and the residuals vs. predicted value analysis showed no mean bias (P = 0.71). In feedlot cattle, MOLLY had the lowest root MSPE with almost all errors from random sources (correlation coefficient estimate = 0.69). The IPCC model also had good agreement with observed values, and no significant mean (P = 0.74) or linear bias (P = 0.11) was detected when residuals were plotted against predicted values. A fixed methane conversion factor (Ym) might be an easier alternative to diet-dependent variable Ym. Based on the results, the 2 mechanistic models were used to simulate methane emissions from representative US diets and were compared with the IPCC model. The average Ym in dairy cows was 5.63% of GE (range 3.78 to 7.43%) compared with 6.5% +/- 1% recommended by IPCC. In feedlot cattle, the average Ym was 3.88% (range 3.36 to 4.56%) compared with 3% +/- 1% recommended by IPCC. Based on our simulations, using IPCC values can result in an overestimate of about 12.5% and underestimate of emissions by about 9.8% for

  9. Estimating daily methane production in individual cattle with irregular feed intake patterns from short-term methane emission measurements.

    Science.gov (United States)

    Cottle, D J; Velazco, J; Hegarty, R S; Mayer, D G

    2015-12-01

    Spot measurements of methane emission rate (n = 18 700) by 24 Angus steers fed mixed rations from GrowSafe feeders were made over 3- to 6-min periods by a GreenFeed emission monitoring (GEM) unit. The data were analysed to estimate daily methane production (DMP; g/day) and derived methane yield (MY; g/kg dry matter intake (DMI)). A one-compartment dose model of spot emission rate v. time since the preceding meal was compared with the models of Wood (1967) and Dijkstra et al. (1997) and the average of spot measures. Fitted values for DMP were calculated from the area under the curves. Two methods of relating methane and feed intakes were then studied: the classical calculation of MY as DMP/DMI (kg/day); and a novel method of estimating DMP from time and size of preceding meals using either the data for only the two meals preceding a spot measurement, or all meals for 3 days prior. Two approaches were also used to estimate DMP from spot measurements: fitting of splines on a 'per-animal per-day' basis and an alternate approach of modelling DMP after each feed event by least squares (using Solver), summing (for each animal) the contributions from each feed event by best-fitting a one-compartment model. Time since the preceding meal was of limited value in estimating DMP. Even when the meal sizes and time intervals between a spot measurement and all feeding events in the previous 72 h were assessed, only 16.9% of the variance in spot emission rate measured by GEM was explained by this feeding information. While using the preceding meal alone gave a biased (underestimate) of DMP, allowing for a longer feed history removed this bias. A power analysis taking into account the sources of variation in DMP indicated that to obtain an estimate of DMP with a 95% confidence interval within 5% of the observed 64 days mean of spot measures would require 40 animals measured over 45 days (two spot measurements per day) or 30 animals measured over 55 days. These numbers suggest that

  10. Methane - quick fix or tough target? New methods to reduce emissions.

    Science.gov (United States)

    Nisbet, E. G.; Lowry, D.; Fisher, R. E.; Brownlow, R.

    2016-12-01

    Methane is a cost-effective target for greenhouse gas reduction efforts. The UK's MOYA project is designed to improve understanding of the global methane budget and to point to new methods to reduce future emissions. Since 2007, methane has been increasing rapidly: in 2014 and 2015 growth was at rates last seen in the 1980s. Unlike 20thcentury growth, primarily driven by fossil fuel emissions in northern industrial nations, isotopic evidence implies present growth is driven by tropical biogenic sources such as wetlands and agriculture. Discovering why methane is rising is important. Schaefer et al. (Science, 2016) pointed out the potential clash between methane reduction efforts and food needs of a rising, better-fed (physically larger) human population. Our own work suggests tropical wetlands are major drivers of growth, responding to weather changes since 2007, but there is no acceptable way to reduce wetland emission. Just as sea ice decline indicates Arctic warming, methane may be the most obvious tracker of climate change in the wet tropics. Technical advances in instrumentation can do much in helping cut urban and industrial methane emissions. Mobile systems can be mounted on vehicles, while drone sampling can provide a 3D view to locate sources. Urban land planning often means large but different point sources are typically clustered (e.g. landfill or sewage plant near incinerator; gas wells next to cattle). High-precision grab-sample isotopic characterisation, using Keeling plots, can separate source signals, to identify specific emitters, even where they are closely juxtaposed. Our mobile campaigns in the UK, Kuwait, Hong Kong and E. Australia show the importance of major single sources, such as abandoned old wells, pipe leaks, or unregulated landfills. If such point sources can be individually identified, even when clustered, they will allow effective reduction efforts to occur: these can be profitable and/or improve industrial safety, for example in the

  11. Atmospheric constraints on the methane emissions from the East Siberian Shelf

    Directory of Open Access Journals (Sweden)

    A. Berchet

    2015-09-01

    Full Text Available Sub-sea permafrost and hydrates in the East Siberian Arctic Ocean Continental Shelf (ESAS constitute a substantial carbon pool, and a potentially large source of methane to the atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8–17 Tg CH4 y−1. Here, we propose insights based on atmospheric observations to evaluate these estimates. Isotopic observations suggest a biogenic origin (either terrestrial or marine of the methane in air masses originating from ESAS during summer 2010. The comparison of high-resolution simulations of atmospheric methane mole fractions to continuous methane observations during the entire year 2012 confirms the high variability and heterogeneity of the methane releases from ESAS. Simulated mole fractions including a 8 Tg CH4 y−1 source from ESAS are found largely overestimated compared to the observations in winter, whereas summer signals are more consistent with each other. Based on a comprehensive statistical analysis of the observations and of the simulations, annual methane emissions from ESAS are estimated in a range of 0.5–4.3 Tg CH4 y−1.

  12. Estimating dispersed and point source emissions of methane in East Anglia: results and implications

    Science.gov (United States)

    Harris, Neil; Connors, Sarah; Hancock, Ben; Jones, Pip; Murphy, Jonathan; Riddick, Stuart; Robinson, Andrew; Skelton, Robert; Manning, Alistair; Forster, Grant; Oram, David; O'Doherty, Simon; Young, Dickon; Stavert, Ann; Fisher, Rebecca; Lowry, David; Nisbet, Euan; Zazzeri, Guilia; Allen, Grant; Pitt, Joseph

    2016-04-01

    We have been investigating ways to estimate dispersed and point source emissions of methane. To do so we have used continuous measurements from a small network of instruments at 4 sites across East Anglia since 2012. These long-term series have been supplemented by measurements taken in focussed studies at landfills, which are important point sources of methane, and by measurements of the 13C:12C ratio in methane to provide additional information about its sources. These measurements have been analysed using the NAME InTEM inversion model to provide county-level emissions (~30 km x ~30 km) in East Anglia. A case study near a landfill just north of Cambridge was also analysed using a Gaussian plume model and the Windtrax dispersion model. The resulting emission estimates from the three techniques are consistent within the uncertainties, despite the different spatial scales being considered. A seasonal cycle in emissions from the landfill (identified by the isotopic measurements) is observed with higher emissions in winter than summer. This would be expected from consideration of the likely activity of methanogenic bacteria in the landfill, but is not currently represented in emission inventories such as the UK National Atmospheric Emissions Inventory. The possibility of assessing North Sea gas field emissions using ground-based measurements will also be discussed.

  13. Methane emissions from process equipment at natural gas production sites in the United States: liquid unloadings.

    Science.gov (United States)

    Allen, David T; Sullivan, David W; Zavala-Araiza, Daniel; Pacsi, Adam P; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Lamb, Brian K; Sawyer, Robert F; Seinfeld, John H

    2015-01-01

    Methane emissions from liquid unloadings were measured at 107 wells in natural gas production regions throughout the United States. Liquid unloadings clear wells of accumulated liquids to increase production, employing a variety of liquid lifting mechanisms. In this work, wells with and without plunger lifts were sampled. Most wells without plunger lifts unload less than 10 times per year with emissions averaging 21,000-35,000 scf methane (0.4-0.7 Mg) per event (95% confidence limits of 10,000-50,000 scf/event). For wells with plunger lifts, emissions averaged 1000-10,000 scf methane (0.02-0.2 Mg) per event (95% confidence limits of 500-12,000 scf/event). Some wells with plunger lifts are automatically triggered and unload thousands of times per year and these wells account for the majority of the emissions from all wells with liquid unloadings. If the data collected in this work are assumed to be representative of national populations, the data suggest that the central estimate of emissions from unloadings (270 Gg/yr, 95% confidence range of 190-400 Gg) are within a few percent of the emissions estimated in the EPA 2012 Greenhouse Gas National Emission Inventory (released in 2014), with emissions dominated by wells with high frequencies of unloadings.

  14. Prediction and evaluation of enteric methane emissions from lactating dairy cows using different levels of covariate information

    NARCIS (Netherlands)

    Santiago-Juarez, B.; Moraes, L.E.; Appuhamy, J.A.D.R.N.; Pellikaan, W.F.; Casper, D.P.; Tricarico, J.; Kebreab, E.

    2016-01-01

    The dairy sector contributes to global warming through enteric methane (CH4) emissions. Methane is also a loss of energy to the ruminant. Several studies have developed CH4 prediction models to assess mitigation strategies to reduce emissions. However, the majority of these models have low

  15. Quantification of Methane and VOC Emissions from Natural Gas Production in Two Basins with High Ozone Events

    Science.gov (United States)

    Edie, R.; Robertson, A.; Snare, D.; Soltis, J.; Field, R. A.; Murphy, S. M.

    2015-12-01

    Since 2005, the Uintah Basin of Utah and the Upper Green River Basin of Wyoming frequently exceeded the EPA 8-hour allowable ozone level of 75 ppb, spurring interest in volatile organic compounds (VOCs) emitted during oil and gas production. Debate continues over which stage of production (drilling, flowback, normal production, transmission, etc.) is the most prevalent VOC source. In this study, we quantify emissions from normal production on well pads by using the EPA-developed Other Test Method 33a. This methodology combines ground-based measurements of fugitive emissions with 3-D wind data to calculate the methane and VOC emission fluxes from a point source. VOC fluxes are traditionally estimated by gathering a canister of air during a methane flux measurement. The methane:VOC ratio of this canister is determined at a later time in the laboratory, and applied to the known methane flux. The University of Wyoming Mobile Laboratory platform is equipped with a Picarro methane analyzer and an Ionicon Proton Transfer Reaction-Time of Flight-Mass Spectrometer, which provide real-time methane and VOC data for each well pad. This independent measurement of methane and VOCs in situ reveals multiple emission sources on one well pad, with varying methane:VOC ratios. Well pad emission estimates of methane, benzene, toluene and xylene for the two basins will be presented. The different emission source VOC profiles and the limitations of real-time and traditional VOC measurement methods will also be discussed.

  16. Comparison of Propane and Methane Performance and Emissions in a Turbocharged Direct Injection Dual Fuel Engine

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, C. M.; Polk, A. C.; Shoemaker, N. T.; Srinivasan, K. K.; Krishnan, S. R.

    2011-01-01

    With increasingly restrictive NO x and particulate matter emissions standards, the recent discovery of new natural gas reserves, and the possibility of producing propane efficiently from biomass sources, dual fueling strategies have become more attractive. This paper presents experimental results from dual fuel operation of a four-cylinder turbocharged direct injection (DI) diesel engine with propane or methane (a natural gas surrogate) as the primary fuel and diesel as the ignition source. Experiments were performed with the stock engine control unit at a constant speed of 1800 rpm, and a wide range of brake mean effective pressures (BMEPs) (2.7-11.6 bars) and percent energy substitutions (PESs) of C 3 H 8 and CH 4. Brake thermal efficiencies (BTEs) and emissions (NO x, smoke, total hydrocarbons (THCs), CO, and CO 2) were measured. Maximum PES levels of about 80-95% with CH 4 and 40-92% with C 3 H 8 were achieved. Maximum PES was limited by poor combustion efficiencies and engine misfire at low loads for both C 3 H 8 and CH 4, and the onset of knock above 9 bar BMEP for C 3 H 8. While dual fuel BTEs were lower than straight diesel BTEs at low loads, they approached diesel BTE values at high loads. For dual fuel operation, NO x and smoke reductions (from diesel values) were as high as 66-68% and 97%, respectively, but CO and THC emissions were significantly higher with increasing PES at all engine loads

  17. Genetic parameters for predicted methane production and potential for reducing enteric emissions through genomic selection.

    Science.gov (United States)

    Haas, Y de; Windig, J J; Calus, M P L; Dijkstra, J; Haan, M de; Bannink, A; Veerkamp, R F

    2011-12-01

    Mitigation of enteric methane (CH₄) emission in ruminants has become an important area of research because accumulation of CH₄ is linked to global warming. Nutritional and microbial opportunities to reduce CH₄ emissions have been extensively researched, but little is known about using natural variation to breed animals with lower CH₄ yield. Measuring CH₄ emission rates directly from animals is difficult and hinders direct selection on reduced CH₄ emission. However, improvements can be made through selection on associated traits (e.g., residual feed intake, RFI) or through selection on CH₄ predicted from feed intake and diet composition. The objective was to establish phenotypic and genetic variation in predicted CH₄ output, and to determine the potential of genetics to reduce methane emissions in dairy cattle. Experimental data were used and records on daily feed intake, weekly body weights, and weekly milk production were available from 548 heifers. Residual feed intake (MJ/d) is the difference between net energy intake and calculated net energy requirements for maintenance as a function of body weight and for fat- and protein-corrected milk production. Predicted methane emission (PME; g/d) is 6% of gross energy intake (Intergovernmental Panel on Climate Change methodology) corrected for energy content of methane (55.65 kJ/g). The estimated heritabilities for PME and RFI were 0.35 and 0.40, respectively. The positive genetic correlation between RFI and PME indicated that cows with lower RFI have lower PME (estimates ranging from 0.18 to 0.84). Hence, it is possible to decrease the methane production of a cow by selecting more-efficient cows, and the genetic variation suggests that reductions in the order of 11 to 26% in 10 yr are theoretically possible, and could be even higher in a genomic selection program. However, several uncertainties are discussed; for example, the lack of true methane measurements (and the key assumption that methane

  18. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

    Directory of Open Access Journals (Sweden)

    R. Locatelli

    2013-10-01

    Full Text Available A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr−1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr−1 in North America to 7 Tg yr−1 in Boreal Eurasia (from 23 to 48%, respectively. At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly

  19. Prediction of methane emissions from beef cattle in tropical production systems

    Energy Technology Data Exchange (ETDEWEB)

    McCrabb, G.J.; Hunter, R.A. [CSIRO, Rockhampton, Qld. (Australia). Division of Tropical Agriculture

    1999-07-01

    The northern beef cattle herd accounts for more than half of Australia's beef cattle population, and is a major source of anthropogenic methane emissions for Australia. National Greenhouse Gas Inventory predictions of methane output from Australian beef cattle are based on a predictive equation developed for British breeds of sheep and cattle offered temperate forage-based diets. However, tropical forage diets offered to cattle in northern Australia differ markedly from temperate forage-based diets used in the United Kingdom to develop the predictive equations. The paper reviews recent respiration chamber measurements of daily methane production for Brahman cattle offered a tropical forage or high grain diet, and compares them with values predicted using methodologies of the Australian National Greenhouse Gas Inventory Committee and the Intergovernmental Panel on Climate Change. It is concluded that a reliable inventory of methane emissions for cattle in northern Australia can only be achieved after a wider range of tropical forage species has been investigated. Some opportunities for reducing methane emissions of beef cattle by dietary manipulation are discussed.

  20. Modeling Methane Emission from Rice Paddy Soils:I.Model Development

    Institute of Scientific and Technical Information of China (English)

    HUANGYAO; R.L.SASS; 等

    1999-01-01

    With an understanding of the processes of methane production,oxidation and emission,a semi-empirical model,focused on the contributions of rice plants to the processes and also the influence of environmental factors,was developed to predict methane emission from rice paddy soils.In the present model,the amount of methane transported from the soil to the atmosphere was determined by the rates of CH4 production and an emitted fraction.The rates of CH4 production in irrgated rice soils were computed from the availability of methanogenic substrates that are primarily derived from rice plants and added organic matter and the influence of soil texture.soil redox potential and temperature,The fraction of methane emitted was assumed to be modulated by the rice plants and declines with rice growth and development.To make it applicable to a wider area with limited data sets.a simplified version of the model was also derived to predict methane emission in a more practical manner.

  1. Relative contributions of hypoxia and natural gas extraction to atmospheric methane emissions from Lake Erie

    Science.gov (United States)

    Disbennett, D. A.; Townsend-Small, A.; Bourbonniere, R.; Mackay, R.

    2013-12-01

    Reduced oxygen availability in lakes due to summer stratification can create conditions suitable for methanogenic activity, which ultimately contributes to atmospheric methane emissions. Lake Erie has persistent low oxygen conditions in bottom waters during summer, which contributes to methane production through anaerobic organic matter respiration. Lake Erie also has substantial subsurface natural gas deposits that are currently being extracted in Canadian waters. We hypothesized that the lake would be a source of methane to the atmosphere in late summer, prior to fall turnover, and that natural gas wells and pipelines would contribute to additional methane emissions from resource extraction areas in Canadian waters. Initial sampling was conducted at a total of 20 sites in central and western Lake Erie during early September 2012. Sites were selected to collect samples from a wide range of environmental conditions in order to better establish the baseline flux from these areas. We selected an array of sites in the offshore environment, sites from a very shallow bay and sites within the Canadian gas fields. Air samples were gathered using floating flux chambers tethered to the research vessel. Dissolved gas water samples were collected using a Van Dorn bottle. We found a consistent positive flux of methane throughout the lake during late summer, with flux rates adjacent to natural gas pipelines up to an order of magnitude greater than elsewhere. Stable isotope analysis yielded results that were not entirely expected. The δ13C of surface samples from areas of fossil fuel extraction and suspected biogenic sources were very similar, likely due to oxidation of methane in the water column. Additional sampling occurred during 2012 and 2013 concentrating on bottom waters and surface fluxes which should allow us to further constrain sources of CH4 from Lake Erie. This project is an effort to constrain the global warming potential of hypoxia in the Great Lakes, and

  2. Heritability estimates for enteric methane emissions from Holstein cattle measured using noninvasive methods.

    Science.gov (United States)

    Lassen, Jan; Løvendahl, Peter

    2016-03-01

    The objective of this study was to estimate heritability of enteric methane emissions from dairy cattle. Methane (CH4) and CO2 were measured with a portable air-sampler and analyzer unit based on Fourier transform infrared detection. Data were collected on 3,121 Holstein dairy cows from 20 herds using automatic milking systems. Three CH4 phenotypes were acquired: the ratio between CH4 and CO2 in the breath of the cows (CH4_RATIO), the estimated quantified amount of CH4 (in g/d) measured over a week (CH4_GRAMSw), and CH4 intensity, defined as grams of CH4 per liter of milk produced (CH4_MILK). Fat- and protein-corrected milk (FPCM) and live weight data were also derived for the analysis. Data were analyzed using several univariate and bivariate linear animal models. The heritability of CH4_GRAMSw and CH4_MILK was 0.21 with a standard error of 0.06, and the heritability of CH4_RATIO was 0.16 with a standard error of 0.04. The 2 CH4 traits CH4_GRAMSw and CH4_RATIO were genetically highly correlated (rg=0.83) and they were strongly correlated with FPCM, meaning that, in this study, a high genetic potential for milk production will also mean a high genetic potential for CH4 production. The genetic correlation between CH4_MILK and FPCM and live weight showed similar patterns as the other CH4 phenotypes, although the correlations in general were closer to zero. The genetic correlations between the 3 CH4 phenotypes and live weight were low and only just significantly different from zero, meaning there is less indication of a genetic relationship between CH4 emission and live weight of the cow. None of the residual correlations between the ratio of CH4 and CO2, CH4 production in grams per day, FPCM, and live weight were significantly different from zero. The results from this study suggest that CH4 emission is partly under genetic control, that it is possible to decrease CH4 emission from dairy cattle through selection, and that selection for higher milk yield will lead to

  3. Methane emission to the atmosphere from landfills in the Canary Islands

    Science.gov (United States)

    Hernández, Pedro A.; Asensio-Ramos, María; Rodríguez, Fátima; Alonso, Mar; García-Merino, Marta; Amonte, Cecilia; Melián, Gladys V.; Barrancos, José; Rodríguez-Delgado, Miguel A.; Hernández-Abad, Marta; Pérez, Erica; Alonso, Monica; Tassi, Franco; Raco, Brunella; Pérez, Nemesio M.

    2017-04-01

    . To quantify the the diffuse or fugitive CO2 and CH4 emission, gas efflux contour maps were constructed using sequential Gaussian simulation (sGs) as interpolation method. Considering that (a) there are 5 controlled landfills in the Canary Islands, (b) the average area of the 23 studied cells is 0.17 km2 and (c) the mean value of the CH4 emission estimated for the studied cells range between 6.9 and 8.1 kt km-2 y-1, the estimated CH4 emission to the atmosphere from landfills in the Canary Islands showed a range of 7.0 - 7.8 kt y-1. On the contrary and for the same period of time, the PRTR-Spain estimates CH4 emission in the order of 10.3 - 14.9 kt y-1, nearly two times our estimated value. This result demonstrates the need to perform direct measurements to estimate the surface fugitive emission of CH4 from landfills. Bingemer, H. G., and P. J. Crutzen (1987). The production of methane from solid wastes, J. Geophys. Res. 92, 2182-2187

  4. Quantifying wetland methane emissions with process-based models of different complexities

    Directory of Open Access Journals (Sweden)

    J. Tang

    2010-08-01

    Full Text Available Bubbling is an important pathway of methane emissions from wetland ecosystems; however the concentration-based threshold function approach in current biogeochemistry models of methane is not sufficient to represent the complex ebullition process. Here we revise an extant process-based biogeochemistry model, the Terrestrial Ecosystem Model into a multi-substance model (CH4, O2, CO2 and N2 to simulate methane production, oxidation, and transport (particularly ebullition with different model complexities. When ebullition is modeled with a concentration-based threshold function and if the inhibition effect of oxygen on methane production and the competition for oxygen between methanotrophy and heterotrophic respiration are retained, the model is a two-substance system. Ignoring the role of oxygen, while still modeling ebullition with a concentration-based threshold function, reduces the model to a one-substance system. These models were tested through a group of sensitivity analyses at two temperate peatland sites in Michigan. We demonstrate that only the four-substance model with a pressure-based ebullition algorithm is able to capture the episodic emissions induced by a sudden decrease in atmospheric pressure. All models captured the retardation effect on methane efflux from an increase in surface standing water which results from the inhibition of diffusion and the increase in rhizospheric oxidation. We conclude that to more accurately account for the effects of atmospheric pressure dynamics and standing water on methane effluxes, the multi-substance model with a pressure-based ebullition algorithm should be used in the future to quantify global wetland CH4 emissions. Further, to more accurately simulate the pore water gas concentrations and different pathways of methane transport, an exponential root distribution function should be used and the phase-related parameters should be treated as

  5. Quantifying wetland methane emissions with process-based models of different complexities

    Directory of Open Access Journals (Sweden)

    J. Tang

    2010-11-01

    Full Text Available Bubbling is an important pathway of methane emissions from wetland ecosystems. However the concentration-based threshold function approach in current biogeochemistry models of methane is not sufficient to represent the complex ebullition process. Here we revise an extant process-based biogeochemistry model, the Terrestrial Ecosystem Model into a multi-substance model (CH4, O2, CO2 and N2 to simulate methane production, oxidation, and transport (particularly ebullition with different model complexities. When ebullition is modeled with a concentration-based threshold function and if the inhibition effect of oxygen on methane production and the competition for oxygen between methanotrophy and heterotrophic respiration are retained, the model becomes a two-substance system. Ignoring the role of oxygen, while still modeling ebullition with a concentration-based threshold function, reduces the model to a one-substance system. These models were tested through a group of sensitivity analyses using data from two temperate peatland sites in Michigan. We demonstrate that only the four-substance model with a pressure-based ebullition algorithm is able to capture the episodic emissions induced by a sudden decrease in atmospheric pressure or by a sudden drop in water table. All models captured the retardation effect on methane efflux from an increase in surface standing water which results from the inhibition of diffusion and the increase in rhizospheric oxidation. We conclude that to more accurately account for the effects of atmospheric pressure dynamics and standing water on methane effluxes, the multi-substance model with a pressure-based ebullition algorithm should be used in the future to quantify global wetland CH4 emissions. Further, to more accurately simulate the pore water gas concentrations and different pathways of methane transport, an exponential root distribution function should be used

  6. Future methane, hydroxyl, and their uncertainties: key climate and emission parameters for future predictions

    Directory of Open Access Journals (Sweden)

    C. D. Holmes

    2013-01-01

    Full Text Available Accurate prediction of future methane abundances following a climate scenario requires understanding the lifetime changes driven by anthropogenic emissions, meteorological factors, and chemistry-climate feedbacks. Uncertainty in any of these influences or the underlying processes implies uncertainty in future abundance and radiative forcing. We simulate methane lifetime in three chemical transport models (CTMs – UCI CTM, GEOS-Chem, and Oslo CTM3 – over the period 1997–2009 and compare the models' year-to-year variability against constraints from global methyl chloroform observations. Using sensitivity tests, we find that temperature, water vapor, stratospheric ozone column, biomass burning and lightning NOx are the dominant sources of interannual changes in methane lifetime in all three models. We also evaluate each model's response to forcings that have impacts on decadal time scales, such as methane feedback, and anthropogenic emissions. In general, these different CTMs show similar sensitivities to the driving variables. We construct a parametric model that reproduces most of the interannual variability of each CTM and use it to predict methane lifetime from 1980 through 2100 following a specified emissions and climate scenario (RCP 8.5. The parametric model propagates uncertainties through all steps and provides a foundation for predicting methane abundances in any climate scenario. Our sensitivity tests also enable a new estimate of the methane global warming potential (GWP, accounting for stratospheric ozone effects, including those mediated by water vapor. We estimate the 100-yr GWP to be 32, which is 25% larger than past assessments.

  7. Methane emissions from rice fields under continuous straw return in the middle-lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Pengfu Hou; Ganghua Li; Shaohua Wang; Xin Jin; Yiming Yang; Xiaoting Chen; Chengqiang Ding

    2013-01-01

    A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane (CH4) emissions from rice fields in which,the rice-wheat rotation system is the most dominant planting pattern.The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year.The analyses for the present study were conducted in the second (2011) and third (2012) rice growing seasons.Four treatments,namely,the continuous return of wheat straw and rice straw in every season (WR),of rice straw but no wheat straw return (R),of wheat straw but no rice straw return (W) and a control with no straw return (CK),were laid out in a randomized split-plot design.The total seasonal CH4 emissions ranged from 107.4 to 491.7 kg/ha (2011) and 160.3 to 909.6 kg/ha (2012).The increase in CH4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year,respectively,in relation to CK.We observed less methane emissions in the treatment R than in CK by 14%-43%,but not statistically significant.Treatment R could increase rice productivity while no more CH4 emission occurs.The difference in the total CH4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season,which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.

  8. Warmer temperature accelerates methane emissions from the Zoige wetland on the Tibetan Plateau without changing methanogenic community composition

    Science.gov (United States)

    Cui, Mengmeng; Ma, Anzhou; Qi, Hongyan; Zhuang, Xuliang; Zhuang, Guoqiang; Zhao, Guohui

    2015-01-01

    Zoige wetland, locating on the Tibet Plateau, accounts for 6.2% of organic carbon storage in China. However, the fate of the organic carbon storage in the Zoige wetland remains poorly understood despite the Tibetan Plateau is very sensitive to global climate change. As methane is an important greenhouse gas and methanogenesis is the terminal step in the decomposition of organic matter, understanding how methane emissions from the Zoige wetland is fundamental to elucidate the carbon cycle in alpine wetlands responding to global warming. In this study, microcosms were performed to investigate the effects of temperature and vegetation on methane emissions and microbial processes in the Zoige wetland soil. A positive correlation was observed between temperature and methane emissions. However, temperature had no effect on the main methanogenic pathway—acetotrophic methanogenesis. Moreover, methanogenic community composition was not related to temperature, but was associated with vegetation, which was also involved in methane emissions. Taken together, these results indicate temperature increases methane emissions in alpine wetlands, while vegetation contributes significantly to methanogenic community composition and is associated with methane emissions. These findings suggest that in alpine wetlands temperature and vegetation act together to affect methane emissions, which furthers a global warming feedback loop. PMID:26109512

  9. Effects of different fertilizers on methane emission from paddy field of ...

    African Journals Online (AJOL)

    deltafuture

    increased as the application rate of urea-N was increased. ... fertilizer was added for the control (CK). ... urea as dressing fertilizer 15 days after transplanting in pot. Three ..... conditions on the release of methane, the amount of methanogens.

  10. Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

    Science.gov (United States)

    Karanjekar, Richa V; Bhatt, Arpita; Altouqui, Said; Jangikhatoonabad, Neda; Durai, Vennila; Sattler, Melanie L; Hossain, M D Sahadat; Chen, Victoria

    2015-12-01

    Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual.

  11. Relationship between residual feed intake and enteric methane emission in Nellore cattle

    Directory of Open Access Journals (Sweden)

    Maria Eugênia Zerlotti Mercadante

    2015-07-01

    Full Text Available Feed intake and average daily gain (ADG in Nellore cattle were determined to calculate residual feed intake in two performance tests: first during the growth phase (RFIgrowth and then during a measurement of the methane emission phase (RFImet. During the RFIgrowth test, 62 males and 56 females were classified as low-, medium-, and high-RFI. Enteric methane emission was measured in 46 animals; 23 males used for RFImet measurement plus 23 females (22 low-RFIgrowth and 24 high-RFIgrowth. Diet consisted of Brachiaria brizantha cv. Marandu hay (445 g/kg DM and concentrate (555 g/kg DM. During the RFIgrowth and RFImet phases, DMI was lower in the animals with low RFI, with no difference in ADG. Residual feed intake was -0.359 and 0.367 kg DM/d for low- and high-RFI animals. Enteric methane emission (g/d, g/kg BW0.75 and g/kg ADG did not differ between RFIgrowth classes. Enteric methane emission (g/d was higher in high RFImet and lower in low RFImet males. Spearman correlations among traits obtained during both tests, which were high between metabolic BW (r = 0.959 and between DMI (r = 0.718, and zero between ADG (r = -0.062, resulted in moderate correlation between RFIgrowth and RFImet (r = 0.412. However, it is not possible to confirm that high-efficiency animals release less enteric methane, since different results were obtained when enteric methane was compared between the RFIgrowth and RFImet classes.

  12. Estimation of Methane Emissions from Slurry Pits below Pig and Cattle Confinements

    DEFF Research Database (Denmark)

    Petersen, Søren O.; Olsen, Anna Bang; Elsgaard, Lars

    2016-01-01

    and cattle slurry differed significantly at 0.030 and 0.011 kg CH4 kg-1 VS (volatile solids). Current estimates of CH4 emissions from pig and cattle manure management correspond to 0.032 and 0.015 kg CH4 kg-1, respectively, indicating that slurry pits under animal confinements are a significant source......Quantifying in-house emissions of methane (CH4) from liquid manure (slurry) is difficult due to high background emissions from enteric processes, yet of great importance for correct estimation of CH4 emissions from manure management and effects of treatment Technologies such as anaerobic digestion....... In this study CH4 production rates were determined in 20 pig slurry and 11 cattle slurry samples collected beneath slatted floors on six representative farms; rates were determined within 24 h at temperatures close to the temperature in slurry pits at the time of collection. Methane production rates in pig...

  13. Investigation on Methane Decomposition and the Formation of C2 Hydrocarbons in DC Discharge Plasma byEmission Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    贺建勋; 韩媛媛; 高爱华; 周引穗; 陆治国

    2004-01-01

    The IR emission spectra of methane were measured under DC glow discharge conditions. The distinct difference in time between methane decomposition and C2 hydrocarbons formation was specially pointed out. C2 hydrocarbons formed at the end of methane decomposition. The optimum condition for C2 hydrocarbon formation was studied and the optimum combination between electric current density and methane input quantity was suggested. The appropriate reaction conditions for methane decomposition and C2 hydrocarbons formation are different, so high yield of C2 hydrocarbons will be probably obtained when different conditions are taken.

  14. ECOS E-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database

    Energy Technology Data Exchange (ETDEWEB)

    Parisien, Lia [The Environmental Council Of The States, Washington, DC (United States)

    2016-01-31

    This final scientific/technical report on the ECOS e-MATRIX Methane and Volatile Organic Carbon (VOC) Emissions Best Practices Database provides a disclaimer and acknowledgement, table of contents, executive summary, description of project activities, and briefing/technical presentation link.

  15. Constraints on sea to air emissions from methane clathrates in the vicinity of Svalbard

    Science.gov (United States)

    Pisso, Ignacio; Vadakkepuliyambatta, Sunil; Platt, Stephen Matthew; Eckhardt, Sabine; Allen, Grant; Pitt, Joseph; Silyakova, Anna; Hermansen, Ove; Schmidbauer, Norbert; Mienert, Jurgen; Myhre, Cathrine Lund; Stohl, Andreas

    2016-04-01

    Methane stored in the seabed in the form of clathrates has the potential to be released into the atmosphere due to ongoing ocean warming. The Methane Emissions from Arctic Ocean to Atmosphere (MOCA, http://moca.nilu.no/) proje sct conducted measurement campaigns in the vicinity of Svalbard during the summers of 2014 and 2015 in collaboration with the Centre for Arctic Gas Hydrate, Environment and Climate (CAGE, https://cage.uit.no/) and the MAMM (https://arcticmethane.wordpress.com) project . The extensive set of measurements includes air (BAe 146) and ship (RV Helmer Hansen) borne methane concentrations, complemented with the nearby monitoring site at Zeppelin mountain. In order to assess the atmospheric impact of emissions from seabed methane hydrates, we characterised the local and long range atmospheric transport during the aircraft campaign and different scenarios for the emission sources. We present a range of upper bounds for the CH4 emissions during the campaign period as well as the methodologies used to obtain them. The methodologies include a box model, Lagrangian transport and elementary inverse modelling. We emphasise the analysis of the aircraft data. We discuss in detail the different methodologies used for determining the upper flux bounds as well as its uncertainties and limitations. The additional information provided by the ship and station observations will be briefly mentioned.

  16. Simulating the effects of grassland management and grass ensiling on methane emission from lactating cows

    NARCIS (Netherlands)

    Bannink, A.; Smits, M.C.J.; Kebreab, E.; Mills, J.A.N.; Ellis, J.L.; Klop, A.; France, J.; Dijkstra, J.

    2010-01-01

    A dynamic, mechanistic model of enteric fermentation was used to investigate the effect of type and quality of grass forage, dry matter intake (DMI) and proportion of concentrates in dietary dry matter (DM) on variation in methane (CH4) emission from enteric fermentation in dairy cows. The model rep

  17. Understanding Methane Emission from Natural Gas Activities Using Inverse Modeling Techniques

    Science.gov (United States)

    Abdioskouei, M.; Carmichael, G. R.

    2015-12-01

    Natural gas (NG) has been promoted as a bridge fuel that can smooth the transition from fossil fuels to zero carbon energy sources by having lower carbon dioxide emission and lower global warming impacts in comparison to other fossil fuels. However, the uncertainty around the estimations of methane emissions from NG systems can lead to underestimation of climate and environmental impacts of using NG as a replacement for coal. Accurate estimates of methane emissions from NG operations is crucial for evaluation of environmental impacts of NG extraction and at larger scale, adoption of NG as transitional fuel. However there is a great inconsistency within the current estimates. Forward simulation of methane from oil and gas operation sites for the US is carried out based on NEI-2011 using the WRF-Chem model. Simulated values are compared against measurements of observations from different platforms such as airborne (FRAPPÉ field campaign) and ground-based measurements (NOAA Earth System Research Laboratory). A novel inverse modeling technique is used in this work to improve the model fit to the observation values and to constrain methane emission from oil and gas extraction sites.

  18. Measurements and modeling to quantify emissions of methane and VOCs from shale gas operations: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Presto, Albert A [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-06-30

    The objectives of the project were to determine the leakage rates of methane and ozone-forming Volatile Organic Compounds (VOCs) and the emission rates of air toxics from Marcellus shale gas activities. Methane emissions in the Marcellus Shale region were differentiated between “newer” sources associated with shale gas development and “older” sources associated with coal or conventional natural gas exploration. This project conducted measurements of methane and VOC emissions from both shale and non-shale natural gas resources. The initial scope of the project was the Marcellus Shale basin, and measurements were conducted in both the western wet gas regions (southwest PA and WV) and eastern dry gas region (northeast PA) of the basin. During this project, we obtained additional funding from other agencies to expand the scope of measurements to include additional basins. The data from both the Marcellus and other basins were combined to construct a national analysis of methane emissions from oil & gas production activities.

  19. Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets

    NARCIS (Netherlands)

    Hulshof, R.B.A.; Berndt, A.; Gerrits, W.J.J.; Dijkstra, J.; Zijderveld, van S.M.; Newbold, J.R.; Perdok, H.B.

    2012-01-01

    The objective of this study was to determine the effect of dietary nitrate on methane emission and rumen fermentation parameters in Nellore × Guzera (Bos indicus) beef cattle fed a sugarcane based diet. The experiment was conducted with 16 steers weighing 283 ± 49 kg (mean ± SD), 6 rumen cannulated

  20. Methane emissions from enteric fermentation in dairy cows, 1990-2008

    NARCIS (Netherlands)

    Bannink, A.

    2011-01-01

    The Dutch protocol for the national inventory estimates the methane emission of the average Dutch dairy cow based on a Tier 3 approach. A dynamic, mechanistic model is used to represent the enteric fermentation processes, using annual national statistics on feed intake and feed composition as model

  1. Dietary strategies to reducing N excretion from cattle: implications for methane emissions

    NARCIS (Netherlands)

    Dijkstra, J.; Oenema, O.; Bannink, A.

    2011-01-01

    Ruminants turn human inedible into human edible products, but at a cost of excretion of various pollutants. Implications of dietary measures for cattle to reduce faecal and urinary nitrogen losses on methane emissions are reviewed. Reducing the dietary protein content decreases nitrogen excretion in

  2. Methane emission from natural wetlands: interplay between emergent macrophytes and soil microbial processes. A mini review

    NARCIS (Netherlands)

    Laanbroek, H.J.

    2010-01-01

    Background: According to the Intergovernmental Panel on Climate Change (IPCC) 2007, natural wetlands contribute 20–39 % to the global emission of methane. The range in the estimated percentage of the contribution of these systems to the total release of this greenhouse gas is large due to difference

  3. Temperature and moisture affect methane and nitrous oxide emission from bovine manure patches in tropical conditions

    NARCIS (Netherlands)

    Mazzetto, A.M.; Barneze, A.S.; Feigl, B.J.; Groenigen, van J.W.; Oenema, O.; Cerri, C.C.

    2014-01-01

    Animal production systems are important sources of greenhouse gases (GHG), especially methane (CH4) and nitrous oxide (N2O). Brazilian beef production is almost exclusively (more than 90%) pasture-based. GHG emissions from faeces deposited in pastures have been extensively studied in temperate clima

  4. Methane emissions measured at two California landfills by OTM-10 and an acetylene tracer method

    Science.gov (United States)

    Methane emissions were measured at two municipal solid waste landfills in California using static flux chambers, an optical remote sensing approach known as vertical radial plume mapping (VRPM) using a tunable diode laser (TDL) and a novel acetylene tracer method. The tracer meth...

  5. Estimation of waste water treatment plant methane emissions: methodology and results from a short campaign

    Directory of Open Access Journals (Sweden)

    C. E. Yver-Kwok

    2013-10-01

    Full Text Available This paper describes different methods to estimate methane emissions at different scales. These methods are applied to a waste water treatment plant (WWTP located in Valence, France. We show that Fourier Transform Infrared (FTIR measurements as well as Cavity Ring Down Spectroscopy (CRDS can be used to measure emissions from the process to the regional scale. To estimate the total emissions, we investigate a tracer release method (using C2H2 and the Radon tracer method (using 222Rn. For process-scale emissions, both tracer release and chamber techniques were used. We show that the tracer release method is suitable to quantify facility- and some process-scale emissions, while the Radon tracer method encompasses not only the treatment station but also a large area around. Thus the Radon tracer method is more representative of the regional emissions around the city. Uncertainties for each method are described. Applying the methods to CH4 emissions, we find that the main source of emissions of the plant was not identified with certainty during this short campaign, although the primary source of emissions is likely to be from solid sludge. Overall, the waste water treatment plant represents a small part (3% of the methane emissions of the city of Valence and its surroundings,which is in agreement with the national inventories.

  6. Modeling of methane bubbles released from large sea-floor area: Condition required for methane emission to the atmosphere

    OpenAIRE

    Yamamoto, A.; Yamanaka, Y.; Tajika, E.

    2009-01-01

    Massive methane release from sea-floor sediments due to decomposition of methane hydrate, and thermal decomposition of organic matter by volcanic outgassing, is a potential contributor to global warming. However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from the sea-floor to reach the atmosphere. Massive methane release from a large sea-floor area would result in methane-saturated seawater, thus some methane would reach the atm...

  7. Modeling Methane Emission from Rice Paddy Soils:Ⅱ.Model Validation and Application

    Institute of Scientific and Technical Information of China (English)

    HUANGYAO; R.L.SASS; 等

    1999-01-01

    A simulation model developed by the authors(Huang et al.,1999) was validated against independent field measurements of methane emission from rice paddy soils in Texas of USA,Tuzu of China and Vercelli of Italy.A simplified version of the simulation model was further validated against methane emission measurements from various regions of the world including Italy,China,Indonesia,Philippines and the Unitewd States.Model validation suggested that the seasonal variation of methane emission was mainly regulated by rice growth and development and that methane emisson could be predicted from rice net productivity,cultivar character,soil texture and temperature,and organic matter amendments.Model simulations in general agreed with the observations.The compariosn between computed and measured methane emission resulted in correlation coefficients r2 values from 0.450 to 0.952,significant at 0.01-0.001 probability level.On the basis of available information on rice cultivated area.growth duration,grain yield,soil texture and temperature,methane emission from rice paddy soils of mainland China was estimated for 28 rice cultivated provinces /municipal cities by employing the validated model.The calculated daily methane emission rates,on a provincial scale,ranged from 0.12 to 0.71 g m-2 with an average of 0.26 g m-2,A total amount of 7.92Tg CH4 per year,raging from 5.89 to 11.17 Tg year-1,was estimated to be released from Chinese rice paddy soils.Of the total,45% was emitted from the single-rice growing season,and 19%and 36% were from the early-rice and the late-rice growing seasons,respectively.Approximately 70% of the total was emitted in the region located at latitude between 25° and 32°N.The emissions from rice fields in Sichuan and Hunan provinces were calculated to be 2.34 Tg year-1,accounting for approximately 30% of the total.

  8. Fugitive methane emissions from natural, urban, agricultural, and energy-production landscapes of eastern Australia

    Science.gov (United States)

    Kelly, Bryce F. J.; Iverach, Charlotte P.; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.

    2015-04-01

    Modern cavity ringdown spectroscopy systems (CRDS) enable the continuous measurement of methane concentration. This allows for improved quantification of greenhouse gas emissions associated with various natural and human landscapes. We present a subset of over 4000 km of continuous methane surveying along the east coast of Australia, made using a Picarro G2301 CRDS, deployed in a utility vehicle with an air inlet above the roof at 2.2 mAGL. Measurements were made every 5 seconds to a precision of coal mines, unconventional gas developments (coal seam gas; CSG), and leaks detected in cities and country towns. In areas of dryland crops the median methane concentration was 1.78 ppm, while in the irrigation districts located on vertisol soils the concentration was as low as 1.76 ppm, which may indicate that these soils are a sink for methane. In the Hunter Valley, New South Wales, open-cut coal mining district we mapped a continuous 50 km interval where the concentration of methane exceeded 1.80 ppm. The median concentration in this interval was 2.02 ppm. Peak readings were beyond the range of the reliable measurement (in excess of 3.00 ppm). This extended plume is an amalgamation of plumes from 17 major pits 1 to 10 km in length. Adjacent to CSG developments in the Surat Basin, southeast Queensland, only small anomalies were detected near the well-heads. Throughout the vast majority of the gas fields the concentration of methane was below 1.80 ppm. The largest source of fugitive methane associated with CSG was off-gassing methane from the co-produced water holding ponds. At one location the down wind plume had a cross section of approximately 1 km where the concentration of methane was above 1.80 ppm. The median concentration within this section was 1.82 ppm, with a peak reading of 2.11 ppm. The ambient air methane concentration was always higher in urban environments compared to the surrounding countryside. Along one major road in Sydney we mapped an interval that

  9. Application of portable gas detector in point and scanning method to estimate spatial distribution of methane emission in landfill.

    Science.gov (United States)

    Lando, Asiyanthi Tabran; Nakayama, Hirofumi; Shimaoka, Takayuki

    2017-01-01

    Methane from landfills contributes to global warming and can pose an explosion hazard. To minimize these effects emissions must be monitored. This study proposed application of portable gas detector (PGD) in point and scanning measurements to estimate spatial distribution of methane emissions in landfills. The aims of this study were to discover the advantages and disadvantages of point and scanning methods in measuring methane concentrations, discover spatial distribution of methane emissions, cognize the correlation between ambient methane concentration and methane flux, and estimate methane flux and emissions in landfills. This study was carried out in Tamangapa landfill, Makassar city-Indonesia. Measurement areas were divided into basic and expanded area. In the point method, PGD was held one meter above the landfill surface, whereas scanning method used a PGD with a data logger mounted on a wire drawn between two poles. Point method was efficient in time, only needed one person and eight minutes in measuring 400m(2) areas, whereas scanning method could capture a lot of hot spots location and needed 20min. The results from basic area showed that ambient methane concentration and flux had a significant (pmethane emissions in the expanded area by using Kriging method. The average of estimated flux from scanning method was 71.2gm(-2)d(-1) higher than 38.3gm(-2)d(-1) from point method. Further, scanning method could capture the lower and higher value, which could be useful to evaluate and estimate the possible effects of the uncontrolled emissions in landfill.

  10. Bottom-up simulations of methane and ethane emissions from global oil and gas systems 1980 to 2012

    Science.gov (United States)

    Höglund-Isaksson, Lena

    2017-02-01

    Existing bottom-up emission inventories of methane from global oil and gas systems do not satisfactorily explain year-on-year variation in atmospheric methane estimated by top-down models. Using a novel bottom-up approach this study quantifies and attributes methane and ethane emissions from global oil and gas production from 1980 to 2012. Country-specific information on associated gas flows from published sources are combined with inter-annual variations in observed flaring of associated gas from satellite images from 1994 to 2010, to arrive at country-specific annual estimates of methane and ethane emissions from flows of associated gas. Results confirm trends from top-down models and indicate considerably higher methane and ethane emissions from oil production than previously shown in bottom-up inventories for this time period.

  11. Reduction of ruminant methane emissions - a win-win-win opportunity for business, development, and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, R. [Appropriate Technology International, Washington, DC (United States)

    1997-12-31

    This paper describes research efforts of The Global Livestock Producers Program (GLPP) in establishing self-sustaining enterprises for cost-effective technologies (i.e., animal nutrition and genetic improvement) and global methane emissions reductions in developing world nations. The US Environmental Protection Agency has funded several studies to examine the possibilities of reducing ruminant methane emissions in India, Tanzania, Bangladesh, and Brazil. The results of the studies showed that: (1) many developing countries` production systems are inefficient, and (2) great potential exists for decreasing global methane emissions through increasing animal productivity. From this effort, the GLPP established livestock development projects in India, Zimbabwe, and Tanzania, and is developing projects for Bangladesh, Nepal, and Brazil. The GLPP has developed a proven methodology for assessing ruminant methane and incorporating methane emissions monitoring into viable projects.

  12. Methane emissions proportional to permafrost carbon thawed in Arctic lakes since the 1950s

    Science.gov (United States)

    Walter Anthony, Katey; Daanen, Ronald; Anthony, Peter; Schneider von Deimling, Thomas; Ping, Chien-Lu; Chanton, Jeffrey P.; Grosse, Guido

    2016-09-01

    Permafrost thaw exposes previously frozen soil organic matter to microbial decomposition. This process generates methane and carbon dioxide, and thereby fuels a positive feedback process that leads to further warming and thaw. Despite widespread permafrost degradation during the past ~40 years, the degree to which permafrost thaw may be contributing to a feedback between warming and thaw in recent decades is not well understood. Radiocarbon evidence of modern emissions of ancient permafrost carbon is also sparse. Here we combine radiocarbon dating of lake bubble trace-gas methane (113 measurements) and soil organic carbon (289 measurements) for lakes in Alaska, Canada, Sweden and Siberia with numerical modelling of thaw and remote sensing of thermokarst shore expansion. Methane emissions from thermokarst areas of lakes that have expanded over the past 60 years were directly proportional to the mass of soil carbon inputs to the lakes from the erosion of thawing permafrost. Radiocarbon dating indicates that methane age from lakes is nearly identical to the age of permafrost soil carbon thawing around them. Based on this evidence of landscape-scale permafrost carbon feedback, we estimate that 0.2 to 2.5 Pg permafrost carbon was released as methane and carbon dioxide in thermokarst expansion zones of pan-Arctic lakes during the past 60 years.

  13. Prediction of methane emissions during the extraction of close-to-roof layer of a seam of large thickness

    Institute of Scientific and Technical Information of China (English)

    KRAUSE Eugeniusz; QU Xian-chao

    2012-01-01

    Prediction of methane emissions at the stage of longwall planning constitutes the basis for the determination of the appropriate method and parameters of ventilation and selection of prevention means including the methane drainage technology.The growth of methane saturation of coal seams with the extraction depth,with simultaneously increasing output concentration,contributes to the increase of the quantity of methane emitted into longwall areas.The subject matter of the article has been directed at the predicted quantity of methane emissions into planned longwalls with roof caving in the layer of seams adjacent to the roof of large thickness.The performed prognostic calculations of methane emissions into the longwall working were referred to two sources,i.e.methane liberated during coal mining by means of a cutter-loader and methane originating from the degasification of the floor layer destressed by the longwall conducted in the close-to-roof layer.The calculations of predictions allow to refer to the planned longwall,on account of the emitting methane,with possible and safe output quantity.Planning of extraction in the close-to-roof layer of a seam of large thickness with roof caving is especially important in conditions of increasing methane saturation with the depth of deposition and should be preceded by a prognostic analysis for determining the extraction possibilities of the planned longwall.

  14. Interactive effects of temperature and UVB radiation on methane emissions from different organs of pea plants grown in hydroponic system.

    Science.gov (United States)

    Abdulmajeed, Awatif M; Derby, Samantha R; Strickland, Samantha K; Qaderi, Mirwais M

    2017-01-01

    There is no information on variation of methane (CH4) emissions from plant organs exposed to multiple environmental factors. We investigated the interactive effects of temperature and ultraviolet-B (UVB) radiation on CH4 emissions from different organs of pea (Pisum sativum L. var. UT234 Lincoln). Plants were grown hydroponically under two temperatures (22/18°C and 28/24°C; 16h day/8h night) and two levels of UVB radiation [0 and 5kJm(-2) d(-1)] in controlled-environment growth chambers for ten days, after two weeks of initial growth under ambient temperatures. Methane emission, dry mass, growth index, electrical conductivity (EC), pectin, total chlorophyll content, gas exchange and flavonoids were measured in the appropriate plant organs - leaf, stem and root. Higher temperatures increased CH4 emissions, leaf mass ratio, and shoot: root mass ratio. Neither temperature nor UVB had significant effects on leaf, stem, root and total dry mass, EC, pectin, total chlorophyll, as well as specific leaf mass. Among plant organs, there were differences in CH4, EC, pectin and total chlorophyll. Methane and EC were highest for the stem and lowest for the leaf; leaf had highest, but stem had lowest, pectin content; total chlorophyll was highest in the leaf but lowest in the root. Higher temperatures decreased leaf flavonoids, net carbon dioxide assimilation, and water use efficiency. Overall, environmental stressors increased aerobic CH4 emission rates, which varied with plant organs. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Separating methane emissions from biogenic sources and natural gas by vertical column enhancements of ammonia, ethane, and methane in the Colorado Front Range

    Science.gov (United States)

    Chiu, R.; Volkamer, R. M.; Blumenstock, T.; Hase, F.; Hannigan, J. W.; Kille, N.; Frey, M.; Kumar Sha, M.; Orphal, J.

    2015-12-01

    Methane sources in the Colorado Front Range include biogenic sources from cattle feedlots and natural gas operations. Although numerous studies have measured methane emissions, there remains significant uncertainty regarding the relative contributions of these various methane emission sources. Here we present data from a March 2015 field campaign that deployed two Bruker EM27 Sun Fourier Transform Spectrometers (FTS) and the University of Colorado Solar Occultation Flux (CU-SOF) FTS in Eaton, Colorado; the former were used to measure enhancements in the methane vertical column densities (VCD), while the latter was used to measure ethane and ammonia VCDs. A third EM27 FTS was deployed to a background site in Westminster, Colorado which was far removed from cattle and petroleum operations. Northerly winds make possible the determination of methane VCD column enhancement from Westminster to Eaton. All instruments were compared during several background days at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. This presentation explores the potential of methane source attribution using ammonia as a tracer for feedlot emissions and ethane as a tracer for petroleum emissions.

  16. Methane emission from naturally ventilated livestock buildings can be determined from gas concentration measurements.

    Science.gov (United States)

    Bjerg, Bjarne; Zhang, Guoqiang; Madsen, Jørgen; Rom, Hans B

    2012-10-01

    Determination of emission of contaminant gases as ammonia, methane, or laughing gas from natural ventilated livestock buildings with large opening is a challenge due to the large variations in gas concentration and air velocity in the openings. The close relation between calculated animal heat production and the carbon dioxide production from the animals have in several cases been utilized for estimation of the ventilation air exchange rate for the estimation of ammonia and greenhouse gas emissions. Using this method, the problem of the complicated air velocity and concentration distribution in the openings is avoided; however, there are still some important issues remained unanswered: (1) the precision of the estimations, (2) the requirement for the length of measuring periods, and (3) the required measuring point number and location. The purpose of this work was to investigate how estimated average gas emission and the precision of the estimation are influenced by different calculation procedures, measuring period length, measure point locations, measure point numbers, and criteria for excluding measuring data. The analyses were based on existing data from a 6-day measuring period in a naturally ventilated, 150 milking cow building. The results showed that the methane emission can be determined with much higher precision than ammonia or laughing gas emissions, and, for methane, relatively precise estimations can be based on measure periods as short as 3 h. This result makes it feasible to investigate the influence of feed composition on methane emission in a relative large number of operating cattle buildings and consequently it can support a development towards reduced greenhouse gas emission from cattle production.

  17. Correlating Well-Pad Characteristics and Methane Emissions in the Marcellus Shale

    Science.gov (United States)

    Lu, J.; Caulton, D.; Lane, H.; Stanton, L. G.; Zondlo, M. A.

    2015-12-01

    Methane leaks from petrochemical activity are significant contributors to the total amount of methane in the atmosphere. While natural gas has been praised as a cleaner source of fuel than coal, methane's potent global-warming potential could pose barriers in reducing greenhouse gas footprints if significant leaks are observed from the natural gas supply chain. A field campaign spanning two and a half weeks was undertaken in July 2015 to quantify the levels of methane emitted from sites of petrochemical activity in the Marcellus Shale. Additional campaigns are expected in late 2015 and early 2016. Measurements of methane and carbon dioxide were taken downwind of known well sites using open-path laser spectroscopy mounted to the roof of the mobile platform. Approximately 250 well sites were visited, covering over 2000 miles on the road. The majority of the well pads were in southwestern Pennsylvania, but the compiled database includes wells in West Virginia and northeastern Pennsylvania. The data set consists of a variety of operators and equipment types spread over several counties. Correlating well pad characteristics with emission levels may provide useful insight into predicting which well pads are likely to be large emitters. Using the inverse Gaussian plume model and meteorology data from the NOAA Ready archive, the emissions from each transect were calculated. Preliminary results were examined with respect to two easily identifiable variables: the number of wells at each well pad and the operator. Higher emissions were not correlated with increased number of wells, despite the fact that additional infrastructure may provide additional leak pathways. In fact, the emission levels for pads with only a singular well, which accounted for nearly 70% of the wells analyzed thus far, had a range of 0 to 9 grams of methane per second. Sites with two or more wells tended to be concentrated on the lower end of the distribution. Higher emissions were also distributed

  18. Physical injury stimulates aerobic methane emissions from terrestrial plants

    Directory of Open Access Journals (Sweden)

    Z.-P. Wang

    2009-04-01

    Full Text Available Physical injury is common in terrestrial plants as a result of grazing, harvesting, trampling, and extreme weather events. Previous studies demonstrated enhanced emission of non-microbial CH4 under aerobic conditions from plant tissues when they were exposed to increasing UV radiation and temperature. Since physical injury is also a form of environmental stress, we sought to determine whether it would also affect CH4 emissions from plants. Physical injury (cutting stimulated CH4 emission from fresh twigs of Artemisia species under aerobic conditions. More cutting resulted in more CH4 emissions. Hypoxia also enhanced CH4 emission from both uncut and cut Artemisia frigida twigs. Physical injury typically results in cell wall degradation, which may either stimulate formation of reactive oxygen species (ROS or decrease scavenging of them. Increased ROS activity might explain increased CH4 emission in response to physical injury and other forms of stress. There were significant differences in CH4 emissions among 10 species of Artemisia, with some species emitting no detectable CH4 under any circumstances. Consequently, CH4 emissions may be species-dependent and therefore difficult to estimate in nature based on total plant biomass. Our results and those of previous studies suggest that a variety of environmental stresses stimulate CH4 emission from a wide variety of plant species. Global change processes, including climate change, depletion of stratospheric ozone, increasing ground-level ozone, spread of plant pests, and land-use changes, could cause more stress in plants on a global scale, potentially stimulating more CH4 emission globally.

  19. Nitrogen deposition effects on carbon dioxide and methane emissions from temperate peatland soils

    Energy Technology Data Exchange (ETDEWEB)

    Aerts, Rien; Caluwe, Hannie de [Utrecht Univ., Dept. of Plant Ecology and Evolutionary Biology, Utrecht (Norway)

    1999-04-01

    Northern peatlands are important sources of carbon dioxide and methane emissions to the atmosphere. Increased atmospheric N deposition may have a significant impact on the emission of these greenhouse gases. We studied CO{sub 2} and CH{sub 4} emissions from untreated peat soils from a eutrophic and a mesotrophic fen in a high N deposition area (the Netherlands) and from a mesotrophic fen in a low N deposition area (north-east Poland). In addition, we investigated the effects of N, P and glucose amendments on the emissions of CO{sub 2} and CH{sub 4} from these soils. Nitrogen availability (extractable NH{sub 4}) in untreated peat from the high N area was 2.5-7.5 times higher than in the low N area, whereas the pH was 0.9-1.7 units lower. Using 6-week laboratory incubations of peat columns, we found that mean dayly CO{sub 2} emission from untreated peat soils from the high N area was lower than that from the low N area. Both linear and multiple regression analysis showed that CO{sub 2} emission was positively related to soil pH (r{sup 2}=0.64). Additional N supply led to pH reduction and to lower CO{sub 2} emission, especially in the low N peat soils. Thus, increased atmospheric N deposition leads, probably as a result of soil acidification, to lower CO{sub 2} emission. Although glucose amendments resulted in increase CO{sub 2} and CH{sub 4} emission, we did not find evidence that this was caused by increase mineralization of native peat. Mean daily CH{sub 4}-C emission was about 1-2 orders of magnitude lower than mean daily CO{sub 2}-C emission. In the untreated peat soils from the high N eutrophic site, methane emission was higher than in the high N mesotrophic site and in the low N mesotrophic site. Linear regression analysis showed a positive relation between methane emission and soil fertility variables (r{sup 2}=0.42-0.55), whereas a multiple regression model revealed that methane emission was determined by N-related soil chemistry variable (r{sup 2

  20. A High-Speed Continuous Recording High Flow Gas Sampler for Measuring Methane Emissions from Pneumatic Devices at Oil and Natural Gas Production Facilities

    Science.gov (United States)

    Ferrara, T.; Howard, T. M.

    2016-12-01

    Studies attempting to reconcile facility level emission estimates of sources at oil and gas facilities with basin wide methane flux measurements have had limited success. Pneumatic devices are commonly used at oil and gas production facilities for process control or liquid pumping. These devices are powered by pressurized natural gas from the well, so they are known methane sources at these sites. Pneumatic devices are estimated to contribute 14% to 25% of the total greenhouse gas emissions (GHG) from production facilities. Measurements of pneumatic devices have shown that malfunctioning or poorly maintained control systems may be emitting significantly more methane than currently estimated. Emission inventories for these facilities use emission factors from EPA that are based on pneumatic device measurements made in the early 1990's. Recent studies of methane emissions from production facilities have attempted to measure emissions from pneumatic devices by several different methods. These methods have had limitations including alteration of the system being measured, the inability to distinguish between leaks and venting during normal operation, or insufficient response time to account of the time based emission events. We have developed a high speed recording high flow sampler that is capable of measuring the transient emissions from pneumatic devices. This sampler is based on the well-established high flow measurement technique used in oil and gas for quantifying component leak rates. In this paper we present the results of extensive laboratory controlled release testing. Additionally, test data from several field studies where this sampler has been used to measure pneumatic device emissions will be presented.

  1. Heritability estimates for methane emission in Holstein cows using breath measurements

    DEFF Research Database (Denmark)

    Lassen, Jan; Madsen, Jørgen; Løvendahl, Peter

    2012-01-01

    cows. On a total of 683 dairy cows a Fourier Transformed Infrared (FTIR) measuring unit was used to make large scale individual methane emission records. The cows were measured in 7 herds during their visits to automatic milking systems (AMS). The FTIR unit air inlet was mounted in the front part...... model included fixed effects of herd, month, days in milk, lactation number, and random effects of animal and residual. Variance components were estimated in an animal model design using a pedigree containing 9661 animals. The heritability of the methane to carbon dioxide ratio was moderate (0...

  2. Genetic and phenotypic variance and covariance components for methane emission and postweaning traits in Angus cattle.

    Science.gov (United States)

    Donoghue, K A; Bird-Gardiner, T; Arthur, P F; Herd, R M; Hegarty, R F

    2016-04-01

    Ruminants contribute 80% of the global livestock greenhouse gas (GHG) emissions mainly through the production of methane, a byproduct of enteric microbial fermentation primarily in the rumen. Hence, reducing enteric methane production is essential in any GHG emissions reduction strategy in livestock. Data on 1,046 young bulls and heifers from 2 performance-recording research herds of Angus cattle were analyzed to provide genetic and phenotypic variance and covariance estimates for methane emissions and production traits and to examine the interrelationships among these traits. The cattle were fed a roughage diet at 1.2 times their estimated maintenance energy requirements and measured for methane production rate (MPR) in open circuit respiration chambers for 48 h. Traits studied included DMI during the methane measurement period, MPR, and methane yield (MY; MPR/DMI), with means of 6.1 kg/d (SD 1.3), 132 g/d (SD 25), and 22.0 g/kg (SD 2.3) DMI, respectively. Four forms of residual methane production (RMP), which is a measure of actual minus predicted MPR, were evaluated. For the first 3 forms, predicted MPR was calculated using published equations. For the fourth (RMP), predicted MPR was obtained by regression of MPR on DMI. Growth and body composition traits evaluated were birth weight (BWT), weaning weight (WWT), yearling weight (YWT), final weight (FWT), and ultrasound measures of eye muscle area, rump fat depth, rib fat depth, and intramuscular fat. Heritability estimates were moderate for MPR (0.27 [SE 0.07]), MY (0.22 [SE 0.06]), and the RMP traits (0.19 [SE 0.06] for each), indicating that genetic improvement to reduce methane emissions is possible. The RMP traits and MY were strongly genetically correlated with each other (0.99 ± 0.01). The genetic correlation of MPR with MY as well as with the RMP traits was moderate (0.32 to 0.63). The genetic correlation between MPR and the growth traits (except BWT) was strong (0.79 to 0.86). These results indicate that

  3. Emission Flux and Carbon Isotopic Composition of Methane from Rice Paddies in Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    李金华; 曹景蓉; 等

    1997-01-01

    Methane emission flux from rice paddies in Guizhou province shows obvious three stage diurnal variations;It is relatively low from the morning to the noon,then successively increases in the afternoon and at night,and finally follows a gradual decrease.The δ13C values of trace methane emitted from rice paddies in Guizhou Province range from-64.5‰to -54.1‰ with an average of -60.7‰,very close to the reported values from America or Kenya.

  4. Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling

    Directory of Open Access Journals (Sweden)

    A. Budishchev

    2014-09-01

    Full Text Available Most plot-scale methane emission models – of which many have been developed in the recent past – are validated using data collected with the closed-chamber technique. This method, however, suffers from a low spatial representativeness and a poor temporal resolution. Also, during a chamber-flux measurement the air within a chamber is separated from the ambient atmosphere, which negates the influence of wind on emissions. Additionally, some methane models are validated by upscaling fluxes based on the area-weighted averages of modelled fluxes, and by comparing those to the eddy covariance (EC flux. This technique is rather inaccurate, as the area of upscaling might be different from the EC tower footprint, therefore introducing significant mismatch. In this study, we present an approach to validate plot-scale methane models with EC observations using the footprint-weighted average method. Our results show that the fluxes obtained by the footprint-weighted average method are of the same magnitude as the EC flux. More importantly, the temporal dynamics of the EC flux on a daily timescale are also captured (r2 = 0.7. In contrast, using the area-weighted average method yielded a low (r2 = 0.14 correlation with the EC measurements. This shows that the footprint-weighted average method is preferable when validating methane emission models with EC fluxes for areas with a heterogeneous and irregular vegetation pattern.

  5. A prediction equation for enteric methane emission from dairy cows for use in NorFor

    DEFF Research Database (Denmark)

    Nielsen, N I; Volden, H; Åkerlind, M;

    2013-01-01

    A data-set with 47 treatment means (N = 211) was compiled from research institutions in Denmark, Norway, and Sweden in order to develop a prediction equation for enteric methane (CH4) emissions from dairy cows. The aim was to implement the equation in the Nordic feed evaluation system Nor...... enteric methane emissions is uncertain until evaluated on an independent data-set....... emission. Based on the present research, we concluded, therefore, that the equation CH4 = 1.23 (±0.08) × DMI – 0.145 (±0.039) × FA + 0.012 (±0.005) × NDF (RMSE = 3.10 MJ CH4/d; CV = 14.3%; R2 = 0.75) is most suited for being implemented in NorFor. However, the ability of the proposed equation to predict...

  6. Design and evaluation of a porous burner for the mitigation of anthropogenic methane emissions.

    Science.gov (United States)

    Wood, Susie; Fletcher, David F; Joseph, Stephen D; Dawson, Adrian; Harris, Andrew T

    2009-12-15

    Methane constitutes 15% of total global anthropogenic greenhouse gas emissions. The mitigation of these emissions could have a significant near-term effect on slowing global warming, and recovering and burning the methane would allow a wasted energy resource to be exploited. The typically low and fluctuating energy content of the emission streams makes combustion difficult; however porous burners-an advanced combustion technology capable of burning low-calorific value fuels below the conventional flammability limit-are one possible mitigation solution. Here we discuss a pilot-scale porous burner designed for this purpose. The burner comprises a cylindrical combustion chamber filled with a porous bed of alumina saddles, combined with an arrangement of heat exchanger tubes for preheating the incoming emission stream. A computational fluid dynamics model was developed to aid in the design process. Results illustrating the burner's stable operating range and behavior are presented: stable ultralean combustion is demonstrated at natural gas concentrations as low as 2.3 vol%, with transient combustion at concentrations down to 1.1 vol%; the system is comparatively stable to perturbations in the operating conditions, and emissions of both carbon monoxide and unburned hydrocarbons are negligible. Based on this pilot-scale demonstration, porous burners show potential as a methane mitigation technology.

  7. Assessing Wetland Methane Emission Changes in the Conterminous U.S. from 1973 to 2010

    Science.gov (United States)

    Liu, J.; Zhu, Z.; Sleeter, B. M.; Zhu, Q.; Soulard, C. E.

    2014-12-01

    Climate and human land use are the main drivers of terrestrial ecosystem methane (CH4) emissions. Wetland expansion and contraction, methane production and release, as well as the interactions of methane with the carbon cycle, are processes critical to the examination of climate change mitigation strategies. This study uses the parallel Integrated Biosphere Simulator (pIBIS) and the State-and-Transition Simulation Model (ST-Sim) to simulate the climate-driven and land-use-driven CH4 emissions in the U.S. from 1973 to 2010. The ST-Sim model is used to backcast annual historical wetland cover from 2010 to 1973 based on recent baseline wetland maps (i.e. National Land Cover Dataset and National Wetland Inventory), historical land cover change trends, and probabilistic spatial multipliers. The pIBIS model is used to simulate the change of wetland water table depth and the production, oxidation, and transportation processes of CH4. Simulations are performed at 1-km spatial resolution using Department of Energy super-computing resources. Post-simulation programs are developed to analyze the spatial distribution and temporal trends of CH4 emissions in relation to inter-annual wetland area variation and climate (rainfall and temperature) variation. Relationships between CH4 emission and carbon sequestration and CO2 emission are also analyzed. Keywords: climate change, land cover change, land use change, greenhouse gas, biogeochemical model

  8. Emissions of greenhouse gases (methane and nitrous oxide) from cattle slurry storage in Northern Europe

    Science.gov (United States)

    Rodhe, L.; Ascue, J.; Nordberg, Å.

    2009-11-01

    Total greenhouse gas (GHG) emissions from stored manure corresponded to 14% of overall GHG emissions from Swedish agriculture in 2006 according to calculations using standard values for a cool climate. The present study identified storage conditions for cattle slurry in different regions of Sweden, developed methodology for measuring GHGs from slurry stored under similar conditions to full-scale storage, and determined annual GHG emissions (methane and nitrous oxide) from stored cattle slurry under Swedish conditions. Temperature measurements in full-scale storage of cattle slurry on farms showed a mean annual slurry temperature of 9.7°C in south-west Sweden and 5.6°C in the north. The closed chamber methodology and equipment developed for measuring GHG emissions were implemented for one year in a pilot-scale plant with similar conditions to full-scale storage as regards slurry temperature, climate and filling/emptying routines. During winter (Oct-April), methane emissions from stored cattle slurry were 3.6 g CH4-C per kg VS, while during summer (May-Sept) they were 6.5 g CH4-C per kg VS. This corresponded to an annual methane conversion factor (MCF) of 2.7%. Losses of nitrous oxide were close to zero.

  9. A correction in the CDM methodological tool for estimating methane emissions from solid waste disposal sites.

    Science.gov (United States)

    Santos, M M O; van Elk, A G P; Romanel, C

    2015-12-01

    Solid waste disposal sites (SWDS) - especially landfills - are a significant source of methane, a greenhouse gas. Although having the potential to be captured and used as a fuel, most of the methane formed in SWDS is emitted to the atmosphere, mainly in developing countries. Methane emissions have to be estimated in national inventories. To help this task the Intergovernmental Panel on Climate Change (IPCC) has published three sets of guidelines. In addition, the Kyoto Protocol established the Clean Development Mechanism (CDM) to assist the developed countries to offset their own greenhouse gas emissions by assisting other countries to achieve sustainable development while reducing emissions. Based on methodologies provided by the IPCC regarding SWDS, the CDM Executive Board has issued a tool to be used by project developers for estimating baseline methane emissions in their project activities - on burning biogas from landfills or on preventing biomass to be landfilled and so avoiding methane emissions. Some inconsistencies in the first two IPCC guidelines have already been pointed out in an Annex of IPCC latest edition, although with hidden details. The CDM tool uses a model for methane estimation that takes on board parameters, factors and assumptions provided in the latest IPCC guidelines, while using in its core equation the one of the second IPCC edition with its shortcoming as well as allowing a misunderstanding of the time variable. Consequences of wrong ex-ante estimation of baseline emissions regarding CDM project activities can be of economical or environmental type. Example of the first type is the overestimation of 18% in an actual project on biogas from landfill in Brazil that harms its developers; of the second type, the overestimation of 35% in a project preventing municipal solid waste from being landfilled in China, which harms the environment, not for the project per se but for the undue generated carbon credits. In a simulated landfill - the same

  10. The estimation of methane emissions from landfills with different cover systems

    Science.gov (United States)

    Park, S.; Lee, K.; Sung, K.

    2006-12-01

    Methane is a very potent greenhouse gas, second only to CO2 as an anthropogenic contributor to global warming. Landfills are important anthropogenic source in the CH4 emissions. Microbially mediated CH4 oxidation in landfills with conventional soil covers can serve as an efficient biological sink. Methane from modern sanitary landfills equipped with composite covers and gas collection system is vented directly to the atmosphere, except for some of the largest landfills at which it is collected and burned. However, previous laboratory research has shown that biofilters have the potential to reduce CH4 emissions from landfills with modern composite covers. In this study a CH4 emission model was developed. The model used the calculated CH4 oxidation rates to estimate CH4 emissions from landfills constructed with conventional soil covers, modern composite covers, and modern composite covers plus biofilters. According to the CH4 emission rates predicted by CH4 emission model, it was estimated that 90% of the generated CH4 was emitted to the atmosphere for landfills with modern composite cover. For landfills with modern composite cover plus biofilters, an average of only 9% of the generated CH4 was estimated to be emitted. For landfills with conventional covers, an average of 83% of the generated CH4 was estimated to be emitted. By comparing the CH4 emission rates from three different landfill types, the use of a properly managed biofilter should be an effective technique to reduce CH4 emissions from landfills.

  11. Geological emission of methane from the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    TANG Junhong; BAO Zhengyu; XIANG Wu; GOU Qinghong

    2008-01-01

    A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.

  12. Hydrogen stable isotopic constraints on methane emissions from oil and gas extraction in the Colorado Front Range, USA

    Science.gov (United States)

    Townsend-Small, A.; Botner, E. C.; Jimenez, K.; Blake, N. J.; Schroeder, J.; Meinardi, S.; Barletta, B.; Simpson, I. J.; Blake, D. R.; Flocke, F. M.; Pfister, G.; Bon, D.; Crawford, J. H.

    2015-12-01

    The climatic implications of a shift from oil and coal to natural gas depend on the magnitude of fugitive emissions of methane from the natural gas supply chain. Attempts to constrain methane emissions from natural gas production regions can be confounded by other sources of methane. Here we demonstrate the utility of stable isotopes, particularly hydrogen isotopes, for source apportionment of methane emissions. The Denver, Colorado area is home to a large oil and gas field with both conventional oil and gas wells and newer hydraulic fracturing wells. The region also has a large metropolitan area with several landfills and a sizable cattle population. As part of the DISCOVER-AQ and FRAPPE field campaigns in summer 2014, we collected three types of canister samples for analysis of stable isotopic composition of methane: 1), samples from methane sources; 2), samples from two stationary ground sites, one in the Denver foothills, and one in an oil and gas field; and 3), from the NCAR C-130 aircraft in samples upwind and downwind of the region. Our results indicate that hydrogen isotope ratios are excellent tracers of sources of methane in the region, as we have shown previously in California and Texas. Use of carbon isotope ratios is complicated by the similarity of natural gas isotope ratios to that of background methane. Our results indicate that, despite the large amount of natural gas production in the region, biological sources such as cattle feedlots and landfills account for at least 50% of total methane emissions in the Front Range. Future work includes comparison of isotopes and alkane ratios as tracers of methane sources, and calculation of total methane fluxes in the region using continuous measurements of methane concentrations during aircraft flights.

  13. A UAV-based gas sensing system for detecting fugitive methane emissions

    Science.gov (United States)

    Hugenholtz, C.; Barchyn, T.; Myshak, S.; Bauer, J.

    2016-12-01

    Methane is one of the most prevalent greenhouse gases emitted by human activities and is a major component of government-led initiatives to reduce GHG emissions in Canada, the USA, and elsewhere. In light of growing demand for measurements and verification of atmospheric methane concentration across the oil and gas supply chain, an autonomous airborne gas sensing system was developed that combines a small UAV and a lightweight gas monitor. This paper outlines the technology, analytics, and presents data from a case study to demonstrate the proof of concept. The UAV is a fixed-wing (2.2 m wingspan), battery-operated platform, with a flight endurance of 80-120 minutes. The gas sensor onboard the UAV is a tunable diode laser absorption spectrometer that uses an integrated transmitter/receiver unit and a remote, passive retro-reflector. The transmitter is attached to one of the winglets, while the other is coated with reflective material. The total weight of the UAV and gas sensor is 4.3 kg. During flight, the system operates autonomously, acquiring averages of raw measurements at 1 Hz, with a recorded resolution of 0.0455 ppm. The onboard measurement and control unit (MCU) for the gas sensor is integrated with the UAV autopilot in order to provide time-stamped and geotagged concentration measurements, and to provide real-time flight adjustments when concentration exceeds a pre-determined threshold. The data are retrieved from the MCU when the mission is complete. In order to demonstrate the proof of concept, we present results from a case study and outline opportunities for translating the measurements into decision making.

  14. Energy partitioning and methane emission by sheep fed sorghum silages at different maturation stages

    Directory of Open Access Journals (Sweden)

    F.S. Machado

    2015-06-01

    Full Text Available Energy partitioning and methane production by sheep fed silages of three commercially available sorghum hybrids (BRS 610, BR 700 and BRS 655 harvested at three maturation stages (milk, soft dough and floury were evaluated in open circuit respiration chambers. A complete randomized design was used in a 3 × 3 (hybrids × maturity stages factorial arrangement, and the means were compared by the Student-Newman-Keuls (SNK test (P0.10 among the treatments for the apparent digestibility of gross energy and metabolizability (qm. An interaction (P0.10 among treatments occurred in the daily methane production. There is substantial genetic diversity within sorghum species, determining different nutritional values. Sorghum genetics and maturity at harvest should not be an opportunity to reduce the contribution of agriculture to methane emissions.

  15. Utilization of stabilized wastes for reducing methane emission from municipal solid waste disposal.

    Science.gov (United States)

    Chiemchaisri, Wilai; Chiemchaisri, Chart; Boonchaiyuttasak, Jindaruch

    2013-08-01

    Stabilized solid wastes were utilized to mitigate methane emission from the landfill. Loose texture of plastic wastes encouraged air diffusion from the soil surface whereas fine organic fraction has good water holding capacity and nutrients to stimulate methane oxidation reaction. Biological methane oxidation capacity in stabilized waste layer was found to be up to 34.1 g/m(3)d. Microbial activity test revealed methanotrophic activities of plastic and degraded organic wastes were in the same order. The mixture of plastic and fine degraded organic waste matrix provided sufficient porosity for oxygen transfer and supported the growth of methanotrophs throughout 0.8m depth of waste layer. Fluorescent in situ hybridization (FISH) analysis confirmed the presence of methanotrophs and their population was found varied along waste depth.

  16. Mitigation strategies for methane emissions from agricultural sources

    Energy Technology Data Exchange (ETDEWEB)

    Duxbury, J.M. [Cornell Univ., Ithaca, NY (United States)

    1993-12-31

    Anthropogenic emissions of CH{sub 4} account for 70% of total global emissions of this greenhouse gas. Current anthropogenic emissions of CH{sub 4} in the US are estimated to be between 24-30 Tg CH{sub 4} or 7-9% of the global anthropogenic total. By comparison the US is responsible for 27% of anthropogenic emissions of CO{sub 2} from fossil fuel use. Table 1 shows that the major anthropogenic sources of CH{sub 4} in the US are landfills (37%), domestic livestock and livestock waste (31%) and the coal mining/natural gas/petroleum industries (28%). On a global basis it is estimated that US landfills contribute 30% to the global landfill total, whereas livestock (including waste) and the coal mining/natural gas/petroleum industries each contribute about 8% to their respective global totals. The US is an insignificant contributor (< 1%) to global emissions of CH{sub 4} from rice paddies.

  17. Methane emissions from the upwelling area off Mauritania (NW Africa

    Directory of Open Access Journals (Sweden)

    A. Kock

    2008-08-01

    Full Text Available Coastal upwelling regions have been identified as sites of enhanced CH4 emissions to the atmosphere. The coastal upwelling area off Mauritania (NW Africa is one of the most biologically productive regions of the world's ocean but its CH4 emissions have not been quantified so far. More than 1000 measurements of atmospheric and dissolved CH4 in the surface layer in the upwelling area off Mauritania were performed as part of the German SOPRAN (Surface Ocean Processes in the Anthropocene study during two cruises in March/April 2005 (P320/1 and February 2007 (P348. During P348 enhanced CH4 saturations of up to 200% were found close to the coast and were associated with upwelling of South Atlantic Central Water. An area-weighted, seasonally adjusted estimate yielded overall annual CH4 emissions in the range from 1.6 to 2.9 Gg CH4. Thus the upwelling area off Mauritania represents a regional hot spot of CH4 emissions but seems to be of minor importance for the global oceanic CH4 emissions.

  18. Emission control system

    Science.gov (United States)

    Parrish, Clyde F. (Inventor); Chung, J. Landy (Inventor)

    2009-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

  19. Estimation of methane and nitrous oxide emissions from rice field with rice straw management in Cambodia.

    Science.gov (United States)

    Vibol, S; Towprayoon, S

    2010-02-01

    To estimate the greenhouse gas emissions from paddy fields of Cambodia, the methodology of the Intergovernmental Panel on Climate Change (IPCC) guidelines, IPCC coefficients, and emission factors from the experiment in Thailand and another country were used. Total area under rice cultivation during the years 2005-2006 was 2,048,360 ha in the first crop season and 298,529 ha in the second crop season. The emission of methane from stubble incorporation with manure plus fertilizer application areas in the first crop season was estimated to be 192,783.74 ton higher than stubble with manure, stubble with fertilizer, and stubble without fertilizer areas. The fields with stubble burning emitted the highest emission of methane (75,771.29 ton) followed by stubble burning with manure (22,251.08 ton), stubble burning with fertilizer (13,213.27 ton), and stubble burning with fertilizer application areas (3,222.22 ton). The total emission of methane from rice field in Cambodia for the years 2005-2006 was approximately 342,649.26 ton (342.65 Gg) in the first crop season and 36,838.88 ton (36.84 Gg) in the second crop season. During the first crop season in the years 2005-2006, Battambang province emitted the highest amount of CH(4) (38,764.48 ton) and, in the second crop season during the years 2005-2006, the highest emission (8,262.34 ton) was found in Takeo province (8,262.34 ton). Nitrous oxide emission was between 2.70 and 1,047.92 ton in the first crop season and it ranged from 0 to 244.90 ton in the second crop season. Total nitrous oxide emission from paddy rice field was estimated to be 9,026.28 ton in the first crop season and 1,091.93 ton in the second crop season. Larger area under cultivation is responsible for higher emission of methane and nitrous oxide. Total emission of nitrous oxide by using IPCC default emission coefficient was approximately 2,328.85 ton. The total global warming potential of Cambodian paddy rice soil is 11,723,217.03 ton (11,723 Gg

  20. Determination of methane emissions in three hydroelectric dams in Costa Rica

    Directory of Open Access Journals (Sweden)

    Jorge Herrera

    2013-12-01

    Full Text Available The emission fluxes of methane (CH4 across air–water interface were measured in three hydroelectric dams in Costa Rica (Brasil, Nuestro Amo and Cote Lake during three years cycle (2009-2011, using the floating static chamber technique. Samples were taken during one week, both day and night time, through four campaigns per year. For the methane flux determination the water surface was divided in a 4x4 grid equally spaced. During this period, CH4 fluxes showed average values that ranged from 759 – 4282 (Brasil, 77 – 733 (Nuestro Amo and 10,9 – 44,2 mg CH4 m-2 d-1 (Cote Lake, respectively. The fluxes of CH4 showed both strong seasonal and diurnal variations. CH4 emission rate was highest in dry season and there was a significant difference for CH4 emissions between day and night, the ratios between nighttime to daytime methane flux increased from 0,35 to 0,72, 0,43 to 0,64 for Brasil and Nuestro Amo, respectively in this season. CH4 emission was correlated positively with soil temperature, water table and chlorophyll a water concentrations.

  1. Methane Emissions and Microbial Communities as Influenced by Dual Cropping of Azolla along with Early Rice

    Science.gov (United States)

    Liu, Jingna; Xu, Heshui; Jiang, Ying; Zhang, Kai; Hu, Yuegao; Zeng, Zhaohai

    2017-01-01

    Azolla caroliniana Willd. is widely used as a green manure accompanying rice, but its ecological importance remains unclear, except for its ability to fix nitrogen in association with cyanobacteria. To investigate the impacts of Azolla cultivation on methane emissions and environmental variables in paddy fields, we performed this study on the plain of Dongting Lake, China, in 2014. The results showed that the dual cropping of Azolla significantly suppressed the methane emissions from paddies, likely due to the increase in redox potential in the root region and dissolved oxygen concentration at the soil-water interface. Furthermore, the floodwater pH decreased in association with Azolla cultivation, which is also a factor significantly correlated with the decrease in methane emissions. An increase in methanotrophic bacteria population (pmoA gene copies) and a reduction in methanogenic archaea (16S rRNA gene copies) were observed in association with Azolla growth. During rice cultivation period, dual cropping of Azolla also intensified increasing trend of 1/Simpson of methanogens and significantly decreased species richness (Chao 1) and species diversity (1/Simpson, 1/D) of methanotrophs. These results clearly demonstrate the suppression of CH4 emissions by culturing Azolla and show the environmental and microbial responses in paddy soil under Azolla cultivation.

  2. Use of a New Low-Power Laser-Based Instrumentation to Measure Methane Emissions from Remote Permafrost Regions

    Science.gov (United States)

    Burba, George; Sturtevant, Cove; Peltola, Olli; Schreiber, Peter; Zulueta, Rommel; Haapanala, Sami; Mammarella, Ivan; Rinne, Janne; Vesala, Timo; McDermitt, Dayle; Oechel, Walt

    2013-04-01

    The permafrost regions store significant amount of organic materials under anaerobic conditions, leading to large methane production and accumulation in the upper layers of bedrock, soil and ice. These regions are currently undergoing dramatic change in response to warming trends, and may become a significant potential source of global methane release under a warming climate over following decades and centuries. Present measurements of methane fluxes in permafrost regions have mostly been made with static chamber techniques, and very few were done with the eddy covariance approach using closed-path analyzers. Although chambers and closed-path analyzers have advantages, both techniques have significant limitations, especially for remote or portable research in cold regions. Static chamber measurements are discrete in time and space, and particularly difficult to use over polygonal tundra with highly non-uniform micro-topography and active water layer. They also may not capture the dynamics of methane fluxes on varying time scales (hourly to annual). In addition, placement of the chamber may disturb the surface integrity causing a significant over-estimation of the measured flux. Closed-path gas analyzers for measuring methane eddy fluxes employ advanced technologies such as TDLS (Tunable Diode Laser Spectroscopy), ICOS (Integrated Cavity Output Spectroscopy), WS-CRDS (wavelength scanned cavity ring-down spectroscopy), but require high flow rates at significantly reduced optical cell pressures to provide adequate response time and sharpen absorption features. Such methods, when used with the eddy covariance technique, require a vacuum pump and a total of 400-1500 Watts of grid power for the pump, climate control, and analyzer systems. The weight of such systems often exceeds 100-200 lbs, restricting practical applicability for remote or portable field studies. As a result, spatial coverage of eddy covariance methane flux measurements in cold regions remains limited

  3. Study of methane hydrate as a future energy resource: low emission extraction and power generation

    Science.gov (United States)

    Chen, L.; Yamada, H.; Kanda, Y.; Sasaki, H.; Okajima, J.; Iga, Y.; Komiya, A.; Maruyama, S.

    2016-08-01

    With the fast increase of world energy consumption in recent years, new and sustainable energy sources are becoming more and more important. Methane Hydrate is one promising candidate for the future energy supply of humankind, due to its vast existence in permafrost regions and near-coast seabed. This study is focused on the effective low emission utilization of methane hydrate from deep seabed. The Nankai Trough of Japan is taken as the target region in this study for methane hydrate extraction and utilization system design. Low emission system and power generation system with CCS (Carbon Capture and Sequestration) processes are proposed and analyzed for production rate and electricity generation efficiency problem study. It is found that the gas production price can reach the current domestic natural gas supply price level if the production rate can be improved. The optimized system is estimated to have power efficiency about 35%. In addition, current development and analysis from micro-to-macro scale methane hydrate production and dissociation dynamics are also discussed into detail in this study.

  4. Identification of urban gas leaks and evaluation of methane emission inventories using mobile measurements

    Science.gov (United States)

    Zazzeri, Giulia; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Butler, Dominique; Lanoisellé, Mathias; Nisbet, Euan G.

    2017-04-01

    Leakages from the natural gas distribution network, power plants and refineries account for the 10% of national methane emissions in the UK (http://naei.defra.gov.uk/), and are identified as a major source of methane in big conurbations (e.g. Townsend-Small et al., 2012; Phillips et al., 2013). The National Atmospheric Emission Inventories (NAEI) website provides a list of gas installations, but emissions from gas leakage, which in the inventories are estimated on the basis of the population distribution, are difficult to predict, which makes their estimation highly uncertain. Surveys with a mobile measurement system (Zazzeri et al., 2015) were carried out in the London region for detection of fugitive natural gas and in other sites in the UK (i.e. Bacton, Southampton, North Yorkshire) to identify emissions from various gas installations. The methane isotopic analysis of air samples collected during the surveys, using the methodology in Zazzeri et al. (2015), allows the calculation of the δ13C signature characterising natural gas in the UK. The isotopic value of the natural gas supply to SE London has changed a little in recent years, being close to -34 ‰ over 1998-99 period (Lowry et al., 2001) and close to -36 ‰ since at least 2002. Emissions from gas installations, such as pumping stations in NE England (-41 ± 2 ‰ ) were detected, but some of them were not listed in the inventories. Furthermore, the spatial distribution of the gas leaks identified during the surveys in the London region does not coincide with the distribution suggested by the inventories. By locating both small gas leaks and emissions from large gas installations, we can verify how these methane sources are targeted by national emission inventories. Lowry, D., Holmes, C.W., Rata, N.D., O'Brien, P., and Nisbet, E.G., 2001, London methane emissions: Use of diurnal changes in concentration and δ13C to identify urban sources and verify inventories: Journal of Geophysical Research

  5. Temperate Forest Methane Sink Diminished by Tree Emissions

    Science.gov (United States)

    Megonigal, P.; Pitz, S.

    2015-12-01

    Global budgets ascribe 4-10% of atmospheric CH4 sinks to upland soils and assume that soils are the sole surface for CH4 exchange between upland forests and the atmosphere. The prevailing dogma that upland forests are sinks of atmospheric CH4 was challenged a decade ago by large discrepancies in bottom-up versus top-down models of CH4 concentrations over upland forests that are still unexplained. Evidence of a novel abiotic mechanism for CH4 production from plant tissue is too small to explain the discrepancy. Alternative hypotheses for this observation have been proposed, but not tested. Here we demonstrate that CH4 is emitted from the stems of dominant tree species in an upland forest. Tree emissions occur throughout the growing season while soils adjacent to the trees are consuming CH4, challenging the concept that forests are uniform sinks of CH4. Scaling by stem surface area showed the forest to be a net CH4 source during a wet sample in June and a reduced CH4 sink by 5% annually. High frequency measurements revealed diurnal cycling in the rate of CH4 emissions, pointing to soils as the CH4 source and transpiration as the most likely pathway for CH4 transport. We propose the forests are smaller CH4 sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements.

  6. Methane Leak Detection and Emissions Quantification with UAVs

    Science.gov (United States)

    Barchyn, T.; Fox, T. A.; Hugenholtz, C.

    2016-12-01

    Robust leak detection and emissions quantification algorithms are required to accurately monitor greenhouse gas emissions. Unmanned aerial vehicles (UAVs, `drones') could both reduce the cost and increase the accuracy of monitoring programs. However, aspects of the platform create unique challenges. UAVs typically collect large volumes of data that are close to source (due to limited range) and often lower quality (due to weight restrictions on sensors). Here we discuss algorithm development for (i) finding sources of unknown position (`leak detection') and (ii) quantifying emissions from a source of known position. We use data from a simulated leak and field study in Alberta, Canada. First, we detail a method for localizing a leak of unknown spatial location using iterative fits against a forward Gaussian plume model. We explore sources of uncertainty, both inherent to the method and operational. Results suggest this method is primarily constrained by accurate wind direction data, distance downwind from source, and the non-Gaussian shape of close range plumes. Second, we examine sources of uncertainty in quantifying emissions with the mass balance method. Results suggest precision is constrained by flux plane interpolation errors and time offsets between spatially adjacent measurements. Drones can provide data closer to the ground than piloted aircraft, but large portions of the plume are still unquantified. Together, we find that despite larger volumes of data, working with close range plumes as measured with UAVs is inherently difficult. We describe future efforts to mitigate these challenges and work towards more robust benchmarking for application in industrial and regulatory settings.

  7. Atmospheric constraints on global emissions of methane from plants

    NARCIS (Netherlands)

    Houweling, S.; Rockmann, T.; Aben, I.; Keppler, F.; Krol, M.C.; Meirink, J.F.; Dlugokencky, E.J.; Frankenberg, C.

    2006-01-01

    We investigate whether a recently proposed large source of CH4 from vegetation can be reconciled with atmospheric measurements. Atmospheric transport model simulations with and without vegetation emissions are compared with background CH4, d13C-CH4 and satellite measurements. For present–day CH4 we

  8. Atmospheric constraints on global emissions of methane from plants

    NARCIS (Netherlands)

    Houweling, S.; Rockmann, T.; Aben, I.; Keppler, F.; Krol, M.; Meirink, J.F.; Dlugokencky, E.J.; Frankenberg, C.

    2006-01-01

    We investigate whether a recently proposed large source of CH4 from vegetation can be reconciled with atmospheric measurements. Atmospheric transport model simulations with and without vegetation emissions are compared with background CH4, delta C-13-CH4 and satellite measurements. For present - day

  9. Data sets to assess methane emissions from untreated cattle and pig slurry and solid manure storage systems in the German and Austrian emission inventories

    DEFF Research Database (Denmark)

    Dammgen, U; Amon, B; Hutchings, Nicholas John;

    2012-01-01

    Methane emissions have to be reported within the Framework Convention on Climate Change. They are assessed according to the guidelines provided by IPCC. However, the methane conversion factors provided in the guidance documents published in 1996, 2000 and 2006 differ considerably. The literature ...

  10. Data sets to assess methane emissions from untreated cattle and pig slurry and solid manure storage systems in the German and Austrian emission inventories

    DEFF Research Database (Denmark)

    Dammgen, U; Amon, B; Hutchings, Nicholas John

    2012-01-01

    Methane emissions have to be reported within the Framework Convention on Climate Change. They are assessed according to the guidelines provided by IPCC. However, the methane conversion factors provided in the guidance documents published in 1996, 2000 and 2006 differ considerably. The literature...

  11. Enteric methane emissions and lactational performance of Holstein cows fed different concentrations of coconut oil.

    Science.gov (United States)

    Hollmann, M; Powers, W J; Fogiel, A C; Liesman, J S; Bello, N M; Beede, D K

    2012-05-01

    To determine if dietary medium-chain fatty acids (FA; C(8) to C(14)) may mitigate enteric methane emissions, 24 cows were blocked by body size (n=2) and randomly assigned to 1 sequence of dietary treatments. Diets were fed for 35 d each in 2 consecutive periods. Diets differed in concentrations of coconut oil (CNO; ~75% medium-chain FA): 0.0 (control) or 1.3, 2.7, or 3.3% CNO, dry matter basis. The control diet contained 50% forage (74% from corn silage), 16.5% crude protein (60% from rumen-degradable protein), 34% neutral detergent fiber (NDF; 71% from forage), and 28% starch, dry matter basis. Data and sample collections were from d 29 to 35 in environmentally controlled rooms to measure methane (CH(4)) production. Methane emitted was computed from the difference in concentrations of inlet and outlet air and flux as measured 8 times per day. Control cows emitted 464 g of CH(4)/d, consumed 22.9 kg of DM/d, and produced 34.8 kg of solids-corrected milk/d and 1.3 kg of milk fat/d. Treatment with 1.3, 2.7, or 3.3% dietary CNO reduced CH(4) (449, 291, and 253 g/d, respectively), but concomitantly depressed dry matter intake (21.4, 17.9, and 16.2 kg/d, respectively), solids-corrected milk yield (36.3, 28.4, and 26.8 kg/d, respectively), and milk fat yield (1.4, 0.9, and 0.9 kg/d, respectively). The amount of NDF digested in the total tract decreased with increased dietary CNO concentrations; thus, CH(4) emitted per unit of NDF digested rose from 118 to 128, 153, and 166 g/kg across CNO treatments. Dietary CNO did not significantly affect apparent digestibility of CP but increased apparent starch digestibility from 92 to 95%. No FA C(10) or shorter were detected in feces, and apparent digestibility decreased with increasing FA chain length. Coconut oil concentrations of 2.7 or 3.3% decreased yields of milk FA C(14). The highest milk fat concentration (3.69%; 1.3% CNO) was due to the greatest yields of C(12) to C(16) milk FA. Milk FA concentrations of C(18:2 trans-10,cis

  12. Stochastic prediction and control to methane in coalmine

    Institute of Scientific and Technical Information of China (English)

    WU Wen-zhong

    2011-01-01

    The ventilation system plays an essential role in underground workings,and improvements in dilution effect to stochastic methane build-up at cul-de-sac of a coalmine require the installation of mixed ventilation system.For 4-12-1 1N02.8A centrifugal ventilation fan,the characteristic operating function of its mixed ventilation system is calculated from ventilation quantity and total pressure in the actual working status.At cul-de-sac of the reference coalmine,the evolution of methane concentration is a compound Poisson process and equivalent to a Brownian motion for Gaussian distributed increments.Solution of stochastic differential equation driven by mixed ventilation system,with dilution equation for its closure,provides parameters of mine ventilation system for keeping methane concentration within the permissible limit at cul-de-sac of the reference coalmine.These results intend to shed some light on application of blowing-sucking mixed ventilation systems in underground workings,and establish stochastic trends to consider methane control in coalmines.

  13. Effects of acidifying pig diets on emissions of ammonia, methane and sulfur from slurry during storage

    DEFF Research Database (Denmark)

    Eriksen, Jørgen; Nørgaard, Jan Værum; Poulsen, Hanne Damgaard

    2014-01-01

    Ammonia (NH3) volatilization from intensive livestock production is a threat to natural ecosystems. This study investigated pig diet manipulation by 1% (w/w) benzoic acid (BA) amendment and lowering of dietary electrolyte balance through substituting 1.4% (w/w) CaCO3 with 2.0% (w/w) CaCl2. Urine...... conditions of restricted S feeding. Methane emissions were increased by 73% in diets with CaCl2. An initial delay in methane (CH4) emissions was investigated in a separate experiment with manipulation of pH (5.4, 6.7 or 8.8) and inoculation with adapted pig slurry (0, 4, 11, or 19%), which showed...

  14. A micrometeorological technique for detecting small differences in methane emissions from two groups of cattle

    Science.gov (United States)

    Laubach, Johannes; Grover, Samantha P. P.; Pinares-Patiño, Cesar S.; Molano, German

    2014-12-01

    Potential approaches for reducing enteric methane (CH4) emissions from cattle will require verification of their efficacy at the paddock scale. We designed a micrometeorological approach to compare emissions from two groups of grazing cattle. The approach consists of measuring line-averaged CH4 mole fractions upwind and downwind of each group and using a backward-Lagrangian stochastic model to compute CH4 emission rates from the observed mole fractions, in combination with turbulence statistics measured by a sonic anemometer. With careful screening for suitable wind conditions, a difference of 10% in group emission rates could be detected. This result was corroborated by simultaneous measurements of daily CH4 emissions from each animal with the sulfur hexafluoride (SF6) tracer-ratio technique.

  15. Estimating methane emissions from biological and fossil-fuel sources in the San Francisco Bay Area

    Science.gov (United States)

    Jeong, Seongeun; Cui, Xinguang; Blake, Donald R.; Miller, Ben; Montzka, Stephen A.; Andrews, Arlyn; Guha, Abhinav; Martien, Philip; Bambha, Ray P.; LaFranchi, Brian; Michelsen, Hope A.; Clements, Craig B.; Glaize, Pierre; Fischer, Marc L.

    2017-01-01

    We present the first sector-specific analysis of methane (CH4) emissions from the San Francisco Bay Area (SFBA) using CH4 and volatile organic compound (VOC) measurements from six sites during September - December 2015. We apply a hierarchical Bayesian inversion to separate the biological from fossil-fuel (natural gas and petroleum) sources using the measurements of CH4 and selected VOCs, a source-specific 1 km CH4 emission model, and an atmospheric transport model. We estimate that SFBA CH4 emissions are 166-289 Gg CH4/yr (at 95% confidence), 1.3-2.3 times higher than a recent inventory with much of the underestimation from landfill. Including the VOCs, 82 ± 27% of total posterior median CH4 emissions are biological and 17 ± 3% fossil fuel, where landfill and natural gas dominate the biological and fossil-fuel CH4 of prior emissions, respectively.

  16. Application of a methane carbon isotope analyzer for the investigation of δ13C of methane emission measured by the automatic chamber method in an Arctic Tundra

    Science.gov (United States)

    Mastepanov, Mikhail; Christensen, Torben

    2014-05-01

    Methane emissions have been monitored by an automatic chamber method in Zackenberg valley, NE Greenland, since 2006 as a part of Greenland Ecosystem Monitoring (GEM) program. During most of the seasons the measurements were carried out from the time of snow melt (June-July) until freezing of the active layer (October-November). Several years of data, obtained by the same method, instrumentation and at exactly the same site, provided a unique opportunity for the analysis of interannual methane flux patterns and factors affecting their temporal variability. The start of the growing season emissions was found to be closely related to a date of snow melt at the site. Despite a large between year variability of this date (sometimes more than a month), methane emission started within a few days after, and was increasing for the next about 30 days. After this peak of emission, it slowly decreased and stayed more or less constant or slightly decreasing during the rest of the growing season (Mastepanov et al., Biogeosciences, 2013). During the soil freezing, a second peak of methane emission was found (Mastepanov et al., Nature, 2008); its amplitude varied a lot between the years, from almost undetectable to comparable with total growing season emissions. Analysis of the multiyear emission patterns (Mastepanov et al., Biogeosciences, 2013) led to hypotheses of different sources for the spring, summer and autumn methane emissions, and multiyear cycles of accumulation and release of these components to the atmosphere. For the further investigation of this it was decided to complement the monitoring system with a methane carbon isotope analyzer (Los Gatos Research, USA). The instrument was installed during 2013 field season and was successfully operating until the end of the measurement campaign (27 October). Detecting both 12C-CH4 and 13C-CH4 concentrations in real time (0.5 Hz) during automatic chamber closure (15 min), the instrument was providing data for determination of

  17. Which role for methane emissions reduction in climate change mitigation policies; Quel role pour les reductions d'emission de methane dans la lutte contre le changement climatique?

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, O. [Met Office-Hadley Centre (United Kingdom)

    2010-02-15

    Various arguments have been put forward to justify a rapid action to mitigate climate change through reductions in methane emissions. As part of a multi-gas emission reduction approach this requires defining an equivalence between methane and carbon dioxide. In this article, we discuss the physical and economical basis for a quantitative estimate of such an equivalence. Although this equivalence depends on a parameter which involves a value judgement on the most appropriate timescale for climate change, we show that it is difficult to justify a methane weight that is much different from the 100-year global warming potential that is currently used in the framework of the Kyoto protocol. (author)

  18. Mitigation of ammonia, nitrous oxide and methane emissions from manure management chains: a meta-analysis and integrated assessment

    NARCIS (Netherlands)

    Yong, Y.; Velthof, G.L.; Oenema, O.

    2015-01-01

    Livestock manure contributes considerably to global emissions of ammonia (NH3) and greenhouse gases (GHG), especially methane (CH4) and nitrous oxide (N2O). Various measures have been developed to mitigate these emissions, but most of these focus on one specific gas and/or emission source. Here, we

  19. Mitigation of ammonia, nitrous oxide and methane emissions from manure management chains: a meta-analysis and integrated assessment

    NARCIS (Netherlands)

    Yong, Y.; Velthof, G.L.; Oenema, O.

    2015-01-01

    Livestock manure contributes considerably to global emissions of ammonia (NH3) and greenhouse gases (GHG), especially methane (CH4) and nitrous oxide (N2O). Various measures have been developed to mitigate these emissions, but most of these focus on one specific gas and/or emission source. Here, we

  20. Genetic parameters for methane emissions predicted from milk mid-infrared spectra in dairy cows

    OpenAIRE

    Kandel, Purna Bhadra; Vanrobays, Marie-Laure; Vanlierde, Amélie; Dehareng, Frédéric; Froidmont, Eric; Pierre DARDENNE; Lewis, E.; Buckley, F.; Deighton, MH; McParland, S.; Gengler, Nicolas; Soyeurt, Hélène

    2013-01-01

    Genetic selection of low methane (CH4) emitting animals is additive and permanent but the difficulties associated with individual CH4 measurement result in a paucity of records required to estimate genetic variability of CH4 traits. Recently, it was shown that direct quantification of CH4 emissions by mid-infrared spectroscopy (MIR) from milk. The CH4 prediction equation was developed using 452 SF6 CH4 measurements with associated milk spectra and the calibration equation wa...