AS3.12
Orals: Thu, 27 Apr | Room M1
The sabotage of the Nord Stream pipelines on 26 September 2022 led to the largest event of methane venting to the atmosphere on record. The pipelines contained about 300 000 tonnes of methane, and an estimate based on Europe's ICOS network quantified the emissions to the atmosphere at 90 000-300 000 tonnes of methane in the first days of the event (Ramonet et al., 2022). The vast majority of methane that vented from the pipelines into the water likely escaped to the atmosphere near-instantly via bubble transport, which had largely ceased by 1 October 2022. However, a fraction dissolved into the water. To investigate the possibility of a "long tail" of release of this dissolved methane to the atmosphere, we conducted airborne surveys of the leak area on 5 October 2022. Methane data were recorded with a Picarro G2401m onboard the HELiPOD platform, a drag probe attached to a helicopter with a rope, down to 30 m above sea level. We observed methane enhancements of up to 300 ppb above atmospheric background, in an area about 30 km both up- and downwind of the leak locations. Using an inverse model of atmospheric transport, we show that the atmospheric data can be explained by an area source and estimate a source strength on the order of tens of tonnes of methane per hour on the day of observations. To better understand the spatial distribution of the emissions, especially emissions upwind of the leak locations, we further run a model of oceanic transport for tracers released at the leak locations and couple it to a Wanninkhof-model of diffusive emissions. The areal emission distribution we find with this model has some similarities to the emission pattern retrieved using the airborne measurements. We conclude that a significant amount of methane was dissolved in the Baltic Sea during the outgassing event following the Nord Stream explosions. Methane that was initially dissolved in the surface layer still escaped to the atmosphere days after the initial outgassing event.
How to cite: Reum, F., Marshall, J., Bretschneider, L., Glockzin, M., Huntrieser, H., Gottschaldt, K.-D., Lampert, A., Lichtenstern, M., Miller, S. M., Pätzold, F., Pühl, M., Rehder, G., and Roiger, A.: Methane emissions from the Baltic Sea nine days after the Nord Stream explosions, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14408, https://doi.org/10.5194/egusphere-egu23-14408, 2023.
Methane is emitted during the production and transportation of fossil fuels. Methane emissions result also from intensive livestock farming and agricultural practices as well as by the decay of organic waste. The leakage throughout the extraction, processing and transportation of natural gas releases methane straight into the atmosphere. Due to the damage to the Nord Stream gas pipelines on 26 September 2022 leaks have appeared close to the Danish island of Bornholm in the Baltic Sea, which releases large amounts of methane in the pipeline into the atmosphere within just a few days. In our study, we simulated the transport of methane plume in Nord Stream case by using DWD’s regional Icosahedral Nonhydrostatic (ICON) model with its transport scheme ART (Aerosols and Reactive Trace gases) extension.
The model is run for Limited Area Mode (LAM) with a horizontal spatial resolution of 6.5 km and 60 model levels. As source strength of methane emissions were used the estimates which were calculated by the German Federal Environmental Agency (Umwelt Bundesamt). An assumption, that a constant 700 kg/s of gas had been leaking since September 26 was used for the hourly model run to simulate the methane plume between September 26 and October 1 2022.
The model results had been compared to the potential methane signals of Nord Stream leaks detected at Integrated Carbon Observation System (ICOS) stations. According to our simulations, we found a good fit with respect to ICOS observations for the stations Hyltemossa, Birkenes and Norunda. Further analysis has been conducted to look at vertical profiles at different heights and also into correlation coefficients between the model and observations.
In this Nord Stream case, our simulation demonstrates modelling capabilities of the ICON-ART model and its associated quantitative assessment of methane emissions.
This work has been funded by the German Federal Ministry for Digital and Transport programme for Development and Implementation of Copernicus services for public needs within the HoTC project.
How to cite: Sunkisala, A., Mamtimin, B., Rösch, T., Roth, F., and Kaiser-Weiss, A.: Nord Stream methane leaks case: ICON-ART model simulation versus observations at various ICOS stations, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7158, https://doi.org/10.5194/egusphere-egu23-7158, 2023.
Carbon dioxide and methane are the two primary anthropogenic climate-forcing agents and are the dominant source of uncertainty in the global carbon budget. We present the first observations of methane and carbon dioxide point source plumes from the oil&gas, waste management, and energy sectors using the Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer. An initial analysis of results from selected countries in the Middle East and Central Asia indicate that Turkmenistan has both the greatest number and largest methane emissions observed in this study. EMIT measures 285 distinct wavelengths between 381 and 2493 nm with a 7.4 nm spectral resolution and an 80 km image swath with a 60 m spatial resolution. EMIT’s daily coverage is equivalent to an area the size of South Africa and its revisit frequency will permit an assessment of emissions over time. By providing the locations of emission sources, these results offer the potential to improve our understanding of global greenhouse gas budgets and to inform mitigation strategies.
Figure 1: Example of 12 methane plumes observed by NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) mission east of Hazar, Turkmenistan.
How to cite: Thorpe, A., Green, R., Thompson, D., Brodrick, P., Chapman, J., Elder, C., Irakulis Loitxate, I., Cusworth, D., Ayasse, A., Duren, R., Guanter, L., and Frankenberg, C.: Mapping methane and carbon dioxide point sources from space with EMIT, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9429, https://doi.org/10.5194/egusphere-egu23-9429, 2023.
The reduction of anthropogenic methane emissions, and especially those from the fossil fuel industry, is one of the most effective ways to slow down global warming in the next decade. Methane emissions from fossil fuel activities often happen as plumes emanating from strong point sources, such as flares, compressor stations, storage tanks, and mine vents.
The Sentinel-5P TROPOMI mission can detect the largest plumes from these sources daily and at a global scale thanks to its continuous spatial coverage and daily temporal resolution. Complementary to TROPOMI, several high spatial resolution satellite missions with sensitivity to methane are now being used to attribute plumes to point sources. These missions, so-called point-source imagers in the methane mapping context, sample the methane absorption features in the shortwave infrared with a spatial resolution of 20-60 m, enabling the detection and attribution of plumes from point sources >200-1000 kg/h. Point-source imagers can be hyperspectral (also known as imaging spectrometers), including the GHGSat, PRISMA, EnMAP, and EMIT missions, and multispectral instruments, such as Sentinel-2, Landsat, and WorldView-3. The observations by these point-source imagers often follow a previous identification of large methane hotspot areas by TROPOMI.
In connection with this increasing landscape of methane-observing satellites, the United Nations Environment Programme (UNEP) is implementing a Methane Alert and Response system (MARS) as part of its International Methane Emissions Observatory (IMEO). MARS was recently launched at COP27 in direct support to the Global Methane Pledge. It relies on the combined use of multiple methane-observing satellites for the systematic detection, attribution and monitoring of methane sources. In its initial phase, the focus is on point sources associated to the energy sector.
In this contribution, we will describe the satellite component of MARS and will provide examples of how satellites are being used to detect and mitigate active methane point sources from the energy sector around the world.
How to cite: Guanter, L., Irakulis-Loitxate, I., Maasakkers, J. D., Aben, I., Lelong, C., Randles, C. A., Zavala-Araiza, D., Hamburg, S. P., and Caltagirone, M.: Methane Alert and response system (MARS): IMEO’s satellite-based system for detection and attribution of methane point sources around the world, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9548, https://doi.org/10.5194/egusphere-egu23-9548, 2023.
Methane (CH4) is the second most important greenhouse gas after CO2. The TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel 5 Precursor (S5-P) satellite measures CH4 at a high horizontal resolution of 7 × 7 km2, showing the capability on identifying and quantifying the sources at a local to regional scale. The Middle East is one of the strong CH4-emitting regions in the world. However, it is difficult to estimate the emissions here because of the uncertainties caused by bright surfaces and high aerosol loadings. Furthermore, several sources are located near the coast or in places with complex topography, where satellite observations are often of reduced quality. We use the product from the University of Bremen, WMF-DOAS XCH4 v1.8 product, which has good spatial coverage over the ocean and mountains, to estimate the emissions in the Middle East. The Aerosol Optical Depth (AOD) data from the MODIS/Aqua satellite instrument, which has a similar overpass time as TROPOMI, was adopted to filter potential unreliable XCH4 in the product.
For the inversion, we use the divergence method of Liu et al., (2021), which has been proven to be a fast and efficient way to estimate CH4 emissions from satellite observations. We have improved our method by comparing the fluxes in different directions for better background corrections over areas with complicated topographies. The temporal filter was established to further filter false emissions caused by surface albedos. We derived CH4 emissions on a grid of 0.2° from 2018 to 2021 and compared them to the latest bottom-up inventory EDGAR v7.0 in the same years. We found significantly lower emissions than EDGAR for the locations that are mainly determined by observed gas-flaring from satellites. Apart from sources of oil/gas production, the emissions from livestock in Saudi Arabia's irrigation zones, which have been reported neither in EDGAR nor other previous studies, are identified and quantified by using our divergence method. Another unexpected finding is that emissions from landfills are fairly stable and strong in some cities like Tehran.
How to cite: Liu, M., van der A, R., van Weele, M., Eskes, H., Veefkind, P., Zhang, X., Kang, H., and Ding, J.: Current potential of CH4 emission estimates using TROPOMI in the Middle East, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7910, https://doi.org/10.5194/egusphere-egu23-7910, 2023.
In May 2022, GHGSat added 3 satellites to its growing methane monitoring constellation, bringing the total to 5 commercial satellites now in operation. Each satellite has a detection threshold of about 100 kg/h and a 25 meters spatial resolution, enabling them to attribute industrial emissions to individual facilities. With its constellation, GHGSat can measure any site in the world with a repeatable methodology multiple times per year, giving a unique view of localized methane emissions on a global scale.
This presentation will focus on the insights that can be obtained from aggregate industrial methane emissions data measured by the GHGSat constellation. Example use cases ranging from local to global monitoring will be presented. In addition, we will discuss the constellation’s imaging capabilities and current methane measurement accuracy. Finally, an update on the next phase of the constellation will be given.
How to cite: Strupler, M., Girard, M., Jervis, D., MacLean, J.-P., Marshall, D., McKeever, J., Ramier, A., and Young, D.: Insights on methane emissions using GHGSat’s constellation, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2304, https://doi.org/10.5194/egusphere-egu23-2304, 2023.
Reported methane (CH4) emissions from Romania's onshore oil and gas (O&G) production contribute 16% to onshore O&G emissions in Europe (55 out of 346 kt, IEA estimate). In October 2019, CH4 emissions from the O&G infrastructure were measured during the ROMEO campaign with a wide range of in situ measurement techniques in southern Romania. The measurements confirmed a log-normal distribution of emissions with a small number "super-emitters" contributing strongly to the overall emissions.
However, overall emissions remain uncertain because some CH4 super-emitters are difficult to identify with ground-based campaigns due to the large number of potential sources and sometimes elevated emission plumes. In contrast, airborne imaging spectrometers are well suited for identifying super-emitters due to their good spatial coverage and sensitivity to vertical columns. To identify super-emitters, the airborne AVIRIS-NG imaging spectrometer was flown in July 2021 in southern Romania covering an area of about 3000 km2 that contains about 80% of known O&G infrastructure in the region.
CH4 enhancements in the AVIRIS-NG lines were retrieved using a quantitative matched-filter method. In total, 38 emission plumes were identified that were assigned to 26 individual sources. Emissions were estimated using the integrated mass enhancement approach and ranged from 13 to 515 kg/h, which suggests annual emissions of about 30 kt assuming continuous emission rates. The sites were visited by ground crews, who confirmed that at least 17 of the sources were also active in December 2022.
The observed 30 kt/a from only 26 sources already represent more than half of the reported emissions from the onshore O&G emissions in entire Romania. The campaign demonstrates the importance of airborne imaging spectrometers to identify and quantify CH4 super-emitters for monitoring CH4 emissions from O&G infrastructure.
How to cite: Kuhlmann, G., Brunner, D., Emmenegger, L., Schwietzke, S., Zavala-Araiza, D., Thorpe, A., Hueni, A., and Röckmann, T.: Quantifying methane super-emitters from oil and gas production in Romania with the AVIRIS-NG imaging spectrometer, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6751, https://doi.org/10.5194/egusphere-egu23-6751, 2023.
The CoMet 2.0 Arctic airborne greenhouse gas measurement campaign took place over Canada in Summer of 2022. For the campaign, the German research aircraft HALO has been equipped with various instruments for remote-sensing and in-situ measurements of CO2 and CH4 and flown over target areas with potential sources of greenhouse gases, either natural (wetlands, thawing permafrost, etc.) or anthropogenic (oil and gas drilling sites, oil-sand mining, open-pit coal mines, landfills as well as biomass-burning in forest fires). With the city of Edmonton, Alberta as campaign base, a variety of sources of methane released due to human activity and adding substantially to the Canadian anthropogenic CH4 budget were conveniently within reach for our measurements.
This presentation focuses on a selection of anthropogenic sources of CH4 in Canada as well as the Valdemingómez and Pinto landfill sites near Madrid, which were targeted during a test flight. We show first results of the evaluation of active remote-sensing measurements that were conducted with DLR's CHARM-F lidar system. By using the Integrated-Path Differential-Absorption (IPDA)-lidar technique, CHARM-F enables measurements of total column concentrations of methane and carbon dioxide along flight tracks. After further adding wind information from auxiliary measurements or models, emission fluxes from localized sources can be estimated. We will highlight the top emitters in terms of estimated emission rate of CH4 (in the 10kt/year range). Those are likely the most promising candidates for mitigation attempts.
How to cite: Fruck, C., Quatrevalet, M., Fix, A., Wolff, S., Wirth, M., and Ehret, G.: First Quantitative Assessment of Anthropogenic Methane Sources Investigated by the CHARM-F Lidar during the CoMet 2.0 Arctic Airborne Campaign, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7283, https://doi.org/10.5194/egusphere-egu23-7283, 2023.
Anthropogenic greenhouse gas (GHG) emissions remain the main concern for global climate change. To reduce and mitigate those emissions both anthropogenic and natural sources must be identified and quantified. However, high northern latitude wetland regions may also overlap with, e.g., fossil fuel extraction sites. Consequently, commonly used passive satellite sensors are often challenged to observe and disentangle those emissions due to challenging illumination conditions and their large ground scene size, respectively.
To investigate anthropogenic and wetland GHG emissions, a team of scientists deployed a comprehensive suite of instruments aboard the German Research aircraft HALO (High Altitude and Long Range Research) during the CoMet 2.0 Arctic mission conducted in Canada in August and September 2022. During the campaign, passive airborne remote sensing measurements by MAMAP2D-Light (Methane airborne mapper 2D light) were combined with active airborne remote sensing measurements by CHARM-F (CH4 Airborne Remote Monitoring – Flugzeug) and in situ GHG concentration measurements, also including an extensive suite of meteorological parameters.
Those column and in-situ concentration observations of CH4 and CO2 will be used to identify and quantify emissions over a wide range of source types and scales in Canada (and Europe). This comprises single point source emissions (e.g., power plants), small areal sources such as landfills (e.g, the Valdemingomez and Pinto landfills in Madrid) and opencast coal mines, and extensive oil and gas exploration sites, including oil sand areas, which might be embedded in natural wetland regions or river deltas. The imaging capabilities of the MAMAP2D-Light instrument enable precise localisation of emissions and therefore mitigation strategies in the case of, e.g., leakages. This work will summarize and present first results and emission estimates from the CoMet 2.0 Arctic mission with a focus on localised emitters observed by the airborne imaging instrument MAMAP2D-Light.
How to cite: Krautwurst, S., Borchardt, J., Huhs, O., Gerilowski, K., Fruck, C., Galkowski, M., Burrows, J. P., Gerbig, C., Fix, A., Bösch, H., and Bovensmann, H.: Anthropogenic and natural CH4 and CO2 emissions observed by a combination of passive, active, and in situ airborne measurements during the CoMet 2.0 Arctic mission in Canada 2022, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13484, https://doi.org/10.5194/egusphere-egu23-13484, 2023.
The province of Saskatchewan, Canada, came under new oil and gas industry emission regulations in 2020 to meet Canada’s methane emission reduction target for 2025. Although the province reportedly met its reduction target only two years into a five-year commitment, this finding was based on a bottom-up inventory whose operator-reported data had not been public until very recently. With these data made public for the first time, we recreated the federal government inventory for Saskatchewan (2012-2022) to better understand where and how emissions have changed in response to new regulations. Not only will this shed light on the regulations themselves (an updated version of which will be under review for Canada’s longer-term targets), but this inventory will also permit more detailed comparisons with forthcoming top-down measurements.
Since new measurements are expected to be included in this inventory structure, we also used recently published aerial LiDAR measurements to update the inventory. Importantly, while the unmodified inventory confirms the significant emission reduction reported by the Saskatchewan Government (~45% reduction), the inclusion of aerial measurement data suggests that emissions may have actually increased over the same time period. We discuss how the manner in which new measurements are included can influence the emission reductions relative to an uncertain baseline year, and we discuss whether a trend can be calculated reliably. Careful consideration will therefore be needed when including new measurement data into existing inventories.
How to cite: Seymour, S., Xie, D., MacKay, K., and Li, H.: Oil and gas industry emissions in Saskatchewan, Canada: a case study in uncertain reduction trends, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8659, https://doi.org/10.5194/egusphere-egu23-8659, 2023.
The global warming potential of methane on a 20-year scale is 80 times larger than that of carbon dioxide. Therefore reducing anthropogenic methane emissions can mitigate greenhouse gas-induced atmospheric warming in the short term. Thus, source attribution and budgeting of methane emissions have received particular attention in recent years. Coal mining activities were found to be accountable for approximately one-tenth of anthropogenic methane emissions. Observations of point sources (like coal mine ventilation shafts) by plume imagery from aircraft of satellites are emerging as a powerful and reliable tool for emission estimates. Yet, while these measurements cover large areas in a short time, the instrument revisiting rates do not allow observation of temporal variability of sources.
We present the results of a case study on source dynamics of coal mine ventilation shafts conducted in the Upper Silesian Coal Basin (USCB), Poland, in June 2022. We deployed a HySpex SWIR-384 hyperspectral camera at 1 km distance to a coal mine ventilation shaft. The camera repeatedly observed blue-sky scattered sunlight above the shaft in the shortwave infrared spectral range, taking approximately 1 minute per image. We detect methane plumes reliably using an adapted matched filter algorithm in the 2.3 μm absorption band. Co-located wind-lidar measurements allow us to estimate source emissions rates by the integrated mass enhancement (IME) method. Thereby, we produce several hundred emission estimates per day based on plume imagery, with an average uncertainty below 300 kg/h for minutely estimates under favourable measurement conditions. Our case study covers four consecutive days and reveals substantial source dynamics on all observed time scales from minutes to days. A 10-minute running average of the emissions can be a factor of 2 smaller or larger than the daily mean and daily averaged emissions ranged from 1.39 tCH4/h to 4.44 tCH4/h.
How to cite: Knapp, M., Scheidweiler, L., Külheim, F., Kleinschek, R., Necki, J., Jagoda, P., and Butz, A.: Quantifying emission dynamics of coal mine ventilation shafts with a stationary hyperspectral camera, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7506, https://doi.org/10.5194/egusphere-egu23-7506, 2023.
Measurements have shown that abandoned oil and gas wells emit methane to the atmosphere, but the estimates of methane emissions at the national scales remain highly uncertain. Here, we provide an overview of available measurement data and studies investigating factors linked to high methane-emitting abandoned wells. We then analyze abandoned oil and gas well data in Canada and the United States to estimate methane emissions for both countries and evaluate uncertainties in the national estimates. Available measurement data indicate that average methane emission rates used as emission factors vary by 3 orders of magnitude or more, even after accounting for plugging status. Plugging status has been shown to be an important predictor of high methane emitting wells; however, there may be other important factors such as age, depth, fluid type and geographical region. Such well attribute data are not consistently available for many abandoned and orphaned oil and gas wells in Canada and the United States. Overall, there is a need for additional measurements of methane emissions from abandoned oil and gas wells and compilation of well attributes to reduce uncertainties in national estimates.
How to cite: Kang, M., Boutot, J., Bowman, L., and El Hachem, K.: Methane emissions from abandoned oil and gas wells: measurements and uncertainties , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8744, https://doi.org/10.5194/egusphere-egu23-8744, 2023.
Abandoned hydrocarbon (oil and gas) wells (AOG) represent a poorly studied source of atmospheric methane, potentially contributing to total anthropogenic fossil methane emission and related climatic impact. Methane leakage from AOG was measured only in a few countries (U.S.A., Canada, the Netherlands, United Kingdom), and available inventories in other countries are incomplete or need quality checks. Methodologies for gas flux measurement are not standardized. New studies have recently started in Italy in order to inventory onshore AOG, design multiple and versatile techniques for methane flux measurement, which can be adaptable to different typologies of well-heads, and to execute first measurements. Preliminary data revealed the existence of several AOW releasing relevant amounts of methane (orders of 101 ton yr-1), which are up to two orders of magnitude above those typically observed in North America. Contextualization of such “mega-emitters” (their percentage with respect to total AOW, technical conditions, possible existence in other countries) is necessary to assess average emission factors and derive bottom-up methane emission estimates at national and global scale.
How to cite: Procesi, M., Etiope, G., Ciotoli, G., and Moroni, M.: Methane emissions from abandoned hydrocarbon wells in Italy: inventory, measurement techniques and the role of mega-emitters, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7282, https://doi.org/10.5194/egusphere-egu23-7282, 2023.
Fugitive emissions from gas distribution are a top target for reduction of CH4 emissions to atmosphere with the UN considering that emissions from fossil fuel activities can be reduced by 61% (UN, 2021). Once the emissions are identified there are mitigation solutions to stop the leaks far more easily than emissions from waste and agricultural sectors. The RHUL group has identified fugitive methane from UK sources using a mobile survey vehicle since 2013, initially to identify plumes and characterise the emissions by source category using isotopic signatures (δ13C) and ethane to methane ratios (C2:C1). More recent measurements have focussed on CH4 emissions from buried city gas pipelines, primarily London, and development of methodology for interpreting data from a range of different high-precision instruments.
Much of the gas in the UK distribution system has very similar charactersistics once mixing downstream of terminals has taken place. This is typically characterised by δ13C signature of -39 ± 1 ‰ and C2:C1 of 0.055 ± 0.015, which make it distinct from agricultural, waste and combustion CH4 sources. The small proportion of gas coming from the Southern North Sea and Morecambe Bay fields (now <20%) is more enriched in 13C (-34 to -28 ‰) and terminals receiving gas from these locations have different emission signatures; that for the Bacton terminal can be traced downstream toward London.
City measurements by Picarro 2301 and LGR UMEA of London and Birmingham pipeline gas leaks in 2019 have been used to quantify emissions using methodology developed by Weller et al. (2019) and refined by Maazallahi et al. (2020). A total estimated emission for the Greater London area of 2.2 kT (Fernandez et al., in prep.), is much lower than the inventory suggests and lower than estimates and from aircraft or fixed site measurements. While fugitive gas emissions from rural areas (pipelines and above-ground infrastructure) are much larger than the inventory suggest, lowering expected urban emissions, and small peaks of <200 ppb cannot be definitively characterised as gas leaks, leading to underestimation, the methodology for leak emissions estimation needs further refinement for dense urban environments. A range of instruments measuring at 0.3 to 10Hz and different emissions methodologies are currently being assessed through repeat surveys of some London boroughs.
Maazallahi et al., 2020, Atmos. Chem. Phys., 20, 14717–14740, https://doi.org/10.5194/acp-20-14717-2020
United Nations Environment Programme, 2021, Emissions Gap Report 2021: The Heat Is On – A World of Climate Promises Not Yet Delivered, Nairobi
Weller et al., 2019, PLoS One 14, e0212287, https://doi.org/10.1371/journal.pone.0212287
How to cite: Lowry, D., France, J., Fernandez, J., al-Shalan, A., Fisher, R., Vogel, F., and Nisbet, E.: Fugitive Methane Across the UK Gas Distribution Network from Terminals to Cities: Characterisation and Methodology Development, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15766, https://doi.org/10.5194/egusphere-egu23-15766, 2023.
Methane (CH4) is the second most important anthropogenic greenhouse gas after carbon dioxide (CO2). Main CH4 sources are linked to the human use of fossil fuels (oil, gas, coal) and human-related or natural biogenic processes such as agriculture, waste management or wetlands. While biogenic emissions of CH4 contain present-day atmospheric radiocarbon (14C) levels, CH4 derived from fossil sources is 14C-free so that 14CH4 measurements can be used as a source apportionment proxy to distinguish fossil from biogenic CH4 sources.
A dedicated setup to analyze 14CH4 was developed at the Laboratory for the Analysis of Radiocarbon with AMS, University of Bern. Typical samples are 60L of atmospheric air collected in bags, which, after extraction, result in about 60 µg carbon in CH4-derived CO2 form, enough for a 14C gas measurement on a MICADAS (Mini Carbon Dating System) accelerator mass spectrometer.
Since 2019, biweekly air samplings have been conducted at three sites in Switzerland: the high altitude research station Jungfraujoch (3580 m asl) considered as a European continental background station, a tall tower in Beromünster and an urban site in Bern. A fourth site (with a tall tower) in Sottens has been visited since June 2021.
Beside these in situ measurements, an atmospheric 14CH4 transport model was developed to simulate 14CH4 values for each sampling. It is based on the Lagrangian transport and dispersion model FLEXPART, two CH4 emission inventories (Meteotest EKAT for Switzerland, TNO-CAMS v4.2 for the rest of Europe), a priori 14CH4 signatures for each emission type and the weather model COSMO. 14CH4 emissions from pressurized water reactors (PWR) of nuclear power plants in Switzerland and neighboring countries are also taken into consideration.
This contribution will show the in situ 14CH4 measurements as well as corresponding simulations and emphasize that the sporadic transport of 14CH4 emitted from PWRs is greatly influencing the overall signal measured over the Swiss Plateau making CH4 source apportionment for this region very challenging.
How to cite: Laemmel, T., Geissbühler, D., Henne, S., Brunner, D., Leuenberger, M., and Szidat, S.: Capabilities of CH4 source apportionment using atmospheric 14CH4 measurements: Switzerland as a case study, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11383, https://doi.org/10.5194/egusphere-egu23-11383, 2023.
The Ebro River Delta, in the northwestern Mediterranean basin, has an extension of 320 km2 and is mainly covered by rice fields. Rice fields are known to be one of the main sources of anthropogenic methane emissions, and a better estimation of its temporal variability in relation to the different rice cultivation phases is important to help with the implementation of emission reduction strategies (Àgueda et al., 2017),
In the framework of the ClimaDat network, an atmospheric station was installed in the middle of the Ebro Delta in 2012. A Picarro G2301 for greenhouse gases (GHG) atmospheric concentrations and an ARMON (Atmospheric Radon Monitor) for atmospheric 222Rn concentrations were collocated among other instruments. Nocturnal hourly atmospheric observations of CH4 and 222Rn measured between 2013 and 2019 were used to apply the Radon Tracer Method (RTM) for retrieving CH4 fluxes over the footprint area.
The Ebro River Delta has a reduced dimension and a complex meteorological regime highly influenced by the Ebro channelled winds and the sea breezes, making it difficult to calculate GHG fluxes using global or regional inversion models. However, the use of high-resolution backtrajectories (model WRF-Flexpart) coupled with the traceRadon daily radon flux maps for Europe (Karsten et al., 2022), with a resolution of 0.05 degrees, has allowed the use of the RTM in this complex area.
Methane fluxes estimated by RTM were compared with fluxes directly measured with chambers in past studies (Martínez-Eixarch et al., 2018) and with data obtained by the EDGAR inventory (Crippa et al., 2022). Results show a promising agreement between methane fluxes obtained with different methods, and a variability clearly governed by the rice crop cycle which is not reflected in the methane emissions values reported in EDGAR inventories.
References
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Karstens, U., Levin, I. (2022). traceRadon monthly radon flux map for Europe 2006-2022 (based on ERA5-Land soil moisture), Miscellaneous, https://hdl.handle.net/11676/XPxf8v5gfDWmi6BZ597euAJ7
Martínez-Eixarch, M., Alcaraz, C., Viñas, M., Noguerol, J., Aranda, X., Prenafeta-Boldu, F. X., Saldaña-De la Vega, J. A., del Mar Catala, M. and Ibáñez, C.: Neglecting the fallow season can significantly underestimate annual methane emissions in Mediterranean rice fields, PLoS One, 13(5), doi:10.1371/journal.pone.0198081, 2018.
How to cite: Curcoll, R., Morguí, J.-A., Àgueda, A., Vargas, A., and Grossi, C.: Variability of methane fluxes at the Ebro Delta due to rice field: comparison between inventories and Radon Tracer Method based results., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1261, https://doi.org/10.5194/egusphere-egu23-1261, 2023.
Methane emissions from the waste sector may represent a significant fraction of the global anthropogenic methane budget. However, few comprehensive studies across the broad landscape of waste operations exist to validate existing bottom-up models that underpin reporting programs and national inventories. In this study, we flew two airborne imaging spectrometers to map emissions at large landfills across 18 states in the U.S. and three provinces in Canada between 2016-2022. This technology is particularly sensitive to point source methane emissions and can geolocate source locations to within several meters. We observed point sources at a high fraction (52%) of sites and observed high emission persistence (60%), or point source detection frequency, at sites we surveyed multiple times. Airborne derived emissions correlate poorly with EPA reported emission and are on average higher, which could point to some issues with models that underpin reporting protocols. We validated imaging spectrometer aerial emission rates against the Scientific Aviation mass balance technique at 15 landfills, and find good agreement between these two independent measurement systems. Sustained measurements across many landfills and waste sites are needed to validate inventories and provide actionable data for industry operators and enforcement agencies.
How to cite: Cusworth, D., Duren, R., Ayasse, A., and Thorpe, A.: Methane Emissions Across a Diverse Set of Large Landfills in the United States and Canada, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9802, https://doi.org/10.5194/egusphere-egu23-9802, 2023.
Canada is a signatory to the Global Methane Pledge and is aiming to achieve a 75% cut in methane from 2030 levels from oil and gas production through regulatory updates and a 50% cut in waste sector emissions using new regulations. Despite numerous large-scale studies that have measured and identified emission sources from Canada's oil and gas sector, there are virtually no measurements of emissions from landfills in Canada. As such, inventory values for landfill emissions are based on a combination of industry-submitted data and emission factors. Canada could design better policies and regulations if policymakers had access to actual emission rates and source types. Therefore, we designed and carried out a large-scale measurement campaign targeting minimally 125 landfills across Canada, using aircraft mass balance measurements and truck-based measurements (i.e., downwind and onsite transects) coupled with Gaussian inversions to determine emission rate. This study focuses on methodologies used to determine source locations, or methane hotspots, on the landfill surface. In Particular, source attribution methods included a Lagrangian back trajectory footprint analysis of mobile surveys, onsite mixing ratios and winds measured with the truck, as well as Landsat thermal retrievals that have been shown in prior studies to correlate with methane hotspots. Measurements were carried out between June and December 2022 using one or more measurement methodologies for a total of 143 sites. We performed truck-based measurements of mixing ratios across navigable portions of 59 landfills. All indicators showed some correlation to mixing ratios collected onsite, although Lagrangian analysis products from downwind measurements were somewhat more reliable in flagging hotspots than the satellite thermal indices. The indicators often highlighted the active disposal face, leachate impoundment ponds, or compost areas, as the active source area. This study will help contribute much-needed source information for solid waste sector regulatory design in Canada and has the potential to help improve models of landfill methane generation.
How to cite: Khaleghi, A., Bourlon, E., Stuart, J., Martino, R., Vogt, J., Coyle, L., LeVernois, M., Lavoie, M., Perrine, G., Kennedy, A., Boyd, M., Kennedy, S., Hammer, M., Ars, S., Vogel, F., Gilbertson, E., Mahdianpari, M., and Risk, D.: A comparison of methane source localization methods in landfills across Canada using truck-based measurement, Lagrangian stochastic back trajectory modeling, and Landsat thermal images, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10442, https://doi.org/10.5194/egusphere-egu23-10442, 2023.
Posters on site: Thu, 27 Apr, 10:45–12:30 | Hall X5
Methane is a powerful greenhouse gas with a globally averaged atmospheric mole fraction of 1908±2 ppb in 2021, nearly three times the pre-industrial abundance. The annual increase of methane between 2020 and 2021 was the highest since continuous measurement began (WMO,2022). More than 60% of global CH4 emissions are attributed to human activities. Reducing methane in the short term will help to achieve the Paris Agreement goal to keep warming to <1.5°C and help in reaching many Sustainable Development Goals due to multiple co-benefits of methane mitigation. The fossil fuel sector is one of the largest anthropogenic emitters of methane and a target for CH4 reductions, with the UN stating that an emissions reduction of 61% is possible, but there is now urgent need to implement this (Nisbet et al, 2019).
Sources of fugitive methane emissions in the UK have been identified and characterized by mobile measurement survey in vehicles (e.g. Lowry et al ,2020) and aircraft (e.g. France et al., 2021). Since 2017, vehicles surveys for UN and NERC-UK projects have identified emissions from production platforms, onshore terminals, compressor stations, offtake stations, gas governors and pipeline failures.
Vehicle surveys utilized different suites of instruments: Picarro G2301 and G2210-i Los Gatos Research Ultraportable Methane-Ethane (LGR UMEA), and LiCor 7810 GHG analyzers, all measuring methane. Air bags were filled in plumes during surveys to measure the carbon isotopic signature (δ13C) at different points in the gas distribution supply chain. The range of signatures identified is from -43.7 to -32.4 ‰ (n=182), showing an enrichment relative to atmospheric background (-48 to -47.5‰), with the southern North Sea production that feeds into the Bacton Terminal identified as the most enriched at -31.8 ±1.5‰ (n=13).
Ethane:methane ratio is a useful diagnostic for gas attribution. Since 2018 the LGR UMEA ethane data has been used to identify distribution leaks as this gas is not a component of waste, agricultural or coal sources. The ratio of C2H6:CH4 (C2:C1) during surveys of gas allows separation of pyrogenic and thermogenic (>0.03) from biogenic (<0.005) sources (Rella et al, 2015: Lowry et al, 2020), with UK gas distribution dominantly in the range 0.04 to 0.08, and it is consistent for fugitive plumes transected on multiple passes.
Most of the larger peaks have been located downwind of offtake stations on the high-pressure mains network. The 2021 surveys focused on identification of emitting facilities and their isotopic and C2:C1 characterization. Recent surveys in 2022 targeted emission plumes for multiple passes with 10Hz and 1Hz instruments to select suitable candidates for Gaussian plume emission modelling, with potential to upscale to a national emission for facilities of this category.
France et al., 2021, Atmos. Meas. Tech., 14, 71–88, 10.5194/amt-14-71-2021
Lowry et al., 2020, Science of the Total Environ., 708, 134600, 10.1016/j.scitotenv.2019.134600
Nisbet et al., 2019., Global Biogeochem. Cycles, 33, 25pp, 10.1029/2018GB006009
Rella et al., 2015., Atmos. Meas. Tech., 8, 4539–4559, 10.5194/amt-8-4539-2015.
World Meteorological Organisation, 2022. (WMO) greenhouse gas bulletin. [Online]. Available at: https://public.wmo.int/en/resources/library/wmo-greenhouse-gas-bulletin. (Accessed 9 December 2022)
How to cite: Al-Shalan, A., Lowry, D., Fisher, R., France, J., Fernandez, J., and Lanoiselle, M.: Fugitive Methane Detection from UK Above Ground Gas Infrastructure, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1141, https://doi.org/10.5194/egusphere-egu23-1141, 2023.
In this study, we examine a maximum of 13 years (2009-2021) of the observational datasets of columnar dry-air mole fractions of methane (XCH4), from the Greenhouse gases Observation SATellite (GOSAT) GOSAT-1 (2009-2021) on board the IBUKI satellite and vertical profiles of CH4 from the Atmospheric Infrared Sounder (AIRS) on board AQUA satellite. We also use the XCH4 and vertical distributions over the Indian subcontinent from the JAMSTEC’s MIROC4 atmospheric chemistry transport model (ACTM) from 2009-2021, after convolution with GOSAT-1 and AIRS a priori profiles and averaging kernels.
A comparison of observed and modeled CH4 and XCH4 reveals that MIROC4-ACTM provides explicit insights into the spatio-temporal variability of atmospheric methane over the Indian region. Global CH4 emission inventory EDGARv7.0 reports a total of ~30 Mt of anthropogenic emissions in India in 2020 while GAINS emissions stand at ~33Mt for the same year. The ACTM simulations from this study are also examined to retrieve preliminary information on the quality of these constructed bottom-up fluxes of methane (EDGAR and GAINS).
Our time series analysis of GOSAT-1 shows the annual mean XCH4 has increased by 100 ppb from 2009 to 2021 over the Indian subcontinent, compared to 85 ppb globally in the latitude band of 6.25 °N-41.25 °N. Observations from both AIRS and GOSAT-1 show distinct seasonality in the vertical profiles of CH4 and XCH4 over the entire region, respectively. Seasonality in the CH4 concentration over India in boundary layer heights (>850 hPa) is affected majorly by the local emission strengths while in the middle (400- 600 hPa) and upper (< 200 hPa) troposphere it is governed by the convective transport of surface emissions signals and redistribution in the monsoon winds in the upper troposphere. GOSAT-1 shows highest XCH4 of ~1900 ppb (2021) in northern India (North of 20° N) in winter season (November) while AIRS shows highest CH4 ~1910 ppb in summer month of May at 200 hPa for the same year. Based on the findings from the vertical (AIRS) and total column (GOSAT-1) distribution of CH4, our analysis suggests that 3D variability of CH4 over the entire Indian region is governed by a diverse spread of surface emissions and global monsoon divergent wind circulations.
Through this study, the reasons for these observed patterns of CH4 are explored in light of forward model results using an ACTM by combining and comparing the strengths of AIRS and GOSAT-1.
How to cite: shikha, D., Dey, S., and K. Patra, P.: A view of 3D variability of atmospheric methane over India using MIROC4-ACTM simulations, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2237, https://doi.org/10.5194/egusphere-egu23-2237, 2023.
As global warming continues to be one of the greatest threats to Earth environment, the detection and monitoring of natural and anthropogenic emissions of greenhouse gases holds a critical role as the first step of any danger reduction policy. New generation spaceborne hyperspectral instruments cover large portions of the Earth while maintaining a high enough spectral and spatial resolution to investigate the contribution of single molecular species and accurately localize their emission source. The Matched Filter method is used to search enhanced concentrations of methane in the atmospheric column. PRISMA, ASI’s newest hyperspectral sensor, data are analysed. Both strong and weak CH4 emissions, in multiple scenarios, are investigated. It is demonstrated that PRISMA data allow also the identification of methane non-punctual sources when the land gas emission is very high. An estimated flux in the order of 4000 kg/h is found for a case study considering a landfill in India.
How to cite: Masin, F., Maestri, T., and Martinazzo, M.: About the use of Satellite Hyperspectral Images for Methane Detection, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6606, https://doi.org/10.5194/egusphere-egu23-6606, 2023.
In the worldwide effort to reach the 1.5-degree target, governments try to mitigate anthropogenic methane emissions. One example is the oil & gas sector, which is responsible for the second most anthropogenic methane emission source after agriculture. Abandoned oil and gas wells are seen as a promising target, as they can in some cases emit up to several tons of methane per year. However, only the USA includes emissions from such wells into their yearly greenhouse gas emission inventory and only for a few other countries like Canada, the United Kingdom, Romania and the Netherlands measured data on methane emissions from abandoned gas wells are available. Most countries do not even have sufficient data regarding numbers, positions, and status of their abandoned wells let alone the related methane emissions. Germany has about 20,000 abandoned wells, which are generally filled and buried, however, it is unclear, whether they are emitting methane or not.
Here, we present our approach and first data to fill this knowledge gap for Germany regarding methane emissions from onshore-abandoned oil and gas wells. For our first measuring campaign we focused on five regions in Lower Saxony (Federal State in Northern Germany) measuring 29 wells, covering both backfilled exploration and abandoned production wells of oil and gas fields. We will present our preliminary results including rates of soil methanotrophy focusing on one region with both, shallow oil wells and industrial peat production. Our data demonstrate the necessity for detailed knowledge on background methane emissions and cycling particularly in such methane-laden settings.
How to cite: Jordan, S., Schlömer, S., Krüger, M., and Blumenberg, M.: Methane cycling at buried abandoned wells in a peat-rich area in northern Germany – curse or blessing for atmospheric emissions and emission studies?, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6837, https://doi.org/10.5194/egusphere-egu23-6837, 2023.
A field campaign using UAV-based measurements to derive methane fluxes from a large landfill site in North Manchester was conducted in the summer of 2022. The system comprises the newly developed ABB lightweight (3kg) Hoverguard greenhouse gas analyser based on the off-Axis Integrated Cavity Output Spectroscopy (with a precision of 0.9 ppb for CH4 at 1 Hz), an on-board TriSonica™ Mini wind sensor and the DJI M600 pro hexacopter. Fluxes and corresponding flux uncertainties were calculated using the mass-balance method from 6 flight surveys conducted downwind of the active landfill. Accurate and reliable wind measurements sampled from instrumentation onboard rotary-wing UAVs remains a challenge, which was found to dominate flux uncertainty in this study. This study presents a low-cost and repeatable methodology for hotspot methane emission quantification.
How to cite: Yong, H., Allen, G., and Ricketts, H.: UAV-based methane emission quantification at a UK landfill site, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7229, https://doi.org/10.5194/egusphere-egu23-7229, 2023.
There is consensus that climate change is mostly driven by anthropogenic greenhouse gas emissions. In addition to CO2 emissions, which have been the subject of public debate for a long time, increased awareness of methane (CH4) emissions has developed in recent years. CH4 is considered the 2nd most important contributor to radiative forcing, making it the most important non-CO2 greenhouse gas.
Due to the relatively short lifetime of the gas in the atmosphere compared to CO2, the reduction of methane emissions can lead to a climate benefit on relatively short time horizons. In order to effectively reduce emissions, the polluters must be better understood and recognized. Here, we combine methane eddy covariance observations in combination with a variety of other trace gases and meteorological parameters that have been recorded since August 2020 in an Alpine city (Innsbruck, Austria) to investigate urban methane emissions. For an accurate comparison with bottom-up emission inventories we test different gap-filling methods with the help of meteorological parameters as well as other tracer fluxes, such as NO, NO2, or CO2. In order to quantify methane emissions in urban areas as annual totals, a complete, gap-free flux dataset is desired. We have developed different statistical gap filling models which are able to predict CH4 fluxes at the study location. The method is based on a boosted regression tree model with a variety of meteorological and astronomical parameters, as well as other trace gas fluxes serving as input. Different combinations of these input parameters are tested for accuracy of their prediction. Contrasting other gap filling methods, used over uninhabited areas, adding gases like CO2 or NO can serve as important additional predictors, because sectors related to combustion processes are considered as important contributors to CH4 emissions. In this presentation we discuss CH4 flux measurements performed during the last 2,5 years over an urban area, and highlight first results on the performance of the developed gap filling models.
How to cite: Stichaner, M., Lamprecht, C., Graus, M., Goded, I., Jensen, N., and Karl, T.: A statistical gap filling model for methane fluxes over an urban area in the Alps, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7706, https://doi.org/10.5194/egusphere-egu23-7706, 2023.
Sewer systems, which consist of wastewater treatment plants (WWTPs) and sewer networks, are important urban water infrastructure that helps to improve water quality and prevent flooding. While they are recognized as a major source of methane emissions with considerable potential, accurate quantification of methane emissions from sewage systems has not yet been achieved. Here, we measured atmospheric methane from the urban sewer network using a mobile laboratory, which consists of the electric vehicle and monitoring instruments for Greenhouse Gas (GHG) such as carbon dioxide (CO2), methane (CH4), and ethane (C2H6). The mobile measurements of sewer networks are conducted in Gwanak district of Seoul in South Korea from September 2022. More than 3,000 manholes and rain gutters in commercial and residential areas were measured for the methane emissions of the combined sewer network type in Gwanak district. The methane emissions from urban sewer network were found to be significant in the study area. However, these emissions are currently not included in the national GHG inventory. Further details of our findings will be introduced at the European Geosciences Union (EGU) General Assembly 23.
This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (No.2019H1D3A1A01101988)
How to cite: Joo, J., Jeong, S., Shin, J., and Chang, D. Y.: Quantification of methane emissions from urban sewer network, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11170, https://doi.org/10.5194/egusphere-egu23-11170, 2023.
Methane (CH4) is after carbon dioxide the second most important anthropogenic greenhouse gas. Due to its comparatively short lifetime of ~10 years, a significant reduction in anthropogenic CH4 emissions would help to reduce the atmospheric concentration within a decade with near term temperature benefits. However, the development of efficient mitigation strategies needs to be informed by identifying, locating and quantifying CH4 emissions from the different sectors. A large part of CH4 emissions from the global oil and gas sector is expected to arise from offshore production, which currently however is understudied. Off the coast of Gabon and Angola, oil and gas production is spread over more than 800 kilometres across a wide variety of offshore installations, covering both shallow waters and deep sea. Here we report on airborne measurements conducted using the DLR Falcon along the west coast of Central Africa in September 2022. The DLR Falcon was equipped with a suite of different in-situ instruments to measure CH4 and a series of other trace species, as well as meteorological variables. Measurements were taken during 15 science flights to quantify emissions related to offshore oil production. We will present and discuss our airborne results on regional and facility-scales, in dependency of e.g. infrastructure type and age, and compare them with available inventory estimates and industry reportings. Our collected data, co-funded by the International Methane Emissions Observatory (IMEO), will help coal, oil and gas companies and governments, to prioritize their methane emission mitigation .
How to cite: Roiger, A., Eckl, M., Puehl, M., Gottschaldt, K.-D., Braeuer, T., Aufmhoff, H., Eirenschmalz, L., Sakellariou, F., Neumann, G., ventura, G., and Cadete, W.: Methane emissions from offshore oil and gas production activities in Gabon and Angola: First results from the airborne METHANE-To-Go campaign 2022, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13551, https://doi.org/10.5194/egusphere-egu23-13551, 2023.
Acting on the significant contribution of methane to climate change, the global methane emission reduction pledge was launched at the 2021 United Nations Climate Change Conference (COP26) and has been signed by more than 100 countries. The majority of anthropogenic methane emissions have been spewed from the energy, waste and agriculture sectors which can be measured with source-specific choice of instruments, measurement platforms and evaluation methods to feed mitigation plans. Maaz Maps (www.maazmaps.com), with more than a decade of experience in methane emission studies, aims to support the global methane pledge with international collaborations by bridging between academia and industry to fill gaps and accelerate the global methane emission reduction efforts. Currently this startup is contracted by GERG (The European Gas Research Group) to scientifically evaluate methane emission reports from several technology providers: results of a measurement campaign performed at a compressor station will be shown. In this campaign, the technology providers applied bottom-up and top-down quantification methods using in-situ or remote sensing techniques. The instruments were either directly operated by walking individuals or installed on various platforms: helicopter, cars, tripods, drones, truck or poles. Various quantification methods including mass balance, tracer method and inverse modelling, correlation factors were applied to quantify sources. In this presentation, we are going to introduce the startup and reconciliation overview of the bottom-up and top-down quantification methods from the campaign.
How to cite: Maazallahi, H.: Maaz Maps: a science-based startup to accelerate and support the global methane pledge, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-16176, https://doi.org/10.5194/egusphere-egu23-16176, 2023.
Recent atmospheric methane concentrations show an accelerated increase, but the contributions of the underlying emitters are poorly understood. Recording the stable carbon isotope ratio of methane (δ13C(CH4)) is a powerful tool for CH4 source attribution and the understanding of the global methane budget. The airborne measurement of δ13C(CH4) provides the advantages of reaching remote areas and covering large-scale regions, but is challenging regarding sufficient precision while maintaining high spatial measurement density. The state of the art technique is to collect airborne gas samples for subsequent laboratory analysis by isotope ratio mass spectrometry, with high δ13C(CH4) precision of 0.05 ‰. Here we present an innovative in situ airborne system for the measurement of δ13C(CH4), called MIRACLE. MIRACLE consists of a conventional Picarro cavity ring down greenhouse gas analyzer (G2210-i) for the measurement of CH4 and δ13C(CH4), and a sampler unit. The sampler enables the collection of six gas samples in 2 l stainless steel tanks, in a short time (20 s each) via a metal bellows pump, which allows for the specific sampling of small-scale features, such as point source emissions. The sampling is followed by an extended period of subsequent analysis (up to 10 min). Using this setup, we achieve sufficient δ13C(CH4) precision (1σ uncertainty of 0.34 ‰) and an average of five samples per flight hour, allowing for a large number of samples for long flights. Due to the resulting dense coverage with sufficient precision, this novel approach allows for airborne δ13C(CH4) characterization of small-scale methane emitters and large-scale gradients. We employed MIRACLE aboard the research aircraft HALO during the CoMet 2.0 Arctic campaign in summer 2022, which focused on characterizing natural and anthropogenic methane sources in Canada. In this presentation, a proof of concept for the instrument is elaborated, including the investigation of sample purity and measurement comparisons with other instruments. Additionally, we show δ13C(CH4) signatures revealed by the method of Keeling analysis of measurements obtained during CoMet 2.0 and compare them to previous studies. The airborne operation of the MIRACLE instrument combines the advantages of increased precision δ13C(CH4) measurements, typically only possible under stable laboratory conditions, with the in situ, near real time data analysis and the large-scale sampling of secluded areas. MIRACLE will be deployed during the DLR GHGMon campaign (June 2023) to investigate the δ13C(CH4) ratio of agricultural sources of methane in the Netherlands.
How to cite: Waldmann, P., Lichtenstern, M., Reum, F., Ziereis, H., Fiehn, A., Gałkowski, M., Gerbig, C., Fix, A., and Roiger, A.: Development and First Deployment of an Innovative Airborne δ13C(CH4) In Situ Measurement Setup, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14191, https://doi.org/10.5194/egusphere-egu23-14191, 2023.
More than two thirds of global anthropogenic greenhouse gas (GHG) emissions originate from cities. Urban mitigation policies need a reliable emission data basis to effectively reduce emissions and given inventory uncertainties at the level of single cities, there is growing interest in measurement-based methods to support urban GHG emissions monitoring. Inverse modelling is a measurement-based approach that integrates atmospheric observations with emission inventories, whereby the inventories serve as prior estimates that are subsequently constrained against the observations. While such inverse systems rely on modelling frameworks that typically utilise in situ and/or remote measurements of atmospheric GHG mixing ratios, there is scope for city-scale inverse frameworks to utilise other types of GHG observations, such as flux measurements.
In this study, we investigate such an approach based on a two month field campaign between 15th of May and 20th of July in 2022 in Vienna, Austria. In particular, for the prior information, we use tall-tower eddy covariance observations to constrain the CH4 emissions within the tower's flux footprint and combine the measurements with 1km x 1km inventory data of the larger city area of Vienna. This refined and measurement-supported inventory serves as a-priori information for both, a Bayesian- and a Phillips-Tikhonov based inversion approach. The observational input for the inversion methods is delivered by MUCCnet (Munich Urban Carbon Column network) instruments consisting of four ground-based, sun-viewing FTIR spectrometers (EM27/SUN), with three of these instruments located on the outskirts of Vienna and one instrument located at the bottom of the tall-tower close to the city center.
This study investigates the synergetic aspects of two different measurement systems: the eddy-covariance system is particularly sensitive to near field emissions with a range of hundreds of meters upwind of the tower, whereas the ground-based remote sensing instruments observe the differential total column concentration and are therefore sensitive to emissions originating several Kilometers upwind. Applying both measurement systems within a city inversion framework may indeed represent a viable option for further constraining city emissions and improving urban GHG emissions monitoring.
How to cite: Luther, A., Forstmaier, A., Tang, H., Bettinelli, J., Ghaith, G., Aigner, P., Makowski, M., Fasano, E., Meeran, K. M., Leitner, S., Watzinger, A., Matthews, B., and Chen, J.: MUCCnet visiting Vienna: refining inverse model prior information with tall-tower flux measurements, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15369, https://doi.org/10.5194/egusphere-egu23-15369, 2023.
This paper reports on the deposition of tin oxides nanoparticles thin films by MAPLE (Matrix Assisted Pulsed Laser Evaporation) for use as conductometric gas sensors. First gas sensors based on SnO₂ were developed by Naoyoshi Tagouchi in 1968; the importance of this material for gas sensing applications grew according to the needs of improved gas detecting sensibility and variety. The target was obtained by freezing a solution of tin oxide nanoparticles obtained by Laser Pyrolysis using tetramethyl tin and ethylene combined with an oxidized at-mosphere as reactive gas mixture. Two types of nanopowders samples have been selected: the first contains mainly tin(II) oxide whereas the second contains mainly tin(IV) oxide. The as prepared samples were also thermally treated at 300⁰C for 3 hours in order to decrease the proportion of the SnO phase. One of the thermally treated powders exhibits an almost pure SnO₂ phase as determined from the XRD pattern. The resulted thin films were analyzed by X-Ray diffraction, Atomic Force Microscopy and Electron Microscopy for structural and morphological properties; preliminary electrical tests were conducted and the results show good capability for methane detection.
How to cite: Dumitru, M., Filipescu, M., Dumitrache, F., and Mihailescu, A.: Conductometric sensors for atmospheric applications, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14653, https://doi.org/10.5194/egusphere-egu23-14653, 2023.
Methane emissions are the second leading cause of global warming. Because of the near-term warming potential of atmospheric methane, reducing its emissions will be essential to achieve the UNFCCC climate objectives. Reducing methane emissions from oil and gas operations is among the most cost-effective and efficient actions governments can take to meet global climate goals. In the "net zero emissions by 2050" scenario, methane emissions decline rapidly in the coming years, reaching this reduction potential by 2030. This is primarily a result of the rapid deployment of emission reduction measures and technologies, leading to the elimination of all technically avoidable methane emissions within this decade.
Current regulations are based on methane emissions figures from regional and national inventories. However, it has been shown repeatedly in the literature that these have a strong tendency to underestimate actual emission levels. In order to be able to move towards adapted and personalized regulations, it is necessary to aim at new methods -other than the current too generalized inventories- improving the current assessment of emission trends at the level of the whole O&G supply chain. Emission profiles should be estimated by operator, by type of O&G site, or by site infrastructures to design and to implement specific regulations.
In order to establish the most complete emission profiles possible - taking into account the current lack of continuous coverage - a maximum of measurements at various scales (satellite, UAVS, group) of methane emissions for a site or infrastructure should be collected by operator/site/infrastructure.
We therefore propose in this paper O&GProfile,an automatic method to associate GHGSat methane plume detections to detections from other satellite and airbone campaign already tagged by oil and gas sites type (Gathering & boosting, processing, production) and their respective operators. O&GProfile is based on the use of unsupervised machine learning methods for classification purposes,with automated correction of the classification results. By association of GHGsat data to tagged CarbonMapper and Gao data (method mame), our method provides an informed GHGSat dataset necessary to study profile of emissions by site and operators. The study of these site emissions profiles over the period 2020-2021 in the Delaware and Midland basins in the Permian also allows us to connect GHGSat detections to the Gao and carbon mapper detections.
How to cite: Guisiano, J. E., Lauvaux, T., Cifarelli, C., Moulines, É., and Sublime, J.: O&GProfile : Automated attribution of GHGSat point source methane emissions detections to O&G infrastructures for site emissions profile analysis (Permian), EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15237, https://doi.org/10.5194/egusphere-egu23-15237, 2023.
Abstract: Greenhouse gases and associated pollutants (CO, NOx, VOCs, aerosols) are measured from a small airplane, mobile laboratory, and towers. Through mass balance calculations and comparison to numerical models such as CMAQ-GHG we estimate the total flux from the cities of Baltimore, MD and Washington, DC. Emissions inventories were found to underestimate methane emissions substantially and have been improved. Major sources include leakage in the natural gas delivery system and biogenic processes including landfills. Measurements with high spatial and temporal resolution reveal hot spots of high concentrations often associated with pollutants such as black carbon (BC) and NO2 that pose a health hazard in disadvantaged communities.
How to cite: Dickerson, R., Ren, X., and Karion, A.: "Measurements and models of GHGs and short-lived pollutants in the Baltimore/Washington area: Emissions and environmental justice", EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-121, https://doi.org/10.5194/egusphere-egu23-121, 2023.
Methane is considered to be the second largest contributor to the greenhouse effect after CO2, with a higher increase of its atmospheric concentration over the industrial era compared to other greenhouse gases, as CO2 or nitrous oxide. At least 50% of CH4 emissions come from anthropogenic activities in urban and rural areas, due to the combustion of fossil fuels, waste and wastewater treatment, leaks from the natural gas distribution system, etc.
Although, CH4 is more than 20 times more potent than CO2 in producing the greenhouse effect, it has a short residence time in the atmosphere, which makes the mitigation measures more effective in minimizing these emissions and bringing a short-term advantage to the climate.
Methane concentrations were determined at street-level in the city center, commercial area, residential area, and green area of Cluj-Napoca, Romania. A portable West Systems fluxmeter was used. The instrument is based on Tunable Diode Laser Absorption Spectroscopy, that allows high precision measurements and very low detection limit, of 0.1 ppm. By eliminating wind effects at street-level, the residential area recorded the least values of these emissions, around the CH4 average atmospheric concentration. Similarly, the emissions in the commercial area were fluctuating around same atmospheric concentration average, but strongly depending on the traffic density. On the sidewalk, at about 1.3 m height, the recorded methane concentrations ranged between 1.9 and 6.0 ppm. The highest values occurred at the passage of heavy vehicles as trucks.
Concentrations of tens or even hundreds ppm CH4 were measured close to the drains that collect water run-off from the streets, and even higher at manhole covers of the sanitary sewerage system.
However, the outcomes of this study indicate the need for further investigation of CH4 emissions in the urban area and the importance of the isotopic characterization of these emissions in order to identify their sources for prioritizing the CH4 mitigation measures.
How to cite: Hmoudah, M., Baciu, C., and Pop, C.: Sources of Methane Emissions in the Urban Atmosphere - Case Study: Cluj-Napoca City, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-508, https://doi.org/10.5194/egusphere-egu23-508, 2023.
Methane’s high Global Warming Potential (GWP) and short atmospheric life relative to carbon dioxide have led to methane mitigation as a cost-effective and realistic near-term action that serves as a bridge to longer-term mitigation options. This paper calculated coal mine methane (CMM) emissions from 636 individual coal mines in Shanxi Province based on the Intergovernmental Panel on Climate Change (IPCC) Tier 2 approach. 5 sets of emission factors were used to compile this bottom-up inventory. Each coal mine is classified into 3 different coal mine gas ranks based on the method issued by the National Coal Mine Safety Administration and the National Energy Administration. Haft-hourly eddy-covariance measurements of methane flux from 1 mine (xhv) over a 5-month period were used to quantify and constrain the high-frequency variation in emissions. From the perspective of probability density, 15.5% of the total data is covered by the boxes overlapping the different bottom-up emissions estimates, while 53.5% of the total data falls in the single box below the floor of the bottom-up measurements. The in-situ measurements offer scaling factors (RATIO correction) for updating the preliminary bottom-up coal mine methane emissions datasets. A statistical approach is applied to individual coal mines by grouping them by coal mine gas rank. From the perspective of cumulative probability, the CMM flux shows a pattern that low gas rank < high gas rank < outburst rank. We have compared the CMM emissions with EDGAR-COAL and GFEI. In 2019, the EDGAR and GFEI inventory results show that methane emissions from coal mines in Shanxi Province are 7.27 Tg and 6.29 Tg, respectively. Our results range from 4.41-7.63 Tg. In Changzhi city, over the region in which this dataset has emissions that EDGAR-COAL and GFEI do not identify the emissions are [44.35,125.60,354.02] and [398.22,1125.81,3185.22] with the unit in ug (m-2 s-1), respectively. The values in brackets are results after RATIO correction, corresponding to cumulative percentages 30, 50 and 70 respectively. Over the region that EDGAR-COAL has misidentified coal mines, the emissions are 128.27 ug (m-2 s-1). Over the region that EDGAR and our inventory both have emissions, the EDGAR-COAL emissions are 357.65 ug (m-2 s-1), while our emissions are about 353.87 ug (m-2 s-1). Over the region where GFEI has misidentified coal mines, the emissions are 181.18 ug (m-2 s-1). Over the region that GFEI and our inventory both have emissions, the GFEI emissions are 164.04 ug (m-2 s-1). There are no regions where we have emissions while GFEI has no emissions in Changzhi city. These facility-level inventories can help identify mitigation opportunities at specific mines, and support the design of more effective policies.
How to cite: Hu, W., Qin, K., He, Q., and Cohen, J. B.: Chinese Coal Mines Methane Emissions Constrained by High-Frequency Measurements, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5036, https://doi.org/10.5194/egusphere-egu23-5036, 2023.
The Upper Silesian Coal Basin in southern Poland belongs to one of the strongest emitting regions of anthropogenic methane (CH4) in Europe. A major part of these CH4 emissions is related to the coal mining industry, which are in focus of the METHANE-To-Go-Poland project presented here. For the first time, a unique helicopter towed probe (HELiPOD) was used to capture CH4 plumes from selected coal mine ventilation shafts. The HELiPOD probe (weight 325 kg, length 5 m) was equipped with a 3D wind anemometer and trace gas in situ instrumentation (Picarro G2401-m and Licor-7700) to measure CH4 with a high precision (1 ppb) and temporal resolution (up to 40 Hz), which is necessary for a precise calculation of the CH4 mass flux. In June and October 2022, repeated upwind and downwind probing of the plumes from selected shafts (4 shafts, 16 flights) were performed at different horizontal distances from the source (~500 m - 5 km) and altitudes (~20 m – 2 km). This way, both the inflow amount of CH4 and the horizontal/vertical dispersion of the CH4 plumes from the shafts were captured. Depending on wind speed, wind direction and stability, suitable flight patterns were developed for every flight. In addition, two controlled CH4 releases were successfully carried out to prove the novel measurement concept. Mobile ground-based CH4 measurements complemented the airborne probing.
In this presentation, mass flux calculations based on measurements from the two airborne CH4 instruments (with different measurement techniques) will be compared and uncertainties determined. Furthermore, CH4 mass flux calculations resulting from coinciding satellite measurements (GHGSat: swath width <15 km, spatial resolution <27 m) over the same ventilation shafts combined with high-resolved GEOS-FP wind data are presented. Finally, the uncertainties of the two different top-down approaches (air- and satellite-borne) are compared, in addition to different flight strategies. Comparisons with production data from the Polish coal mine industry are foreseen in near future (bottom-up approach). Subsequently, the same kind of airborne concept is envisaged for the METHANE-To-Go-Oman field experiment in autumn 2023, which will focus on CH4 emissions from the on-shore oil and gas exploration and production in Oman. Our collected data, funded by the International Methane Emissions Observatory (IMEO), will help coal, oil and gas companies as well as governments, to prioritize their CH4 emission mitigation strategies, actions and policies.
How to cite: Huntrieser, H., Förster, E., Lichtenstern, M., Pätzold, F., Bretschneider, L., Lampert, A., Necki, J., Jagoda, P., Taupin, Q., Holl, D., and Roiger, A.: Quantifying methane emissions from industrial activities: A novel helicopter-borne application for coal mine ventilation shafts in Poland and perspectives , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9152, https://doi.org/10.5194/egusphere-egu23-9152, 2023.
Methane CH4 is an important anthropogenic greenhouse gas and its rising concentration in the atmosphere contributes significantly to global warming. Satellite measurements of the column-averaged dry-air mole fraction of atmospheric methane, denoted as XCH4, can be used to provide information about the location of methane sources and on their emissions, which can help to improve emission inventories and review policies to mitigate climate change.
The Sentinel-5 Precursor (S5P) satellite with the TROPOspheric Monitoring Instrument (TROPOMI) onboard was launched in October 2017 into a sun-synchronous orbit with an equator crossing time of 13:30. TROPOMI measures reflected solar radiation in different wavelength bands to generate various data products and combines daily global coverage with high spatial resolution. TROPOMI's observations in the shortwave infrared (SWIR) spectral range yield methane with a horizontal resolution of typically 5.5 x 7 km2.
We used a monthly XCH4 data set (2018-2021) generated with the WFM-DOAS retrieval algorithm, developed at the University of Bremen, to detect regions with temporally persistent, locally enhanced XCH4. At first, we applied a spatial high-pass filter to the XCH4 data set to filter out the large-scale methane fluctuations. The resulting anomaly ΔXCH4 maps show the difference of the local XCH4 values compared to its surroundings. We then analyzed the monthly anomaly maps to identify potential source regions with persistent XCH4 enhancements by utilizing different filter criteria, such as the number of months in which the local methane anomalies ΔXCH4 must exceed certain threshold values. As a next step, we used a simple mass balance method to estimate the monthly emissions and the corresponding uncertainties of the detected potential source regions from the monthly averaged XCH4 maps. In the last step, we interpreted the emissions of the potential source regions in terms of the source type, by comparing the detected potential source regions with emission databases based on a spatial analysis.
In this presentation, the algorithm and initial results concerning the detection of regions with temporally persistent, local XCH4 enhancements, originating from localized potential methane sources (e.g., wetlands, coal mining areas, oil and gas fields) are presented.
How to cite: Vanselow, S., Schneising-Weigel, O., Buchwitz, M., Bovensmann, H., and Burrows, J. P.: Detection of local atmospheric methane enhancements by analyzing Sentinel-5 Precursor satellite data, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9174, https://doi.org/10.5194/egusphere-egu23-9174, 2023.
Canada was an early adopter of methane regulation in the oil and gas sector, and recently announced a more ambitious goal to reduce 75% of methane emissions by 2030. New stricter methane regulations should also help reduce loading of air pollutants typically associated with methane emissions (H2S, VOCs, ozone). To examine regional emission trends and to derive an inventory estimate for Canada’s upstream oil and gas sector, we measured methane emissions at 6650 sites across six major oil and gas producing regions in Canada. Our research suggests that methane emissions from the oil and gas industry are underestimated in Canada by ~1.5. For Canada’s largest producing province, Alberta, we found a greater than 1000-fold variation in methane intensity per unit of fossil energy production within the cohort of oil and gas producers. Producer self-published methane emission intensities in ESG materials showed a low bias and tended to mirror regulatory submissions that require reporting only on specific source types. Our measurements suggest that methane-associated pollutants produced by oil and gas activities are also underestimated and communities near these activities may face higher loading of methane-accessory contaminants than might be predicted by Canada’s National Pollutant Release Inventory (NPRI). Using accepted pollutant emission factors, reported flaring and other combustion activity, the federal methane inventory, and our methane measurements, we generated air quality exposure maps reflecting air pollutant loads on Canadian communities. Stricter methane regulation has the potential to significantly decrease methane, but also pollutant loads in several heavy oil communities including the Lloydminster - Bonnyville area.
How to cite: Lavoie, M., Risk, D., MacKay, K., and Bourlon, E.: Underestimation of reported methane emissions, and air pollutant loadings, from upstream oil and gas activities in Canada, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10259, https://doi.org/10.5194/egusphere-egu23-10259, 2023.
Canada is the third largest oil and gas producer, with over 500,000 active and inactive wells, mostly located in the Western Canada Sedimentary Basin (WCSB). A large, undetermined fraction of Canada’s GHG emissions emanate from oil and gas infrastructure. Governments and industry are all committed to immediately reducing methane leaks to the atmosphere from surface casing vent flows (SCVF) and ground migration (GM) of both new and old wells. Methane carbon isotopic composition offers insight into the source of unwanted gas emissions. A geospatial tool would help to attribute and reduce GHG emissions from contour maps of ẟ13C of methane and other hydrocarbons of production, SCVF, and GM gases across the WCSB. These “Isoscapes” of production gases vary systematically, reflecting the local geology. SCVF and GM isoscapes are offset from the production ones because the SCVF most often are shallower than the target formations, and the GM gas may be oxidized in soils. The difference between the production and SCVF isoscapes can be used to attribute methane emissions from tanks and production infrastructure, compared to leaks from the wells themselves. The isoscapes directly facilitate the plugging of problem wells. The maps are based on over 3,000 locations where we used isotope fingerprinting (i.e., Rowe & Muehlenbachs, 1999) to identify the source depth of a leak. Regulatory measurements mandate that the leaks are sealed at their source depth, greatly adding to the cost of plugging any well. The SCVF isoscapes suggest the likely source depth of an unsampled leaking well, thus greatly simplifying its remediation. Applying such information beyond a local case study may contribute to accounting for the GH contribution from regional oil and gas activities in Canada and elsewhere.
Reference
Rowe, D., & Muehlenbachs, A. (1999). Low-temperature thermal generation of hydrocarbon gases in shallow shales. Nature, 398(6722), 61-63.
How to cite: Gonzalez Arismendi, G. and Muehlenbachs, K.: A proposal to use “Isoscapes” of fugitive gases from oil and gas wells to facilitate the reduction and attribution of methane emissions and plugging of faulty wells, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10636, https://doi.org/10.5194/egusphere-egu23-10636, 2023.
The oil and gas (O&G) sector contributes significantly to the anthropogenic part of the methane cycle in the atmosphere while having the most effective opportunities for emission mitigation with technically feasible and cost-effective options. Romania is a key O&G producer within the EU Region of Transylvania with its active gas fields being in the focus of the second measurement campaign in the ROMEO project. Teams from European collaborations were deploying various techniques (GPM, OTM-33A, High Flow Sampler, Tracer release) for quantifications of the methane emission rates. In June of 2021, AGH deployed the large-scale flux chamber with help of scientists from UBB, Romania, and in cooperation with local O&G operator – Rom-Gas. Construction was designed and built to be used in the case of small gas installations like the single Christmas tree and was tested intensively during this campaign. A hemispheric structure with a diameter of 6 meters and volume of approximately 55 m3 was used to check the tightness of different gas wells in suitable conditions (size, terrain, meteorology). The methane concentration increase was measured by the OA-ICOS technique. We used an LGR MGGA-918 analyser while additional airflow and air mixing inside the chamber were provided with additional ventilators.
In this presentation, methane emission rates calculations based on deployments of large-scale flux chambers in Transylvania will be compared to other techniques. Verification of the chamber was developed using controlled release tests of methane and acetylene. Moreover, the estimated uncertainty of the measurement technique will be presented. Finally, the potential for use of a large-scale flux chamber as a direct ground based measurement technique and complementary to other direct and indirect techniques will be discussed.
The research results presented in this paper have been developed with the use of equipment financed from the funds of the "Excellence Initiative - Research University" program at AGH University of Science and Technology. The authors thank all the members of the ROMEO campaign, in particular, Thomas Roeckmann for providing an opportunity to be part of this measurement campaign.
How to cite: Jagoda, P., Nęcki, J., Bartyzel, J., Radovici, A., Mereuta, A., Roeckmann, T., and Figura, A.: Application of the large-scale flux chamber for quantification of methane release rate at Transylvanian gas fields., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11773, https://doi.org/10.5194/egusphere-egu23-11773, 2023.
Methane (CH4) is a potent greenhouse gas but its sources remain poorly quantified in the Eastern Mediterranean and Middle East (EMME) region where major oil and gas production takes place. Light alkanes, such as ethane (C2H6), are co-emitted with CH4 by oil and gas activities and are promising tracers for quantifying the methane emissions from this sector. Cyprus is an ideal location for studying the composition of regional air masses and for characterizing different emission source signatures at a regional scale. A Picarro G2401 greenhouse gas analyzer and two field-based Gas Chromatography Flame Ionization Detectors (GC-FID) for Non-Methane Hydrocarbons (NMHC) measurements were deployed during two campaigns, one in “urban” (Nicosia) and one in “regional background” (Cape Greko) environment respectively. The campaign at the regional background site consisted in continuous methane and NMHCs (C2-C12) observations using a mobile laboratory that was deployed at the south-eastern edge of the island between December 2021 and February 2022. This location was chosen to capture airmasses of remote south and eastern origin, uninfluenced by local sources. We use these observations to 1) evaluate the significance of long-range transported versus local sources in Cyprus, 2) identify and document regional anthropogenic methane sources, and 3) assess the accuracy of the EDGAR sectoral emission inventory over EMME. Positive Matrix Factorization (PMF) analysis of the NMHC dataset resulted in the identification of four distinct sources namely tropospheric background, urban, heavy oil combustion, and transported from Middle East. The latest occurred during three distinct episodes and on average, had the highest NMHC concentrations. Generally, the different urban and regional signatures/sources displayed good and variable correlations between CH4 and C2 to C6-NMHCs. By investigating the PMF results together with CH4 concentrations and an atmospheric dispersion model (FLEXPART), we provide a comprehensive characterization of the pollution sources at regional scale over the Eastern Mediterranean region.
How to cite: Germain-Piaulenne, E., Paris, J.-D., Bourtsoukidis, E., Quehe, P.-Y., Michael Pikridas, M., Desservettaz, M., Baisnee, D., Liu, Y., Gros, V., and Sciare, J.: Methane source identification using Non-Methane Hydrocarbon (NMHC) source apportionment in the Eastern Mediterranean and Middle East region, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13865, https://doi.org/10.5194/egusphere-egu23-13865, 2023.
A reduction in anthropogenic methane emissions is vital to limit near-term global warming. A small number of so-called super-emitters is responsible for a disproportionally large fraction of total methane emissions. Since late 2017, the TROPOspheric Monitoring Instrument (TROPOMI) has been in orbit providing daily global coverage of methane mixing ratios at a resolution of up to 7x5.5 km2, enabling the detection of these super-emitters for the first time at global scale. However, TROPOMI produces millions of observations each day, which together with the complexity of the methane data, makes manual inspection infeasible. We have therefore designed a two-step machine learning approach using a Convolutional Neural Network to detect plume-like structures in the methane data and subsequently apply a Support Vector Classifier to distinguish emission plumes from retrieval artefacts. The models are trained on pre-2021 data, and subsequently applied to all 2021 observations. We detect 2974 plumes in 2021 with a mean estimated source rate of 44 t h-1 and 5-95th percentile range of 8-122 t h-1. These emissions originate from 94 persistent emission clusters and hundreds of transient sources. Based on bottom-up emission inventories, we find that most detected plumes are related to urban areas / landfills (35%), followed by plumes from gas infrastructure (24%), oil infrastructure (21%) and coal mines (20%). For twelve (clusters of) TROPOMI detections, we "tip-and-cue" targeted observations and analysis of high-resolution satellite instruments to identify the exact sources responsible for these plumes. Using the high-resolution observations from GHGSat, PRISMA and Sentinel-2, we detect and analyze both persistent and transient facility-level emissions underlying the TROPOMI detections. We will show observations of emissions from landfills and fossil fuel exploitation facilities, for the latter we find up to ten facilities contributing to one TROPOMI detection. In addition to our examination of 2021, we will show results from applying our automated machine learning pipeline continuously on TROPOMI data from as recently as three days ago. Our automated TROPOMI-based monitoring system in combination with high-resolution satellite data allows for the detection, precise identification and monitoring of these methane super-emitters, which is essential for mitigating their emissions and reaching the goals of the Global Methane Pledge of reducing global anthropogenic methane emissions with 30% by 2030.
How to cite: Schuit, B. J., Maasakkers, J. D., Bijl, P., Mahapatra, G., Van den Berg, A.-W., Yaakoub, M., Pandey, S., Lorente, A., Borsdorff, T., Houweling, S., Varon, D. J., McKeever, J., Jervis, D., Girard, M., Irakulis-Loitxate, I., Gorroño, J., Guanter, L., Cusworth, D. H., and Aben, I.: Automated detection and monitoring of methane super-emitters using satellite data, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-16557, https://doi.org/10.5194/egusphere-egu23-16557, 2023.
This study establishes a regional inverse framework to refine methane (CH4) emission inventories for Melbourne, Australia. Methane is a long-lived greenhouse gas and the second most significant contributor to radiative forcing from greenhouse gases after carbon dioxide. Improved understanding of methane emissions from different sectors in Australia is necessary to focus and prioritise mitigation efforts and to track progress towards emissions reduction; however, methane emissions are uncertain, especially at fine resolution (urban and regional scales) needed for mitigation. Moreover, improving predictions of atmospheric methane mole fractions requires precise and accurate emission estimates; However, previous studies indicate a mismatch between current emission estimates and atmospheric observations.
Here, we use a combination of surface atmospheric measurements of methane and an inversion approach based on Bayes’ theorem to improve urban-scale methane emission estimates for Melbourne, Australia. Our inversion system is a Python-based four-dimensional variational (Py4DVar) data assimilation system. Due to lack of local methane inventories, prior emission estimates for Melbourne are compiled from globally-accessible datasets, including (1) anthropogenic emissions from the Emissions Database for Global Atmospheric Research (EDGAR), (2) fire emissions from the Global Fire Assimilation System (GFAS) dataset and (3) biogenic emissions from the Model of Emissions of Gases and Aerosols from Nature (MEGAN). Boundary condition adjustments are made using Kennaook/Cape Grim continuous in-situ CH4 mole fraction measurements and the Whole Atmosphere Community Climate Model (WACCM) dataset. The boundary condition adjustments are necessary to develop the efficiency of the regional inversion. The main goal of our inversion system is to provide more precise estimates of regional methane emissions. Independent satellite measurement comparisons are used to assess the system.
The comparison with assimilated data shows improvements in modelling methane mole fraction at the suburban Aspendale site with a bias reduction from ~70 ppb (prior) to ~3 ppb (posterior). Our detailed investigations indicate that although the prior results in a reasonable match of modelled mole fraction with observations, the EDGAR dataset does not provide a realistic spatial pattern for the main anthropogenic sources (enteric fermentation and landfills) around Melbourne. The possibility of improving the spatial distribution of the prior emissions has been tested using available local/global datasets, including national maps of livestock and landfills. Eventually, to obtain more comprehensive improved emission inventories in Melbourne, more CH4 mole fraction observational data are required in this area. The results of this study are being used to expand the methane monitoring network for Melbourne.
How to cite: Shahrokhi, N., Trudinger, C. M., Rayner, P. J., Loh, Z. M., Stavert, A. R., Krummel, P. B., Fraser, P. J., Etheridge, D. M., Dunse, B. L., Luhar, A., and Thomas, S.: Supporting Methane Mitigation Efforts by Improving Urban-scale Methane Emission Estimates in Melbourne, Australia. Part 1: Modelling, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4716, https://doi.org/10.5194/egusphere-egu23-4716, 2023.
Posters virtual: Thu, 27 Apr, 10:45–12:30 | vHall AS
Methane (CH4) is the second greatest contributor to climate forcing after carbon dioxide (CO2). Methane has a considerably shorter atmospheric lifetime compared to CO2 (12 yr c.f. 300-1000 yr) but a higher warming potential in the atmosphere (GWP100yr 28, (IPCC, 2014)). Most anthropogenic emissions come from landfills, wastewater treatment plants, leaks in the fossil fuel supply chain and ruminant livestock. The reduction of anthropogenic methane emissions is key to maintaining the feasibility of the Paris Agreement. The Global Methane Pledge launched at COP26 aims to reduce methane emissions by 30% relative to 2020 by 2030. Urban areas are an ideal target to reduce methane emissions given that they account for around 20% of the total emissions whilst they occupy only 3% of the land surface. Urban methane mitigations plans are proven to have a high impact reducing GHG emissions and bringing co-benefits in public health through improvements in air quality.
Australia is a signatory to both the Paris Agreement and the Global Methane Pledge and have an important potential emission reduction in urban areas. Melbourne is the second most populous city in Australia with over 5 million people (around 1/5 of Australia’s population) and it is projected to become the most populated by 2050. A recent study attempted to improve methane emission inventories for Melbourne using an inversion system, global emission data and atmospheric measurements (Shahrokhi , 2022). Their results showed that current emission datasets do not accurately represent the spatial distribution and total estimates of methane emissions over Melbourne. Hence, an improved emission inventory is required for Melbourne. This will reduce the uncertainty and limitations of current methane emission estimates and support the formulation of effective emissions mitigation plans. Essential to this is the expansion of the Melbourne urban observational network, which is currently too sparse to accurately detect emissions. Here we present our preliminary progress on the development of a comprehensive methane observation network. This project aims to combine different measurement techniques to achieve a better representation of methane mole fraction variability in the Melbourne region, to inform inverse modelling estimates of emissions. We use a combination of mobile and stationary ground observations in key parts of the city to better capture and represent methane emissions. Future work includes the comparison of high precision analysers with low-cost sensors, improvement of source attribution by measurements of methane isotopes and other tracers, and the use of “AirCore” technology to obtain vertical methane profiles.
References
IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.
Shahrokhi, N. 2022. Regional Methane Inversion for Melbourne, Australia, using in-situ measurements. Online poster [accessed 10 Jan 2022]. Available from: https://agu2022fallmeeting-agu.ipostersessions.com/default.aspx?s=2F-7B-00-39-98-DC-28-09-C3-90-81-25-D7-44-E2-D2#
How to cite: Ramirez Gamboa, J., Loh, Z., Stavert, A., Krummel, P., Shahrokhi, N., Trudinger, C., Caldow, C., Spencer, D., and Roulston, C.: Supporting Methane Mitigation Efforts by Improving Urban-scale Methane Emission Estimates in Melbourne, Australia. Part 2: Developing the methane observation network for the Melbourne region, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10725, https://doi.org/10.5194/egusphere-egu23-10725, 2023.
