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/K004964/1
负责人：
John Adrian Pyle
金额：
$ 4.15万
依托单位：
University of Cambridge
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%2FK004964%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，并有助于影响臭氧的大气化学。南部热带甲烷源和下沉构成了全球甲烷预算的重要组成部分。目前，南部甲烷生长速率的主要异常是有记录库最大的。尽管它重要性，但热带甲烷的可变性却相对较少。该建议是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以及对突然生长事件的机制的理解。南部热带甲烷的来源各不相同，每种都有自己生产的甲烷中的同位素特征。在热带S.美国和南部非洲南部的西部地区，湿地非常广泛，但是这些湿地的甲烷排放数据非常稀疏。非洲和美国的Savanna草原大火，也是大型反刍动物种群的重要来源。最近有主要的碳氢化合物发现，人为来源也在增加。热带OH是主要的全球甲烷水槽。提升是。是一个独特的，英国管理的实验地点，用于研究甲烷预算。从表面上看，空气几乎总是从南大西洋中纬度到达的贸易风，在升天之后，它成为亚马逊的背景空气。在贸易逆转之上，升天的空气是热带的，其起源定期在非洲和S.美国之间切换。目前，皇家霍洛威（Royal Holloway）维持连续的高精度CH4和CO2测量（CRDS仪器），以及CH4和E. Falkland的CH4中D13C的烧瓶测量。从方法论上讲，该项目将重点放在南部热带地区的甲烷上，进行竞选研究，尤其是在升天方面，并建模结果。测量将包括CRD在升天中进行的连续测量，福克兰E. falklands，RRS JC Ross的双年大西洋样本，以及乌干达，秘鲁和玻利维亚CH4的CH4和D13C的TEDLAR BAG样品收集。竞选研究将包括在秘鲁安装CRD仪器，以及使用无人驾驶系统（UAV）在上方的贸易风反转上样品，以及源运动，以表征非洲和S. America CH4排放的D13C签名。拟议的直升机无人机部署利用了新的专业知识，这将代表着大气采样的重要无人机的重要部署。因此，这种部署解决了针对地球与环境科学的下一代平台的NERC范围研究中提出的关键科学挑战之一。建模研究也是最先进的，并且将包括区域轨迹分析，以评估非洲和美国的来源投入以及CH4的D13C的全球模型，对项目进行的测量进行了测试。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排放量快速增长的可能性。