Investigation of the Southern Methane Anomaly: causes, implications, and relevance to past global events.

南部甲烷异常的调查：原因、影响以及与过去全球事件的相关性。

基本信息

批准号：
NE/K006045/1
负责人：
Euan Nisbet
金额：
$ 35.07万
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：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK006045%2F1
关键词：
Investigation Southern Methane Anomaly causes

项目摘要

Methane is the second most important greenhouse gas and contributes to the atmospheric chemistry affecting ozone. Southern tropical methane sources and sinks constitute a significant component of the global methane budget. The current major anomaly in southern methane growth rate is among the largest on record. Yet despite its importance, tropical methane variability has received relatively little study. This proposal is to investigate the southern tropical methane budget. The work will improve quantification of southern tropical sources and the understanding of the mechanisms of sudden growth events. Southern tropical methane sources are varied, each having their own isotopic signature in the methane they produce. Wetlands are very extensive in southern tropical S. America and in western parts of southern sub-equatorial Africa, but data on methane emissions from these wetlands are very sparse. Fires in savanna grasslands in Africa and S. America are also significant sources, as are the large ruminant animal populations. Anthropogenic sources are also increasing, with major recent hydrocarbon discoveries. Tropical OH is the major global methane sink. Ascension Is. is a uniquely located, UK-administered, experimental site for studying the methane budget. At surface the air is almost always SE Trade wind, which arrives from the South Atlantic middle latitudes, and, after Ascension, becomes the background air for Amazonia. Above the trade wind inversion, the air over Ascension is tropical, its origin switching regularly between Africa and S. America. Currently Royal Holloway sustains continuous high-precision CH4 and CO2 measurement (CRDS instrument) and also flask measurement of d13C in CH4 on Ascension, as well as on E. Falkland Is. and on RRS JC Ross.Methodologically, the project will focus on the measurement of methane in the southern tropics, carrying out campaign studies, especially on Ascension, and modelling the results. Measurement will include continuous measurement by CRDS in Ascension, E. Falklands, bi-annual Atlantic transects by RRS JC Ross, and Tedlar bag sample collection for CH4 and d13C of CH4 in Uganda, Peru and Bolivia. Campaign studies will include installation of a CRDS instrument in Peru and use of an unmanned aerial system (UAV) to sample above the Trade Wind Inversion on Ascension, as well as source campaigns to characterise d13C signatures of CH4 emissions in Africa and S. America. The proposed helicopter UAV deployment exploits new expertise and would represent an important UK deployment of a substantial UAV for atmospheric sampling. This deployment therefore addresses one of the key science challenges set out in the NERC scoping study for next-generation platforms for Earth & Environmental Science. Modelling studies are also state-of-the-art, and will include regional trajectory analysis to assess source inputs across Africa and S. America, and global modelling of d13C of CH4, tested against the measurements made in the project.The results will be used to assess the importance of southern tropical methane in the global budget, the causes of rapid past changes, and the possibility of future rapid growth in emissions.

甲烷是第二重要的温室气体，有助于影响臭氧的大气化学。南部热带甲烷源和汇构成全球甲烷预算的重要组成部分。目前南部甲烷增长率的重大异常是有记录以来最大的异常之一。然而，尽管热带甲烷变化很重要，但其研究相对较少。该提案旨在调查南部热带甲烷预算。这项工作将改善南部热带来源的量化和对突然增长事件机制的理解。南部热带甲烷来源多种多样，每个来源产生的甲烷都有自己的同位素特征。南美洲热带南部和非洲赤道以南西部地区的湿地非常广泛，但有关这些湿地甲烷排放的数据却非常稀少。非洲和南美洲稀树草原的火灾以及大量反刍动物种群也是重要的火灾源。随着最近碳氢化合物的重大发现，人为来源也在增加。热带OH是全球主要的甲烷汇。阿森松岛是一个地理位置独特、由英国管理的用于研究甲烷收支的实验场所。在地表，空气几乎总是东南信风，来自南大西洋中纬度地区，在扬升之后，成为亚马逊流域的背景空气。在信风逆流之上，阿森松岛上空是热带空气，其来源定期在非洲和南美洲之间切换。目前，皇家霍洛威学院在阿森松岛和福克兰群岛上持续进行高精度 CH4 和 CO2 测量（CRDS 仪器）以及 CH4 中 d13C 的烧瓶测量。在方法上，该项目将重点关注南部热带地区的甲烷测量，开展活动研究，特别是关于扬升的研究，并对结果进行建模。测量将包括 CRDS 在阿森松岛、福克兰群岛进行的连续测量、RRS JC Ross 每年两次的大西洋横断面测量以及乌干达、秘鲁和玻利维亚对 CH4 和 CH4 d13C 的 Tedlar 袋样品采集。活动研究将包括在秘鲁安装 CRDS 仪器，使用无人机系统 (UAV) 在扬升信风逆温上方进行采样，以及表征非洲和南美洲 CH4 排放的 d13C 特征的源活动。拟议的直升机无人机部署利用了新的专业知识，并将代表英国部署大量无人机进行大气采样的重要举措。因此，这一部署解决了 NERC 下一代地球与环境科学平台范围界定研究中提出的关键科学挑战之一。建模研究也是最先进的，将包括区域轨迹分析以评估非洲和南美洲的源输入，以及 CH4 d13C 的全球建模，并根据项目中的测量结果进行测试。结果将是用于评估南部热带甲烷在全球预算中的重要性、过去快速变化的原因以及未来排放量快速增长的可能性。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

d13C methane source signatures from tropical wetland and rice field emissions.

热带湿地和稻田排放的 d13C 甲烷源特征。

DOI：
http://dx.10.1098/rsta.2020.0449
发表时间：
2022
期刊：
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
影响因子：
0
作者：
France JL
通讯作者：
France JL

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