Variations in Column Concentration of Greenhouse Gases in China and Their Response to the 2015–2016 El Niño Event

Since the industrial revolution, enhancement of atmospheric greenhouse gas concentrations as a result of human activities has been the primary cause of global warming. The monitoring and evaluation of greenhouse gases are significant prerequisites for carbon emission control. Using monthly data of global atmospheric carbon dioxide (CO₂) and methane (CH₄) column concentrations (hereinafter XCO₂ and XCH₄, respectively) retrieved by the Greenhouse Gas Observation Satellite (GOSAT), we analyzed the variations in XCO₂ and XCH₄ in China during 2010–2022 after confirming the reliability of the data. Then, the influence of a strong El Niño event in 2015–2016 on XCO₂ and XCH₄ variations in China was further studied. The results show that the retrieved XCO₂ and XCH₄ from GOSAT have similar temporal variation trends and significant correlations with the ground observation and emission inventory data of an atmospheric background station, which could be used to assess the variations in XCO₂ and XCH₄ in China. XCO₂ is high in spring and winter while XCH₄ is high in autumn. Both XCO₂ and XCH₄ gradually declined from Southeast China to Northwest and Northeast China, with variation ranges of 401–406 and 1.81–1.88 ppmv, respectively; and the high value areas are located in the middle–lower Yangtze River basin. XCO₂ and XCH₄ in China increased as a whole during 2010–2022, with rapid enhancement and high levels of XCO₂ and XCH₄ in several areas. The significant increases in XCO₂ and XCH₄ over China in 2016 might be closely related to the strong El Niño–Southern Oscillation (ENSO) event during 2015–2016. Under a global warming background in 2015, XCO₂ and XCH₄ increased by 0.768% and 0.657% in 2016 in China. Data analysis reveals that both the XCO₂ and XCH₄ variations might reflect the significant impact of the ENSO event on glacier melting in the Tibetan Plateau.