Estimation of methane and carbon monoxide emissions in megacities by using simultaneous greenhouse gas and air pollutant observations by “IBUKI-2” (GOSAT-2)
National Institute for Environmental StudiesPeer-Reviewed Publication
The Satellite Observation Center of the Earth System Division of the National Institute for Environmental Studies (NIES) has been publicly providing global concentrations of greenhouse gases (such as carbon dioxide and methane) and an air pollutant (carbon monoxide) obtained from the Greenhouse Gases Observing Satellite-2 "Ibuki-2" (GOSAT-2, launched in October 2018).
In this study, a research team consisting of Dr. Hirofumi Ohyama (Senior Researcher), Dr. Yukio Yoshida (Senior Researcher), and Dr. Tsuneo Matsunaga (Director of the Satellite Observation Center) of the Earth System Division of the NIES developed a method to calculate the enhancement ratios among carbon dioxide, methane, and carbon monoxide concentrations in megacities, using data from GOSAT-2, the only satellite observing all three gases simultaneously. Furthermore, the team evaluated the accuracy of emission databases and estimated the methane and carbon monoxide emissions for approximately 40 cities around the world by using the calculated four-year average enhancement ratios. The results demonstrated that we could independently evaluate the values in emission databases for megacities using data from satellite observations without relying on complicated calculations of atmospheric transport. With continued observations, we anticipate that annual changes of emissions for certain cities can be captured from satellites. Furthermore, the GOSAT-GW satellite, scheduled for launch in FY2025, will be capable of observing carbon dioxide and methane at a greater number of observation points than GOSAT-2 and will also observe atmospheric concentrations of nitrogen dioxide, most of which is distributed around emission sources. These enhancements are expected to further improve the accuracy of emission estimates. The results of this study were published on 5 November 2024 in Environmental Research Letters, an academic journal in the environmental field.
- Journal
- Environmental Research Letters
- Funder
- Ministry of the Environment of Japan