The Sixth Assessment Report (Working Group I) published by the Intergovernmental Panel on Climate Change (IPCC) in August 2021 states, "It is unequivocal that human influence has warmed the atmosphere, ocean and land" and "limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions". The Paris Agreement requires all Parties to prepare national commitments to reduce carbon emission and to steadily achieve the commitments. In these circumstances, satellite observations of atmospheric greenhouse gases (GHGs) are expected to contribute to enhancing the transparency of emission reports published by countries that have ratified the Paris Agreement.
Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) is a Japanese Earth observation satellite. It is the third satellite in the GOSAT Series for observations of GHGs, such as CO2 and methane (CH4) from space and is a successor to Greenhouse gases Observing SATellite (GOSAT), launched in 2009 and GOSAT-2, launched in 2018. GOSAT-GW is scheduled to be launched in Japan's fiscal year 2023.
This satellite will carry two mission instruments: Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3) and Advanced Microwave Scanning Radiometer 3 (AMSR3). The TANSO-3 instrument and its ground systems are being jointly developed by the Ministry of the Environment (MOE) and the National Institute for Environmental Studies (NIES). The Japan Aerospace Exploration Agency (JAXA) is also involved in the development and operation of TANSO-3 under a contract with MOE.
TANSO-3 has the following mission objectives:
- to monitor whole-atmosphere monthly mean concentrations of CO2
- to validate national anthropogenic GHG inventories reported by each country
- to monitor large emission sources of GHGs such as urban areas, power plants, and permafrost
Through the achievements of the above objectives, GOSAT-GW, together with GOSAT and GOSAT-2, will contribute to the mitigation of climate change driven by the increase of GHGs in the Earth's atmosphere.