Keywords:global carbon cycle, satellite observation, GOSAT
Greenhouse gases Observing SATellite (GOSAT) has been monitoring atmospheric column carbon dioxide (XCO2) and methane (XCH4) concentrations from space since its launch in January 2009. The primary goal of GOSAT project is to successfully estimate global carbon budget on subcontinental scales using spatiotemporal distribution of XCO2 and XCH4. GOSAT observations have provided the basis for assessments of the values of space-based measurements of CO2 and CH4 concentrations. Additionally, GOSAT-2 which is the successor of GOSAT is scheduled for launch in the end of 2018. GOSAT-2 aims to monitor spatiotemporal distribution of greenhouse gases with higher level of accuracy and to improve the number of available observation data. This work summarizes GOSAT level 4 products on global CO2 and CH4 flux estimates based on an inversion system and the benefit of GOSAT observations for the study of global carbon cycle. We also introduce a new inversion system which is under construction as GOSAT-2 level 4 system; atmospheric transport and inverse models, a biospheric model using variability of solar-induced chlorophyll fluorescence by GOSAT observations, and a high resolution bottom-up anthropogenic emission inventory.