Methane and other greenhouse gases in the Arctic - measurements, process studies and modelling (MAMM)

北极是大气甲烷和其他温室气体的主要来源，既有自然排放，也有人为排放。北极温室气体源有可能在全球范围内发挥重要作用，改变辐射强迫和大气氧化能力。此外，古代记录和现代研究都表明，一些来源，如湿地和甲烷水合物，可能显示出强烈的正反馈[Nisbet和Cappellaz，2009]，因此变暖助长了变暖。迫切需要根据强度、地理位置、特征(例如湿地、气田、笼状结构)和时间变化(夏季、冬季、白天、夜间)以及评估其变化的脆弱性来量化北极温室气体源。我们将通过一个综合的测量和建模计划来解决这些问题。将从地面和飞机上分析气体混合比率(浓度)、同位素特征和来源通量。过去的和新的测量都将使用一套技术进行建模。通量将被应用到Jules陆地表面模式中。大气建模，包括轨迹和反向建模，将提高对地方/区域尺度的理解，使北极排放在大规模全球大气变化中发挥作用。

The Arctic is a major source of atmospheric methane and other greenhouse gases, with both natural and anthropogenic emissions. Arctic greenhouse gas sources have the potential to be important globally, changing radiative forcing and atmospheric oxidizing capacity. Moreover, both palaeorecords and present-day studies suggest some sources, such as wetlands and methane hydrates, may show strong positive feedbacks [Nisbet and Chappellaz, 2009], so that the warming feeds the warming. It is urgent that Arctic greenhouse gas sources should be quantified, by strength, geographic location, character (e.g. wetland, gasfield, clathrate), and by temporal variation (summer, winter, day, night), and their vulnerability to change assessed. We will address these issues by an integrated program of measurement and modelling. Analysis of gas mixing ratios (concentrations), isotopic character, and source fluxes, will be made both from the ground and aircraft. Both past and new measurements will be modelled using a suite of techniques. Fluxes will be implemented into the JULES land surface model. Atmospheric modelling, including trajectory and inverse modelling will improve understanding on the local/regional scale, placing the role of Arctic emissions in large scale global atmospheric change.