Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions
Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions
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DOI：
10.1038/s43247-021-00314-4
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发表时间：
2021-11-29
影响因子：
7.9
通讯作者：
Neves, Raiane A. L.
中科院分区：
文献类型：
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作者：
Basso, Luana S.;Marani, Luciano;Neves, Raiane A. L.
1999年至2006年期间，大气甲烷浓度几乎保持不变，但此后一直在上升，平均每年约为8 ppb。作为全球最大的天然甲烷来源，湿地排放量的增加可能是造成这一增长的部分原因。热带地区缺乏现场大气甲烷观测，这可能是自上而下和自下而上估算之间存在巨大差异的一个原因。在这里，我们展示了2010年至2018年期间亚马逊河流域四个地点的590个低对流层甲烷浓度垂直剖面。我们发现亚马逊每年排放46.2 +/- 10.3兆吨甲烷（相当于全球排放量的8%），没有时间趋势。基于一氧化碳，17%的来源来自生物质燃烧，其余（83%）主要来自湿地。亚马逊西北部的排放量几乎是季节性的，与弱降水季节性一致，而南部的排放量与土壤水的季节性密切相关。我们还发现了一个明显的东西对比与大通量在东北部，其原因目前尚不清楚。
Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been rising since by an average of similar to 8 ppb per year. Increases in wetland emissions, the largest natural global methane source, may be partly responsible for this rise. The scarcity of in situ atmospheric methane observations in tropical regions may be one source of large disparities between top-down and bottom-up estimates. Here we present 590 lower-troposphere vertical profiles of methane concentration from four sites across Amazonia between 2010 and 2018. We find that Amazonia emits 46.2 +/- 10.3 Tg of methane per year (similar to 8% of global emissions) with no temporal trend. Based on carbon monoxide, 17% of the sources are from biomass burning with the remainder (83%) attributable mainly to wetlands. Northwest-central Amazon emissions are nearly aseasonal, consistent with weak precipitation seasonality, while southern emissions are strongly seasonal linked to soil water seasonality. We also find a distinct east-west contrast with large fluxes in the northeast, the cause of which is currently unclear.