Articles | Volume 25, issue 23
https://doi.org/10.5194/acp-25-18015-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/acp-25-18015-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Measurement report
| 
09 Dec 2025
Measurement report |
| 09 Dec 2025
| 09 Dec 2025
Measurement report: Mobile measurements to estimate urban methane emissions in Tokyo
National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
Yukio Terao
National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
Masahito Ueyama
Graduate School of Agriculture, Osaka Metropolitan University, Sakai, 599-8531, Japan
Satoshi Kameyama
National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
Mark Lunt
Environmental Defense Fund, New York, NY 10010, USA
James Lawrence France
Environmental Defense Fund, New York, NY 10010, USA
Department of Earth Sciences, Royal Holloway University of London, Egham, TW20 0EX, United Kingdom
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We combined long-term methane mole fraction and isotope measurements from eight laboratories that sample high-latitude stations to compare, offset correct and harmonise the datasets into a hemisphere merged timeseries. Because each laboratory uses slightly different methods, we adjusted the data to make it directly comparable. This allowed us to create a consistent record of atmospheric methane concentration and its isotopes from 1988 to 2023.
Masahito Ueyama, Taku Umezawa, Yukio Terao, Mark Lunt, and James Lawrence France
Atmos. Chem. Phys., 25, 12513–12534, https://doi.org/10.5194/acp-25-12513-2025, https://doi.org/10.5194/acp-25-12513-2025, 2025
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Methane (CH4) emissions were measured in the megacity of Osaka, Japan, using mobile and eddy covariance methods. The CH4 emissions were much higher than those reported in local inventories, with natural gas contributing up to 74 % of the emissions. Several CH4 sources not accounted for in current inventories were identified. These results emphasize the need for more comprehensive emissions tracking in urban areas to enhance climate change mitigation efforts.
Satoshi Sugawara, Shinji Morimoto, Shigeyuki Ishidoya, Taku Umezawa, Shuji Aoki, Takakiyo Nakazawa, Sakae Toyoda, Kentaro Ishijima, Daisuke Goto, and Hideyuki Honda
Atmos. Chem. Phys., 25, 11895–11917, https://doi.org/10.5194/acp-25-11895-2025, https://doi.org/10.5194/acp-25-11895-2025, 2025
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We have collected stratospheric air samples using balloon-borne cryogenic samplers over Japan since 1985 and analyzed them for δ13CO2. δ13CO2 has decreased through time in the mid-stratosphere with an average rate of change of −0.026 ± 0.001 ‰ yr−1. We found that stratospheric δ13CO2 variations are governed by airborne production of 13C-depleted CO2 by CH4 oxidation, gravitational separation, and propagation of the decreasing tropospheric δ13CO2 trend into the stratosphere.
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We have developed a high-accuracy dynamic dilution system for generating reference gas mixtures containing carbonyl sulfide (COS). Although COS at ambient levels generally has poor storage stability, our approach involves the dilution of a gas mixture containing micromole-per-mole levels of COS, the stability of which was validated for more than 1 decade. The developed system has excellent dilution performance and will facilitate accurate instrumental calibration for atmospheric COS observation.
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Atmos. Chem. Phys., 22, 6899–6917, https://doi.org/10.5194/acp-22-6899-2022, https://doi.org/10.5194/acp-22-6899-2022, 2022
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Greenhouse gas methane in the Arctic atmosphere has not been accurately reported for 1900–1980 from either direct observations or ice core reconstructions. By using trace gas data from firn (compacted snow layers above ice sheet), air samples at two Greenland sites, and a firn air transport model, this study suggests a likely range of the Arctic methane reconstruction for the 20th century. Atmospheric scenarios from two previous studies are also evaluated for consistency with the firn data sets.
Yosuke Niwa, Yousuke Sawa, Hideki Nara, Toshinobu Machida, Hidekazu Matsueda, Taku Umezawa, Akihiko Ito, Shin-Ichiro Nakaoka, Hiroshi Tanimoto, and Yasunori Tohjima
Atmos. Chem. Phys., 21, 9455–9473, https://doi.org/10.5194/acp-21-9455-2021, https://doi.org/10.5194/acp-21-9455-2021, 2021
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Fires in Equatorial Asia release a large amount of carbon into the atmosphere. Extensively using high-precision atmospheric carbon dioxide (CO2) data from a commercial aircraft observation project, we estimated fire carbon emissions in Equatorial Asia induced by the big El Niño event in 2015. Additional shipboard measurement data elucidated the validity of the analysis and the best estimate indicated 273 Tg C for fire emissions during September–October 2015.
Bibhasvata Dasgupta, Sudhanshu Pandey, Sander Houweling, Malika Menoud, Carina van der Veen, John Miller, Ben Riddell-Young, Sylvia Englund Michel, Peter Sperlich, Shinji Morimoto, Ryo Fujita, Ingeborg Levin, Cordelia Veidt, Stephen Platt, Christine Groot Zwaaftink, Cathrine Lund Myhre, Ceres Woolley Maisch, Rebecca Fisher, Euan G. Nisbet, James France, Rowena Moss, Nicola Warwick, and Thomas Röckmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-5571, https://doi.org/10.5194/egusphere-2025-5571, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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Methane is a strong greenhouse gas, and its rise since the mid-2000s is debated in terms of sources and sinks. Using top-down and bottom-up data, along with inversion models and methane isotopes (δ13C-CH4 and δD-CH4), we find that wetlands are the primary driver of post-2006 increases, followed by agriculture and fossil fuels. Methane's lifetime has decreased by about 0.1 years. We also assess how isotope signatures and sink processes influence uncertainties.
Thomas C. Moore, James R. Hopkins, Will S. Drysdale, Stuart Young, Sri Hapsari Budisulistiorini, Marvin D. Shaw, James L. France, David Lowry, and James D. Lee
EGUsphere, https://doi.org/10.5194/egusphere-2025-5348, https://doi.org/10.5194/egusphere-2025-5348, 2025
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
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The Global Methane Pledge has led to increased effort to reduce methane emissions globally. One sector under increased scrutiny is the oil and gas industry, a major source of methane in this industry is from fugitive emissions (gas leaks). Locating these from pipework in cities requires mobile measurements. This work adapts previous methodologies to detect smaller leaks and suggests previous methods may detect 53.5 % less gas leaks.
Bibhasvata Dasgupta, Malika Menoud, Carina van der Veen, Ingeborg Levin, Cordelia Veidt, Heiko Moossen, Sylvia Englund Michel, Peter Sperlich, Shinji Morimoto, Ryo Fujita, Taku Umezawa, Stephen Platt, Christine Groot Zwaaftink, Cathrine Lund Myhre, Rebecca Fisher, David Lowry, Euan G. Nisbet, James France, Ceres Woolley Maisch, Gordon Brailsford, Rowena Moss, Daisuke Goto, Sudhanshu Pandey, Sander Houweling, Nicola Warwick, and Thomas Röckmann
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We combined long-term methane mole fraction and isotope measurements from eight laboratories that sample high-latitude stations to compare, offset correct and harmonise the datasets into a hemisphere merged timeseries. Because each laboratory uses slightly different methods, we adjusted the data to make it directly comparable. This allowed us to create a consistent record of atmospheric methane concentration and its isotopes from 1988 to 2023.
Tiia Määttä, Ankur Desai, Masahito Ueyama, Rodrigo Vargas, Eric J. Ward, Zhen Zhang, Gil Bohrer, Kyle Delwiche, Etienne Fluet-Chouinard, Järvi Järveoja, Sara Knox, Lulie Melling, Mats B. Nilsson, Matthias Peichl, Angela Che Ing Tang, Eeva-Stiina Tuittila, Jinsong Wang, Sheel Bansal, Sarah Feron, Manuel Helbig, Aino Korrensalo, Ken W. Krauss, Gavin McNicol, Shuli Niu, Zutao Ouyang, Kathleen Savage, Oliver Sonnentag, Robert Jackson, and Avni Malhotra
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This preprint is open for discussion and under review for Biogeosciences (BG).
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We compared ecosystem and plot-scale methane fluxes across wetland and upland sites. Ecosystem-scale fluxes were higher than at plot scale, but differences were small. Vapor pressure deficit, atmospheric pressure, turbulence, and wind direction affected the differences. Both scales could be combined for improved methane flux estimates at coarser temporal scales.
Anna-Maria Virkkala, Isabel Wargowsky, Judith Vogt, McKenzie A. Kuhn, Simran Madaan, Richard O'Keefe, Tiffany Windholz, Kyle A. Arndt, Brendan M. Rogers, Jennifer D. Watts, Kelcy Kent, Mathias Göckede, David Olefeldt, Gerard Rocher-Ros, Edward A. G. Schuur, David Bastviken, Kristoffer Aalstad, Kelly Aho, Joonatan Ala-Könni, Haley Alcock, Inge Althuizen, Christopher D. Arp, Jun Asanuma, Katrin Attermeyer, Mika Aurela, Sivakiruthika Balathandayuthabani, Alan Barr, Maialen Barret, Ochirbat Batkhishig, Christina Biasi, Mats P. Björkman, Andrew Black, Elena Blanc-Betes, Pascal Bodmer, Julia Boike, Abdullah Bolek, Frédéric Bouchard, Ingeborg Bussmann, Lea Cabrol, Eleonora Canfora, Sean Carey, Karel Castro-Morales, Namyi Chae, Andres Christen, Torben R. Christensen, Casper T. Christiansen, Housen Chu, Graham Clark, Francois Clayer, Patrick Crill, Christopher Cunada, Scott J. Davidson, Joshua F. Dean, Sigrid Dengel, Matteo Detto, Catherine Dieleman, Florent Domine, Egor Dyukarev, Colin Edgar, Bo Elberling, Craig A. Emmerton, Eugenie Euskirchen, Grant Falvo, Thomas Friborg, Michelle Garneau, Mariasilvia Giamberini, Mikhail V. Glagolev, Miquel A. Gonzalez-Meler, Gustaf Granath, Jón Guðmundsson, Konsta Happonen, Yoshinobu Harazono, Lorna Harris, Josh Hashemi, Nicholas Hasson, Janna Heerah, Liam Heffernan, Manuel Helbig, Warren Helgason, Michal Heliasz, Greg Henry, Geert Hensgens, Tetsuya Hiyama, Macall Hock, David Holl, Beth Holmes, Jutta Holst, Thomas Holst, Gabriel Hould-Gosselin, Elyn Humphreys, Jacqueline Hung, Jussi Huotari, Hiroki Ikawa, Danil V. Ilyasov, Mamoru Ishikawa, Go Iwahana, Hiroki Iwata, Marcin Antoni Jackowicz-Korczynski, Joachim Jansen, Järvi Järveoja, Vincent E. J. Jassey, Rasmus Jensen, Katharina Jentzsch, Robert G. Jespersen, Carl-Fredrik Johannesson, Chersity P. Jones, Anders Jonsson, Ji Young Jung, Sari Juutinen, Evan Kane, Jan Karlsson, Sergey Karsanaev, Kuno Kasak, Julia Kelly, Kasha Kempton, Marcus Klaus, George W. Kling, Natacha Kljun, Jacqueline Knutson, Hideki Kobayashi, John Kochendorfer, Kukka-Maaria Kohonen, Pasi Kolari, Mika Korkiakoski, Aino Korrensalo, Pirkko Kortelainen, Egle Koster, Kajar Koster, Ayumi Kotani, Praveena Krishnan, Juliya Kurbatova, Lars Kutzbach, Min Jung Kwon, Ethan D. Kyzivat, Jessica Lagroix, Theodore Langhorst, Elena Lapshina, Tuula Larmola, Klaus S. Larsen, Isabelle Laurion, Justin Ledman, Hanna Lee, A. Joshua Leffler, Lance Lesack, Anders Lindroth, David Lipson, Annalea Lohila, Efrén López-Blanco, Vincent L. St. Louis, Erik Lundin, Misha Luoto, Takashi Machimura, Marta Magnani, Avni Malhotra, Marja Maljanen, Ivan Mammarella, Elisa Männistö, Luca Belelli Marchesini, Phil Marsh, Pertti J. Martkainen, Maija E. Marushchak, Mikhail Mastepanov, Alex Mavrovic, Trofim Maximov, Christina Minions, Marco Montemayor, Tomoaki Morishita, Patrick Murphy, Daniel F. Nadeau, Erin Nicholls, Mats B. Nilsson, Anastasia Niyazova, Jenni Nordén, Koffi Dodji Noumonvi, Hannu Nykanen, Walter Oechel, Anne Ojala, Tomohiro Okadera, Sujan Pal, Alexey V. Panov, Tim Papakyriakou, Dario Papale, Sang-Jong Park, Frans-Jan W. Parmentier, Gilberto Pastorello, Mike Peacock, Matthias Peichl, Roman Petrov, Kyra St. Pierre, Norbert Pirk, Jessica Plein, Vilmantas Preskienis, Anatoly Prokushkin, Jukka Pumpanen, Hilary A. Rains, Niklas Rakos, Aleski Räsänen, Helena Rautakoski, Riika Rinnan, Janne Rinne, Adrian Rocha, Nigel Roulet, Alexandre Roy, Anna Rutgersson, Aleksandr F. Sabrekov, Torsten Sachs, Erik Sahlée, Alejandro Salazar, Henrique Oliveira Sawakuchi, Christopher Schulze, Roger Seco, Armando Sepulveda-Jauregui, Svetlana Serikova, Abbey Serrone, Hanna M. Silvennoinen, Sofie Sjogersten, June Skeeter, Jo Snöälv, Sebastian Sobek, Oliver Sonnentag, Emily H. Stanley, Maria Strack, Lena Strom, Patrick Sullivan, Ryan Sullivan, Anna Sytiuk, Torbern Tagesson, Pierre Taillardat, Julie Talbot, Suzanne E. Tank, Mario Tenuta, Irina Terenteva, Frederic Thalasso, Antoine Thiboult, Halldor Thorgeirsson, Fenix Garcia Tigreros, Margaret Torn, Amy Townsend-Small, Claire Treat, Alain Tremblay, Carlo Trotta, Eeva-Stiina Tuittila, Merritt Turetsky, Masahito Ueyama, Muhammad Umair, Aki Vähä, Lona van Delden, Maarten van Hardenbroek, Andrej Varlagin, Ruth K. Varner, Elena Veretennikova, Timo Vesala, Tarmo Virtanen, Carolina Voigt, Jorien E. Vonk, Robert Wagner, Katey Walter Anthony, Qinxue Wang, Masataka Watanabe, Hailey Webb, Jeffrey M. Welker, Andreas Westergaard-Nielsen, Sebastian Westermann, Jeffrey R. White, Christian Wille, Scott N. Williamson, Scott Zolkos, Donatella Zona, and Susan M. Natali
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-585, https://doi.org/10.5194/essd-2025-585, 2025
Preprint under review for ESSD
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This dataset includes monthly measurements of carbon dioxide and methane exchange between land, water, and the atmosphere from over 1,000 sites in Arctic and boreal regions. It combines measurements from a variety of ecosystems, including wetlands, forests, tundra, lakes, and rivers, gathered by over 260 researchers from 1984–2024. This dataset can be used to improve and reduce uncertainty in carbon budgets in order to strengthen our understanding of climate feedbacks in a warming world.
Masahito Ueyama, Taku Umezawa, Yukio Terao, Mark Lunt, and James Lawrence France
Atmos. Chem. Phys., 25, 12513–12534, https://doi.org/10.5194/acp-25-12513-2025, https://doi.org/10.5194/acp-25-12513-2025, 2025
Short summary
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Methane (CH4) emissions were measured in the megacity of Osaka, Japan, using mobile and eddy covariance methods. The CH4 emissions were much higher than those reported in local inventories, with natural gas contributing up to 74 % of the emissions. Several CH4 sources not accounted for in current inventories were identified. These results emphasize the need for more comprehensive emissions tracking in urban areas to enhance climate change mitigation efforts.
Satoshi Sugawara, Shinji Morimoto, Shigeyuki Ishidoya, Taku Umezawa, Shuji Aoki, Takakiyo Nakazawa, Sakae Toyoda, Kentaro Ishijima, Daisuke Goto, and Hideyuki Honda
Atmos. Chem. Phys., 25, 11895–11917, https://doi.org/10.5194/acp-25-11895-2025, https://doi.org/10.5194/acp-25-11895-2025, 2025
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We have collected stratospheric air samples using balloon-borne cryogenic samplers over Japan since 1985 and analyzed them for δ13CO2. δ13CO2 has decreased through time in the mid-stratosphere with an average rate of change of −0.026 ± 0.001 ‰ yr−1. We found that stratospheric δ13CO2 variations are governed by airborne production of 13C-depleted CO2 by CH4 oxidation, gravitational separation, and propagation of the decreasing tropospheric δ13CO2 trend into the stratosphere.
Mark F. Lunt, Stephen J. Harris, Jorg Hacker, Ian Joynes, Tim Robertson, Simon Thompson, and James L. France
Atmos. Meas. Tech., 18, 4413–4431, https://doi.org/10.5194/amt-18-4413-2025, https://doi.org/10.5194/amt-18-4413-2025, 2025
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To ensure robust use of measurement-based approaches to estimate methane emissions from individual sites, it is important to validate the accuracy of the methods used in the field. By using co-emitted carbon dioxide, we evaluate the performance of one such quantification method at liquefied natural gas terminals. We further demonstrate the potential for a more efficient quantification approach via tracer correlation by considering the ratio of methane to carbon dioxide concentrations.
Audrey McManemin, Catherine Juéry, Vincent Blandin, James L. France, Philippine Burdeau, and Adam R. Brandt
EGUsphere, https://doi.org/10.5194/egusphere-2025-3793, https://doi.org/10.5194/egusphere-2025-3793, 2025
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This experiment tested the ability of different technologies to detect and measure methane emissions. Participating teams used satellites, drones, and other systems to estimate methane leak rates without knowing the true rate. Some systems were more accurate than others, and wind and other environmental conditions made measurements harder. Our findings help improve these tools and support efforts to track and reduce methane emissions as new environmental rules take shape in Europe and beyond.
Masahito Ueyama, Yuta Takao, Hiromi Yazawa, Makiko Tanaka, Hironori Yabuki, Tomo'omi Kumagai, Hiroki Iwata, Md. Abdul Awal, Mingyuan Du, Yoshinobu Harazono, Yoshiaki Hata, Takashi Hirano, Tsutom Hiura, Reiko Ide, Sachinobu Ishida, Mamoru Ishikawa, Kenzo Kitamura, Yuji Kominami, Shujiro Komiya, Ayumi Kotani, Yuta Inoue, Takashi Machimura, Kazuho Matsumoto, Yojiro Matsuura, Yasuko Mizoguchi, Shohei Murayama, Hirohiko Nagano, Taro Nakai, Tatsuro Nakaji, Ko Nakaya, Shinjiro Ohkubo, Takeshi Ohta, Keisuke Ono, Taku M. Saitoh, Ayaka Sakabe, Takanori Shimizu, Seiji Shimoda, Michiaki Sugita, Kentaro Takagi, Yoshiyuki Takahashi, Naoya Takamura, Satoru Takanashi, Takahiro Takimoto, Yukio Yasuda, Qinxue Wang, Jun Asanuma, Hideo Hasegawa, Tetsuya Hiyama, Yoshihiro Iijima, Shigeyuki Ishidoya, Masayuki Itoh, Tomomichi Kato, Hiroaki Kondo, Yoshiko Kosugi, Tomonori Kume, Takahisa Maeda, Shoji Matsuura, Trofim Maximov, Takafumi Miyama, Ryo Moriwaki, Hiroyuki Muraoka, Roman Petrov, Jun Suzuki, Shingo Taniguchi, and Kazuhito Ichii
Earth Syst. Sci. Data, 17, 3807–3833, https://doi.org/10.5194/essd-17-3807-2025, https://doi.org/10.5194/essd-17-3807-2025, 2025
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The JapanFlux2024 dataset, created through collaboration across Japan and East Asia, includes eddy covariance data from 83 sites spanning 683 site-years (1990–2023). This comprehensive dataset offers valuable insights into energy, water, and CO2 fluxes, supporting research on land–atmosphere interactions and process models; fosters global collaboration; and advances research in environmental science and regional climate dynamics.
Judith Tettenborn, Daniel Zavala-Araiza, Daan Stroeken, Hossein Maazallahi, Carina van der Veen, Arjan Hensen, Ilona Velzeboer, Pim van den Bulk, Felix Vogel, Lawson Gillespie, Sebastien Ars, James France, David Lowry, Rebecca Fisher, and Thomas Röckmann
Atmos. Meas. Tech., 18, 3569–3584, https://doi.org/10.5194/amt-18-3569-2025, https://doi.org/10.5194/amt-18-3569-2025, 2025
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Measurements of methane with vehicle-based sensors are an effective method to identify and quantify leaks from urban gas distribution systems. We deliberately released methane in different environments and calibrated the response of different methane analysers when they transected the plumes in a vehicle. We derived an improved statistical function for consistent emission estimations using different instruments. Repeated transects reduce the uncertainty in emission rate estimates.
Yosuke Niwa, Yasunori Tohjima, Yukio Terao, Tazu Saeki, Akihiko Ito, Taku Umezawa, Kyohei Yamada, Motoki Sasakawa, Toshinobu Machida, Shin-Ichiro Nakaoka, Hideki Nara, Hiroshi Tanimoto, Hitoshi Mukai, Yukio Yoshida, Shinji Morimoto, Shinya Takatsuji, Kazuhiro Tsuboi, Yousuke Sawa, Hidekazu Matsueda, Kentaro Ishijima, Ryo Fujita, Daisuke Goto, Xin Lan, Kenneth Schuldt, Michal Heliasz, Tobias Biermann, Lukasz Chmura, Jarsolaw Necki, Irène Xueref-Remy, and Damiano Sferlazzo
Atmos. Chem. Phys., 25, 6757–6785, https://doi.org/10.5194/acp-25-6757-2025, https://doi.org/10.5194/acp-25-6757-2025, 2025
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This study estimated regional and sectoral emission contributions to the unprecedented surge of atmospheric methane for 2020–2022. The methane is the second most important greenhouse gas, and its emissions reduction is urgently required to mitigate global warming. Numerical modeling-based estimates with three different sets of atmospheric observations consistently suggested large contributions of biogenic emissions from South Asia and Southeast Asia to the surge of atmospheric methane.
Qing Ying, Benjamin Poulter, Jennifer D. Watts, Kyle A. Arndt, Anna-Maria Virkkala, Lori Bruhwiler, Youmi Oh, Brendan M. Rogers, Susan M. Natali, Hilary Sullivan, Amanda Armstrong, Eric J. Ward, Luke D. Schiferl, Clayton D. Elder, Olli Peltola, Annett Bartsch, Ankur R. Desai, Eugénie Euskirchen, Mathias Göckede, Bernhard Lehner, Mats B. Nilsson, Matthias Peichl, Oliver Sonnentag, Eeva-Stiina Tuittila, Torsten Sachs, Aram Kalhori, Masahito Ueyama, and Zhen Zhang
Earth Syst. Sci. Data, 17, 2507–2534, https://doi.org/10.5194/essd-17-2507-2025, https://doi.org/10.5194/essd-17-2507-2025, 2025
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We present daily methane (CH4) fluxes of northern wetlands at 10 km resolution during 2016–2022 (WetCH4) derived from a novel machine learning framework. We estimated an average annual CH4 emission of 22.8 ± 2.4 Tg CH4 yr−1 (15.7–51.6 Tg CH4 yr−1). Emissions were intensified in 2016, 2020, and 2022, with the largest interannual variation coming from Western Siberia. Continued, all-season tower observations and improved soil moisture products are needed for future improvement of CH4 upscaling.
Neil Humpage, Hartmut Boesch, William Okello, Jia Chen, Florian Dietrich, Mark F. Lunt, Liang Feng, Paul I. Palmer, and Frank Hase
Atmos. Meas. Tech., 17, 5679–5707, https://doi.org/10.5194/amt-17-5679-2024, https://doi.org/10.5194/amt-17-5679-2024, 2024
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We used a Bruker EM27/SUN spectrometer within an automated weatherproof enclosure to measure greenhouse gas column concentrations over a 3-month period in Jinja, Uganda. The portability of the EM27/SUN allows us to evaluate satellite and model data in locations not covered by traditional validation networks. This is of particular value in tropical Africa, where extensive terrestrial ecosystems are a significant store of carbon and play a key role in the atmospheric budgets of CO2 and CH4.
Tia R. Scarpelli, Paul I. Palmer, Mark Lunt, Ingrid Super, and Arjan Droste
Atmos. Chem. Phys., 24, 10773–10791, https://doi.org/10.5194/acp-24-10773-2024, https://doi.org/10.5194/acp-24-10773-2024, 2024
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Under the Paris Agreement, countries must track their anthropogenic greenhouse gas emissions. This study describes a method to determine self-consistent estimates for combustion emissions and natural fluxes of CO2 from atmospheric data. We report consistent estimates inferred using this approach from satellite data and ground-based data over Europe, suggesting that satellite data can be used to determine national anthropogenic CO2 emissions for countries where ground-based CO2 data are absent.
Hideki Nara, Takuya Saito, Taku Umezawa, and Yasunori Tohjima
Atmos. Meas. Tech., 17, 5187–5200, https://doi.org/10.5194/amt-17-5187-2024, https://doi.org/10.5194/amt-17-5187-2024, 2024
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We have developed a high-accuracy dynamic dilution system for generating reference gas mixtures containing carbonyl sulfide (COS). Although COS at ambient levels generally has poor storage stability, our approach involves the dilution of a gas mixture containing micromole-per-mole levels of COS, the stability of which was validated for more than 1 decade. The developed system has excellent dilution performance and will facilitate accurate instrumental calibration for atmospheric COS observation.
Vishnu Thilakan, Dhanyalekshmi Pillai, Jithin Sukumaran, Christoph Gerbig, Haseeb Hakkim, Vinayak Sinha, Yukio Terao, Manish Naja, and Monish Vijay Deshpande
Atmos. Chem. Phys., 24, 5315–5335, https://doi.org/10.5194/acp-24-5315-2024, https://doi.org/10.5194/acp-24-5315-2024, 2024
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This study investigates the usability of CO2 mixing ratio observations over India to infer regional carbon sources and sinks. We demonstrate that a high-resolution modelling system can represent the observed CO2 variations reasonably well by improving the transport and flux variations at a fine scale. Future carbon data assimilation systems can thus benefit from these recently available CO2 observations when fine-scale variations are adequately represented in the models.
Emily Dowd, Alistair J. Manning, Bryn Orth-Lashley, Marianne Girard, James France, Rebecca E. Fisher, Dave Lowry, Mathias Lanoisellé, Joseph R. Pitt, Kieran M. Stanley, Simon O'Doherty, Dickon Young, Glen Thistlethwaite, Martyn P. Chipperfield, Emanuel Gloor, and Chris Wilson
Atmos. Meas. Tech., 17, 1599–1615, https://doi.org/10.5194/amt-17-1599-2024, https://doi.org/10.5194/amt-17-1599-2024, 2024
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We provide the first validation of the satellite-derived emission estimates using surface-based mobile greenhouse gas surveys of an active gas leak detected near Cheltenham, UK. GHGSat’s emission estimates broadly agree with the surface-based mobile survey and steps were taken to fix the leak, highlighting the importance of satellite data in identifying emissions and helping to reduce our human impact on climate change.
Magdalena Pühl, Anke Roiger, Alina Fiehn, Alan M. Gorchov Negron, Eric A. Kort, Stefan Schwietzke, Ignacio Pisso, Amy Foulds, James Lee, James L. France, Anna E. Jones, Dave Lowry, Rebecca E. Fisher, Langwen Huang, Jacob Shaw, Prudence Bateson, Stephen Andrews, Stuart Young, Pamela Dominutti, Tom Lachlan-Cope, Alexandra Weiss, and Grant Allen
Atmos. Chem. Phys., 24, 1005–1024, https://doi.org/10.5194/acp-24-1005-2024, https://doi.org/10.5194/acp-24-1005-2024, 2024
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In April–May 2019 we carried out an airborne field campaign in the southern North Sea with the aim of studying methane emissions of offshore gas installations. We determined methane emissions from elevated methane measured downstream of the sampled installations. We compare our measured methane emissions with estimated methane emissions from national and global annual inventories. As a result, we find inconsistencies of inventories and large discrepancies between measurements and inventories.
Sara M. Defratyka, James L. France, Rebecca E. Fisher, Dave Lowry, Julianne M. Fernandez, Semra Bakkaloglu, Camille Yver-Kwok, Jean-Daniel Paris, Philippe Bousquet, Tim Arnold, Chris Rennick, Jon Helmore, Nigel Yarrow, and Euan G. Nisbet
EGUsphere, https://doi.org/10.5194/egusphere-2023-1490, https://doi.org/10.5194/egusphere-2023-1490, 2023
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We are focused on verification of δ13CH4 measurements in near-source conditions and we have provided an insight into the impact of chosen calculation methods for determined isotopic signatures. Our study offers a step forward for establishing an unified, robust, and reliable analytical technique to determine δ13CH4 of methane sources. Our recommended analytical approach reduces biases and uncertainties coming from measurement conditions, data clustering and various available fitting methods.
Liang Feng, Paul I. Palmer, Robert J. Parker, Mark F. Lunt, and Hartmut Bösch
Atmos. Chem. Phys., 23, 4863–4880, https://doi.org/10.5194/acp-23-4863-2023, https://doi.org/10.5194/acp-23-4863-2023, 2023
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Our understanding of recent changes in atmospheric methane has defied explanation. Since 2007, the atmospheric growth of methane has accelerated to record-breaking values in 2020 and 2021. We use satellite observations of methane to show that (1) increasing emissions over the tropics are mostly responsible for these recent atmospheric changes, and (2) changes in the OH sink during the 2020 Covid-19 lockdown can explain up to 34% of changes in atmospheric methane for that year.
Robert J. Parker, Chris Wilson, Edward Comyn-Platt, Garry Hayman, Toby R. Marthews, A. Anthony Bloom, Mark F. Lunt, Nicola Gedney, Simon J. Dadson, Joe McNorton, Neil Humpage, Hartmut Boesch, Martyn P. Chipperfield, Paul I. Palmer, and Dai Yamazaki
Biogeosciences, 19, 5779–5805, https://doi.org/10.5194/bg-19-5779-2022, https://doi.org/10.5194/bg-19-5779-2022, 2022
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Wetlands are the largest natural source of methane, one of the most important climate gases. The JULES land surface model simulates these emissions. We use satellite data to evaluate how well JULES reproduces the methane seasonal cycle over different tropical wetlands. It performs well for most regions; however, it struggles for some African wetlands influenced heavily by river flooding. We explain the reasons for these deficiencies and highlight how future development will improve these areas.
Bryce F. J. Kelly, Xinyi Lu, Stephen J. Harris, Bruno G. Neininger, Jorg M. Hacker, Stefan Schwietzke, Rebecca E. Fisher, James L. France, Euan G. Nisbet, David Lowry, Carina van der Veen, Malika Menoud, and Thomas Röckmann
Atmos. Chem. Phys., 22, 15527–15558, https://doi.org/10.5194/acp-22-15527-2022, https://doi.org/10.5194/acp-22-15527-2022, 2022
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This study explores using the composition of methane of in-flight atmospheric air samples for greenhouse gas inventory verification. The air samples were collected above one of the largest coal seam gas production regions in the world. Adjacent to these gas fields are coal mines, Australia's largest cattle feedlot, and over 1 million grazing cattle. The results are also used to identify methane mitigation opportunities.
Malika Menoud, Carina van der Veen, Dave Lowry, Julianne M. Fernandez, Semra Bakkaloglu, James L. France, Rebecca E. Fisher, Hossein Maazallahi, Mila Stanisavljević, Jarosław Nęcki, Katarina Vinkovic, Patryk Łakomiec, Janne Rinne, Piotr Korbeń, Martina Schmidt, Sara Defratyka, Camille Yver-Kwok, Truls Andersen, Huilin Chen, and Thomas Röckmann
Earth Syst. Sci. Data, 14, 4365–4386, https://doi.org/10.5194/essd-14-4365-2022, https://doi.org/10.5194/essd-14-4365-2022, 2022
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Emission sources of methane (CH4) can be distinguished with measurements of CH4 stable isotopes. We present new measurements of isotope signatures of various CH4 sources in Europe, mainly anthropogenic, sampled from 2017 to 2020. The present database also contains the most recent update of the global signature dataset from the literature. The dataset improves CH4 source attribution and the understanding of the global CH4 budget.
Taku Umezawa, Satoshi Sugawara, Kenji Kawamura, Ikumi Oyabu, Stephen J. Andrews, Takuya Saito, Shuji Aoki, and Takakiyo Nakazawa
Atmos. Chem. Phys., 22, 6899–6917, https://doi.org/10.5194/acp-22-6899-2022, https://doi.org/10.5194/acp-22-6899-2022, 2022
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Greenhouse gas methane in the Arctic atmosphere has not been accurately reported for 1900–1980 from either direct observations or ice core reconstructions. By using trace gas data from firn (compacted snow layers above ice sheet), air samples at two Greenland sites, and a firn air transport model, this study suggests a likely range of the Arctic methane reconstruction for the 20th century. Atmospheric scenarios from two previous studies are also evaluated for consistency with the firn data sets.
Amy Foulds, Grant Allen, Jacob T. Shaw, Prudence Bateson, Patrick A. Barker, Langwen Huang, Joseph R. Pitt, James D. Lee, Shona E. Wilde, Pamela Dominutti, Ruth M. Purvis, David Lowry, James L. France, Rebecca E. Fisher, Alina Fiehn, Magdalena Pühl, Stéphane J. B. Bauguitte, Stephen A. Conley, Mackenzie L. Smith, Tom Lachlan-Cope, Ignacio Pisso, and Stefan Schwietzke
Atmos. Chem. Phys., 22, 4303–4322, https://doi.org/10.5194/acp-22-4303-2022, https://doi.org/10.5194/acp-22-4303-2022, 2022
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We measured CH4 emissions from 21 offshore oil and gas facilities in the Norwegian Sea in 2019. Measurements compared well with operator-reported emissions but were greatly underestimated when compared with a 2016 global fossil fuel inventory. This study demonstrates the need for up-to-date and accurate inventories for use in research and policy and the important benefits of best-practice reporting methods by operators. Airborne measurements are an effective tool to validate such inventories.
Alice E. Ramsden, Anita L. Ganesan, Luke M. Western, Matthew Rigby, Alistair J. Manning, Amy Foulds, James L. France, Patrick Barker, Peter Levy, Daniel Say, Adam Wisher, Tim Arnold, Chris Rennick, Kieran M. Stanley, Dickon Young, and Simon O'Doherty
Atmos. Chem. Phys., 22, 3911–3929, https://doi.org/10.5194/acp-22-3911-2022, https://doi.org/10.5194/acp-22-3911-2022, 2022
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Quantifying methane emissions from different sources is a key focus of current research. We present a method for estimating sectoral methane emissions that uses ethane as a tracer for fossil fuel methane. By incorporating variable ethane : methane emission ratios into this model, we produce emissions estimates with improved uncertainty characterisation. This method will be particularly useful for studying methane emissions in areas with complex distributions of sources.
Anna-Maria Virkkala, Susan M. Natali, Brendan M. Rogers, Jennifer D. Watts, Kathleen Savage, Sara June Connon, Marguerite Mauritz, Edward A. G. Schuur, Darcy Peter, Christina Minions, Julia Nojeim, Roisin Commane, Craig A. Emmerton, Mathias Goeckede, Manuel Helbig, David Holl, Hiroki Iwata, Hideki Kobayashi, Pasi Kolari, Efrén López-Blanco, Maija E. Marushchak, Mikhail Mastepanov, Lutz Merbold, Frans-Jan W. Parmentier, Matthias Peichl, Torsten Sachs, Oliver Sonnentag, Masahito Ueyama, Carolina Voigt, Mika Aurela, Julia Boike, Gerardo Celis, Namyi Chae, Torben R. Christensen, M. Syndonia Bret-Harte, Sigrid Dengel, Han Dolman, Colin W. Edgar, Bo Elberling, Eugenie Euskirchen, Achim Grelle, Juha Hatakka, Elyn Humphreys, Järvi Järveoja, Ayumi Kotani, Lars Kutzbach, Tuomas Laurila, Annalea Lohila, Ivan Mammarella, Yojiro Matsuura, Gesa Meyer, Mats B. Nilsson, Steven F. Oberbauer, Sang-Jong Park, Roman Petrov, Anatoly S. Prokushkin, Christopher Schulze, Vincent L. St. Louis, Eeva-Stiina Tuittila, Juha-Pekka Tuovinen, William Quinton, Andrej Varlagin, Donatella Zona, and Viacheslav I. Zyryanov
Earth Syst. Sci. Data, 14, 179–208, https://doi.org/10.5194/essd-14-179-2022, https://doi.org/10.5194/essd-14-179-2022, 2022
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The effects of climate warming on carbon cycling across the Arctic–boreal zone (ABZ) remain poorly understood due to the relatively limited distribution of ABZ flux sites. Fortunately, this flux network is constantly increasing, but new measurements are published in various platforms, making it challenging to understand the ABZ carbon cycle as a whole. Here, we compiled a new database of Arctic–boreal CO2 fluxes to help facilitate large-scale assessments of the ABZ carbon cycle.
Shohei Nomura, Manish Naja, M. Kawser Ahmed, Hitoshi Mukai, Yukio Terao, Toshinobu Machida, Motoki Sasakawa, and Prabir K. Patra
Atmos. Chem. Phys., 21, 16427–16452, https://doi.org/10.5194/acp-21-16427-2021, https://doi.org/10.5194/acp-21-16427-2021, 2021
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Long-term measurements of greenhouse gases (GHGs) in India and Bangladesh unveiled specific characteristics in their variations in these regions. Plants including rice cultivated in winter and summer strongly affected seasonal variations and levels in CO2 and CH4. Long-term variability of GHGs showed quite different features in their growth rates from those in Mauna Loa. GHG trends in this region seemed to be hardly affected by El Niño–Southern Oscillation (ENSO).
Mark F. Lunt, Alistair J. Manning, Grant Allen, Tim Arnold, Stéphane J.-B. Bauguitte, Hartmut Boesch, Anita L. Ganesan, Aoife Grant, Carole Helfter, Eiko Nemitz, Simon J. O'Doherty, Paul I. Palmer, Joseph R. Pitt, Chris Rennick, Daniel Say, Kieran M. Stanley, Ann R. Stavert, Dickon Young, and Matt Rigby
Atmos. Chem. Phys., 21, 16257–16276, https://doi.org/10.5194/acp-21-16257-2021, https://doi.org/10.5194/acp-21-16257-2021, 2021
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We present an evaluation of the UK's methane emissions between 2013 and 2020 using a network of tall tower measurement sites. We find emissions that are consistent in both magnitude and trend with the UK's reported emissions, with a declining trend driven by a decrease in emissions from England. The impact of various components of the modelling set-up on these findings are explored through a number of sensitivity studies.
Mehliyar Sadiq, Paul I. Palmer, Mark F. Lunt, Liang Feng, Ingrid Super, Stijn N. C. Dellaert, and Hugo A. C. Denier van der Gon
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2021-816, https://doi.org/10.5194/acp-2021-816, 2021
Publication in ACP not foreseen
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We make use of high-resolution emission inventory of CO2 and co-emitted tracers, satellite measurements, together with nested atmospheric transport model simulation, to investigate how reactive trace gases such as nitrogen dioxide and carbon monoxide can be used as proxies to determine the combustion contribution to atmospheric CO2 over Europe. We find stronger correlation in ratios of nitrogen dioxide and carbon dioxide between emission and satellite observed and modelled column concentration.
Kyle B. Delwiche, Sara Helen Knox, Avni Malhotra, Etienne Fluet-Chouinard, Gavin McNicol, Sarah Feron, Zutao Ouyang, Dario Papale, Carlo Trotta, Eleonora Canfora, You-Wei Cheah, Danielle Christianson, Ma. Carmelita R. Alberto, Pavel Alekseychik, Mika Aurela, Dennis Baldocchi, Sheel Bansal, David P. Billesbach, Gil Bohrer, Rosvel Bracho, Nina Buchmann, David I. Campbell, Gerardo Celis, Jiquan Chen, Weinan Chen, Housen Chu, Higo J. Dalmagro, Sigrid Dengel, Ankur R. Desai, Matteo Detto, Han Dolman, Elke Eichelmann, Eugenie Euskirchen, Daniela Famulari, Kathrin Fuchs, Mathias Goeckede, Sébastien Gogo, Mangaliso J. Gondwe, Jordan P. Goodrich, Pia Gottschalk, Scott L. Graham, Martin Heimann, Manuel Helbig, Carole Helfter, Kyle S. Hemes, Takashi Hirano, David Hollinger, Lukas Hörtnagl, Hiroki Iwata, Adrien Jacotot, Gerald Jurasinski, Minseok Kang, Kuno Kasak, John King, Janina Klatt, Franziska Koebsch, Ken W. Krauss, Derrick Y. F. Lai, Annalea Lohila, Ivan Mammarella, Luca Belelli Marchesini, Giovanni Manca, Jaclyn Hatala Matthes, Trofim Maximov, Lutz Merbold, Bhaskar Mitra, Timothy H. Morin, Eiko Nemitz, Mats B. Nilsson, Shuli Niu, Walter C. Oechel, Patricia Y. Oikawa, Keisuke Ono, Matthias Peichl, Olli Peltola, Michele L. Reba, Andrew D. Richardson, William Riley, Benjamin R. K. Runkle, Youngryel Ryu, Torsten Sachs, Ayaka Sakabe, Camilo Rey Sanchez, Edward A. Schuur, Karina V. R. Schäfer, Oliver Sonnentag, Jed P. Sparks, Ellen Stuart-Haëntjens, Cove Sturtevant, Ryan C. Sullivan, Daphne J. Szutu, Jonathan E. Thom, Margaret S. Torn, Eeva-Stiina Tuittila, Jessica Turner, Masahito Ueyama, Alex C. Valach, Rodrigo Vargas, Andrej Varlagin, Alma Vazquez-Lule, Joseph G. Verfaillie, Timo Vesala, George L. Vourlitis, Eric J. Ward, Christian Wille, Georg Wohlfahrt, Guan Xhuan Wong, Zhen Zhang, Donatella Zona, Lisamarie Windham-Myers, Benjamin Poulter, and Robert B. Jackson
Earth Syst. Sci. Data, 13, 3607–3689, https://doi.org/10.5194/essd-13-3607-2021, https://doi.org/10.5194/essd-13-3607-2021, 2021
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Methane is an important greenhouse gas, yet we lack knowledge about its global emissions and drivers. We present FLUXNET-CH4, a new global collection of methane measurements and a critical resource for the research community. We use FLUXNET-CH4 data to quantify the seasonality of methane emissions from freshwater wetlands, finding that methane seasonality varies strongly with latitude. Our new database and analysis will improve wetland model accuracy and inform greenhouse gas budgets.
Sara M. Defratyka, Jean-Daniel Paris, Camille Yver-Kwok, Daniel Loeb, James France, Jon Helmore, Nigel Yarrow, Valérie Gros, and Philippe Bousquet
Atmos. Meas. Tech., 14, 5049–5069, https://doi.org/10.5194/amt-14-5049-2021, https://doi.org/10.5194/amt-14-5049-2021, 2021
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We consider the possibility of using the CRDS Picarro G2201-i instrument, originally designed for isotopic CH4 and CO2, for measurements of ethane : methane in near-source conditions. The work involved laboratory tests, a controlled release experiment and mobile measurements. We show the potential of determining ethane : methane with 50 ppb ethane uncertainty. The instrument can correctly estimate the ratio in CH4 enhancements of 1 ppm and more, as can be found at strongly emitting sites.
Xinyi Lu, Stephen J. Harris, Rebecca E. Fisher, James L. France, Euan G. Nisbet, David Lowry, Thomas Röckmann, Carina van der Veen, Malika Menoud, Stefan Schwietzke, and Bryce F. J. Kelly
Atmos. Chem. Phys., 21, 10527–10555, https://doi.org/10.5194/acp-21-10527-2021, https://doi.org/10.5194/acp-21-10527-2021, 2021
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Many coal seam gas (CSG) facilities in the Surat Basin, Australia, are adjacent to other sources of methane, including agricultural, urban, and natural seeps. This makes it challenging to estimate the amount of methane being emitted into the atmosphere from CSG facilities. This research demonstrates that measurements of the carbon and hydrogen stable isotopic composition of methane can distinguish between and apportion methane emissions from CSG facilities, cattle, and many other sources.
Yosuke Niwa, Yousuke Sawa, Hideki Nara, Toshinobu Machida, Hidekazu Matsueda, Taku Umezawa, Akihiko Ito, Shin-Ichiro Nakaoka, Hiroshi Tanimoto, and Yasunori Tohjima
Atmos. Chem. Phys., 21, 9455–9473, https://doi.org/10.5194/acp-21-9455-2021, https://doi.org/10.5194/acp-21-9455-2021, 2021
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Fires in Equatorial Asia release a large amount of carbon into the atmosphere. Extensively using high-precision atmospheric carbon dioxide (CO2) data from a commercial aircraft observation project, we estimated fire carbon emissions in Equatorial Asia induced by the big El Niño event in 2015. Additional shipboard measurement data elucidated the validity of the analysis and the best estimate indicated 273 Tg C for fire emissions during September–October 2015.
Shona E. Wilde, Pamela A. Dominutti, Grant Allen, Stephen J. Andrews, Prudence Bateson, Stephane J.-B. Bauguitte, Ralph R. Burton, Ioana Colfescu, James France, James R. Hopkins, Langwen Huang, Anna E. Jones, Tom Lachlan-Cope, James D. Lee, Alastair C. Lewis, Stephen D. Mobbs, Alexandra Weiss, Stuart Young, and Ruth M. Purvis
Atmos. Chem. Phys., 21, 3741–3762, https://doi.org/10.5194/acp-21-3741-2021, https://doi.org/10.5194/acp-21-3741-2021, 2021
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We use airborne measurements to evaluate the speciation of volatile organic compound (VOC) emissions from offshore oil and gas (O&G) installations in the North Sea. The composition of emissions varied across regions associated with either gas, condensate or oil extraction, demonstrating that VOC emissions are not uniform across the whole O&G sector. We compare our results to VOC source profiles in the UK emissions inventory, showing these emissions are not currently fully characterized.
Max Thomas, James France, Odile Crabeck, Benjamin Hall, Verena Hof, Dirk Notz, Tokoloho Rampai, Leif Riemenschneider, Oliver John Tooth, Mathilde Tranter, and Jan Kaiser
Atmos. Meas. Tech., 14, 1833–1849, https://doi.org/10.5194/amt-14-1833-2021, https://doi.org/10.5194/amt-14-1833-2021, 2021
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We describe the Roland von Glasow Air-Sea-Ice Chamber, a laboratory facility for studying ocean–sea-ice–atmosphere interactions. We characterise the technical capabilities of our facility to help future users plan and perform experiments. We also characterise the sea ice grown in the facility, showing that the extinction of photosynthetically active radiation, the bulk salinity, and the growth rate of our artificial sea ice are within the range of natural values.
James L. France, Prudence Bateson, Pamela Dominutti, Grant Allen, Stephen Andrews, Stephane Bauguitte, Max Coleman, Tom Lachlan-Cope, Rebecca E. Fisher, Langwen Huang, Anna E. Jones, James Lee, David Lowry, Joseph Pitt, Ruth Purvis, John Pyle, Jacob Shaw, Nicola Warwick, Alexandra Weiss, Shona Wilde, Jonathan Witherstone, and Stuart Young
Atmos. Meas. Tech., 14, 71–88, https://doi.org/10.5194/amt-14-71-2021, https://doi.org/10.5194/amt-14-71-2021, 2021
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Measuring emission rates of methane from installations is tricky, and it is even more so when those installations are located offshore. Here, we show the aircraft set-up and demonstrate an effective methodology for surveying emissions from UK and Dutch offshore oil and gas installations. We present example data collected from two campaigns to demonstrate the challenges and solutions encountered during these surveys.
Cited articles
Ars, S., Vogel, F., Arrowsmith, C., Heerah, S., Knuckey, E., Lavoie, J., Lee, C., Pak, N. M., Phillips, J. L., and Wunch, D.: Investigation of the Spatial Distribution of Methane Sources in the Greater Toronto Area Using Mobile Gas Monitoring Systems, Environ. Sci. Technol., 54, 15671–15679, https://doi.org/10.1021/acs.est.0c05386, 2020.
Baker, A. K., Schuck, T. J., Brenninkmeijer, C. A. M., Rauthe-Schöch, A., Slemr, F., van Velthoven, P. F. J., and Lelieveld, J.: Estimating the contribution of monsoon-related biogenic production to methane emissions from South Asia using CARIBIC observations, Geophys. Res. Lett., 39, L10813, https://doi.org/10.1029/2012GL051756, 2012.
Bureau of Construction of Tokyo Metropolitan Government: https://www.kensetsu.metro.tokyo.lg.jp, last access: 31 January 2025 (in Japanese).
Bureau of Environment of Tokyo Metropolitan Government: https://www.kankyo.metro.tokyo.lg.jp/climate/zenpan/emissions_tokyo/, last access: 25 October 2025 (in Japanese).
Bureau of Urban Development: Tokyo Metropolitan Government: Land Use in Tokyo Special-Ward Area 2021 Edition, https://www.toshiseibi.metro.tokyo.lg.jp/seisaku/tochi_c/tochi_kekka_r3.html (last access: 31 January 2025), 2023 (in Japanese).
Chandra, N., Patra, P. K., Bisht, J. S. H., Ito, A., Umezawa, T., Saigusa, N., Morimoto S., Aoki, S., Janssens-Maenhout, G., Fujita, R., Takigawa, M., Watanabe, S., Saitoh, N., and Canadell, J. G: Emissions from the oil and gas sectors, coal mining and ruminant farming drive methane frowth over the past three decades, J. Meteorol. Soc. Jpn., 99, 309–337, https://doi.org/10.2151/jmsj.2021-015, 2021.
Chandra, N., Patra, P. K., Fujita, R., Höglund-Isaksson, L., Umezawa, T., Goto, D., Morimoto, S., Vaughn, B. H., and Röckmann, T.: Methane emissions decreased in fossil fuel exploitation and sustainably increased in microbial source sectors during 1990–2020, Communications Earth & Environment, 5, 147, https://doi.org/10.1038/s43247-024-01286-x, 2024.
Collins, W. J., Webber, C. P., Cox, P. M., Huntingford, C., Lowe, J., Sitch, S., Chadburn, S. E., Comyn-Platt, E., Harper, A. B., Hayman, G., and Powell, T.: Increased importance of methane reduction for a 1.5 degree target, Environ. Res. Lett., 13, 054003, https://doi.org/10.1088/1748-9326/aab89c, 2018.
Commane, R., Hallward-Driemeier, A., and Murray, L. T.: Intercomparison of commercial analyzers for atmospheric ethane and methane observations, Atmos. Meas. Tech., 16, 1431–1441, https://doi.org/10.5194/amt-16-1431-2023, 2023.
Crippa, M., Guizzardi, D., Pisoni, E., Solazzo, E., Guion, A., Muntean, M., Florczyk, A., Schiavina, M., Melchiorri, M., and Hutfilter, A. F.: Global anthropogenic emissions in urban areas: patterns, trends, and challenges, Environ. Res. Lett., 16, 074033, https://doi.org/10.1088/1748-9326/ac00e2, 2021.
Crippa, M., Guizzardi, D., Pagani, F., Banja, M., Muntean, M., Schaaf, E., Monforti-Ferrario, F., Becker, W. E., Quadrelli, R., Risquez Martin, A., Taghavi-Moharamli, P., Köykkä, J., Grassi, G., Rossi, S., Melo, J., Oom, D., Branco, A., San-Miguel, J., Manca, G., Pisoni, E., Vignati, E., and Pekar, F.: GHG emissions of all world countries, Publications Office of the European Union, Luxembourg, JRC138862, https://doi.org/10.2760/4002897, 2024.
Defratyka, S. M., Paris, J.-D., Yver-Kwok, C., Fernandez, J. M., Korben, P., and Bousquet, P.: Mapping Urban Methane Sources in Paris, France, Environ. Sci. Technol., 55, 8583–8591, https://doi.org/10.1021/acs.est.1c00859, 2021.
Etheridge, D. M., Steel, L. O., Francey, R. J., and Langenfelds, R. L.: Atmospheric methane between 1000 A. D. and present: evidence of anthropogenic emissions and climatic variability, J. Geophys. Res., 103, 15979–15993, https://doi.org/10.1029/98JD00923, 1998.
Fernandez, J. M., Maazallahi, H., France, J. L., Menoud, M., Corbu, M., Ardelean, M., Calcan, A., Townsend-Small, A., van der Veen, C., Fisher, R. E., Lowry, D., Nisbet, E. G., and Röckmann T.: Street-level methane emissions of Bucharest, Romania and the dominance of urban wastewater, Atmos. Environ.: X, 13, 100153, https://doi.org/10.1016/j.aeaoa.2022.100153, 2022.
Helfter, C., Tremper, A. H., Halios, C. H., Kotthaus, S., Bjorkegren, A., Grimmond, C. S. B., Barlow, J. F., and Nemitz, E.: Spatial and temporal variability of urban fluxes of methane, carbon monoxide and carbon dioxide above London, UK, Atmos. Chem. Phys., 16, 10543–10557, https://doi.org/10.5194/acp-16-10543-2016, 2016.
Hopkins, F. M., Ehleringer, J. R., Bush, S. E., Duren, R. M., Miller, C. E., Lai, C.-T., Hsu, Y.-K., Carranza, V., and Randerson, J. T.: Mitigation of methane emissions in cities: How new measurements and partnerships can contribute to emissions reduction strategies, Earth's Future, 4, 408–425, https://doi.org/10.1002/2016EF000381, 2016a.
Hopkins, F. M., Kort, E. A., Bush, S. E., Ehleringer, J. R., Lai, C.-T., Blake, D. R., and Randerson, J. T.: Spatial patterns and source attribution of urban methane in the Los Angeles Basin, J. Geophys. Res.-Atmos., 121, 2490–2507, https://doi.org/10.1002/2015JD024429, 2016b.
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Short summary
Effective mitigation actions require accurate understanding of methane emission characteristics in cities. We conducted atmospheric methane and ethane measurements using a vehicle in the world’s largest megacity, Tokyo, to identify locations and types of emissions and to examine preliminary estimates of their magnitudes. Waste sectors and fugitive natural gas emissions were found to be the major urban sources, and our data suggested need of improved accounting of natural gas related emissions.
Effective mitigation actions require accurate understanding of methane emission characteristics...
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