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，相对于 1850-19001 年，占 2010-2019 年温室气体驱动变暖的 35%。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，其中内陆水域排放是全球甲烷来源中最不确定的（如果不是最不确定的）2。与内陆水域甲烷排放相关的不确定性来源包括对不同规模和河流顺序的排放的经验驱动因素如何响应不同河流流量、河流管理制度（例如筑坝）、包括温度在内的季节变化的了解不足光的可用性和土地利用类型，这些都会影响养分浓度，进而影响生态系统的新陈代谢3。此前，由于缺乏包括河段规模流量数据的大规模河网数据产品，解决跨越空间和时间的甲烷排放的全系统驱动因素受到限制。最近发布的全球河段规模、河流流量模型 MERIT-Hydro4 和 35 年的相关流量数据 (GRADES)5 现在允许开发生物地球化学模型，用于跟踪溶解成分（例如通过内陆的甲烷）的级联通量和转化以以前不可能的分辨率对世界范围内的水域进行研究，从而能够生成本地结论以及全球结论。 项目目标 这项研究的主要目标是使用基于模型和基于现场的相结合的方法来量化大规模（国家、大陆和/或全球）内陆水域（包括河流、水库、湖泊、湿地和河口）甲烷排放的控制和驱动因素，并预测未来排放量将如何变化。建模组件将依赖于现有的高分辨率水文和地理信息系统数据产品作为系统主干，并结合学生收集的经验观测数据、机械或动力学数据以及机器学习方法来约束甲烷排放机制。现场数据将包括使用安装在河流和水体战略采样点的浮动温室气体通量室。跨学科方法将使学生能够开发一个项目，该项目整合了（1）水文模型、（2）生物地球化学模型和（3）气候模型的元素。该项目的成果将与IPCC和全球碳项目利益相关者（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。