Spatially Resolved Isotopic Source Signatures of Wetland Methane Emissions
Spatially Resolved Isotopic Source Signatures of Wetland Methane Emissions
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DOI：
10.1002/2018gl077536
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发表时间：
2018-04-28
影响因子：
5.2
通讯作者：
Hornibrook, E. R. C.
中科院分区：
文献类型：
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作者：
Ganesan, A. L.;Stell, A. C.;Hornibrook, E. R. C.
我们提出了第一个空间分辨湿地三角洲C-13（CH 4）源签名地图的基础上，湿地生态系统的数据表征，并表现出良好的协议与湿地签名来自大气观测。源签名地图解决了纬度差异的北方高纬度（平均相似67.8%）和热带（平均相似56.7%）湿地之间的相似10%，并显示出显着的区域变化的顶部的纬度梯度。我们评估的错误，旨在分离CH 4源和汇的逆模拟研究比较大气三角洲C-13（CH 4）使用我们的空间分辨地图对全球统一的湿地三角洲C-13（CH 4）签名的共同假设。我们发现一个更大的半球间梯度，一个更大的高纬度季节性周期，和较小的趋势在2000-2012年期间。这意味着，错误的CH 4通量将得出，以补偿所施加的偏见，不利用空间分辨的签名的最大的CH 4排放源。当与观测到的信号大小相比时，这些偏差是显著的。简明语言摘要大气中甲烷的浓度正在增加。为了了解这种变化背后的原因，碳同位素被用来帮助确定排放源和汇的变化。我们提出了一个新的全球地图的碳同位素签名与湿地甲烷排放量，最大的全球甲烷排放到大气中。我们展示了这种新合成的信息如何能够更准确地了解大气中甲烷含量和增加率变化的原因。
We present the first spatially resolved wetland delta C-13(CH4) source signature map based on data characterizing wetland ecosystems and demonstrate good agreement with wetland signatures derived from atmospheric observations. The source signature map resolves a latitudinal difference of similar to 10% between northern high-latitude (mean similar to 67.8%) and tropical (mean similar to 56.7%) wetlands and shows significant regional variations on top of the latitudinal gradient. We assess the errors in inverse modeling studies aiming to separate CH4 sources and sinks by comparing atmospheric delta C-13(CH4) derived using our spatially resolved map against the common assumption of globally uniform wetland delta C-13(CH4) signature. We find a larger interhemispheric gradient, a larger high-latitude seasonal cycle, and smaller trend over the period 2000-2012. The implication is that erroneous CH4 fluxes would be derived to compensate for the biases imposed by not utilizing spatially resolved signatures for the largest source of CH4 emissions. These biases are significant when compared to the size of observed signals.Plain Language Summary Concentrations of methane are increasing in the atmosphere. In order to understand the reasons behind such variations, carbon isotopes are used to help identify changes in emission sources and sinks. We present a new global map of the carbon isotope signature associated with wetland methane emissions, the largest global source of methane to the atmosphere. We show how this newly synthesized information can lead to more accurate understanding of the causes of variations in the amount and rate of increase of methane in the atmosphere.