Methane emissions from inland waters: Quantifying the largest uncertainty in the global methane budget

内陆水域甲烷排放：量化全球甲烷预算中最大的不确定性

• 批准号: 2887249
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2887249
• 关键词: Methane; emissions; inland; waters; Quantifying

Methane (CH4) is the second most important greenhouse gas after carbon dioxide, accounting for 35% of the greenhouse gas-driven warming in 2010-2019 relative to 1850-19001. Methane emissions continue to increase annually at a rate of 18.1 ppb/yr. Globally, aquatic ecosystems account for approximately half of methane sources, with inland water emissions among the most, if not the most, uncertain worldwide methane source2. Sources of uncertainty associated with the methane emissions in inland waters include a poor understanding of how the empirical drivers of emissions change across rivers of varying sizes and stream orders in response to different river flows, river management regimes (e.g. damming), seasonal changes including temperature and light availability, and land use types, which influence nutrient concentrations and in turn, ecosystem metabolism3. Addressing the whole-system drivers of methane emissions across space and time has previous been limited by the absence of large-scale river network data products that include flow data at the reach scale. The recent publication of the global reach-scale, river flow model MERIT-Hydro4 and 35 years of associated flow data (GRADES)5 now allows for the development of biogeochemical models that track the cascading fluxes and transformations of dissolved constituents such as methane through inland waters worldwide at previously impossible resolutions, enabling local conclusions to be generated as well as global.Project goalsThe primary goal of this research is to use a combined model- and field-based approach to quantify the large-scale (national, continental, and/or global) controls and drivers of methane emissions from inland waters, including rivers, reservoirs, lakes, wetlands, and estuaries, and forecast how emissions will change in the future. The modelling component will rely on the high-resolution hydrological and GIS data products now available as the system backbone, with methane emission mechanisms constrained using a combination of empirical observation field data collected by the student, mechanistic or kinetic data, and machine learning approaches. Field data will include the use of floating greenhouse gas flux chambers installed on rivers and water bodies at strategic sampling points. An interdisciplinary approach will allow the student to develop a project that integrates elements of (1) hydrological modelling, (2) biogeochemical modelling, and (3) climate modelling. The project outcome will be directly relevant to IPCC and Global Carbon Project stakeholders (https://www.globalcarbonproject.org/), as well as local and national governments aiming to meet climate emissions goals.

甲烷(CH4)是仅次于二氧化碳的第二大温室气体，占2010年至2019年温室气体导致的全球变暖的35%，而2010年至2019年的比例为1850年至19001。甲烷排放量继续以每年18.1 ppb的速度增加。在全球范围内，水生生态系统约占甲烷来源的一半，内陆水域的排放即使不是世界范围内最不确定的甲烷来源，也是最不确定的2。与内陆水域甲烷排放相关的不确定性来源包括：对不同河流流量、河流管理制度(如筑坝)、季节性变化(包括温度和光照有效性)、土地利用类型等影响养分浓度并进而影响生态系统新陈代谢的不同大小和河流顺序的排放的经验驱动因素理解不足。解决跨空间和跨时间的甲烷排放的全系统驱动因素以前受到缺乏大规模河网数据产品的限制，这些产品包括河段尺度上的流量数据。最近出版的全球河段尺度河流流量模型MERIT-HUD4和35年的相关流量数据(等级)5现在允许开发生物地球化学模型，以以前不可能的分辨率跟踪甲烷等溶解成分通过世界内陆水域的级联通量和转化，从而能够得出局部和全球的结论。项目目标这项研究的主要目标是使用基于模型和现场的组合方法来量化内陆水域(包括河流、水库、湖泊、湿地和河口)甲烷排放的大规模(国家、大陆和/或全球)控制和驱动因素，并预测未来排放将如何变化。建模部分将依赖目前作为系统主干的高分辨率水文和地理信息系统数据产品，并使用学生收集的经验观测现场数据、机械或动力学数据以及机器学习方法来限制甲烷排放机制。实地数据将包括使用在战略采样点的河流和水体上安装的浮动温室气体通量室。跨学科的方法将允许学生开发一个综合了(1)水文模型、(2)生物地球化学模型和(3)气候模型的元素的项目。项目成果将与政府间气候变化专门委员会和全球碳项目利益攸关方(https://www.globalcarbonproject.org/)，)以及旨在实现气候排放目标的地方和国家政府直接相关。