Methane and total hydrocarbon analyzer to sample emission from peatlands

气候变化和大气组成通过大气气体的辐射和热特性紧密联系在一起。人们主要关注三种温室气体(温室气体)--二氧化碳、甲烷和N2O，以及水蒸气的重要性。然而，政府间气候变化专门委员会承认，还有其他可能具有重要意义的痕量气体，但它们排放到大气中的不确定性太大，无法用任何程度的信心来评估它们的作用。这类痕量气体中只有一类是挥发性有机化合物(VOCs)。这些VOCs既有人为来源，也有生物来源。尽管它们是从陆地生态系统排放的，主要是作为非甲烷碳氢化合物(NMHC)。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-因此它们参与了正向和负向气候反馈。尽管几乎所有的VOCs测量都是在热带生态系统中进行的，但由于众所周知的VOCs排放者--常绿灌木和苔藓--覆盖了大部分北部泥炭地，它们可能是VOCs的一个重要来源。泥炭地以储存大量碳而闻名，但还没有研究对它们的VOC排放进行表征。我们的目标是在我们过去两年在北部泥炭地运行的自动化室系统中增加两个新的分析仪器，使我们能够连续测量NMHC。有了这些测量，我们将检查排放与环境和生态控制VOC通量之间的关系。*这项研究将为我们提供关于陆地生态系统VOC排放的重要补充，并帮助我们描述它们在气候系统负反馈循环中的可能作用。如果来源被证明是重要的，我们将使用这项研究的结果是将VOCs的产生和排放纳入我们的泥炭地生物地球化学模型。

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.