Quantifying methane emissions in remote tropical settings: a new 3D approach

量化偏远热带地区的甲烷排放：新的 3D 方法

基本信息

批准号：
NE/S00159X/1
负责人：
Euan Nisbet
金额：
$ 52.06万
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：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FS00159X%2F1
关键词：
Quantifying methane emissions remote tropical

项目摘要

The purpose of this proposal is to develop a viable methodology to quantify methane emissions in remote seasonal tropical wetland settings in Africa, and thus to place constraints on the causes of growth. The NERC/Met Office FAAM aircraft is scheduled to be deployed to Uganda in early 2019: this proposal builds on the opportunity that deployment offers, by adding a detachment to the major seasonal southern tropical wetlands in Zambia's Congo and Zambesi river drainages. Atmospheric methane began rising rapidly in 2007, after a period of stability, and the growth rate then accelerated in 2014 and subsequent years. Concurrently with the rise, the methane burden has shown a marked isotopic shift, becoming more C-13 depleted. We do not know why the methane growth and isotopic shift is happening. Much of the growth since 2007 has been in the tropics, and sub-tropics. One hypothesis for the growth and isotopic shift in the methane burden is that methane emissions from tropical wetlands and cattle are rapidly increasing, as a response to the tropical expansion and increased precipitation that has accompanied meteorological warming. An alternative hypothesis is that a marked decline in OH, the main sink, has lengthened methane's lifetime. Thus determining the flux and isotopic signatures of methane emissions from large representative seasonal African wetlands is a key requirement, enabling models to have better treatment of tropical latitudinal zones, so that the methane puzzle can be understood.African tropical wetlands are dominated by C-13 rich C4 plants such as papyrus, and subsistence cattle also graze C4 plants. In comparison to temperate and cool climate sources, biogenic methane emitted to the air from African wetlands and cattle has a very different isotopic signature, richer in 13C. This isotopic signature of methane from African wetlands overlaps somewhat with some fossil fuel emissions. To use isotopes effectively to differentiate between source types in the global budget (e.g. fossil fuels or wetlands and cattle) it is urgent that much better information is obtained on the regional isotopic signatures of African biogenic emissions. Methane growth since 2007 has been so rapid that methane is already far from its expected pathway under the UN Paris Agreement on Climate Change. There is a large discrepancy between reported national emissions inventories and atmsopheric estimates: in particular there is an urgent need for better tropical inventories if the budget is to be understood.To address these problems, we intend:1. To conduct a FAAM (Facility for Airborne Atmospheric Measurement) field deployment over Zambian wetlands, as a southern 'add-on' to our planned MOYA deployment to Uganda in January 2019, to measure wet-season greenhouse gas fluxes from the very extensive Zambian wetlands and farming areas around Lakes Bangweulu and Mweru, and in the Kafue and Zambesi basins. Flights would be carried out downwind of major wetland source regions, quantifying emission plumes at the height of the wet season.2. To help solve the 'are emissions rising or is the OH sink falling?' debate, on-ground campaigns will be used to determine d13C[CH4] and dD[CH4] isotopic signatures, measured in emissions from Zambian C4 wetlands. The lack of measurement of isotopic signatures of tropical emissions is a crucial impediment to successful global inverse modelling (Turner et al., 2017; Rigby et al., 2017). 3. To develop low-cost ways of quantifying emission fluxes and determining isotopic signatures from major sources in remote tropical settings, including wetlands, cattle and biomass burning. In particular, a simple drone (UAV) and balloon bag-sampling methodology will be tested.4. To improve 'bottom-up' assessment of local emission inventors, working with local colleagues in Zambia and Zimbabwe to construct national methane emission inventories, and thus support the intentions of the Paris Agreement.

该提案的目的是开发一种可行的方法来量化非洲偏远季节性热带湿地环境中的甲烷排放，从而限制增长的原因。 NERC/英国气象局 FAAM 飞机计划于 2019 年初部署到乌干达：该提案以部署提供的机会为基础，在赞比亚刚果和赞比西河流域的主要季节性南部热带湿地增设一支分遣队。经过一段稳定期后，大气甲烷含量于 2007 年开始快速上升，并于 2014 年及随后几年加速增长。在上升的同时，甲烷负荷也显示出明显的同位素变化，C-13 变得更加贫乏。我们不知道为什么会发生甲烷增长和同位素变化。 2007年以来的增长大部分来自热带和亚热带地区。关于甲烷负荷增长和同位素变化的一种假设是，热带湿地和牛的甲烷排放量正在迅速增加，这是对伴随气象变暖的热带扩张和降水增加的反应。另一种假设是，主要汇 OH 的显着下降延长了甲烷的寿命。因此，确定非洲大型代表性季节性湿地的甲烷排放通量和同位素特征是一项关键要求，使模型能够更好地处理热带纬度区域，从而理解甲烷难题。非洲热带湿地以 C-13 为主丰富的 C4 植物，如纸莎草，自给牛也吃 C4 植物。与温带和凉爽气候来源相比，非洲湿地和牛排放到空气中的生物甲烷具有非常不同的同位素特征，13C含量更丰富。非洲湿地甲烷的同位素特征与一些化石燃料排放有所重叠。为了有效地利用同位素来区分全球预算中的来源类型（例如化石燃料或湿地和牛），迫切需要获得有关非洲生物排放的区域同位素特征的更好信息。自 2007 年以来，甲烷增长速度如此之快，以至于甲烷排放量已经远远偏离了《联合国巴黎气候变化协定》规定的预期路径。报告的国家排放清单和大气估计之间存在很大差异：特别是如果要了解预算，迫切需要更好的热带清单。为了解决这些问题，我们打算：1。在赞比亚湿地进行 FAAM（机载大气测量设施）现场部署，作为我们计划于 2019 年 1 月在乌干达部署 MOYA 的南部“附加项目”，以测量赞比亚大片湿地的雨季温室气体通量Bangweulu 湖和 Mweru 湖周围以及 Kafue 和 Zambesi 盆地的农业区。飞行将在主要湿地源区的顺风处进行，量化雨季高峰期的排放羽流。2。帮助解决“排放量是上升还是 OH 汇下降？”争论中，地面活动将用于确定 d13C[CH4] 和 dD[CH4] 同位素特征，在赞比亚 C4 湿地的排放中进行测量。缺乏对热带排放同位素特征的测量是全球反演建模成功的一个关键障碍（Turner 等，2017；Rigby 等，2017）。 3. 开发低成本方法来量化排放通量并确定偏远热带地区主要来源（包括湿地、牛和生物质燃烧）的同位素特征。特别是，将测试简单的无人机（UAV）和气球袋采样方法。4。为了改进对当地排放发明人的“自下而上”评估，与赞比亚和津巴布韦当地同事合作，建立国家甲烷排放清单，从而支持《巴黎协定》的意图。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Very large fluxes of methane measured above Bolivian seasonal wetlands.

在玻利维亚季节性湿地上方测量到非常大的甲烷通量。

DOI：
http://dx.10.1073/pnas.2206345119
发表时间：
2022
期刊：
Proceedings of the National Academy of Sciences of the United States of America
影响因子：
11.1
作者：
France JL
通讯作者：
France JL

Very Strong Atmospheric Methane Growth in the 4 Years 2014-2017: Implications for the Paris Agreement

2014-2017 四年间大气甲烷增长非常强劲：对《巴黎协定》的影响