Methane Emission Estimates by the Global High-Resolution Inverse Model Using National Inventories

• Main Authors: Fenjuan Wang, Shamil Maksyutov, Aki Tsuruta, Rajesh Janardanan, Akihiko Ito, Motoki Sasakawa, Toshinobu Machida, Isamu Morino, Yukio Yoshida, Johannes W. Kaiser, Greet Janssens-Maenhout, Edward J. Dlugokencky, Ivan Mammarella, Jost Valentin Lavric, Tsuneo Matsunaga
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Remote Sensing
• Subjects: methane emissions; ntfvar; gosat; edgarv4.3.2; unfccc reports
• Online Access: https://www.mdpi.com/2072-4292/11/21/2489

We present a global 0.1° × 0.1° high-resolution inverse model, NIES-TM-FLEXPART-VAR (NTFVAR), and a methane emission evaluation using the Greenhouse Gas Observing Satellite (GOSAT) satellite and ground-based observations from 2010–2012. Prior fluxes contained two variants of anthropogenic emissions, Emissions Database for Global Atmospheric Research (EDGAR) v4.3.2 and adjusted EDGAR v4.3.2 which were scaled to match the country totals by national reports to the United Nations Framework Convention on Climate Change (UNFCCC), augmented by biomass burning emissions from Global Fire Assimilation System (GFASv1.2) and wetlands Vegetation Integrative Simulator for Trace Gases (VISIT). The ratio of the UNFCCC-adjusted global anthropogenic emissions to EDGAR is 98%. This varies by region: 200% in Russia, 84% in China, and 62% in India. By changing prior emissions from EDGAR to UNFCCC-adjusted values, the optimized total emissions increased from 36.2 to 46 Tg CH₄ yr⁻¹ for Russia, 12.8 to 14.3 Tg CH₄ yr⁻¹ for temperate South America, and 43.2 to 44.9 Tg CH₄ yr⁻¹ for contiguous USA, and the values decrease from 54 to 51.3 Tg CH₄ yr⁻¹ for China, 26.2 to 25.5 Tg CH₄ yr⁻¹ for Europe, and by 12.4 Tg CH₄ yr⁻¹ for India. The use of the national report to scale EDGAR emissions allows more detailed statistical data and country-specific emission factors to be gathered in place compared to those available for EDGAR inventory. This serves policy needs by evaluating the national or regional emission totals reported to the UNFCCC.