Graphical Abstract

Tohjima, Y., Y. Niwa, K. Tsuboi, and K. Saito, 2022: Did Atmospheric CO2 and CH4 observation at Yonagunijima detect fossil-fuel CO2 reduction due to COVID-19 lockdown? J. Meteor. Soc. Japan, 100, 437-444.
Graphical Abstract Published


Plain Language Summary: Atmospheric observation at Yonagunijima is generally influenced by air masses from the Asian continent during winter because of the East Asian monsoon. The atmospheric carbon dioxide and methane observed at Yonagunijima during a period from January to March in 1998-2020 were analyzed. After the influences of the local biotic emissions on the short-term variability were reduced, the variability ratios (ΔCO2/ΔCH4) showed a marked decrease in February 2020 associated with the considerable reduction of the fossil fuel-derived CO2 emission in China presumably caused by the COVID-19 lockdown. This result convinced us that the variability ratio could be useful to investigate the relative emission changes in the upwind region.