MethaneSAT is a satellite that observes the total column dry-air mole fraction of methane (XCH4) at high spatial resolution (100 m x 400 m) and precision (20 - 40 ppb) over target areas of 200 km x 200 km. Its observations uniquely enable the simultaneous quantification of discrete point and dispersed area methane sources within a single scene, addressing a critical gap in space-based methane monitoring. The mission focuses on characterizing methane emissions from the oil and gas industry, targeting over 80% of the sector’s global emissions.
We present methane observations from MethaneSAT and showcase a methodology to quantify sources within the target area. Emissions of discrete point sources causing distinct methane plumes are quantified using the Divergence Integral algorithm1. Additionally, an inverse modeling approach, informed by atmospheric transport simulated with the Stochastic Time Inverted Lagrangian Transport (STILT)2 model, is employed to constrain the magnitude and location of dispersed sources.
1Chulakadabba et al., 2023: Methane point source quantification using MethaneAIR: a new airborne imaging spectrometer
2Lin et al., 2003: A near-field tool for simulating the upstream influence of atmospheric observations: The Stochastic Time-Inverted Lagrangian Transport (STILT) model
How to cite: Knapp, M., Benmergui, J., Kyzivat, E., Zhang, Z., Sargent, M., Roche, S., Miller, C. C., Ayvazov, S., Russi, M., and Wofsy, S. C.: MethaneSAT: Quantifying Discrete and Dispersed Methane Sources on Basin-Scales, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3528, https://doi.org/10.5194/egusphere-egu25-3528, 2025.
The United States is the world’s largest emitter of methane from oil and gas and the second-largest methane emitter overall. Inversions of atmospheric observations provide an empirical method for evaluating progress on emission goals. Here, we present U.S. annual methane emission trends from 2019 to 2024 at up to ~25 km resolution inferred from analytical inversion of blended TROPOMI+GOSAT satellite observations. For each year, we use the U.S. Greenhouse Gas Inventory as the prior estimate, then generate an ensemble of posterior emission estimates by applying the Integrated Methane Inversion (IMI 2.0) inverse modeling framework. Our results include closed-form error characterization through analytical minimization of the Bayesian cost function and uncertainties derived from the ensemble of inversion estimates. The high resolution of our posterior estimate allows us to generate sector-resolved emissions at the national, state, and basin level. Our results comprehensively assess U.S. progress on methane mitigation and demonstrate the capability of advanced modeling tools for rapid generation of top-down emission estimates to inform climate policy.
How to cite: Estrada, L., Jacob, D., Varon, D., He, M., East, J., Sulprizio, M., Balasus, N., Hancock, S., and Bowman, K.: Quantifying U.S. methane emission trends (2019-2024) through high resolution inversion of satellite observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2167, https://doi.org/10.5194/egusphere-egu25-2167, 2025.
Global gas flaring from the oil and gas industry was estimated to be 148 billion cubic meters in 2023, based on satellite observations from the Visible Infrared Imaging Radiometer Suite (VIIRS; World Bank, 2024). Both lit and unlit flares are sources of potent greenhouse gases and health hazards, making it a source requiring accurate global monitoring. The VIIRS instrument often forms the basis for gas flaring volumes, but our study reveals that these estimates are underestimated in Canada, and potentially elsewhere.
Comparing VIIRS flaring observations with industry reporting across Western Canada for 2012-2023, we found that industry reports ~2.3-times more gas flaring than estimated by satellite. This appears to be primarily the result of small/medium-sized flares going undetected (generally less than 350 m3/h, or 220 kg/h, assuming 90% methane content), but we also estimate that ~17% of industry-reported flaring was missed because of enclosed combustors, which do not have a flame visible to VIIRS. For flares that are detected by VIIRS, aggregate volume estimates agree within ~8% of industry reporting, although individual flares can be +/- an order of magnitude from industry reporting, similar to offshore findings from Brandt (2020).
If this issue of underestimated flaring volumes from VIIRS is limited to Canada, global gas flaring estimates would increase by only 1%, but Canada would be the 10th most flaring country (up from 23rd). However, if undetected flares are more widespread, global flaring could be much more deeply underestimated. VIIRS’s theoretical detection limits imply that smaller flares should be detected, implying other factors are impacting detection/quantification, such as VIIRS data filtering, flaring practices (e.g., daytime-only blowdown flaring), or persistent cloud cover.
References
Brandt AR. 2020. Accuracy of satellite-derived estimates of flaring volume for offshore oil and gas operations in nine countries. Environmental Research Communications 2(5). IOP Publishing. doi: 10.1088/2515-7620/ab8e17
World Bank. 2024. Global Gas Flaring Tracker Report. (June). Washington, DC. Available at https://www.worldbank.org/en/programs/gasflaringreduction/global-flaring-data. Accessed 2024 Jul 2.
How to cite: Seymour, S., Xie, D., and Kang, M.: Global gas flaring volumes may be underestimated: comparisons with over a decade of industry reporting in Canada, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3295, https://doi.org/10.5194/egusphere-egu25-3295, 2025.
UNEP's International Methane Emissions Observatory (IMEO) launched the Methane Alert and Response System (MARS) in 2023 to provide open, reliable, and actionable data to those individuals with the agency to act on them and ultimately reduce methane emissions. MARS uses satellite observations to detect and monitor large methane emissions and then notifies governments and companies worldwide. With the development of MARS, IMEO opened a new level of transparency that reveals dozens of large methane emissions around the world every week. Thanks to the synergistic use of more than a dozen different open-access satellite missions, combined with the development of Machine Learning models that support and optimize the work of the MARS analysis group, IMEO provides the largest open-access database of point source methane emissions detected with different satellites. At the same time, since its launch in January 2023, MARS has directly notified stakeholders of more than 1900 methane plumes linked to the oil and gas (O&G) sector in about 30 countries. As a result of these notifications, IMEO has confirmed a number of mitigated emission sources following stakeholder action. Throughout the MARS process, we also learn new information and lessons about the accuracy of our measurements, the root causes behind the observed emissions, and the real feasibility of mitigating emission sources under different scenarios and geographic areas, among others.
While MARS notifications are currently on sent for recent O&G point source emissions, it also has the capability to detect and monitor emissions from other sectors, such as coal and waste. Additionally, we have the ability to explore satellite archive data to conduct more in-depth analyses of the historical behaviour of the emitters. As a result, IMEO is currently expanding MARS’ capacity to further support IMEO's scientific studies and its efforts towards increasing transparency in the metallurgical coal and waste sectors to drive emissions reduction.
In this contribution, we will show case studies we have recently dealt with, lessons learned, improvements, and new data and methodologies integrated into MARS based on scientific research. We will also give an overview of IMEO’s efforts in the metallurgical coal sector and in the waste sector through scientific studies and with the support of remote sensing data generated through MARS.
How to cite: Irakulis-Loitxate, I., Montesino-SanMartin, M., Mateo-García, G., Demeter, M., Bonazzi, G., Vaughan, A., Ruzicka, V., de Jong, T. A., Sharma, S., Maasakkers, J. D., Aben, I., Valverde, A., Field, R. A., Kasprzak, M., Menoud, M., Abichou, T., Tibrewal, K., Guanter, L., and Calcan, A.: UNEP's IMEO Methane Alert and Response System to drive the mitigation of anthropogenic methane emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19083, https://doi.org/10.5194/egusphere-egu25-19083, 2025.
Observational constraints on national scale methane emissions are needed to assist progress towards the goals of the Paris Agreements and the Global Methane Pledge. Here, we use 2023 blended TROPOMI+GOSAT observations of atmospheric methane in multiple analytical inversions to estimate emissions for all countries of the world at up to 25 km resolution. Prior emissions estimates are spatially distributed according to state-of-the-science bottom-up inventories, and country-level prior totals are adjusted by sector to match the emissions most recently reported to the UNFCCC. We enhance each inversion’s ability to capture point-source emissions not included in bottom-up inventories by redistributing oil-gas and coal emissions based on a gridded inventory constructed from GHGSat plume and null detections, and by enforcing native resolution emissions optimization at locations where plumes were observed by point source imagers including PRISMA, Sentinel-2, Landsat, EnMAP, GOES, and EMIT, and where large plumes were detected by TROPOMI. Our global total posterior emission of 562 Tg for 2023 is in line with previous coarse-scale global inversion studies. The inversions’ high resolution allows source separation and independent optimization of individual countries, confirmed by small posterior error correlations between countries. China (52.7 Tg), the U.S. (32.2 Tg), India (25.7 Tg), Brazil (18.5 Tg), and Indonesia (10.7 Tg) have the highest anthropogenic emissions, representing 14%, 9%, 7%, 5%, and 3% of the global total anthropogenic source, respectively. Uncertainty estimates come from an inversion ensemble with varied inversion parameters. Results provide an estimate of emissions from all countries in a globally consistent inverse modeling framework, serve as a direct comparison and aid of countries’ UNFCCC reporting, and provide up-to-date observational constraints on emissions from countries where reporting is unfeasible or out of date.
How to cite: East, J. D., Jacob, D. J., Jervis, D., Estrada, L. A., Balasus, N., Chen, Z., Hancock, S. E., Sulprizio, M. P., Varon, D. J., and Worden, J. R.: High-resolution estimates of national methane emissions for all countries of the world using TROPOMI observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14476, https://doi.org/10.5194/egusphere-egu25-14476, 2025.
Methane is a potent greenhouse gas, and detailed understanding of its contributions from different countries and source sectors is necessary for climate action. Livestock is the dominant anthropogenic methane source, but bottom-up estimates of its emissions have high uncertainties. Inversions of satellite observations of atmospheric methane can offer valuable top-down information, but the related uncertainties need to be carefully characterized. Colombia has a large proportion of methane from livestock, and past work over the region has identified discrepancies between bottom-up and top-down emissions estimates, particularly for the livestock sector. Here, we explore this discrepancy in detail by quantifying 2023 methane emissions in Colombia and the contributions from different sectors at up to ~12 km × 12 km resolution including error characterization using an analytical inversion ensemble of TROPOMI and GOSAT satellite observations of atmospheric methane. We also assess the potential of future Carbon-I satellite observations to further reduce uncertainties in emissions. We show that choices in the inversion setup, including the number of state vector elements and the prior emission inventories, have a significant impact on emission estimates. The high resolution of our inversion results allows us to relate our emission estimates to bottom-up processes. Results demonstrate the ability of satellite observations of methane to improve our process-based understanding of methane emissions in Colombia.
How to cite: Hancock, S., Estrada, L., Balasus, N., East, J., Sulprizio, M., Wang, X., Chen, Z., Varon, D., Jiménez, R., Ardila, A., Morales-Rincon, L., Rojas, N., Frankenberg, C., and Jacob, D.: Evaluating the Utility of Satellite Observations for Improving Bottom-Up National Emission Inventories: Application to Colombia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4622, https://doi.org/10.5194/egusphere-egu25-4622, 2025.
This work describes observations made over the past three years at high gas coal mines in Shanxi and Xinjiang observed from underground; surface concentrations and fluxes; horizontal and upward looking FTIR; high spatial resolution remote sensing using moderate spectral resolution (GF5 and PRISMA); and lower spatial resolution remote sensing using high spectral resolution (TROPOMI). Systematic analysis is made using flexible, mass-conserving, and computationally fast inversion tools. High resolution emissions are computed and analyzed considering spatial variation, wind, three-dimensional spread, and observational uncertainty. These emissions are observed to contain fat tail distributions and uncertainties. When applied in attribution forward-backward mode, a probabilistic attribution is computable, with results consistent between different observations tyles when and where they were made. Attribution is sometimes possible both for the known sources and other second source (i.e., adjacent mines, additional fissures or ventilation shafts, or long-range transport from outside the domain). Advantages, weaknesses, and ranges of uncertainties of each observation type is explored.
These results are then used to train mesoscale mass conservation systems that govern the transport, diffusion, and interactions, allowing for emissions estimation, uncertainty, and attribution. These trained models are applied to TROPOMI and other observations at the kilometer to 10-kilometer scale, and demonstrate day-by-day and grid-by-grid emissions which are quantifiable and reasonable when compared with independent surface observations. Furthermore, the results are shown to be smooth and consistent across some other coal mining areas, when and where observational uncertainties were initially strictly considered in the model fitting and after unbiased analysis is applied.
Issues of when the errors are large or emissions estimations are not reliable are discussed including: different coal fields, underground coal fires, high absorbing aerosol conditions, and variable topography. When emissions can be computed under these conditions, reasons are given, and future work options are discussed. New measurements and campaigns and modeling enhancements will be discussed. In specific, limitations on the current generation of surface and remotely sensed measurements will be made in terms of ever tightening emissions rules. Steps to rectify the identified gaps are proposed.
General results reflect current understanding: high gas mines are significant sources of methane emissions which require active mitigation or yield emissions larger than current bottom-up estimates. Treating emissions as normally distributed leads to results not being sufficiently robust to extrapolate to annual or longer datasets. Some scientific points raised include: active consideration of observational error frequently leads to emissions inversions not being reliable; applying unbiased filters to observational uncertainty removes both high and low emissions inversions, allowing more confidence in unfiltered low emissions sources; attribution of multiple sources on a single TROPOMI grid may be easier when applied over a common coal field, allowing field wide emissions predictions under lower-gas or higher mitigation conditions.
How to cite: Cohen, J., Hu, W., Liu, Y., Lu, F., Wang, S., Zheng, B., Lu, L., Tiwari, P., He, Q., and Qin, K.: Observing Chinese Coal Mine Methane Emissions Smoothly Across Scales: Powering Future Mitigation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8493, https://doi.org/10.5194/egusphere-egu25-8493, 2025.
Monitoring and mitigating methane emissions from super-emitting sources is critical for addressing climate change. The TROPOMI instrument onboard Sentinel-5P provides daily global coverage of methane concentrations at 5.5 × 7 km² resolution, enabling the detection of methane super-emitters (>~8 t hr⁻¹). These data are instrumental in identifying hotspots that can be further investigated using high-resolution (~25 m) satellite instruments to pinpoint facility-level emissions. In support of the UNEP-IMEO Methane Alert and Response System (MARS), we have identified over 250 super-emitter hotspots. These hotspots include oil and gas production sites and urban landfills, while a third are associated with coal mining operations, including unexpected sources like surface coal mines. Given the crucial role of coal in the global energy landscape and steel production, it is essential to monitor and accurately estimate the associated methane emissions.
This work highlights the synergy between TROPOMI and high-resolution instruments through an analysis of surface coal mine clusters in Kazakhstan, Russia, and India. We estimate 2021-2023 annual methane emissions from these three clusters using TROPOMI data in a Bayesian inversion approach. Our results align with emissions calculated using UNFCCC emission factors and mine-level production data, except in India, where significantly lower emissions are observed. Comparisons with bottom-up gridded emission inventories EDGAR v7 & GFEI v2 reveal notable discrepancies, primarily due to inaccuracies in spatial disaggregation. In Kazakhstan, methane emissions increase substantially between 2021 and 2023 despite stable coal production, suggesting that coal seam characteristics and other factors influence emission dynamics. Our emission estimates align closely with GHGSat-based estimates across all mines and years where a sufficient number of GHGSat observations are available. Moreover, spatial correlations are identified between GHGSat-detected methane enhancements and mining activities within the mine. Additionally, atmospheric temperature inversions are found to significantly contribute to the accumulation of methane within the mine pit, complicating emission quantifications based on high-resolution observations. The findings of this study underscore the importance of combining TROPOMI data with high-resolution satellite data to refine methane emission estimates from complex sources like surface coal mines.
How to cite: Sharma, S., Maasakkers, J. D., Dogniaux, M., McKeever, J., Jervis, D., Girard, M., Schuit, B. J., Jong, T. A. D., Irakulis-Loitxate, I., Balasus, N., Varon, D. J., and Aben, I.: Estimating methane emissions from surface coal mines using satellite observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13054, https://doi.org/10.5194/egusphere-egu25-13054, 2025.
In 2022, Australia produced over 450 million tonnes of coal, accounting for approximately 7% of global production. About 75% of this output came from coal mines located in the Bowen Basin (Queensland) and the Hunter Coalfields (New South Wales). According to Australia’s 2022 UNFCCC submissions, open-cut and underground coal mining contributes around one-fifth of the nation’s methane emissions, positioning it as a key focus for methane mitigation efforts. These emissions are calculated using a combination of IPCC Tier 2 methodologies, which rely on average basin-specific coal gas contents, and IPCC Tier 3 methodologies, which involve mine-specific coal core gas distribution modelling. Despite employing higher Tier IPCC reporting methods, top-down studies using the TROpospheric MONitoring Instrument (TROPOMI) have suggested that fugitive methane emissions may be underestimated at some Australian coal mining facilities (Sadavarte et al., 2021; Palmer et al., 2021). However, the spatial resolution of TROPOMI (~7 km by 5.5 km) limits its capability for identifying emissions from individual facilities within an observation footprint cell, which constrains its effectiveness for bottom-up emission verification for individual mines.
Here, we present an overview of findings from a series of mine-scale atmospheric surveys conducted across coal mines in the Bowen Basin between 2022 and 2023, and in the Hunter Coalfields in 2024. These studies utilized aircraft-based in-situ and remote sensing instruments, along with ground-based EM27/SUN Solar Absorption Spectrometers, all capable of isolating methane emission rates from individual coal mine facilities. We discuss the broader implications of these results within the context of Australia’s national and international greenhouse gas reporting framework.
References:
How to cite: Harris, S., Borchardt, J., Hacker, J., Deutscher, N., Kelly, B., Lunt, M., Krautwurst, S., Mcgrath, A., Murphy, A., Bovensmann, H., Field, R., Junkermann, W., Paton-Walsh, C., Jones, N., and Nawaz, H.: Characterization of methane emissions from coal mining in Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13298, https://doi.org/10.5194/egusphere-egu25-13298, 2025.
The mitigation of anthropogenic climate forcing necessitates substantial reductions in methane emissions, given methane's elevated radiative forcing potential. While the Global Methane Pledge establishes a framework for 30% emissions reduction by 2030, precise quantification of fugitive emissions remains challenging due to their stochastic spatiotemporal characteristics.
This investigation presents the application of trailer-mounted Quantum Gas Lidar instrumentation for the detection, visualisation, and quantification of methane flux rates from holes drilled for coal exploration in Queensland, Australia. The methodology leverages high-resolution spatial and temporal sampling capabilities to enable flux quantification of traditionally challenging emission sources. Extended temporal measurement campaigns reveal significant variability in emission rates, highlighting the necessity of continuous monitoring protocols for accurate flux determination.
The results demonstrate the effectiveness of Quantum Gas Lidar technology in fugitive methane quantification, offering uninterrupted accurate measurements through a range of weather conditions. Real-time visualisation and temporal quantification capabilities enhance understanding of emission dynamics. This work illustrates the significance of advanced sensing methodologies in achieving Global Methane Pledge objectives and emphasising the role of innovative monitoring approaches for targeting abatement strategies.
How to cite: Hayes, P. and Hoerning, S.: Quantifying Fugitive Methane from Coal Exploration Boreholes Using A Trailer-Mounted Quantum Gas Lidar System, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1364, https://doi.org/10.5194/egusphere-egu25-1364, 2025.
Tracer Correlation Method (TCM) testing was conducted at a U.S. landfill to quantify fugitive methane emissions, with flux values ranging from 1,353 to 4,996 kg/hr. SEM2Flux, another ground-based method, reported lower fluxes ranging from 430 to 1,177 kg/hr with standard deviations of 24 to 164 kg/hr in the same landfill. The lower flux estimates from SEM2Flux may be due to the limited number of data points, inadequate coverage of the waste footprint, or emissions originating from gas collection infrastructure above ground rather than directly from the landfill surface.
Satellite platforms, including EnMAP, EMIT, and PRISMA, provided broader flux ranges, with values spanning from 2,430 to 9,840 kg/hr. EMIT reported the highest fluxes but also the largest uncertainties, averaging 4,931 kg/hr. EnMAP and PRISMA reported more moderate fluxes with uncertainties of 892 kg/hr and 1,824 kg/hr, respectively. The higher estimates from satellite detections may be related to their detection limit, as it is only possible to detect methane plumes when emissions are large enough, although there may be other factors that have yet to be explored. Satellite data offers broader spatial coverage, high data frequency if the data is requested, and independent measurements based on open data. However, the variability and higher uncertainties underscore the need for validation against reliable ground-based measurements like TCM.
Reported emissions for the site, calculated using the USEPA-recommended methods, equate to hourly fluxes of approximately 754 kg/hr and 740 kg/hr. These values significantly underestimate emissions when compared to TCM, SEM2Flux, and satellite data. The discrepancies between the different technologies/techniques emphasize the need for more comprehensive validation experiments integrating ground-based and satellite measurements to improve emissions inventories and enhance monitoring systems across varying site conditions and methodologies.
This research has been partially funded in the framework of UNEP’s International Methane Emissions Observatory (IMEO).
How to cite: Abichou, T., Irakulis-Loitxate, I., Menoud, M., France, J., and Calcan, A.: Contrasting Methane Emissions from Solid Waste Landfills: Side by Side Assessment of Ground, Drone, and Satellite Based Technologies, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18683, https://doi.org/10.5194/egusphere-egu25-18683, 2025.
Three different landfill methane surface emissions monitoring (SEM) techniques were compared at active and inactive landfills and in separate controlled release tests. The deployed SEM techniques included traditional walking surveys with a human operator equipped with a portable methane concentration analyzer with a sampling pump, the drone-based equivalent of this traditional survey where the methane analyzer is instead mounted to a drone and a long sampling tube drags on the landfill surface, as well as a recently introduced laser-based sensor that mounts beneath a drone and measures path-integrated methane concentration between the drone and the ground. Both drone-based solutions have received commercial interest as they address safety concerns with humans traversing challenging terrain on foot, and can increase the area covered by the survey, especially with the path-integrated sensor which can probe landfill areas with active machinery.
Testing at landfill sites showed that while the drone-mounted, downward-facing laser was the easiest solution to implement in the field, it was also the least effective at identifying hotspots. Although the walking survey and drone-based equivalent produced generally comparable hotspot mappings, the latter was faster to implement and also gave the cleanest and most repeatable indication of hotspots. However, critically, results of the controlled release tests revealed poor correlation between methane surface concentration and emission rate for all techniques. Additionally, parameters such as drone flight speed and the response time of the gas analyzer will affect the absolute magnitude of collected methane concentrations. This is problematic for the likely success and efficiency of current and proposed regulations that require mitigation action based on specific volume fraction (concentration) thresholds such as 500 ppm. Based on these results we recommend that site-total emission quantification techniques should be prioritised in both research and regulations, such that problematic landfills can properly be prioritise for action, which can then be supported by SEM data to identify where on the landfill the emissions are occurring.
How to cite: Festa-Bianchet, S., Cerquozzi, I., Van de Ven, C., and Johnson, M.: Comparison of Three Different Landfill Surface Methane Mapping Techniques: Lessons Learned and Policy Implications, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12688, https://doi.org/10.5194/egusphere-egu25-12688, 2025.
Methane is a short-lived yet extremely potent greenhouse gas in the atmosphere. Methane currently accounts for about one-third of global warming attributed to all greenhouse gases. Landfills, which are the third-largest source of methane emissions, are estimated to emit about 50% more methane than reported by the U.S. Environmental Protection Agency (U.S. EPA) inventory. While some landfills estimate emissions based on waste volume and other specific data, others rely on methane capture and operational information. A previous study on 70 high-emitting landfills in the U.S. revealed that their actual emissions were 77% higher than reported to the EPA. Among the 38 facilities that captured gas, their emissions were, on average, 200% greater than reported. Thus, a more accurate landfill methane emission estimate will have significant impact on our understanding on total atmospheric methane concentrations.
Recent advancements in quantifying landfill emissions reveal that traditional waste decay models are inaccurate for emission estimations due to spatial and temporal variability. Consequently, short-term measurements often fail to represent diurnal average emissions, especially in landfills without gas collection systems. Analyzing the 2020 U.S. EPA Landfill Database, we found that almost 41% of landfills lack gas collection systems. Using the Weather Research and Forecasting model, we simulated barometric pressure over 2267 unique landfills for April 2020. We found that changes in barometric pressure impact methane emissions, with 99% of landfills having more days with higher emissions between 10 AM and 4 PM than other times of the day. This suggests that short-term measurements during these hours, commonly used in field measurements, may overestimate diurnal average emissions, particularly in the absence of gas collection systems. Utilizing an unsaturated soil model, we estimated emission overestimation / underestimation under extreme barometric pressure conditions. Our soil model indicates that emissions measured between 10 AM and 4 PM could be overestimated by up to 25% of their average values. These findings underscore the need for continuous measurements or corrections in short-term emissions to accurately represent diurnal averages for annual greenhouse gas inventories.
For future direction, we aim to fill critical gaps in understanding open waste landfill methane emissions, globally, and improve the accuracy of the atmospheric chemistry models by improving the emission estimations. By providing more accurate estimates of methane emissions from landfills, we will support climate policy development, improve public health outcomes, and advance scientific research.
How to cite: Golbazi, M., Delkash, M., and Imhoff, P.: New Insights for Estimating Diurnal Methane Emissions from Landfills, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21355, https://doi.org/10.5194/egusphere-egu25-21355, 2025.
Wastewater treatment facilities are a significant source of greenhouse gas (GHG) emissions released to the atmosphere (Czepiel et al., 1993). Greenhouse gas emission environmental impact has become one aspect of assessing the performance of waste water treatment plants (WWTPs) (Mohsenpour et al., 2021). A better understanding of current GHG emission rates from these facilities will help to improve national GHG inventories and to develop mitigation strategies. At present there are large uncertainties associated with these emissions, as WWTPs use generalised default emission factors that may have limited applicability to Australian conditions and the specific sewage treatment infrastructure and operations.
Two methane (CH4) emission measurement campaigns were conducted at a sewage treatment plant in Victoria using inverse-dispersion modelling (IDM) coupled with open-path spectroscopic techniques. The first campaign was from February to March 2024 (summer campaign) and the second one was from August to October 2024 (winter campaign). Three open-path lasers (1x Boreal Laser GasFinder 2.0 and 2 x Unisearch Associates Inc.) measured line-averaged gas concentrations at upwind and downwind locations of a sewage treatment lagoon. Real-time CH4 concentrations (ppm over 100 m path-length, one way) were continually measured for over one month during each campaign. Climatic conditions including wind statistics were also recorded with a 3-dimentional sonic anemometer (CSAT3, Campbell Scientific) at a frequency of 10 Hz. These measurements of gas concentration and wind statistics were used as the IDM inputs to calculate CH4 fluxes. During the same periods, effluent samples were also collected and analysed. In this study, we present the CH4 fluxes (μg/m2/s) from the treatment lagoon in summer and winter seasons. The effects of other factors on the emissions including the chemical and physical properties of effluents, aerators operation status, and effluent flow rates were also investigated. We found that measured CH4 emissions were higher than those estimated by national GHG reporting guidelines and seasonal and spatial variations were significant.
How to cite: Bai, M., De Jong, P., Wardrop, P., Butterly, C., and Chen, D.: Measurement of Methane Emissions from a sewage treatment lagoon in Victoria Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14322, https://doi.org/10.5194/egusphere-egu25-14322, 2025.
National greenhouse gas emission reporting in Europe is facilitated by national agencies based on activity data and emission factors, and in some cases, more sophisticated process modeling approaches, for many different activities and emission sectors. These “bottom-up” emission estimates are essential for providing guidance for emission mitigation measures relevant for international treaties and negotiation, for monitoring national progress towards targets, and for separating emissions processes and sector level breakdowns of sources and sinks.
Emissions of gases to the atmosphere result in atmospheric concentrations that are locally enhanced compared to background levels. These enhancements can be measured with precise instrumentation and used to quantify the emissions. When these measurements are evaluated with inverse atmospheric transport models, they can deliver independent “top-down” emission estimates, i.e., emission estimates that are consistent with the measured concentration enhancements. Due to the complexity of atmospheric transport, such estimates are difficult, but they have now reached a level where they can provide independent information on emissions and can support the bottom-up approach.
Switzerland and the UK are two countries that already provide top-down emission estimates as annexes to their annual national emission reports to the UNFCCC. Within the PARIS project we have extended the top-down approach for national scale emission estimates to 6 further countries (Germany, the Netherlands, Italy, Norway, Hungary, Ireland), and produced consistent drafts for annexes to the National Inventory reports for all 8 countries.
A weakness of top-down approaches is that they can not always distinguish between emissions from different source sectors, which makes comparison to the National Inventories difficult. As a second focus of PARIS, we aim at developing measurable signatures to facilitate a more detailed attribution of the derived emissions to specific source sectors. These signatures include measurements of isotopic composition for CH4 and N2O, atmospheric O2 for CO2, other co-emitted species, as well as detailed composition measurements for organic and black carbon aerosols.
This presentation will include some interesting aspects from the draft annexes to the National Inventory Reports, innovative new measurements for source sector attribution and new tools for evaluation and comparison of emission estimates.
How to cite: Röckmann, T., Ganesan, A., Manning, A., and Henne, S. and the The PARIS Team: Bridging inventory reporting and atmospheric inversion estimates of anthropogenic greenhouse gas emissions in Europe: The PARIS project, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20141, https://doi.org/10.5194/egusphere-egu25-20141, 2025.
Methane is a powerful greenhouse gas that is a major contributor to climate change. Quantifying emissions by process is therefore important, especially as many countries (including most European countries) have pledged to drastically reduce their emissions through the Global Methane Pledge and regional regulations. These countries report their emissions annually to the UNFCCC through National Inventory Documents (NIDs).
While reported emissions are estimated using established methods based on bottom-up activity data, the UK and Switzerland additionally include in their NIRs an assessment using atmospheric observations. This independent assessment is derived using atmospheric inverse modelling or “top-down” methods. The Horizon Europe project Process Attribution of Regional emISsions (PARIS) extends “top-down” comparisons with inventories to several additional European countries.
In this work, we carry out a sensitivity analysis of methane inversions over Europe from 2018 to 2023. This enables us to first assess the influence of different inversion parameters, such as the number of sites, the transport model, estimation of boundary conditions, and the role of data filtering and model uncertainty. We thus evaluate our confidence in European methane inversions and identify the main parameters that lead to discrepancies between inversions. Two transport models: NAME and FLEXPART; and three inversion models: ELRIS from Empa, InTEM from MetOffice and RHIME from the University of Bristol are used.
We then focus on a 35 year assessment of methane emissions over the UK over the period (1989-2023) using RHIME and InTEM, thus re-evaluating the emissions reported by the UK over the last few decades using two different inversion models. The RHIME and InTEM estimates are broadly in agreement, however, both estimate significantly lower emissions than those reported in the latest UK NIR for the 1990s and early 2000s. Although fewer sites were available on the 1989-2000 period than in the years covered in the PARIS project, the use of two inversion methods provides additional confidence that a large disagreement between atmospheric measurements and the UK inventory exists until the early 2000s.
How to cite: Danjou, A., Andrews, P., Brito Melo, D., Ramsden, A., De Longueville, H., Redington, A., Murphy, B., Pitt, J., Rigby, M., Manning, A., Henne, S., and Ganesan, A.: Evaluation of inverse models to estimate methane emissions from European countries, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16113, https://doi.org/10.5194/egusphere-egu25-16113, 2025.
Quantifying methane (CH₄) emissions at the scale of medium-sized European cities remains a significant challenge due to the relatively low annual levels, the spatial and temporal heterogeneity of these emissions. We aim to develop a framework for quantifying urban CH4 emission including nature gas and waste emissions, following a protocol compatible with the reporting framework of the Oil & Gas Methane Partnership (OGMP) 2.0 for natural gas distribution operators.
Le Mans, a medium-sized city in the Pays de la Loire region of France with a population of approximately 150,000 is selected as a pilot case. The approach combines mobile measurements and fixed monitoring stations to quantify CH₄ emissions and identify natural gas leaks and other potential emission hotspots in the city.
Here, we report on the tests of five Aeris mid infra-red analysers MIRA LDS intended for fixed deployment in the city to monitor CH₄ concentration variations due to the urban emissions. The resulting system demonstrated sufficient precision, with methane and ethane measurement accuracies better than 5 ppb and a few ppt, respectively. We modified the analysers and implemented a two-level calibration strategy with daily injections to achieve sensor stability.
Additionally, mobile surveys were conducted, covering approximately 36% of the streets of the city Le Mans and parts of the roads in the suburbs. These campaigns aimed to: (1) detect and quantify fugitive point source emissions, (2) characterize large-scale CH₄ variations, (3) evaluate the effect of air inlet location, and (4) quantify emissions from major emitting sites. We identified CH₄ point sources linked to natural gas infrastructure and non-natural gas sources. We distinguish between large plumes presumably from large emitters and fugitive spikes indicative of possible local gas leaks. Over 15 transects have been led across the plume from the wastewater treatment plant (WWTP) in Le Mans and allow to estimate the site’s contribution to the city’s emission. Additionally, the analysis of air inlet positions revealed that higher air inlet locations are more suitable for analyzing the plume transects, whereas lower air inlet positions are better suited for detecting peaks associated to near ground or subsurface fugitive emissions.
Finally, exploiting these results, we discuss the capability of a network of fixed stations to measure small variations of CH4 (of the order of tens of ppb) across the city. These results will lead to the implementation of the fixed network over the next 2 years in the city (at the end of 2026), complemented by continued mobile campaigns to analyze emission trends, variability, and sector-specific contributions.
How to cite: Liu, K., Goxe, M., Broquet, G., Mignot, A., Menant, C., Laurent, O., Potier, E., Bousquet, P., and Paris, J.-D.: Toward a robust quantification of methane emissions in a medium-sized city: initial results from mobile and stationary measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8421, https://doi.org/10.5194/egusphere-egu25-8421, 2025.
Romania’s oil and gas infrastructures belong to the strongest CH4 emitters in Europe. Despite this, quantification of emissions in the region has been limited. During the large multi-scale ROMEO (ROmanian Methane Emissions from Oil and gas) campaign in 2019, top-down methane emission estimates were derived using in-situ measurements from two aircraft, supported by two atmospheric model simulations.
Annual emissions from the Southern Romanian Oil and Gas (O&G) infrastructure were estimated at 227 ± 86 kt CH4 yr⁻¹ resulting in a per-site Emission Factor of 5.3 ± 2.0 kg CH4 h-1 site-1. This is consistent with previously published ground-based site-level measurements conducted during the same period. Low wind conditions during the campaign complicated direct comparisons of individual plumes between measurements and the model simulations. Nevertheless, correlations of CH4 plumes observed during large-scale raster flights and mass balance flights with modelled plumes suggest that the emission factors derived for a limited number of production clusters and regions are representative for the larger southern Romanian production basin.
Our results show agreement between aerial and ground-based estimates and corroborate significant underreporting of methane emissions from Romania's O&G industry to the United Nations Framework Convention on Climate Change (UNFCCC) in 2019. Furthermore, the study highlights substantial underestimation of O&G emissions in the Emissions Database for Global Atmospheric Research (EDGAR) v7.0 for the study domain.
How to cite: Maazallahi, H. and the Airborne In Situ Measurements and Modeling Team of the ROMEO Campaign: Airborne Measurements and Modelling of Methane Emissions from Oil and Gas Industry During the ROMEO Campaign 2019, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4728, https://doi.org/10.5194/egusphere-egu25-4728, 2025.
Historically, the Transylvanian basin is one of the most important natural gas-producing areas in Europe. The existence of commercial gas reserves was incidentally discovered in the early 1900's while drilling for potassium salts in the Miocene deposits that fill the basin. Well #2 Sarmasel, that was positioned close to an area with natural gas emissions, has intercepted very shallow strata containing gas. Drilling had to be stopped on 22 April 1909, after 5 months of work, at a depth of 300 m, due to overwhelming technical difficulties related to the high pressure of gas. Thus, this date marks the beginning of the gas extraction in Transylvania. The well has been left open until 23 June 1910, when a first attempt at closure was made. Twenty hours after closure, gas was observed escaping in a neighbouring field, which required the reopening of the well. A second closure attempt occurred on 31 July 1911, subsequent to the external encasement of the well for the initial 120 meters of depth. No gas leak was detected, and the closure seemed to be effective at this stage. On 29 October 1911, a powerful gas eruption occurred in the fields east of the well, accompanied by considerable gas emissions in the surrounding area, local seismic activity, saline water leakage, and the appearance of several craters located between 100 and 400 meters from the well. The well was reopened once again, until the end of 1913, when it was connected to the pipeline conveying gas to consumers. More than 1.3×109 m3 of gas has been released to the atmosphere during a span of four years. An additional 556×106 m3 of gas was supplied to consumers from 1913 to 1935, when the well was capped. The total volume is around 2 billion cubic meters of gas from a single, 300-meter-deep well! The main crater generated by the 1911 outburst, despite being filled with soil post-explosion, persists in emitting gas that sustains a perpetual fire.
Our research demonstrated that Sarmasel is a case of ongoing, prolonged gas leakage caused by manmade activities (drilling and gas extraction) conducted over a century ago, functioning in conjunction with, and likely intensified by, a natural seepage process. Sarmasel can thus be regarded as a hybrid leakage-seepage system. This study exemplifies the risk of generating fugitive emissions when drilling occurs within a natural seepage system.
Acknowledgments: This work was supported by the Project DTIE21-EN3485 funded by UNEP and by the Project 14/11.11.2023—ENGAGE, PNRR-III-C9-2022—I8, supported by the EU through the Romanian Govt.
How to cite: Baciu, C., Ghiorghiu, E., Ajtai, I., Martonos, I., Hmoudah, M., Orban, A., Lupulescu, A., Spulber, L., Cozma, A., Sfabu, S., Moga, R., and Etiope, G.: Methane emission to the atmosphere from the first gas-producing well in Transylvania, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15400, https://doi.org/10.5194/egusphere-egu25-15400, 2025.
The full range of emissions from oil and gas production, especially offshore, is still not fully understood due to the vast number of sources and lack of observational data. Emissions from shuttle tanker loading are not well characterised, with research limited and mainly non methane volatile organics (NMVOCS) rather than methane (CH4). There is also a grey area on where they should be included in inventories and the latest National Atmospheric Emissions Inventory United Kingdom Green House Gas (NAEI_UK_GHG) Inventory Improvement Report (July 2022) cited evidence for emissions factors from methane (CH4) and non methane volatile organics (NMVOCS) compounds from oil loading as a future priority research area.
This work shows CH4 emissions results from a campaign in October 2023 designed to investigate CH4 and NMVOC emissions from oil loading to shuttle tankers over the whole loading cycle. The project used aircraft measurements from a research aircraft and unmanned aerial vehicle along with different modelling techniques to evaluate emissions from the complete tanker loading process. Increases in CH4 emissions were observed when the shuttle tanker was present when compared to the standard platform operating conditions.
How to cite: Purvis, R., Burton, R., Lee, J., Hopkins, J., Drysdale, W., Moore, T., Allen, G., and Dawson, K.: Methane Emissions from Offshore Shuttle Tanker Loader Installations in the North Sea, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5668, https://doi.org/10.5194/egusphere-egu25-5668, 2025.
Global liquefied natural gas (LNG) exports were around 400 Mt in 2023, with 20% of this production from Australia. The industry-wide extent of methane (CH4) emissions from LNG export terminals are not well characterized in the literature through measurement-based methods, leading to a range of values being used in life cycle analyses. As part of UNEP’s International Methane Emissions Observatory Methane Science Studies, a series of scientific flights were conducted around eight LNG liquefaction terminals in Australia between 2021 and 2024, covering 95% of Australian LNG nameplate capacity. In-situ mole fractions of CH4 and carbon dioxide (CO2) were measured on the research aircraft, in addition to meteorological data, GPS data and measurements of ultrafine particles. The measurements resulted in over 100 CH4 mass balance quantifications and an extensive dataset to explore tracer correlations between CH4 and CO2 which aid emissions quantification and understanding. Here, we present the most extensive measurement-based analysis of site-level emissions to date from LNG export terminals, enabling us to examine industry-wide methane emissions and emission intensities. We explore factors that impact derived emission intensities from different LNG sites and the implications for methane emissions from the wider LNG supply chain.
How to cite: Lunt, M., Hacker, J., Harris, S., and Junkermann, W.: Measurement-based insights into methane emissions from LNG export terminals in Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7528, https://doi.org/10.5194/egusphere-egu25-7528, 2025.
Anthropogenic sources of methane, especially those from the oil and gas industry, are significant. Increasingly, global measurement campaigns have been conducted to capture regional emissions intensity using satellite and mass balance technologies. However, these technologies often lack the fine-scale resolution needed for detailed source attribution, making them difficult to use for mitigation prioritization. Meanwhile, individual operators are employing aerial technologies to measure their assets and assist in leak detection and repair initiatives, but this fine-scale data is not used to inform the regional estimates. This study focuses on reconciling aircraft-based regional mass balance data with aircraft-based point source measurements in identical regions of the Appalachian Basin of the United States in 2024. Aerial LIDAR measurements were used to measure approximately 6000 sites, including all major oil and gas and non-oil and gas sources. Regional mass balance flights were conducted on subdivided polygons encompassing the sites surveyed by the aerial LIDAR measurements. Some emission sources have been deliberately excluded due to cost, such as pipelines, distribution systems and non-producing wells. Comparing the sum of the point sources measured and the mass balance approaches will allow us to examine the relevance of the sources that were not measured. Additionally, while the mass balance measurements and point source measurements occur in the same quarter, the flights are not contemporaneous. It is well documented that emissions from oil and gas sources vary in their size and duration, with large emission events that may be short in duration. This can lead to considerable disagreement between the point source measurements and the regional mass balance estimates. This work will address the short duration, large emission events and their effect on the uncertainty in the regional methane emission estimates.
How to cite: Stokes, S., Yang, S., Allen, D., and Ravikumar, A.: Reconciling Regional Mass Balance and Point Source Measurements for Understanding Methane Emissions in the Appalachian Basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18856, https://doi.org/10.5194/egusphere-egu25-18856, 2025.
Introduction
Methane emissions from oil and gas sector have high spatial and temporal variability. Previous studies with limited sample size and very few (if any) numbers of repeated measurements have often been used to estimate basin and national scale emissions, leading to high uncertainties to the inventory estimation. This study investigates methane emission data on point sources collected in repeated surveys of Permian Basinover 2019–20231, focusing on the spatiotemporal variability of emissions and the sampling strategy for developing a relatively accurate annual emission inventory for large oil gas regions with limited number of surveys that capture the temporal variation and a fraction of the facilities that can cover the spatial variability.
Methodology
We have developed a multi-faceted approach reorganizing repeated flight overpass data into surveys to estimate source persistence and construct emission events characterized by unique combinations of rates, duration (in terms of number of surveys), and frequency (number of repeated events). Using multiple time series construction approaches including discrete event simulations, we model the annual variability of point source emissions at multiple scales: sub-basin (25, 100, 400 km2) and basin (4000 km2), and use random sub-sampling to determine minimum coverage criteria to capture annual emission variability accurately. Our criteria are based on two parameters—the number of surveys conducted and % facilities covered in the basin.
Results and Discussion
Our findings highlight that considerable temporal variability in methane emissions can occur, especially for areas of sub-basin scale (≈100–400 km2). The emission rates of detected facility-scale sources vary significantly across years (average Coefficient of Variation, COV ≈ 2.3). Our results also reveal that emission events are short-lived (≥75% events lasting ≤ 2 surveys), occur infrequently (average persistence ≤ 33%), yet significantly contribute to total detected emissions (~70%). Nevertheless, these intermittent facility-scale emissions translate to significantly lower variability across sub-basin scale surveys (COV ≈ [0.2–1.3]) and basin-scale surveys (COV ≈ 0.5).
We also study the spatial and temporal variability of emission estimates for sub-basin and basin-scale surveys. At the basin scale, even a single survey sufficiently captures the annual emission variability (bias ≤ 10%) and the emission distribution across different sub-basins (cosine similarity of 0.8–1.0). However, at a sub-basin scale, even estimates based on 25 surveys can be biased (bias ≈ 20%). We find low correlations (Spearman R < 0.5) of time series patterns of sub-basin-sub-basin and sub-basin-basin-scale areal emissions, pointing to the diverse emission patterns within the basin.
Concluding Remarks
Our findings on spatial (areal coverage) and temporal (number of surveys) considerations can help build annual emission measurement strategies for oil and gas production regions.
Reference
- Cusworth, et al., 2022. Strong methane point sources contribute a disproportionate fraction of total emissions across multiple basins in the United States, PNAS, 119 (38) e2202338119, https://doi.org/10.1073/pnas.2202338119
How to cite: Xie, D., Bhandari, S., and Albertson, J.: Spatiotemporal Variation of Point Source Emissions in Permian Basin and its Implication on Basin Level Inventory Building and Mitigation , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1675, https://doi.org/10.5194/egusphere-egu25-1675, 2025.
Measurement-based inventories combining source-resolved aerial LiDAR measurements with bottom-up emission and activity data have provided unprecedented insight into the origins and magnitudes of oil and gas sector methane emissions and, in Canada, are now being used to inform methane estimates used in official national greenhouse gas inventory reporting. However, the protocols for creating measurement-based inventories are new and continue to be refined as both measurement technology and scientific understanding of the oil and gas sector improve. In this study, we examine independent, measurement-based inventory estimates derived from aerial survey data collected during 2020, 2021, 2023, and 2024 in the Canadian province of Saskatchewan; 2021, 2023, and 2024 in the province of British Columbia; and 2021 and 2023 in the province of Alberta. Data for each province are used to quantify region-specific sample size requirements, providing important insights into how prescribed sample sizes may need to vary depending on the characteristics of the production basin. Year-over-year emission trends are also examined in detail, which reveal varying degrees of success in reducing emissions in regions with distinct regulatory frameworks while highlighting key remaining sources to target for mitigation.
How to cite: Johnson, M. R., Wilde, S. E., Tyner, D. R., and Conrad, B. M.: Using Repeated Aerial Methane Measurements to Assess Inventory Protocols and Track Year-over-year Trends in Emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12569, https://doi.org/10.5194/egusphere-egu25-12569, 2025.
Oil and gas companies striving to attain the OGMP2.0 “Gold Standard” for methane Measurement, Reporting, and Verification (MRV) are required to find and measure individual methane sources across all their operating assets, and in particular, to verify total emissions using an independent "top-down" measurement. The process of comparing source-level and top-down measurements is termed “reconciliation” and is an essential part of meeting the “Gold Standard”. However, to date, there is no prescriptive OGMP 2.0 protocol on how to reconcile site and source-level measurements, and there are key knowledge gaps regarding calculation methods, required sample sizes, and uncertainty protocols.
This study demonstrates a novel framework for reconciling on site source measurements with independent source-resolved aerial survey data to derive corporate methane emissions and intensity data sufficient to meet or exceed the OGMP 2.0 Gold Standard certification requirements. Critically, the protocol allows for direct analysis of measurement uncertainties. In partnership with an oil and gas producer operating in Canada, a source-level inventory is first created based on extensive ground measurements and company-specific emission factors. Independent source-resolved measurements, covering 100% of the company’s operating assets, are then conducted using Bridger Photonics Inc.’s Gas-Mapping LiDAR (GML). Multi-pass aerial data are analyzed using detailed probability of detection models, which consider the conditions of each pass, and integrated with the bottom-up data to account for unmeasured sources. The result is a comprehensive, verified inventory of total methane emissions for the company. As part of this demonstration, the analysis is repeated using up to four independent aerial surveys, providing real-world insights to the importance of temporal variability in emissions and its influence on required sample sizes for accurate reconciliation. The results have important implications for creating MRV protocols that ensure reported emissions adequately represent the variable nature of emissions, particularly when sample sizes are small because measurements are limited to assets from a single operator as is the case under OGMP2.0 reporting.
How to cite: Wilde, S., Tyner, D., Conrad, B., and Johnson, M.: A Demonstrated Reconciliation of Top-Down and Bottom-Up Methane Measurements to Derive Verified Emission Intensities, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11938, https://doi.org/10.5194/egusphere-egu25-11938, 2025.
Measurement-based methane emissions inventories are essential for U.S. oil and natural gas operators to track their progress toward emissions targets and demonstrate the impact of improved operational and monitoring practices. However, translating raw emission measurement data, whether from continuous monitoring systems, aerial flyovers, or operational cause analyses, into emissions inventories is nontrivial. In this talk, we discuss findings from a United States Department of Energy funded project where we investigated how to combine a bottom-up inventory required by regulatory agencies, data from continuous monitoring systems, data from aerial flyovers, and follow-up operator cause analysis data to develop an operator-level emissions inventory. We introduce the concept of a comprehensive measurement-based emissions inventory, which represents all emissions across the entire time frame, across all spatial assets, and of all emissions sizes. We carefully characterize the extrapolation efforts necessary to create a comprehensive emissions inventory estimate with data from each type of technology. Understanding these methods is essential for operators preparing defensible emissions inventory reports that adhere to reporting frameworks such as Veritas and OGMP 2.0. In many cases, there are several possible extrapolation approaches of varying complexity and with various underlying assumptions. We provide simple examples to illustrate the sensitivity of annual emissions estimates to the various extrapolation approaches and highlight the challenges, strengths, and limitations when working with data from each of the technologies.
How to cite: Fosdick, B., Moore, C., Wong, H. X., Weller, Z., Corbett, A., Roell, Y., Martinez, E., Berry, A., and Gielczowski, N.: Challenges with Developing Comprehensive Oil and Natural Gas Operator-Level Measurement-Based Methane Emissions Inventories in the U.S. , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11837, https://doi.org/10.5194/egusphere-egu25-11837, 2025.
UNEP’s International Methane Emissions Observatory (IMEO) is a data-driven, action-focused initiative. IMEO exists to provide open, reliable, integrated methane emissions data to facilitate actions to reduce methane emissions. The Baseline Science Studies are a subset of IMEO’s science studies, which aim to estimate the current total and sectoral methane emissions (with uncertainties) at country-level through multi-scale measurement studies and integration with existing data. It will assist governments, civil society, industry, and other stakeholders to prioritize actions to reduce methane emissions.
IMEO’s Baseline Studies couple multi-scale top-down approaches with more granular analysis of bottom-up data to improve the understanding of key methane emission sources relevant to selected countries. The focused sectors for methane emission are oil and gas, agriculture and waste. Currently, there are two Baseline Studies at the design phase for Colombia and Nigeria. We will conduct an initial assessment per country through literature and reports, feed the existing prior to satellite inversion model and apportion the emission by sector. Using the literature review and satellite information, we identify the major methane sources and those with large uncertainties in each country, and design small studies to provide measurement data where little to no data in-country is available. By combining activity data and geospatial mapping, the ultimate aim is creating a gridded methane inventory at the country level. This information will be used to update the country level methane budget and build local capacity to enable future estimations and refinement of sectoral emissions. The presentation here will demonstrate the concept and generalised progress of the IMEO baseline studies
How to cite: Li, X., Baranski, M., France, J. L., Velandia Salinas, N., Calcan, A., Balcome, P., Jimenez, R., Velders, G., Jacob, D. J., and Caltagirone, M.: IMEO’s Baseline Science Studies improves country-level methane quantification, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17051, https://doi.org/10.5194/egusphere-egu25-17051, 2025.
Anthropogenic emissions of methane (CH4) are the second-largest anthropogenic source of greenhouse gases after carbon dioxide (CO2) and are a major driver of climate change. Rapid reductions in emissions would help reduce near-term warming. Analysis of satellite data provides information on methane emissions from important localized methane sources such as landfills and fossil fuel extraction sites. This information is used to identify emission sources, quantify their emissions, and monitor progress in reducing emissions. However, this application requires careful analysis of the satellite data because extracting reliable information on atmospheric methane concentration variations and emission estimates from the measured radiance is not trivial, as the measured radiance is affected not only by methane but also by many other interfering effects, including clouds and surface features. Several ESA (GHG-CCI, MEDUSA, SMART-CH4) and EU (EYE-CLIMA) projects focus on the further development of the algorithms needed for reliable emission detection and quantification. This includes the application of the algorithms to several important methane sources and intercomparisons with results from other groups using independently developed methods. In this context, we are developing the HighResolutionFit (HiFI) package, which implements several methods to retrieve atmospheric methane information from high-resolution satellite sensors such as EnMAP and EMIT. The corresponding atmospheric data products are used to obtain emission information using a Cross-Sectional Flux (CSF) method. Here we present the latest status of these activities, including comparisons with corresponding results from other groups.
How to cite: Reuter, M., Hilker, M., Noël, S., Hachmeister, J., Buchwitz, M., Schneising-Weigel, O., Bovensmann, H., Burrows, J. P., and Bösch, H.: Methane retrievals and emission estimates of localized sources from EnMAP and EMIT space-borne data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11860, https://doi.org/10.5194/egusphere-egu25-11860, 2025.
Atmospheric methane (CH4), the second most important greenhouse gas, poses substantial uncertainties with its global emission inventory. We use inverse modeling analyses with Greenhouse Gases Observing Satellite (GOSAT) XCH4 data to reduce those uncertainties and obtain improved quantitative estimates of sectoral monthly methane emissions from January 2010 to December 2019. We first conducted GEOS-Chem simulations with global emission inventories, including GFEIv2, EDGARv8, and WetCHARTs. The model with the global emission inventories showed a cumulative negative bias of approximately -1% per year compared to the GOSAT data, primarily due to the underestimation of tropical wetland emissions. Simulated monthly mean methane concentrations with the Kalman filter were used to optimize monthly variations of different sectoral CH4 emissions over the decade, focusing on anthropogenic sources often assumed to be aseasonal in previous studies. Our inverse analyses resulted in increases of the global CH4 emission trend of 3.86 Tg yr-1 from 2.55 Tg year-1, driven mainly by increases of agricultural and waste management sources. The seasonality of global methane emissions is more prominent in our top-down emission estimates than bottom-up emission, mainly driven by increased agricultural emissions in the Northern Hemisphere and tropical regions during June, July, and August. Furthermore, the top-down estimates of waste management emissions exhibited a significant summer peak in the Northern Hemisphere, indicating its temperature sensitivity, which was previously not recognized. The inverse analysis of methane emissions significantly reduced the spatiotemporal biases of the GEOS-Chem model compared to TCCON XCH4, demonstrating the robustness of the inversion.
How to cite: Oh, S.-I. and Park, R. J.: Constraining the Seasonal and Interannual Variability of Global Sectoral Methane Emissions in the 2010s using GOSAT XCH4 data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8399, https://doi.org/10.5194/egusphere-egu25-8399, 2025.
Methane (CH4), due to its strong global warming potential and roughly decade lifetime, plays a pivotal role in near-term climate mitigation strategies. Coal mine methane (CMM) is a major source of CH4 globally, and particularly so in coal-producing regions. Effective control of CMM emissions is crucial for mitigating climate change impacts. This study integrates multi-scale observational datasets including in-situ observations, column FTIR observations, and daily satellite remote sensing together with high-resolution atmospheric modeling to investigate CH4 transport and source contributions. The steps are hoped to lead to future development of a quantitative inverse modeling system flexible enough to provide for spatially-targeted, high-frequency mitigation strategies and interventions.
The Weather Research and Forecasting model is configured with its greenhouse gas tracer option (WRF-GHG) to separate sources of CH4 on a grid-by-grid basis. This work employs a nested three-domain structure with the central region covering China’s major coal-producing regions, including the Qinshui Coalfield and 139 coal mines at 3km resolution. Ground-based in situ measurements from eddy covariance flux tower, mobile measurements using portable LGR analyzers, and upward looking EM27 FTIR previously deployed by the AERSC team at around 950 m elevation in Changzhi in Shanxi Province, provide high-frequency a priori emissions to drive the model, as well as in situ data to refine the simulations. Observations from TROPOMI, TCCON (in the 9km region) and the GAW WLG station (in the 27km region), provide additional datapoints for comparison and quantification of the spatial, temporal, and goodness of representation of fit. This study resolves CH₄ concentration dynamics across scales, from regional to individual coal mines. It is hoped that the results can offer a quantitative means to identify and attribute emissions from these major emitting regions at high spatial and temporal frequency.
A few interesting scientific points are explained in detail. (1) The WRF-GHG model shows improved agreement with observational datasets, especially so in terms of capturing more extreme events, when the AERSC team’s emissions datasets are used. Quantitative differences between WRF-GHG and TROPOMI_L3 demonstrate that while some areas are robust, other areas have significant differences, explained in part by the improved emissions inventories used herein. (2) Existing inventories lead to average values of XCH4 simulated across 139 individual coal mines being lower than the observations made by the AERSC group, while at the same time leading to average values of XCH4 in a subset of other regions not measured as being much higher than available observations. These regions and differences are detailed, and rationales for these differences are proposed. (3) Near-surface CH4 concentrations show that anthropogenic CH4 emissions contributes only 17.1% of total CH4 within a 12 km radius of coal mining sites which is far too low, although the diurnal variations are closely linked to coal production activities, highlighting the model's robustness in capturing these dynamics but the problems with the spatial and magnitude aspects of current emission inventories.
How to cite: Liu, Y., Qin, K., and Cohen, J. B.: High Spatial and Temporal Resolution Assessment of Methane Emissions in Major Coal-Producing Regions of China Driving In Situ and Column Observations by WRF-GHG, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9311, https://doi.org/10.5194/egusphere-egu25-9311, 2025.
Methane (CH4) is the second most important greenhouse gas (GHG) whose atmospheric abundance is modified by anthropogenic activity. The reduction of CH4 emissions has been identified as an essential mitigation target for slowing man-made climate change. According to inventories, coal mining accounts for roughly 33% of fossil fuel and 11% of all anthropogenic CH4 emissions. Accurate identification of coal mining-related CH4 sources and quantification of their annual emission rate is needed for corporate reporting requirements, national inventory verification, and the development of CH4 mitigation strategies. In Australia, coal mining accounts for approximately 20% of reported CH4 emissions.
In the Bowen Basin in Queensland, Australia, over 40 active mines are distributed over 60,000 km2, with both open-pit and underground coal mines. A study using TROPOMI satellite measurements to estimate CH4 emissions from 3 clusters of coal mines in this region showed discrepancies with reported emissions during 2018 and 2019.
In September-October 2023, the Bowen Basin CH4 Mapping (BBCMap) Campaign was carried out. It was funded by and performed in collaboration with UNEP’s International Methane Emissions Observatory as part of its Methane Science Studies. Two identical HK36 TTC Eco-Dimona research aircraft specifically designed as sensor platforms were deployed to conduct the measurements. One of these aircraft carried the MAMAP2D-Light (Methane Airborne MAPper 2D – Light) imaging spectrometer to estimate atmospheric CH4 and CO2 column anomalies, as well as a LIDAR to provide up-to-date topography scans. The second aircraft was fitted with an LGR UGGA gas analyzer and a suite of meteorological instrumentation to measure atmospheric CH4, CO2, and water vapor concentrations, as well as accurate winds and other basic meteorological parameters. It also carried a bag sampler to capture air samples for later isotopic analysis.
The campaign investigated emissions from approximately 33 mines in the Bowen Basin. In this contribution, we discuss CH4 emission estimates for both open-pit and underground coal mines using both in-situ and remote sensing measurements.
How to cite: Borchardt, J., Harris, S. J., Hacker, J. M., Lunt, M., Krautwurst, S., Bösch, H., Bovensmann, H., Burrows, J. P., Chakravarty, S., Field, R. A., Gerilowski, K., Huhs, O., Junkermann, W., Kelly, B. F. J., Kumm, M., McGrath, A., and Schindewolf, J. and the Campaign Support Team: Methane emissions estimated from airborne measurements from open-pit and underground coal mines in the Bowen Basin, Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16153, https://doi.org/10.5194/egusphere-egu25-16153, 2025.
In recent years, credible atmospheric observations of methane emissions suggest that annual methane emission estimates in inventories for some Australian coal mining regions or facilities may be underestimated. A lack of well-constrained, mine-scale studies for open-cut (pit) coal mines continues to hinder discussions on emission estimates and the refinement of estimation methods for Australian open-cut coal mining facilities. Here, we present preliminary results from aircraft- and ground-based atmospheric measurements recorded in November 2024 in the Hunter Coalfield, NSW, Australia.
Australia employs higher-Tier IPCC methodologies – Tier 2 (basin-specific) and Tier 3 (mine-specific, Methods 2 and 3 ) – under its National Greenhouse and Energy Reporting (NGER) Scheme to estimate open-cut coal mine emissions. These methods rely on the use of coal core gas content to estimate methane emissions from open-cut mine complexes. However, Methods 2 and 3 have never been validated using airborne or ground-based time series observations.
While coarse-resolution satellites like TROPOMI can quantify coal mine emissions at regional scales (Sadavarte et al., 2021; Palmer et al., 2021), their limited spatial resolution reduces their effectiveness for verifying annual inventory reported emissions at the scale of individual mines. Additionally, the ability of point-source imaging satellites to quantify emissions from individual open-cut coal mines remains uncertain. Coal seam blasting prior to extraction can be considered a point source; however, open-cut coal mines have various continuous diffuse methane sources that also need to be quantified. The diffuse sources include, among others, emissions from beneath the pit floor, lateral diffusion along coal seams and other rock strata in the mine walls, rock waste piles, and areas of in situ biological production, such as water management ponds. Aircraft- and ground-based technologies have the potential to measure both point and diffuse sources of methane, thus providing a potential pathway for verifying greenhouse gas inventories determined using approved IPCC methodologies.
During this measurement campaign in the Hunter Coalfield, a research aircraft flew instruments to collect in-situ atmospheric measurements of methane and carbon dioxide mole fractions, along with GPS and meteorological data. These data were used to make rate of methane emission estimates downwind of individual coal mine complexes. Aerosol size and particle number concentration measurements and high-resolution airborne LiDAR imagery were also acquired to aid in source attribution. These measurements were complemented by ground-based EM27/SUN solar absorption spectrometer instruments positioned upwind and downwind of the same coal mining complexes. Comparisons between emissions derived from the aircraft-base, ground station EM27/SUN observations, and operator-reported coal mine methane emissions will be presented.
Palmer, P. I., Feng, L., Lunt, M. F., Parker, R. J., Bösch, H., Lan, X., Lorente, A., and Borsdorff, T.: The added value of satellite observations of methane for understanding the contemporary methane budget, Phil. Trans. R. Soc. A., 379, 20210106, https://doi.org/10.1098/rsta.2021.0106, 2021.
Sadavarte, P., Pandey, S., Maasakkers, J. D., Lorente, A., Borsdorff, T., van der Gon, H. D., Houweling, S., and Aben, I.: Methane emissions from superemitting coal mines in Australia quantified using TROPOMI satellite observations, Environmental Science & Technology, 55, 16573–16580, https://doi.org/10.1021/acs.est.1c03976, 2021.
How to cite: Kelly, B. F. J., Deutscher, N. M., Harris, S. J., Beaton, H., Brain, T., McGrath, A., Hacker, J., Murphy, A., Junkermann, W., Paton-Walsh, C., Jones, N. B., and Nawaz, H.: Aircraft- and ground-based quantification of coal mine methane emissions in the Hunter Coalfields, Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5538, https://doi.org/10.5194/egusphere-egu25-5538, 2025.
Global warming is proceeding rapidly and quick actions are required to suspend the increasing temperatures globally. Here we give an overview of a series of measurement studies, supported and funded by UNEP´s International Methane Emissions Observatory (IMEO) in 2022-2023. Methane (CH4) is the primary focus of all these studies, since it is one of the most potent greenhouse gases, which at the same time has a relative short lifetime. Due to these specific characteristics, CH4 is presently the prime target for mitigating emissions from industrial activities.
Our approach focused on a variety of CH4 emissions from the coal, oil and gas (O&G), and waste industry in Poland and in the Middle East within the framework of METHANE-To-Go-Poland and METHANE-To-Go-Oman. A unique helicopter-towed probe, HELiPOD, was equipped with in situ CH4 instrumentation complemented by mobile ground-based CH4 measurements. The well-known mass balance approach was applied to quantify the CH4 emissions from the targeted sources. Final comparisons of our top-down estimates with bottom-up industry or inventory data have been carried out to assist the involved companies and related governments in prioritizing their CH4 emission mitigation actions and policies for future endeavours. Several non-captured CH4 source strengths, compared to the available bottom-up data, were discovered in the course of these top-down studies. For a number of reasons evaluated during our operations, the novel HELiPOD set-up is proposed to be a suitable platform for upcoming satellite evaluation studies focusing on CH4. In particular, the HELiPOD measurements (CH4 mixing ratio plus 3D wind) can capture the whole vertical and horizontal extension of targeted CH4 plumes, which is necessary for the CH4 mass flux quantification, a number that can be directly comparable to available satellite-based flux rates in UNEP´s Methane Alert and Response System (MARS).
How to cite: Huntrieser, H., Förster, E., Pätzold, F., Bretschneider, L., Maier, N., Necki, J., Bartyzel, J., Jagoda, P., Witschas, B., Roiger, A., Lampert, A., (be´ah), O. E. S. H. C., and Lunt, M.: Methane Emissions from Industrial Activities: Quantification of Selected Polish and Middle East Sources by a Unique Helicopter Probe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10622, https://doi.org/10.5194/egusphere-egu25-10622, 2025.
Non-producing oil and gas wells emit methane, a greenhouse gas with approximately 80 times the warming potential of carbon dioxide over a 20-year period. Reducing methane emissions from the oil and gas industry is crucial in assuring Canada reaches its pledge of cutting greenhouse gas emissions by 40% below 2005 levels by 2030. Currently, British Columbia (BC) hosts approximately 20,000 non-producing oil and gas wells. The British Columbia Energy Regulator (BCER) has been conducting annual LiDAR-based helicopter surveys of methane emissions, with 1,334 non-producing oil and gas wells surveyed from 2017 to 2024. To estimate methane emissions rates using BCER's helicopter survey data, we performed a controlled release test of the Lasen Airborne LiDAR Pipeline Inspection System to evaluate the detection range. The controlled-release testing involved multiple helicopter flyovers over a single site, during which various methane flow rates, ranging from 0.05 to 1.8 kg/hr, were released. We used our test results to combine available BCER aerial survey data and ground-based measurements and estimate total methane emissions from non-producing oil and gas wells across BC.
How to cite: Woolley, L. and Kang, M.: Estimating Methane Emissions from Non-Producing Oil and Gas Wells in British Columbia Using a Helicopter-Based Methane Detection System, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5125, https://doi.org/10.5194/egusphere-egu25-5125, 2025.
More than a hundred thousand documented orphaned oil and gas wells are known to exist in the United States, with potentially millions remaining undocumented. Due to funding shortfalls, many orphaned wells remain unplugged and continue to emit methane, a potent greenhouse gas. Drone-based methane emission measurements can help prioritize mitigation efforts for orphaned wells and aid in locating undocumented orphaned wells, which are wells with unknown locations and conditions. In collaboration with the Pennsylvania Department of Environmental Protection (PA DEP) and the US Department of Energy’s (DOE) Orphan Well Program, we will present the results of drone-based methane emission measurements across four regions in Pennsylvania with a high likelihood of containing undocumented orphaned wells. We will share our insights on the potential for detecting methane emissions using drone-based tunable diode laser absorption spectroscopy (TDLAS), an emerging technology for methane monitoring in the oil and gas sector. Additionally, this work explores the foundation of a screening method for providing first-order estimates of methane emission rates at orphaned well sites. We will compare the methane measurements with potential well locations identified using drone-based magnetometry data, historical maps, LiDAR, and atmospheric data. Our results will be helpful for prioritizing plugging and remediation for the hundreds of thousands, and potentially millions, orphaned wells across the US and the world.
How to cite: Boutot, J., France, J. L., Coleman, M., Peltz, A. S., Fox-Coughlin, V., Keown, N., Viswanathan, H., and Kang, M.: Drone-based methane emissions monitoring from orphaned oil and gas wells in Pennsylvania, US, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12148, https://doi.org/10.5194/egusphere-egu25-12148, 2025.
Flaring is the controlled burning of natural gas, a common practice in the oil and natural gas (O&G) industry. Ideally, the combustion process is supposed to convert the potent methane (CH4) completely into carbon dioxide (CO2), yet in real-world situations this is not the case. According to the International Energy Agency (IEA), flaring is responsible for about 10 % of the total methane emission of the O&G sector. Therefore, it is important to understand and quantify how efficiently the carbon in the flared fuel is converted to CO2, to support the mitigation of flaring emissions. This is especially the case for countries with high reliance on the O&G industry, and a clear commitment to achieve net zero emissions by 2050, such as the Sultanate of Oman.
This study presents the first thorough examination of flaring emissions in Oman using a novel airborne platform. The measurements were performed during the METHANE-To-Go-Oman field experiment funded by UNEP's International Methane Emissions Observatory (IMEO), which was conducted from November to December 2023. It used a unique helicopter-towed probe called HELiPOD. The experiment covered six pre-selected O&G facilities within three concession areas in northern and southern Oman, during ~70 flight hours.
In this study, VIIRS Nightfire data were used to identify the flaring plume positions and measured in situ data from the HELiPOD were used to capture the plume composition. The airborne in-situ instruments include: Picarro G2401-m to measure CH4 and CO2 with a high precision (1 ppb), Licor-7700 for high CH4 temporal resolution measurements up to 40 Hz, and Licor-7500A for CO2. Also, a variety of data related to combustion products and by-products were collected such as aerosols, water vapor, and temperature, which can be used to verify and understand the chemical and physical characteristics of the flaring plumes. Furthermore, various meteorological data were collected during the experiment, such as the 3D wind vector, which was crucial for the flaring plume identification.
The lowest flaring efficiency observed in this study was related to a gas facility. Providing valuable insights into the flaring emissions is the aim of this study, which could be translated into mitigation opportunities for policymakers and the industry.
How to cite: Al-Hinaai, H., Huntrieser, H., Förster, E., Maier, N., Pätzold, F., Bretschneider, L., Lampert, A., Lunt, M., Roiger, A., and Chen, J.: Gas Flaring Efficiencies of Selective Oil and Gas Facilities in the Sultanate of Oman, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12842, https://doi.org/10.5194/egusphere-egu25-12842, 2025.
Methane is the second largest greenhouse gas after carbon dioxide, and the oil and gas industry is a significant anthropogenic methane emission source. In this study, methane emission was estimated in two scenarios from 2000 to 2060. Combined with the emission sources and the cost-effectiveness of current emission reduction technologies, the marginal abatement costs of those technologies in 2030 and 2060 were estimated. The results showed that: methane emissions from petroleum system decreases slightly, while methane emissions from natural gas system will grow slowly in 2020 to 2060. The reduction potential from technology application with negative benefits in 2030 and 2060 was 22.0% and 44.4%, respectively. From 2021 to 2023, the Chinese oil and gas industry have applied remote sensing, vehicle-based or drone-based site level measurements, and leak detection and repair during the national carbon monitoring trial project. The applicability of various measurement methods were tested in diverse oil and gas basins, a measurement-based methodology for the generation of emission factors were raised. In the mid- and long-term, the oil and gas industry of China needs to accelerate the construction of a robust measurement, reporting and verification system (MRV) , moving towards a measurement-based inventory, while providing guidance on methane abatement for local oil and gas operators. The next generation of leak detection and repair technology, and the co-treatment of methane/volatile organic carbon are the future directions for technology development. The incorporation of green economy, China certified emission reduction (CCER) would further foster the application of methane emission measurement and reduction in the industry.
How to cite: Xue, M., Wang, Y., Nie, F., and Jiang, D.: Methane emission reduction potential in the Chinese oil and gas industry, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14581, https://doi.org/10.5194/egusphere-egu25-14581, 2025.
Methane is a critical focus of international efforts to achieve short-term reductions in greenhouse gas emissions. Oil and gas and waste sector methane sources are understood to be the easiest and fastest to mitigate, but require robust measurement-based emissions inventory protocols to identify sources, to prioritize mitigation actions, and to track success or failure in reducing emissions. In particular, the complexity and variability of oil and gas sector sources necessitates combining measurements and data at different scales to accurately define the full distribution of emissions. This presentation describes the use of a hybrid, top-down / bottom-up inventory protocol to inform Colombia’s national methane inventories. The top-down campaign conducted between March and May 2024, comprised aerial LiDAR measurements at 3,826 oil and gas sector sites across 6 different production regions as well as measurements at three landfills. A separate bottom-up campaign is currently scheduled for the first quarter of 2025 and will include OGI surveys at approximately 320 sites, along with targeted measurements of select tanks, compressor engines and flares at a subset of 20 sites. Preliminary results from the top-down approach for both oil and gas and waste sectors will be discussed during the presentation, along with progress toward completing Colombia’s first-ever measurement-based methane inventory for the oil and gas upstream sector. This study, funded by UNEP - International Methane Emissions Observatory (IMEO) is intended to support MMRV development and verified reporting under the International Oil and Gas Methane Partnership (OGMP 2.0).
How to cite: Calderon-Cangrejo, N., Festa-Bianchet, S. A., Conrad, B. M., Tyner, D. R., Wilde, S. E., and Johnson, M. R.: Progress Toward a First Measurement-Based Oil and Gas Sector Methane Inventory for Colombia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13193, https://doi.org/10.5194/egusphere-egu25-13193, 2025.
Romania is one of Europe’s oldest oil and gas (O&G) producers with a history dating back to 1857 and remains one of the major producers within the EU. The country’s O&G sector continues to play a significant role in the regional energy supply, and recent discoveries of large natural gas reserves in the Black Sea highlight Romania’s interest in even further development. However, the recent EU regulation on methane (CH4) emissions requires member states to mitigate and to improve accuracy of measurement, reporting, and verification of emissions. Uncertainty in current CH₄ emission estimates and the lack of empirical data until now presents significant challenges in meeting climate objectives.
The ROMEO (ROmanian Methane Emissions from Oil and Gas) project aimed to provide independent, scientific estimates of CH₄ emissions from Romania’s onshore O&G sector. Using a range of measurement techniques including ground-based, drone-based, and airborne-based platforms, the project focused on the upstream O&G sector during three intensive campaigns in 2019 and 2021. Phase I targeted the oil production region of southern Romania, Phase II focused on gas production sites in Transylvania, and Phase III involved a follow-up survey in southern Romania. Results from the studies reveal a significant underestimation of CH4 emissions in the national inventory from Romania’s O&G industry in 2019 and 2021, highlighting the substantial mitigation potential within the country’s O&G production infrastructure.
This synthesis consolidates findings from the ROMEO project’s multi-scale measurement campaigns and offers a comprehensive assessment of CH₄ emissions across facility types and regions in Romania. The implications of these findings are also discussed for both mitigation strategies and inventory reporting. One of the challenges is that activity data used for the measurements (e.g. oil production sites and other infrastructure locations) are not the same as the ones used in the reporting in countries using the Tier 1 approach (e.g. oil or gas production rates). This simple difference fundamentally complicates the direct incorporation of research findings into the reporting. We explore how field measurements can more effectively inform and improve inventory methodologies and support the development of more accurate emissions inventories.
How to cite: Stavropoulou, F., van der Gon, H. D., Baciu, C., Ardelean, M., Calcan, A., Schwietzke, S., Zavala-Araiza, D., and Röckmann, T.: Synthesis of the ROMEO Project Findings: Assessing Romania’s O&G Methane Emissions and Advancing Accurate Methane Emission Inventories, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19062, https://doi.org/10.5194/egusphere-egu25-19062, 2025.
The vast gas reservoirs in the Transylvanian Basin have been exploited for over a century, primarily managed by the state-owned company ROMGAZ. With over 100 gas fields scattered throughout the region, it remains the foremost gas producer among Central and South-Eastern European countries. The International Energy Agency estimates that 45% of emissions reductions from the energy sector can be achieved at no net monetary cost and could even result in economic savings, considering methane's commercial value as the main component of natural gas.
Five teams with participants from Poland and Romania were deploying various techniques (GPM, OTM-33A, High Flow Sampler, Tracer release, large-scale flux chamber and screenings) for quantifications of the methane emission rates. Additional instruments from other participants of the ROMEO project were shipped to Romania and used for mobile measurements. A total of 520 individual sites from the O&G operator inventory were at least screened for a source of emissions attribution. 160 quantifications with 5 techniques were performed. The study focuses on combining all measurement methods as complementary tools for emission quantifications. We attempt to upscale the emission for the Transylvanian basin based on 18% of the operator’s active inventory in the region.
The findings presented were made possible through equipment funded by the "Excellence Initiative - Research University" program at AGH University of Science and Technology. The authors express their gratitude to all participants and supporters of the ROMEO campaign. Work on this study is supported by UNEP’s IMEO. Future research focused on quantifying emissions from oil and gas is planned as part of the IM4CA “Investigating Methane for Climate Action” project.
How to cite: Jagoda, P., Nęcki, J., Bartyzel, J., Figura-Jagoda, A., Radovici, A., Mereuta, A., Baciu, C., and Roeckmann, T.: Estimation of methane emissions from gas excavation activities in the Transylvanian Basin, Romania., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17584, https://doi.org/10.5194/egusphere-egu25-17584, 2025.
Methane (CH4) emission quantification that is based on ground level measurements of enhancements in CH4 in air concentrations requires instruments that are accurately calibrated with fit for purpose gas standards. Developments in the availability, accuracy and internal consistency of CH4 in air gas standards will be described, with standards now available with standard uncertainties below 1 nmol/mol over the range of below ambient background concentrations to over 3000 nmol/mol. When greater levels of precision are required for the measurement of enhancements in CH4 concentrations, the scale approach for standards can be adopted, as is done for WMO mole fraction scale standards for CH4 in air, with recent comparative measurements demonstrating that internal consistencies between standards of 0.1 nmol/mol can be reached.
According to WMO, the annual increase in atmospheric CH4 was 16 nmol/mol in 2022 and 11 nmol/mol in 2023, both of which exceed the average growth rate observed over the past decade. In addition, enhancements in atmospheric CH4 concentrations at short temporal scales due to localized emissions can be measured at ground-level. When selecting gas calibration standards to be used for such measurements, the achievable uncertainty and internal consistency of the standards used needs to be considered. The aim is to ensure that measured changes can be undoubtedly attributed to atmospheric concentration enhancements, and not to differences in standards used at different sites. Additionally, a consistent system in which all measurement results are traceable to the same references allows different datasets to be combined without the introduction of biases.
To enhance the accuracy, reliability, and robustness of global CH4 measurements over the past two decades, the BIPM, National Metrology Institutes (NMIs) and the WMO’s Central Calibration Laboratory have worked on improving the system of CH4 standards traceable to the International System of Units (SI), and demonstrating equivalence with standards developed for the WMO scale, the latter used principally for background CH4 trend measurements .
Improvements in the compatibility of CH4 in air standards from 2003 to 2023 will be described. Current standards now have accuracies of better than 1 nmol/mol, and pairwise comparisons of standards have demonstrated internal consistencies of 0.1 nmol/mol in sets of standards from National Metrology Institutes and the WMO’s CCL. This builds upon preliminary comparisons of primary CH4-in-air gas standards conducted in 2003 (CCQM-P41), showing a standard deviation of approximately 30 nmol/mol and 10 nmol/mol for a more limited set of standards. Whereas in 2013, the CCQM-K82 comparison studied CH4-in-air primary reference mixtures in the range of 1800 nmol/mol to 2200 nmol/mol, with a demonstrated tenfold improvement in compatibility, with uncertainties of reference values for standards ranging from 0.68 nmol/mol to 0.71 nmol/mol and a standard deviation of 1.70 nmol/mol across the standards. In 2023, a new comparison (CCQM-K82.2023) was conducted to further monitor the compatibility of CH4-in-air primary reference mixtures within the 1800–2200 nmol/mol range. Preliminary results will be discussed, as well as progress in extending the availability of CH4 in air scale standards, when the very highest levels of internal consistency between standards is required.
How to cite: Flores, E., Viallon, J., Choteau, T., Moussay, P., and Wielgosz, R.: Advancements in Methane in Air Standards for ground-based concentration measurement and emissions quantification, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-428, https://doi.org/10.5194/egusphere-egu25-428, 2025.
Natural gas appliances and piping in buildings, or post-meter sources, are estimated to represent 15% of U.S. natural gas distribution sector emissions of methane. However, recent atmospheric methane measurement studies in urban areas indicate that end use emissions may be several times higher than currently estimated in national inventories. National inventories use bottom-up methods to estimate post-meter methane emissions, but due to the relatively small set of direct measurements, if available, many inventory estimates are likely to be highly uncertain. Moreover, there are systematic differences in building heating systems and natural gas appliance usage across countries and regions. For example, North American households mainly use forced air systems that rely on ducts and vents; while in Germany, it is common to distribute heat from a central heating unit through radiators. Therefore, although there have been several publications of direct measurement studies conducted in the U.S., it is difficult to extrapolate these findings to other countries and regions, including Germany, the largest natural gas user in Europe.
To better understand and quantify emissions from natural gas end use in Germany, we analyze spatially-integrated tall-tower eddy covariance surface fluxes of methane and conduct direct measurements of methane emissions from natural gas appliances and piping in homes and other buildings. The measurement data includes gas composition analysis and are analyzed in conjunction with natural gas appliances and building attributes. Our results can inform effective methane emission mitigation strategy development and energy transition policies in Germany and elsewhere.
How to cite: Kang, M., Hilland, R., Weghorst, T., Sanzol Rieth, T., Chen, J., Schloemer, S., Blumenberg, M., and Christen, A.: Direct measurements of methane emissions from natural gas end use in Germany, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5106, https://doi.org/10.5194/egusphere-egu25-5106, 2025.
The increasing atmospheric concentrations of carbon dioxide (CO2) and methane (CH4) from anthropogenic activities pose a major challenge for climate change mitigation. Methane, with a global warming potential 28 times greater than CO2 over a 100-year period, is the second most impactful greenhouse gas (GHG) and requires urgent attention. Effective CH4 reduction hinges on addressing emissions at the level of industrial facilities (natural gas), landfills, and farms. Consequently, the development of reliable tools for site-specific emission detection and quantification is critical for implementing targeted mitigation strategies.
Recent advancements in CH4 atmospheric measurement techniques have enabled in situ mobile technologies deployed on aircraft, cars and now unmanned aerial vehicles (UAVs). UAVs can sample dispersion plumes at both point and facility scales, particularly in challenging locations where traditional methods may fall short (Liu et al., Atmospheric Measurement Techniques, 2024). Here we describe a dual-ground/air approach combining simultaneous CH4 measurements from mobile (car mounted) and aerial (drone-based) systems. This integrated method provides complementary data, offering improved coverage into methane plume dynamics and spatial distribution.
The UAV system employs an ABB LGR GLA131 sensor and 3D wind measurements on a high endurance octocopter with advanced autopilot capabilities, enabling precise detection and quantification of methane sources. The mobile platform features the MIRA Ultra Mobile LDS, delivering high resolution, ground-level emission mapping. Together, these platforms enhance the accuracy and scope of CH4 monitoring efforts.
We present measurements at sites revisited from earlier work that relied only on mobile measurements (Liu et al., Science of The Total Environment, 2023). This earlier work revealed that top-down estimates of methane emissions from waste and livestock in Cyprus exceeded bottom-up national inventory values by 160% and 40%, respectively. Integrating car- and drone-based mapping enables three-dimensional plume characterization providing an enhanced plume sampling and hence more precise quantification estimates. It sheds light on plume development, dispersion, and variability. This framework is particularly advantageous for tackling emissions from diverse and mixed sources such as agricultural operations, industrial facilities, and landfills, where complex environmental and topographical factors influence methane behaviour.
How to cite: Papaconstantinou, R., Paris, J.-D., Quehe, P.-Y., Kezoudi, M., Biskos, G., and Sciare, J.: A dual-platform approach for quantifying methane emissions at site level, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21353, https://doi.org/10.5194/egusphere-egu25-21353, 2025.
Eddy covariance observations are particularly well suited to study emission processes at the ecosystem scale. Here we combine longterm observations of methane, carbon dioxide and nitrogen oxides, with campaign-based observations of NMVOC fluxes in an urban area. The complex dataset allows unravelling the fate of urban methane emissions for the city of Innsbruck. Our analysis shows that most of the methane in the urban area is emitted via pre-flush operation and partially burned methane from poorly maintained gas furnaces. Methane fluxes show a negative temperature dependence and are highly correlated with ethane fluxes. An average ethane to methane flux ratio of 5% is observed, consistent with the gas composition supplied to Western Austria/Southern Germany. The 20y GWP of the emitted methane in the residential, commercial and public sector can be as high as 20-30% relative to CO2. This study shows that the conversion of gas furnaces to heat pumps can have an additional immediate benefit through the reduction unburned methane.
How to cite: Karl, T., Stichaner, M., Jud, W., Lamprecht, C., Jensen, N., Manca, G., Peron, A., Graus, M., and Naqui, S.: Longterm urban eddy covariance observations of methane and other trace gases reveal characteristic anthropogenic emission hotspots, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5202, https://doi.org/10.5194/egusphere-egu25-5202, 2025.
Reducing methane (CH4) emissions offers the opportunity to slow down global temperature rise in the near term. More than 10 % of anthropogenic CH4 is emitted by the degradation of solid waste, when accumulated in open dumps or managed landfills. Methane production at solid waste sites depends upon various parameters, influenced by waste composition and amounts, landfill operation, as well as climate and meteorological variables. Therefore, landfill emissions are spatially and temporally heterogeneous, which challenges global mitigation efforts.
Atmospheric measurements from ground and aerial vehicles can be used to quantify and monitor emissions on a facility level. Large facilities located nearby densely populated areas are emission hotspots that can be detected with satellite instruments. We present a case study of the use of CH4 satellite data to derive emission estimates of the Miramar landfill in California, United States. We used observations from UNEP’s International Methane Emissions Observatory (IMEO), through its Methane Alert and Response System (MARS) to detect and quantify four CH4 plumes measured with EMIT satellite between August 2023 and August 2024. We characterized the landfill in terms of amounts and composition of waste, population served and development index, landfill management and gas capture infrastructure, as well as temperature and precipitations.
Estimated fluxes were 1.69 ± 0.85, 2.74 ± 1.38, 4.79 ± 2.41 t/h and 38.7 ± 19.4 t CH4/h. The exceptionally high maximum likely occurred while the gas collection system was down. The landfill operator declares a total amount of 20,790 t CH4 collected over the year 2023 and reports total emissions equivalent to 1.56 and 0.526 t CH4/h, based on the two US-EPA standards methods. The reported emissions and our observed estimate reveal substantial methane losses, despite apparent gas recovery efforts.
These inconsistencies, combined with the variability in satellite-derived fluxes, underscore the difficulty of aligning measurement methodologies. They highlight the need to integrate satellite observations, landfill operations data, and inventory models to refine methane emission estimates to support more effective mitigation strategies.
Our case further shows that atmospheric measurements and the analysis of landfill characteristics can be used in a global classification of facilities and to derive appropriate emission factors. We therefore identified opportunities brought by this measurement-based approach, going from small scale to larger scale: (1) to target efficient methane mitigation action at large-emitting facilities, (2) to quantify the efficiency of waste management policies, (3) to improve country-reported contributions.
This research has been funded in the framework of UNEP’s IMEO.
How to cite: Menoud, M., Abichou, T., Irakulis Loitxate, I., France, J. L., and Calcan, A.: Improved estimations of waste-related methane emissions using satellite observations: a case study on a US landfill, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16833, https://doi.org/10.5194/egusphere-egu25-16833, 2025.
The detection and quantification of anthropogenic CH4 emissions is still a challenge due to the complex and heterogeneous distribution of the emitters and the large variability, e.g. leakages in the natural gas network, biogas plants, agriculture, waste and wastewater treatment. Mobile measurements at street level, using cars or bicycles, are a good way to detect methane emission sources. The measured CH4 peaks can be converted to emission rates using a Gaussian plume model.
The emission factors for the waste and wastewater sector as well as for biogas plants are still subject to large uncertainties. In this study, mobile measurements for several CH4 source categories in Germany are presented. The main focus is on CH4 emission rates from the waste and wastewater sector and from biogas plants. We performed mobile methane measurements to detect emission plumes from more than 30 different biogas plants in Germany, focusing on one biogas plant for long-term monitoring since 2016. Methane emission rates ranged from 0.1 to 46 kgCH4/h. This corresponds to a loss relative to the biogas production rates of 2 to 13 % l. Measurements at several wastewater treatment plants show CH4 emission factors between 0.04 and 1.9 kg CH4/a per capita.
The determined emission rates are statistically analysed and compared with the emission factor used in regional and national inventories.
How to cite: Schmidt, M., Wietzel, J., Gonser, T., Sauer, I., and Zeleny, M.: Detection and quantification of anthropogenic methane emissions in Germany using mobile measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20392, https://doi.org/10.5194/egusphere-egu25-20392, 2025.
Methane is a significant contributor to global warming, with its radiative forcing being approx. 32 times greater than that of CO2 over a hundred-year time frame. To advance the understanding of the earth's climate and mitigate global warming, collecting precise and reliable CH4 concentration data is essential.
We present a mobile measurement unit to identify and map local methane sources. The unit is mounted on a cargo bike, enabling flexible use in urban areas such as parks, pedestrian zones, or event spaces. It incorporates a high-precision CRDS trace gas analyzer (Picarro G2401) to measure CH4 concentrations and a wind sensor to capture wind speed and direction. A shock-absorbing frame ensures suspension during the transporting of the analyzer and supporting equipment. The mobile unit’s power distribution system allows dynamic switching between mains and battery power and hot-swapping of batteries during operation. A modular software stores the collected data and displays the mapped concentrations in real-time to the cargo bike driver via smartphone.
We conducted 13 measurement trips across Munich, covering a total distance of 170km, to map areas with potential methane emissions, including two wastewater treatment plants, a former landfill, a combined heat and power plant, and the Oktoberfest grounds. Fluctuations up to +2% above the baseline were observed across the city. The baseline was defined as the 5th percentile of all measurements of the corresponding trip. Additionally, significant enhancements of up to 204.9 ppm were detected, which were attributed to an unidentified methane leak near Munich's central station, with an estimated emission rate of 20.5 l/min.
We further integrated an OF-CEAS trace gas analyzer (LI-COR LI7810) into the setup for three side-by-side trips, allowing for a preliminary comparison and assessment of analyzer performance.
With this setup being easily transferable to other cities or, e.g., industrial parks, a versatile tool is present to detect and analyze methane sources and advance methane emission mitigation.
How to cite: Asam, C., Kühbacher, D., Luther, A., Stauber, J., and Chen, J.: Development of a Mobile Measurement Unit to Identify and Map Local Methane Sources, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10770, https://doi.org/10.5194/egusphere-egu25-10770, 2025.
The Oil and Gas Methane Partnership 2.0 (OGMP 2.0), led by the United Nations Environment Programme (UNEP) and supported by the European Commission, is currently the only measurement-based international reporting framework for the oil and gas sector. OGMP 2.0 aims to standardize and enhance the accuracy of methane emission reporting, enabling the industry to systematically quantify and reduce emissions.
This study introduces a robust methodology to meet OGMP Level 5 requirements, which call for site-level methane measurements integrated with specific Emission Factors (EF) and Activity Factors (AF) for individual sources. Previously, emissions reporting relied solely on inventory data, but independent site-level measurements now reconcile source-level inventories (Level 4) and thus enhance confidence in reported emissions.
The Dutch oil and gas sector serves as a case study. In 2023, the Dutch Emission Registration reported 639 kton of methane emissions nationally, which 17 kton (2.7%) attributed to the oil & gas sector. As part of this study, we measured emissions at over hundred oil and gas production and distribution sites.
We demonstrate the application of the Tracer Dispersion Method (TDM) to quantify methane emissions at the site level. This approach involves releasing a tracer gas with a known emission rate and measuring its concentration, along with methane, downwind of the facility with a specially equipped measurement truck. We determine the concentration of various gaseous components, allowing us to differentiate the emissions to the various types of sources that may be present. We drive by at multiple occasions along a predetermined route downwind of the site, enabling us to capture data under various meteorological and operational conditions. This ensures robust data collection and facilitates the automatic determination of the site-level emission factor, significantly reducing associated uncertainties.
This methodology not only complements source-level measurements but also improves the detection of previously unidentified emission sources, enhancing the overall reliability of emission inventories. We will discuss the requirements, advantages, and limitations of the TDM approach and outline next steps for further refinement.
By providing a scalable and accurate methodology for site-level methane quantification, this work contributes to the global effort to achieve transparent and actionable emission reduction strategies in the oil and gas sector.
How to cite: de Bruin, G. J., Velzeboer, I., van Dinter, D., van den Bulk, P., van Mansom, H., Thera, B., and Hensen, A.: Advancing methane emission quantification: a robust methodology for site-level measurements, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14858, https://doi.org/10.5194/egusphere-egu25-14858, 2025.
The oil and gas industry is responsible for 22% of global methane emissions (Saunois et al. 2020), yet accurately quantifying them remains a significant challenge. Oil and gas facilities often underreport methane emissions due to reliance on bottom-up estimation methods based on theoretical calculations and their susceptibility to systematic errors. Accurate top-down quantification tools for methane emission fluxes from this sector are crucial.
We evaluate a novel methodology to quantify methane emission fluxes using the commercially available dispersion model ADMS6 and airborne measurements. The model takes into consideration many parameters such as meteorology, source characteristics, and the dispersion domain topography. This complexity doesn’t implicate high demands on the computing time and the simulation time is short, up to a few minutes.
In September 2024, FAAM flew one mission during a single-blind controlled release experiment organised by Stanford University and TotalEnergies. The International Methane Emissions Observatory sponsored this experiment conducted at the TotalEnergies Anomalies Detection Initiatives (TADI) site in Lacq, southwest France. FAAM targeted three separate releases with controlled methane rates up to 60 g/s. Over 40 orbits were flown at distances at 3.5 and 9 km around the TADI site over 3 hours, at altitudes between 180 and 500 m above ground.
We present fast CO, CO2, CH4, SO2, NOx and 0.1–3 µm aerosol number concentrations and interpret the sampled emission sources. We discuss the meteorological conditions encountered during the mission and their impact on the release atmospheric dispersion modelling. We evaluate the accuracy of our quantification methodology against the known release rates and identify shortcomings and how they can be circumvented. Despite the challenging sampling conditions, we successfully detected emissions and confirmed the extent of our method validity.
How to cite: Łakomiec, P., Bauguitte, S., Monreal Campos, I., Baker, M., Sproson, D., McManemin, A., Brandt, A., Juéry, C., Blandin, V., and Jourde, J.: Validation of a methodology for methane flux quantification from an aircraft using a controlled release experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19193, https://doi.org/10.5194/egusphere-egu25-19193, 2025.
Efficient methane reduction efforts require reliable, measurement-based and transparent inventories. Site-level technologies serve as essential tools for gathering data on emissions at operational sites. However, significant knowledge gaps persist regarding the performance of these technologies in real-world conditions and their effective utilization to enhance the accuracy of reported data by operators. This study evaluates the snapshot reconciliation - an instantaneous comparison- of site and source level quantification methods to provide midstream operators with general recommendations when the relevant quantification methods and reconciliation practices are applied at their sites.
Prior to this campaign, which took place at a compressor station in Zelzate, data from a previous phase of the project conducted in Spain -where controlled releases were carried out in real-world conditions- were analysed to understand the uncertainties associated with site-level technologies. This analysis was used for the selection of technologies with the best performance, i.e. closeness of the technology providers’ emission quantifications to the controlled and blind release rates. In Zelzate, a two-day campaign was designed, consisting of two distinct phases based on the operational status of one of the site’s compressors. During the campaign, site-level quantification methods were deployed in parallel with source-level quantification techniques.
The reconciliation process was assessed to understand how it can be implemented for verifying bottom-up data. Following the results of this test, detailed recommendations for implementing snapshot reconciliation were provided in alignment with OGMP 2.0 (Oil and Gas Methane Partnership 2.0) guideline. These recommendations prioritize identifying and addressing areas of improvement in emission quantification (e.g. bottom-up sampling and measurement strategy) to achieve consolidated Level 5 inventories. Furthermore, reconciliation process should not primarily focus on the potential overlap between site-level and source-level measurements, owing to limited understanding of the uncertainty ranges required for such analyses.
The outcomes of this study offer deep and valuable insights into several key aspects:
- Performance of Site-Level Methods: Understanding the capabilities and limitations of site-level quantification technologies in real-world field conditions.
- Reconciliation Recommendations: Providing practical guidance for implementing effective reconciliation procedures, with a focus on achieving robust and transparent methane inventories.
How to cite: Bescos Roy, V., Maazallahi, H., Ziegler, R., and Zarea, M.: Source and Site Level Reconciliation of Methane Emissions at the Midstream Sector, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18230, https://doi.org/10.5194/egusphere-egu25-18230, 2025.
Posters virtual: Wed, 30 Apr, 14:00–15:45 | vPoster spot 5
EGU25-14903 | Posters virtual | VPS3
Advancing Greenhouse Gas Mapping with JPL Imaging Spectrometers: AVIRIS, EMIT, and Carbon-IWed, 30 Apr, 14:00–15:45 (CEST) vPoster spot 5 | vP5.37
Over the past 15 years, imaging spectrometers developed at the NASA Jet Propulsion Laboratory have significantly advanced the field of remote sensing of methane (CH4) and carbon dioxide (CO2) point source emissions. This began in 2008 with airborne observations from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), 2013 with the next generation AVIRIS-NG instrument, and has culminated with the launch of NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) in 2022.
These instruments have identified thousands of CH4 and CO2 point source emissions across the oil and gas, waste, and energy sectors, contributing in some cases to emission mitigation efforts. As part of an extended mission, EMIT coverage will expand beyond the arid regions of Earth to cover terrestrial surfaces between +51.6° and −51.6° latitude, enabling direct attribution of anthropogenic emissions on a global scale. EMIT's measurements and greenhouse gas data products are accessible through NASA’s Land Processing DAAC and the U.S. GHG Center, with all associated code available as open source. These data are already being utilized by public, private, and non-profit organizations, including UNEP IMEO and the Carbon Mapper Coalition. Additionally, new airborne instruments, such as AVIRIS-3 (2023) and the planned AVIRIS-5, promise enhanced sensitivity to CH4 and CO2 point sources, offering the potential for direct comparisons with satellite-based EMIT observations.
The Carbon Investigation (Carbon-I), a proposed mission for the NASA Earth System Explorer Program, reflects a dramatic advancement in greenhouse gas mapping capability. It provides a unique combination of coverage, high spatial sampling, and very high sensitivity, to permit quantification of emissions that cannot be observed with current technology. With contiguous global observations of CH4, CO2, and CO at 300 m sampling every 28 days with targeted observations at 30 m sampling, Carbon-I will permit emission quantification at the global to regional scales as well as for localized point sources. Consistent with NASA’s Open Source Science Initiative, all Carbon-I data and code will be publicly accessible, empowering Earth Action initiatives worldwide.
How to cite: Thorpe, A., Green, R., Frankenberg, C., Michalak, A., Thompson, D., Brodrick, P., Chadwick, D., Eastwood, M., Scott, V., Frazier, W., Fahlen, J., Coleman, R. W., Xiang, C., Jensen, D., Villanueva-Weeks, C., Lopez, A., Vinckier, Q., Bender, H., Chlus, A., and Chapman, J.: Advancing Greenhouse Gas Mapping with JPL Imaging Spectrometers: AVIRIS, EMIT, and Carbon-I, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14903, https://doi.org/10.5194/egusphere-egu25-14903, 2025.
