American Geophysical Union, Journal of Geophysical Research: Atmospheres, 6(128), 2023
DOI: 10.1029/2022jd037544
Full text: Unavailable
AbstractMethane is thought to have been an important greenhouse gas during the Archean, although its potential warming has been found to be limited at high concentrations due to its high shortwave absorption. We use the Met Office Unified Model, a general circulation model, to further explore the climatic effect of different Archean methane concentrations. Surface warming peaks at a pressure ratio pCH4:pCO2 of approximately 0.1, reaching a maximum of up to 7 K before significant cooling above this ratio. Equator‐to‐pole temperature differences also tend to increase up to pCH4 ≤ 300 Pa, which is driven by a difference in radiative forcing at the equator and poles by methane and a reduction in the latitudinal extend of the Hadley circulation. 3D models are important to fully capture the cooling effect of methane, due to these impacts of the circulation.