据介绍，大气甲烷浓度在过去十年中迅速上升，并在2020-2022年激增，但其变化趋势尚不清楚。
研究人员通过对GOSAT卫星观测数据的逆分析发现，湿热带地区的排放量推动了2010-2019年的增加和随后的2020-2022年的激增，而中纬度北部地区的排放量则有所减少。2020-2022年的激增主要是由赤道亚洲(43%)和非洲(30%)的排放造成的。拉尼娜现象引起热带洪水泛滥，因此，研究人员认为湿地是非洲和赤道亚洲2020-2022年碳排放增加的主要驱动因素。这与GRACE陆地蓄水数据的趋势一致。
相比之下，2010年至2022年期间，美国、俄罗斯和中国等主要人为排放国的排放量相对持平。对流层OH(主要的甲烷汇)浓度在2010-2022年期间没有显示出长期趋势，但在2020-2022年期间有所下降，这促成了甲烷的激增。
附：英文原文
Title: Inverse modeling of 2010–2022 satellite observations shows that inundation of the wet tropics drove the 2020–2022 methane surge
Author: Qu, Zhen, Jacob, Daniel J., Bloom, A. Anthony, Worden, John R., Parker, Robert J., Boesch, Hartmut
Issue&Volume: 2024-9-24
Abstract: Atmospheric methane concentrations rose rapidly over the past decade and surged in 2020–2022 but the causes have been unclear. We find from inverse analysis of GOSAT satellite observations that emissions from the wet tropics drove the 2010–2019 increase and the subsequent 2020–2022 surge, while emissions from northern mid-latitudes decreased. The 2020–2022 surge is principally contributed by emissions in Equatorial Asia (43%) and Africa (30%). Wetlands are the major drivers of the 2020–2022 emission increases in Africa and Equatorial Asia because of tropical inundation associated with La Nia conditions, consistent with trends in the GRACE terrestrial water storage data. In contrast, emissions from major anthropogenic emitters such as the United States, Russia, and China are relatively flat over 2010–2022. Concentrations of tropospheric OH (the main methane sink) show no long-term trend over 2010–2022 but a decrease over 2020–2022 that contributed to the methane surge.
DOI: 10.1073/pnas.2402730121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2402730121