Atmospheric observations of Arctic Ocean methane emissions up to 82° north
Atmospheric observations of Arctic Ocean methane emissions up to 82° north
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DOI：
10.1038/ngeo1452
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发表时间：
2012-05-01
影响因子：
18.3
通讯作者：
Zondlo, M. A.
中科院分区：
文献类型：
--
作者：
Kort, E. A.;Wofsy, S. C.;Zondlo, M. A.
甲烷是一种强效温室气体（1），未来大气负担的不确定性对制定现实的气候预测构成了重要挑战。北极是以永久冻土和甲烷水合物的形式存在的大型甲烷库的所在地（2），在气候变暖的情况下，这些甲烷库很容易受到破坏。此外，甲烷产生于表层海洋（3），北冰洋的表层沃茨中甲烷过饱和（4、5）。然而，这种海洋甲烷的命运是不确定的。在这里，我们使用甲烷的空中观测来评估从遥远的北冰洋到北纬82度的甲烷流出。我们报告了表层海洋附近甲烷浓度增加的层，一氧化碳水平几乎没有或没有增加，表明非燃烧源。我们进一步表明，高甲烷浓度仅限于开放的铅和部分海冰覆盖的地区。根据观测到的甲烷浓度梯度，我们估计海-气通量约为2 mg d（-1）m（-2），与西伯利亚大陆架的排放量相当。我们认为，北冰洋的表面沃茨是甲烷的一个潜在的重要来源，这可能被证明是敏感的海冰覆盖的变化。
Uncertainty in the future atmospheric burden of methane, a potent greenhouse gas(1), represents an important challenge to the development of realistic climate projections. The Arctic is home to large reservoirs of methane, in the form of permafrost soils and methane hydrates(2), which are vulnerable to destabilization in a warming climate. Furthermore, methane is produced in the surface ocean(3) and the surface waters of the Arctic Ocean are supersaturated with respect to methane(4,5). However, the fate of this oceanic methane is uncertain. Here, we use airborne observations of methane to assess methane efflux from the remote Arctic Ocean, up to latitudes of 82 degrees north. We report layers of increased methane concentrations near the surface ocean, with little or no enhancement in carbon monoxide levels, indicative of a non-combustion source. We further show that high methane concentrations are restricted to areas over open leads and regions with fractional sea-ice cover. Based on the observed gradients in methane concentration, we estimate that sea-air fluxes amount to around 2 mg d(-1) m(-2), comparable to emissions seen on the Siberian shelf. We suggest that the surface waters of the Arctic Ocean represent a potentially important source of methane, which could prove sensitive to changes in sea-ice cover.