Global and regional CO2 and CH4 flux distributions derived from the inversion analyses of GOSAT series data and their temporal variations

Global carbon dioxide (CO₂) and methane (CH₄) flux distributions were derived by the inverse model analyses of CO₂ and CH₄ column-average concentration data from Greenhouse gases Observing SATellite (GOSAT) launched in 2009 and its successor (GOSAT-2) launched in 2018. GOSAT Level 4A CO₂ and CH₄ flux products are freely available from GOSAT Data Archive Service. Monthly net CO2 and CH₄ flux values are calculated for 42 land regions and 22 ocean regions for CO₂ and one ocean region for CH₄ using the inversion system with NIES TM atmospheric transport model. The preliminary version of GOSAT-2 Level 4A CO₂ product is being evaluated and will be released to the public in FY2023. GOSAT-2 Level 4A CH₄ product will be generated after the release of CO₂ product. GOSAT-2 Level 4A CO₂ product is generated using the inversion system named NICAM-based Inverse Simulation for Monitoring CO₂ (NISMON- CO₂) with about 2.5-degree grids and monthly time interval. The spatial distributions of small CO₂ sources and sinks will be shown by this product. GOSAT-GW, the third satellite in GOSAT Series to be launched in FY2024, will map CO₂ and CH₄ column concentrations with two spatial observation modes, Wide mode with 910 km swath and 10 km resolution, and Focus Mode with 90 km swath and 3 km or better resolution. Such image data will be used in the inversion analysis to obtain global and regional CO₂ and CH₄ net flux with higher spatial and temporal resolution than GOSAT and GOSAT-2.