Isotopic constraints on the Arctic methane budget

该项目旨在通过测量几个关键地点的d13 C（CH4），并通过轨迹建模研究来确定输入的位置、性质和季节性，从而确定北极活跃的甲烷源。考虑到温室效应正反馈反应的风险，了解北极甲烷的来源至关重要。例子包括笼形物释放、湿地产量增加和火灾排放量急剧增加。甲烷突然失控释放的危险可以说是全球变暖中最大的未知数之一：这里存在着突然而不是渐进的气候变化的重大潜在风险。了解来源的最佳工具是同位素指纹，通过风中的d13 C（CH4）同位素特征识别它们，通过反向轨迹分析追溯到来源。该项目的目的是：1。在选定的关键地点收集环境空气样本，并分析其甲烷混合比例和d13 C（CH4）。2.研究各种北极CH4源，特别是湿地，但也包括火灾、气体沉积物和笼形物，以评估排放的时间、同位素特征和分布。3.使用反向轨迹分析，与区域背景进行比较，以确定来源及其同位素特征和季节性。该项目有几个组成部分：1：环境空气d13 C测量。在高北极地区，在新奥勒松（斯瓦尔巴群岛的斯匹次卑尔根），将在齐柏林山站定期收集袋样，从大西洋西部背景和北极（西伯利亚）东部不同来源的空气（特别是冬季的天然气;夏季的湿地）取样。在北极芬兰的帕拉斯站，就在北极圈上方，将实施类似的采样计划，对来自不太偏北的大西洋的西风和来自俄罗斯的东风进行采样。还将在泰里贝卡（俄罗斯科拉）和鄂毕河河口（气田）收集烧瓶，仅用于混合比分析（彼得堡实验室）。在韦伯恩，入侵的北极空气抵达北大西洋。海岸。将收集大量空气用于d13C（CH4）的高精度分析。最后，在梅斯头，爱尔兰，或替代北大西洋网站，d13 C（CH4）的季节性背景大西洋空气将采样，从加拿大和高北极的火灾或湿地甲烷的远程输入。2源研究将包括在帕拉斯进行的湿地和森林研究，以便在几个季节的一系列实地活动中观测环境空气中的d13 C（CH4）（即释放后）。测量和样品收集将在湿地和森林（塔）上方进行，包括昼夜空气采样和室内实验。其他源研究将包括火灾取样（加拿大）和气体取样。3.反向轨迹建模将利用这些数据来确定区域甲烷排放量。将对到达收集站的空气进行单轨迹研究，与区域和季节性背景空气进行比较，以确定各个来源。这项研究将通过同位素特征识别排放物，从而提出来源类型，并将随着排放强度的变化观察这些季节的变化。多轨迹研究将使用部门分析，以确定北极输入的主要区域。北极现在和将来都可能是地球上变暖最快的地区。它可能成为甲烷的一个非常主要的来源，因此是温室效应的一个强有力的正反馈来源。这是地球上最危险的地区之一，因为“变暖养活了变暖”。这项工作将为国际极地年之后的国际极地研究以及世界气象组织和国际原子能机构（同位素）主持下的联合国全球大气监测做出贡献。更广泛地说，研究结果对于全球理解碳预算和京都进程具有重要意义。

This project is designed to determine the active methane sources in the Arctic by measurement of d13C(CH4) at several key sites, and by trajectory modelling studies to identify the location, nature and seasonality of inputs. Understanding the sources of Arctic methane is essential, given the risk of positive-feedback responses to greenhouse warming. Examples include clathrate release, enhanced wetland output and sharply increased fire emissions. The danger of sudden runaway methane release is arguably among the greatest unknowns in global warming: here lies a significant potential risk of abrupt, rather than gradual climate change. The best tool to understand sources is isotopic fingerprinting, identifying them by their d13C(CH4) isotopic signature in winds, traced back to source by back-trajectory analysis. The intentions in this project are: 1. To collect samples of ambient air at chosen key locations and analyse them for CH4 mixing ratio and d13C(CH4). 2. To study a variety of Arctic CH4 sources, especially wetlands, but also fires, gas deposits and clathrates, to assess timing of emissions, isotopic character, and distribution. 3. To use back-trajectory analysis, compared to regional background, to locate sources and their isotopic character and seasonality. The project has several components: 1: d13C measurements of ambient air. In the High Arctic, at Ny Alesund (Spitsbergen, Svalbard), regular bag samples will be collected at Zeppelin mountain station, sampling air both from the westerly Atlantic background and also easterly Arctic (Siberian) air from varied sources (especially gas in winter; wetland in summer). At Pallas station in Arctic Finland, just above the Arctic circle, a similar sampling program will be implemented to sample westerly air from less northerly Atlantic, and easterly air from Russia. Flasks will also be collected for mixing ratio analysis only (St. Petersburg lab) at Teriberka (Russian Kola) and in the Ob River estuary (gasfields). At Weybourne, incursions of Arctic air arrive at the N. Sea coast. Tanks of air will be collected for high precision analysis of d13C(CH4). Finally, at Mace Head, Ireland, or an alternative North Atlantic site, the d13C(CH4) seasonality in background Atlantic air will be sampled, for distant inputs of fire or wetland methane from Canada and the high Arctic. 2 Source studies.will include wetland and forest studies at Pallas, to observe d13C(CH4) in ambient air (i.e. after release) in a set of field campaigns in several seasons. Measurements and sample collection will be made above wetlands and forests (tower), including diurnal air sampling and chamber experiments. Other source studies will include fire sampling (Canada), and gas sampling. 3. Back-trajectory modelling will use the data to identify regional methane emissions. Single-trajectory studies of air arriving at the collection stations will be used, compared against regional and seasonal background air, to locate individual sources. This study will characterise emissions by isotopic signature and hence suggest source type, and will watch these change over the seasons as emission strength varies. Multiple trajectory studies wil use sector analysis, to identify major regions of Arctic input. The Arctic is now and is in future likely to be the fastest-warming region of the planet. Potentially it could become a very major source of methane, and hence a source of strong positive feedback into greenhouse warming. This is one of the most dangerous regions of the planet in terms of 'warming feeding the warming'. The work will provide a UK contribution both to International Polar studies in the aftermath of IPY, and to the UN's Global Atmosphere Watch, under the aegis of the World Meteorological Organisation and (for isotopes) the International Atomic Energy Agency. More widely, the results will be important to the global understanding of the carbon budget and the Kyoto process.