Is the Arctic Methane budget changing?

北极甲烷预算是否发生变化？

• 批准号: NE/I014683/1
• 负责人: Euan Nisbet
• 金额: $ 45.19万
• 依托单位: Royal Holloway University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI014683%2F1
• 关键词: Arctic; Methane; budget; changing

Methane (CH4) is the second (after CO2) most important greenhouse gas. Sources of CH4 to the atmosphere, both natural and human-driven, have been intensively studied and are now well established; however, their global and regional estimates still suffer from large uncertainties. The region above the Arctic Circle is very important from this perspective because of a unique combination of CH4 emission sources which are active now, e.g. wetlands and forest fires, and those which may become active in the future owing to regional climate change. Potentially important future sources include thawing permafrost soils and CH4-rich oceanic sediments (clathrates). Since the Arctic has been warming much faster compared to the rest of the world, this may trigger various changes in the active CH4 sources as well as those that represent large pools of carbon (permafrost soil) or gaseous CH4 (clathrates). The goal of the proposed project is thus to locate and quantify major sources of Arctic CH4 emissions to the atmosphere and contribute to understanding how these emissions may change with further regional climate warming. At present, the number of Arctic CH4 measurements is simply not sufficient to either make reliable estimates of regional CH4 sources or to understand recent trends in atmospheric CH4 concentrations. In addition to scarce measurements, most Arctic CH4 studies have been supported by campaign-based observations of the local processes responsible for CH4 emissions, mostly in summer when the region is most accessible. But owing to the episodic, and in some instances seasonal, nature of most CH4 source emissions paired against sporadic campaign-based sampling, it has not been possible to produce reliable emission estimates of different Arctic CH4 sources. To address this problem, we propose to establish year-round continuous measurements of CH4 concentration and isotopic composition in ambient air, and to synchronise campaign-based studies with the expected seasonality and location of the CH4 source emissions. Since CH4 emitted from different sources has distinct isotopic 'signatures', it is possible to attribute the observed emissions to the particular sources. This approach requires a retrospective analysis of the air mass trajectories to establish the origin of air with the observed isotopic signature. To be more specific, we propose to establish continuous CH4 measurements at Teriberka, Russia (69.2N, 35.1E; NW Russian Arctic coast), which will provide new insight into central Eurasian Arctic processes. In addition, we plan to carry out detailed isotopic studies of ambient air from several locations in the European and Russian Arctic. These will be compared with records of Arctic air reaching the UK at measurement stations at Barra (Scotland) and Weybourne (Norfolk). Combining our datasets with those from the small number of other Arctic stations of our international colleagues, we will determine whether ongoing changes in the Arctic regional climate are resulting in increased CH4 emissions. Specifically, we will use these concentration and isotopic data with the p-TOMCAT chemical transport and Met Office NAME models to locate Arctic CH4 sources and quantify any interannual changes in emissions. In addition to these main objectives, we plan to make regular measurements of atmospheric concentrations of other gases (CO2, CO, N2O, SF6, H2, O2/N2 and Ar/N2) from glass bottles collected at several Arctic locations. Such measurements will not require additional collections or costs as they will be made in parallel to the CH4 measurements, improving cost efficiency. Measurement of other gas species will help to assess the linked Arctic processes and source emissions of these gases, both on land and at sea, e.g. fire emissions (increased CO), ocean warming, expansion of oceanic 'dead zone' (due to decreased amounts of dissolved O2) and thawing permafrost soils and wetlands.

甲烷 (CH4) 是第二大（仅次于二氧化碳）最重要的温室气体。大气中 CH4 的来源（无论是自然来源还是人为来源）已经经过深入研究，现已得到充分证实；然而，他们的全球和区域估计仍面临很大的不确定性。从这个角度来看，北极圈以上区域非常重要，因为目前活跃的 CH4 排放源具有独特的组合，例如：湿地和森林火灾，以及由于区域气候变化而在未来可能变得活跃的火灾。未来潜在的重要来源包括融化的永久冻土和富含 CH4 的海洋沉积物（包合物）。由于与世界其他地区相比，北极变暖的速度要快得多，这可能会引发活跃 CH4 源以及代表大量碳库（永久冻土）或气态 CH4（包合物）的源的各种变化。因此，拟议项目的目标是定位和量化北极向大气中甲烷排放的主要来源，并有助于了解这些排放可能如何随着区域气候进一步变暖而变化。目前，北极 CH4 测量数量根本不足以对区域 CH4 来源进行可靠估计，也不足以了解大气 CH4 浓度的最新趋势。除了缺乏测量数据外，大多数北极 CH4 研究都得到了对当地 CH4 排放过程的基于活动的观测的支持，这些观测主要发生在该地区最容易到达的夏季。但由于大多数 CH4 源排放的偶发性（有时是季节性）以及基于活动的零星采样，无法对不同的北极 CH4 源进行可靠的排放估算。为了解决这个问题，我们建议对环境空气中的 CH4 浓度和同位素组成进行全年连续测量，并将基于活动的研究与 CH4 源排放的预期季节性和位置同步。由于不同来源排放的 CH4 具有不同的同位素“特征”，因此可以将观察到的排放归因于特定来源。这种方法需要对气团轨迹进行回顾性分析，以通过观察到的同位素特征确定空气的起源。更具体地说，我们建议在俄罗斯捷里别尔卡（北纬 69.2 度，东经 35.1 度；俄罗斯北极海岸西北）建立连续的 CH4 测量，这将为欧亚中部北极过程提供新的见解。此外，我们计划对欧洲和俄罗斯北极地区多个地点的环境空气进行详细的同位素研究。这些数据将与巴拉（苏格兰）和韦伯恩（诺福克）测量站到达英国的北极空气记录进行比较。将我们的数据集与国际同事的少数其他北极站的数据相结合，我们将确定北极区域气候的持续变化是否导致 CH4 排放量增加。具体来说，我们将使用这些浓度和同位素数据以及 p-TOMCAT 化学品运输和 Met Office NAME 模型来定位北极 CH4 来源并量化排放量的任何年际变化。除了这些主要目标之外，我们还计划定期测量在北极多个地点收集的玻璃瓶中其他气体（CO2、CO、N2O、SF6、H2、O2/N2 和 Ar/N2）的大气浓度。此类测量不需要额外的收集或成本，因为它们将与 CH4 测量并行进行，从而提高成本效率。对其他气体种类的测量将有助于评估相关的北极过程和这些气体在陆地和海上的源排放，例如。火灾排放（二氧化碳增加）、海洋变暖、海洋“死亡区”扩大（由于溶解氧气量减少）以及永久冻土和湿地融化。

项目成果

Atmospheric constraints on the methane emissions from the East Siberian Shelf

大气对东西伯利亚大陆架甲烷排放的限制

• DOI: http://dx.10.5194/acp-16-4147-2016
• 发表时间: 2016
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Berchet A

Revised methane emissions from the East Siberian Arctic Shelf EGU2015-11621

东西伯利亚北极陆架修订后的甲烷排放量 EGU2015-11621

• 发表时间: 2015
• 作者: Berchet; A.
• 通讯作者: A.

Real-time analysis of d13C- and dD-CH4 in ambient air with laser spectroscopy: method development and first intercomparison results

实时分析

• DOI: http://dx.10.5194/amt-9-263-2016
• 发表时间: 2016
• 期刊: Atmospheric Measurement Techniques
• 影响因子: 3.8
• 作者: Eyer S

Measurement of the 13 C isotopic signature of methane emissions from northern European wetlands

北欧湿地甲烷排放的 13 C 同位素特征测量

• DOI: http://dx.10.1002/2016gb005504
• 发表时间: 2017
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Fisher R

Top-down estimates of European CH4 and N2O emissions based on four different inverse models

基于四种不同的逆模型对欧洲 CH4 和 N2O 排放量的自上而下估计

• DOI: 10.5194/acp-15-715-2015
• 发表时间: 2014-06-01
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: P. Bergamaschi;M. Corazza;U. Karstens;M. Athanassiadou;R. Thompson;I. Pison;A. Manning;P. Bousquet;A. Segers;A. Vermeulen;G. Janssens‑Maenhout;M. Schmidt;M. Ramonet;F. Meinhardt;T. Aalto;L. Haszpra;J. Moncrieff;M. Popa;D. Lowry;M. Steinbacher;A. Jordan;S. O'Doherty;S. Piacentino;E. Dlugokencky
• 通讯作者: E. Dlugokencky