GOSAT

Gosat, also known as GOSAT (Greenhouse Gases Observing Satellite) or Ibuki, is a Japanese Earth observation satellite developed by JAXA in collaboration with the National Institute for Environmental Studies (NIES) and other partners. It was launched on January 23, 2009, from the Tanegashima Space Center. The mission operates in a sun-synchronous orbit at about 660–700 km altitude, enabling near-daily global coverage.

The spacecraft carries the Thermal and Near infrared Sensor for carbon dioxide and methane (TANSO-FTS) instrument and a Cloud and Aerosol Imager (TANSO-CAI). TANSO-FTS measures the spectral absorption of CO2 and CH4 in the near-infrared and shortwave infrared, enabling retrieval of column-averaged mole fractions (XCO2 and XCH4) on a global scale. CAI provides cloud and aerosol information to improve retrieval accuracy.

Initial mission life was planned for about five years, but GOSAT has been extended multiple times. It has produced long-term data used in climate research and to improve understanding of the carbon cycle, contributing to global greenhouse gas monitoring and supporting validation of other satellite measurements, such as OCO-2.

GOSAT was followed by GOSAT-2 (Ibuki-2), launched in 2018, which continues and enhances greenhouse gas monitoring with updated sensors and capabilities.

Ground data are distributed publicly through JAXA and partner data centers. Data products include XCO2 and XCH4, as well as CAI-derived cloud and aerosol information, making the mission a foundational component of satellite-based greenhouse gas observation.