[A-CG37] Satellite Earth Environment Observation

[ACG37-01] The GOSAT-GW greenhouse gas observing mission: Updates

★Invited Papers

*Hiroshi Tanimoto¹, Tsuneo Matsunaga¹, Takafumi Sugita¹, Hisashi Yashiro¹, Isamu Morino¹, Makoto Saito¹, Hirofumi Ohyama¹, Satoshi Inomata¹, Kohei Ikeda¹, Yu Someya¹, Tamaki Fujinawa¹, Yukio Yoshida¹, Yousuke Yamashita¹, Astrid Mueller¹, Matthias Frey¹, Hyunkwang Lim¹, Hao Xu¹, Tazu Saeki¹, Nobuko Saigusa¹, Yugo Kanaya², Takashi Sekiya², Prabir Patra², Masayuki Takigawa², Yongjoo Choi², Masahiro Yamaguchi², Jagat Bisht², YASUKO KASAI³, Tomohiro Sato³, Ayano Nakamura³, Thi Ngoc Trieu Tran³ (1.National Institute for Environmental Studies, 2.Japan Agency for Marine-Earth Science and Technology, 3.National Institute of Information and Communications Technology)

Keywords:greenhouse gas, emission, Paris Agreement

The Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW), a Japanese Earth observation satellite to be launched, following Greenhouse gases Observing SATellite (GOSAT) and GOSAT-2, will make the first global, space-based observations of the atmospheric carbon dioxide (CO₂), methane (CH₄) and nitrogen dioxide (NO₂) in the Earth’s atmosphere at a horizontal/spatial resolution of 3 km or less by the single satellite platform. It will carry two sensors, one of which is a high-resolution grating spectrometer designed to measure reflected sunlight in the 0.45-um NO₂ band, the 0.76-um O₂ A-band and the CO₂ band at 1.61 um from visible to short-wave infrared wavelength regions to retrieve the column-averaged CO₂ and CH₄ dry air mole fraction (XCO₂ and XCH₄, respectively) and vertical column density of tropospheric NO₂. The GOSAT-GW will fly in a 13:30 sun-synchronous orbit with a 3-day ground-track repeat time, achieving a global coverage within 3 days. The objectives of the GOSAT-GW’s greenhouse gas (GHG) observing mission include (1) monitoring of whole atmosphere global-mean concentrations of GHGs, (2) verification of national (or country-specific) anthropogenic emissions inventory of GHGs, and (3) detection of GHGs emissions from large emission sources, such as megacities, power plants, and permafrost. A comprehensive validation exercise will be made to ensure that the products’ quality meets with the precision needed to quantify the GHG sources and sinks on regional- to national/city-scales, and identify the anthropogenic emissions from large point sources. With a nominal lifetime of 7 years, the GOSAT-GW will provide space-based constraints on the anthropogenic GHG emissions, contributing to the mitigation of climate change, in particular, supporting the Global Stocktake (GST) mechanism, a key element in the Paris Agreement.