Methane and total hydrocarbon analyzer to sample emission from peatlands

气候变化和大气成分通过大气气体的辐射和热特性紧密联系在一起。 人们的注意力主要集中在三大温室气体（GHG）-- CO2、CH 4和N2 O以及水蒸气的重要性上。 然而，政府间气候变化专门委员会认识到，还有其他一些微量气体可能具有重要意义，但其向大气排放的不确定性太大，无法有任何把握地评估其作用。 该组中的一类痕量气体是挥发性有机化合物（VOC）。 VOCs既有人为来源，也有生物来源。 它们是从陆地生态系统中排放出来的，主要是以非甲烷碳氢化合物的形式。 它们很重要，因为它们的光化学氧化导致臭氧的产生，臭氧是一种强烈的温室气体，同时它们也是气溶胶-因此它们参与了积极和消极的气候反馈。 几乎所有的挥发性有机化合物的测量都是在热带生态系统中进行的，但由于已知的挥发性有机化合物排放者万年青灌木和苔藓覆盖了北方大部分泥炭地，它们可能是挥发性有机化合物的重要来源。 泥炭地被认为是巨大的碳储存地，但没有研究表明其挥发性有机化合物的排放特征。 我们的目标是增加一个自动室系统，我们已经在北方泥炭地上运行了两年，两个新的分析仪器，使我们能够连续测量NMHC。 通过这些测量，我们将研究排放量与VOC通量的环境和生态控制之间的关系。 这项研究将为陆地生态系统VOC排放的知识提供重要的补充，我们帮助我们描述它们在气候系统负反馈回路中可能发挥的作用。 如果来源被证明是显着的，那么我们将使用本研究的结果，将挥发性有机化合物的生产和排放到我们的泥炭地土壤地球化学模型。

Climate change and atmospheric composition are tightly linked through the radiative and thermal properties of atmospheric gases.  Much focus has been on the 'big' three greenhouse gases (GHGs) - CO2, CH4, and N2O and overriding importance of water vapour.  However, it is recognized by the Intergovernmental Panel on Climate Change  that there are other trace gases that could be of importance but the uncertainty in their emissions to the atmosphere is too large to assess their role with any level of confidence.  One class of trace gases in this group are the volatile organic compounds (VOCs).  VOCs have both anthropogenic and biogenic origins.  They are emitted from terrestrial ecosystems, mostly as non-methane hydrocarbons (NMHC).  They are important because their photochemical oxidation results in the production ozone which is a strong GHG while at the same time they are also aerosols - hence they are involved in both positive and negative climate feedbacks.  Almost all measurements of VOCs have been done in tropical ecosystems, but since evergreen shrubs and mosses, known emitters of VOCs, cover most northern peatlands they could be a significant source of VOCs.  Peatlands are known as huge stores of carbon, but no study has characterized their emission of VOCs.  Our objective is to add to an automated chamber system we have operated for the last two years on a northern peatland two new analytical instruments that will allow us to measure continuously NMHC.  With these measurements we will examine the relationship between the emissions and the environmental and ecological controls on VOC flux.  This research will provide an important addition to the knowledge of VOC emissions from terrestrial ecosystems and we help us delineate their possible role in a negative feedback loop in the climate system.  If the source proves to be significant then we will use the results of this study to incorporate VOCs production and emissions into our peatland biogeochemistry models.