Spatial-temporal variation in XCH4 during 2009–2021 and its driving factors across the land of the Northern Hemisphere

Methane (CH4) is the second most significant driver of global warming, following carbon dioxide. However, the spatial-temporal variation of CH4 and its driving factors largely remain unclear. Here we selected the Northern Hemisphere as the study area. We used the data from the Total Column Carbon Observing Network (TCCON) to assess the accuracy of the Greenhouse Gases Observing Satellite (GOSAT) Proxy XCH4 (column-averaged dry air mixing ratio of CH4) data. We then analyzed the spatial-temporal distribution of XCH4 in the Northern Hemisphere, and further quantified the influencing factors using geographic detectors. The results showed that during 2009–2021, the annual mean XCH4 increased from 2009 (1775.19 ppb) to 2021 (1872.71 ppb), with an increasing rate of 7.50 ppb/year. The monthly average value was the lowest in May (1805.65 ppb) and the highest in September (1825.63 ppb). The XCH4 in the low-latitude region was higher than that in the high-latitudinal region. The geographic detector showed that anthropogenic activities were the main factors affecting the XCH4. Our results revealed the spatial-temporal patterns XCH4 and their driving factors in the Northern Hemisphere, and thus provided a scientific basis for the management of this greenhouse gas in the future.