Topic B: The Enigma of the Soil Hydrogen Sink Variability [ELGAR]

主题 B：土壤氢汇变异之谜 [ELGAR]

• 批准号: NE/X013405/1
• 负责人: Joshua Dean
• 金额: $ 19.36万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX013405%2F1
• 关键词: Topic; Enigma; Soil; Hydrogen; Sink

At COP 26, countries agreed to reduce their carbon dioxide (CO2) and methane (CH4) emissions, with a focus on reducing fossil fuel use. This will leave an energy gap, which many countries plan to replace using hydrogen (H2) as an energy carrier. Hydrogen is a small molecule, and susceptible to leakage at all stages of delivery from production to the end-user. Inevitably, this will increase atmospheric H2 concentrations that have remained relatively stable for the last two decades. The primary removal mechanism for atmospheric H2 is via its diffusion into soils where it is consumed by microbes. This accounts for circa two-thirds of its removal. The other sink is through its atmospheric reaction with the hydroxyl radical, and increases in atmospheric H2 will extend the lifetimes of CH4 and ozone (O3). Both are important greenhouse gases, and tropospheric O3 is also an air pollutant that impacts human health and ecosystems. In the stratosphere, increased H2 concentrations can lead to increased water, leading to depletion of protective O3. The dominant H2 soil sink is poorly constrained and it is not clear how it will respond to increasing atmospheric H2 in a changing climate, making predictions of future H2 atmospheric impacts uncertain. The enigma of the soil H2 sink strength needs to be investigated for atmospheric modellers to develop robust forecasts of the impact of future H2 levels. To address this knowledge gap we created a team of atmospheric scientists, biogeochemists and biogeochemical modellers. Project ELGAR will study controls and variations of soil H2 uptake rates and develop numerical algorithms for implementation into global models. Soil H2 uptake is a passive diffusion process, hence, porous soils are stronger sinks than compacted or waterlogged soil, with low diffusion rates. Many soil microbes utilise H2 as an energy source. H2 uptake rates are controlled by i.e. soil temperature, pH and carbon. Building on this knowledge, we will quantify soil H2 sink rates from a range of soil in response to soil parameters, climates, and vegetation cover: (i) Laboratory manipulations using soils from the UK (8 sites), and the tropics (min. 2 sites) will provide data on the response to soil moisture, temperature, H2 concentrations, pH, and fluxes of CO2, CH4, N2O, required for the models. (ii) We will deliver 1-year real-world observations of spatial and temporal soil H2 uptake: (a) Static chambers inform on within-field spatial and temporal variability and effects of land management. (b) Direct H2 flux measurements by the aerodynamic flux gradient method will study the relationship between H2 uptake and meteorology, and in-soil H2 concentrations and fluxes of CO2, CH4, N2O, CO at UKCEH's Easter Bush monitoring site, and (c) indirect flux measurements, derived from atmospheric H2 decay in conjunction with measurements of ozone deposition and radon accumulation, at a second, drier site. ELGAR will develop a soil model of H2 uptake, drawing on recently published H2 modelling work. The model will run at the site, national and global scale, and be suitable to link to atmospheric chemistry and transport models. It will be constructed on well-established soil organic matter modelling approaches and use ELGAR measurement data to derive response functions and constrain model parameters. Simulations run at the global scale will investigate the impacts of soil properties, climate and vegetation types on H2 uptake and release. ELGAR will collaborate with atmospheric modellers, including those funded under Topics A and C under this call to ensure the new process understanding feeds into improved atmospheric predictions during and beyond the project lifetime. Data will be stored at a NERC data centre and we will educate the public on the importance of soils as a sink for atmospheric H2 and engage with policymakers and farmers regarding the importance of minimising soil compaction and maintaining field drains in the H2 economy.

在COP 26时，各国同意减少其二氧化碳（CO2）和甲烷（CH4）的排放，重点是减少化石燃料的使用。这将留下能源差距，许多国家计划使用氢（H2）作为能量载体来代替该差距。氢是一个小分子，在从生产到最终用户的各个递送阶段都易于泄漏。不可避免地，这将增加大气中的H2浓度，这些浓度在过去二十年中一直保持稳定。大气H2的主要去除机制是通过扩散到土壤中被微生物消耗的土壤。这是其拆除的大约三分之二的三分之二。另一个水槽是通过其与羟基自由基的大气反应，大气H2的增加将延长CH4和臭氧的寿命（O3）。两者都是重要的温室气体，对流层O3也是影响人类健康和生态系统的空气污染物。在平流层中，H2浓度升高会导致水增加，导致保护性O3的耗竭。主要的H2土壤水槽受到限制很差，尚不清楚它在不断变化的气候下如何响应大气H2的响应，从而预测了未来H2大气影响的预测。需要研究土壤H2沉水池强度的谜团，以使大气建模者对未来H2水平的影响进行强有力的预测。为了解决这一知识差距，我们创建了一个大气科学家，生物地球运动员和生物地球化学建模者团队。 Elgar项目将研究土壤H2摄取率的控制和变化，并开发用于实施全球模型的数值算法。土壤H2摄取是一个被动扩散过程，因此，多孔土壤比压实或水口的土壤更强，扩散率低。许多土壤微生物将H2用作能源。 H2吸收率由土壤温度，pH和碳控制。在这些知识的基础上，我们将根据土壤参数，气候和植被覆盖范围来量化土壤H2下沉速率：（i）使用来自英国的土壤（8个地点）和热带地区的土壤进行实验室操作（Min。 2个站点）将提供有关模型所需的二氧化碳，CH4，N2O的土壤水分，温度，H2浓度，pH和通量的响应的数据。 （ii）我们将对空间和时间土壤H2吸收的1年现实世界观察：（a）静态室内的静态室内空间内和时间变异性以及土地管理的影响。 （b）通过空气通量梯度法的直接H2通量测量方法将研究H2摄取与气象学之间的关系，以及在UKCEH的Easter Bush Monitory和（C）的CO2，CH4，N2O的土壤内H2浓度和通量（C）间接通量测量结果，与大气H2衰减以及臭氧沉积和ra积的测量相结合，在第二个干燥的位点。 Elgar将利用最近发布的H2建模工作来开发H2吸收的土壤模型。该模型将在国家和全球范围内运行，并适合与大气化学和运输模型联系起来。它将在建立良好的土壤有机物建模方法上构建，并使用Elgar测量数据来得出响应函数并约束模型参数。在全球范围内进行的模拟将研究土壤特性，气候和植被类型对H2吸收和释放的影响。埃尔加（Elgar）将与大气建模者合作，包括根据此呼叫的主题A和C资助的模型，以确保新的过程理解在项目寿命期间和之后的大气预测中的改进。数据将存储在NERC数据中心，我们将教育公众关于土壤作为大气H2的水槽的重要性，并与决策者和农民互动，以最大程度地减少土壤压实并维持H2经济中的田间排水。