GOSAT-GW GHG Mission Overview

The GOSAT-GW (Global Observing SATellite for Greenhouse gases and Water cycle) is a new Japanese satellite mission to be launched in FY2023 targeting global observations of both greenhouse gases and water vapor. The greenhouse gases observing mission is co-developed by Ministry of Environment (MoE) and National Institute for Environmental Studies (NIES). This mission’s aim is to make global observations of greenhouse gases (such as CO2 and CH4) and air pollutant (NO2). For this purpose, the TANSO-3 (Total Anthorpogenic and Natural emission mapping SpectrOmeter-3) sensor is being developed by JAXA.

01. Monitoring of monthly average concentrations of global atmospheric GHGs

It remains important to continue monitoring of the whole atmosphere global-mean concentrations. Therefore, GOSAT-GW shall continue the long-term observations of GHGs and provide global atmospheric concentrations of these species, following the GOSAT and GOSAT-2 missions.

  • The main target gas is CO2, the most important among the anthropogenic greenhouse gases.
  • The efforts of global GHG observation mission to be continued.
  • It shall be possible to update each month the calculation of the average global atmospheric concentrations.
  • The observation sensor shall observe a wide area and maintain a field of view equivalent to that of GOSAT and GOSAT-2 (about 10 km in terms of direct view on the ground).
  • It shall make observations in 3-day cycles around the globe similarly to GOSAT and GOSAT-2.

02. Verification of country-specific anthropogenic GHG emissions

GOSAT-GW shall improve the accuracy, transparency, and reliability of GHG verifications prepared and published by countries under the Paris Agreement.

  • The target GHGs shall be CO2 and CH4.
  • GOSAT-GW shall make it possible to verify anthropogenic emissions in Japan every year. The uncertainty in the estimation shall not exceed 15% (1σ).
  • Assessment of major CO2-emitting countries (Eighteen countries listed in the World Energy Source CO2 Emissions (2014) published by the Ministry of the Environment.) shall be made using the above method to the extent possible with regard to observability.
  • To improve the reliability of country-specific verifications, verification of CO2 emissions from metropolitan areas participating in the C40 Cities Climate Leadership Group (92 cities as of 2018), shall be conducted to the extent possible with regard to observability.

03. Monitoring of large-scale emission sources

In addition to monitoring emissions from large-scale emission sources that can have substantial impacts on the anthropogenic GHG emissions estimates, GOSAT-GW shall try to detect unknown emission sources that have not yet been elucidated by current observational techniques or included in the traditional inventory emission database.

  • The target GHG shall be CO2 and CH4.
  • Observation area and conditions shall include metropolitan areas and power plants and permafrost.

Metropolitan areas and power plants

GOSAT-GW shall be able to observe the Tokyo Metropolitan Area (all wards and the Tama district) in the same orbit. It shall also be able to observe C40 cities across the world at least once every three days. Furthermore, it shall be able to observe power plants (those with emissions of 6.5 MtCO2/year or more, which account for about half of the total emissions of power plants around the world) in a spatial resolution equivalent to less than 3 km (desirably less than 1 km) of surface distance.


For permafrost at northern high latitudes in the Northern Hemisphere, GOSAT-GW shall be able to capture the target gases possibly emitted from the thawing of the soil surface layer during the northern summer (around June-August).

  • GOSAT-GW shall be able to simultaneously observe NO2 that helps identify the sources of CO2 emissions originating from fossil fuel combustion, with the same observation width and spatial resolution as CO2 observations.