Comment on egusphere-2026-3879
Abstract
Abstract. Accurate methane (CH4) emission estimates are essential for attributing regional CH4 sources and quantifying their spatial and temporal variability, particularly in high-emission regions of China under stringent mitigation policies. Here, we apply CTDAS-WRF, a regional inversion framework that couples the CarbonTracker Data Assimilation Shell (CTDAS) with WRF-Chem, to quantify CH4 emissions over East Asia. Through Observing System Simulation Experiments (OSSEs), we find that the system can recover ~61 % of the imposed prior-to-truth adjustment in the Yangtze River Delta (YRD), 68 % in South Korea, and 93 % in northern Japan, indicating good performance in observation-rich regions. Using a composite prior for anthropogenic emissions based on EDGAR_2024 and CAMS v6.2, the 2022 inversion yields total posterior emissions of 7.530.09 Tg yr-1 in the YRD, which is 11.0 % lower than the prior (8.46 Tg yr-1). Prior anthropogenic emissions are overestimated by 12.7 % (0.9 Tg yr-1), while prior natural emissions are also higher by 0.03 Tg yr-1. Daily posterior emissions exhibit a much stronger seasonal cycle and peak in summer, with natural sources and rice cultivation dominating the summertime underestimate in the prior. Independent evaluation at in situ station further supports the posterior improvement, with the daily mean absolute error reduced by 3.4 ppb (11.0 %) relative to the prior simulation. This work highlights the importance of accounting for seasonal variability in YRD emissions and provides a basis for future inversions that integrate in situ and satellite observations to better constrain the CH4 budget of East Asia.
Authors 14
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Affiliation as printed
Integrated Research on Energy, Environment and Society (IREES), Energy and Sustainability Research Institute Groningen, University of Groningen, Groningen, 9747 AG, the Netherlands
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Huilin Chen corresponding
University of Groningen · Nanjing University
Affiliation as printed
Center for Isotope Research (CIO), Energy and Sustainability Research Institute Groningen (ESRIG), University of Groningen, Groningen, the Netherlands
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China
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Affiliation as printed
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China
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Affiliation as printed
Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China
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Chinese Academy of Sciences · Shanghai Advanced Research Institute
Affiliation as printed
Center for Advanced Energy Systems and Equipment, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
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Nanjing University of Information Science and Technology · Zhejiang University of Technology
Affiliation as printed
Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China
Zhejiang Carbon Neutral Innovation Institute & Zhejiang International Cooperation Base for Science and Technology on Carbon Emission Reduction and Monitoring, Zhejiang University of Technology, Hangzhou 310014, China
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National Institute for Environmental Studies
Affiliation as printed
Satellite Observation Center, Earth System Division, National Institute for Environmental Studies (NIES), Japan
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Royal Netherlands Meteorological Institute
Affiliation as printed
Research & Development Satellite Observations, Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands
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Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
Affiliation as printed
Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
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Westlake University · Zhejiang University
Affiliation as printed
College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310030, Zhejiang, China
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University of Groningen · Leibniz Association · Potsdam Institute for Climate Impact Research
Affiliation as printed
Integrated Research on Energy, Environment and Society (IREES), Energy and Sustainability Research Institute Groningen, University of Groningen, Groningen, 9747 AG, the Netherlands
Potsdam Institute of Climate Impact Research (PIK), Member of Leibniz Association, Potsdam 14473, Germany
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Wageningen University & Research
Affiliation as printed
Meteorology and Air Quality group, Wageningen University, Wageningen, the Netherlands
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Affiliation as printed
Integrated Research on Energy, Environment and Society (IREES), Energy and Sustainability Research Institute Groningen, University of Groningen, Groningen, 9747 AG, the Netherlands
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Space Research Organisation Netherlands · Vrije Universiteit Amsterdam
Affiliation as printed
Department of Earth Sciences, Vrije Universiteit, Amsterdam, the Netherlands
SRON, Netherlands Institute for Space Research, Leiden, the Netherlands
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