POLYGRAM - POLYisotopologues of GReenhouse gases: Analysis and Modelling

POLYGRAM - 温室气体的多同位素体：分析和建模

• 批准号: NE/V007203/1
• 负责人: Grant Forster
• 金额: $ 83.75万
• 依托单位: University of East Anglia
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV007203%2F1
• 关键词: POLYGRAM; POLYisotopologues; GReenhouse; gases; Analysis

The greenhouse gases carbon dioxide (CO2) and methane (CH4) are by far the biggest contributors to recent and ongoing climate change. Of all the known greenhouse gases (excluding water vapour), CO2 and CH4 have the highest concentrations in the atmosphere and they are rising rapidly. CO2 is particularly problematic because there is so much of it (about 200 times more than CH4) and because once emitted to the atmosphere, much of it will stay there for several hundred years. Whereas, by comparison, CH4 has a lifetime in the atmosphere of about a decade, but it is a much more potent greenhouse gas than CO2 - that is, for equal amounts of CO2 and CH4 in the atmosphere, CH4 will trap heat radiation about 70 times more effectively than CO2 (over a 20-year time period).With the ratification of the Paris Agreement, the world has committed to avoiding dangerous climate change and the most obvious way to do this is by reducing emissions of CO2 and CH4. How will we know if emission mitigation policies are effective? Which nations or regions are meeting their emissions reduction targets? How will natural CO2 and CH4 fluxes respond to extreme weather events? And which aspects of the carbon cycle remain unsolved? For example, despite decades of study, scientists are still not sure why CH4 emissions are currently rising. To answer these questions we need to be able to measure and quantify CO2 and CH4 emissions and concentrations, and have the ability to separately quantify natural and manmade sources. Our current abilities to do so are severely limited, especially for CH4, which has a diverse array of natural and manmade sources. If we cannot determine the effectiveness of mitigation policies, then our ability to predict climate change impacts will be compromised by large uncertainties.'Polyisotopologues' are one very promising new tool for distinguishing between different source emissions. The chemical elements that make up CO2 and CH4 molecules (carbon (C), oxygen (O) and hydrogen (H)) can have different masses, called isotopes. Different sources can have different isotopic 'fingerprints' or 'signatures' (because source reaction processes may favour a lighter or heavier molecule), thus measuring isotopic signatures is a useful way to gain insight into sources. Isotopic measurements have been made routinely for several decades; whereas the state-of-the-art technology developed in this project would allow us to measure molecules with more than one rare isotope. For example, most C has a relative atomic mass of 12 and H a mass of 1. The rarer isotopes of C and H have masses of 13 and 2, respectively. Isotopologues of CH4, which are measured routinely, include 12CH4, 13CH4 and 12CH3D (where 'D' represents the heavy H atom with mass 2). Whereas polyisotopologues of CH4 include 13CH3D and 12CH2D2 - these are far more challenging to measure, yet could provide invaluable insight into source emissions and sinks.POLYGRAM (POLYisotopologues of GReenhouse gases: Analysis and Modelling) will push the frontiers for both CO2 and CH4 polyisotopologue measurement capability using the latest advances in laser spectroscopic analysis and very high-resolution isotope ratio mass spectrometry. In addition to these challenging technological developments, we will establish a small global atmospheric sampling network to examine latitudinal and longitudinal variations in polyisotopologues, which will help us to constrain overall global budgets of CO2 and CH4. We will carry out field campaigns to determine polyisotopologue source signatures, for example, of CH4 from wetlands, cattle and landfills, and of CO2 from plant photosynthesis and respiration, and from fossil fuel burning. We will conduct laboratory experiments to estimate the reaction rates for CH4 isotopologues when they are oxidised and destroyed in the atmosphere. Finally, we will carry out atmospheric transport modelling for both gases to better interpret and understand the measurements.

到目前为止，二氧化碳（CO2）和甲烷（CH4）是近期和持续的气候变化的最大贡献者。在所有已知的温室气体（不包括水蒸气）中，二氧化碳和CH4在大气中的浓度最高，并且它们正在迅速上升。二氧化碳尤其有问题，因为它的大部分（比CH4多200倍），并且因为一旦进入大气，其中的大部分都会呆了几百年。 Whereas, by comparison, CH4 has a lifetime in the atmosphere of about a decade, but it is a much more potent greenhouse gas than CO2 - that is, for equal amounts of CO2 and CH4 in the atmosphere, CH4 will tr​​ap heat radiation about 70 times more effectively than CO2 (over a 20-year time period).With the ratification of the Paris Agreement, the world has committed to avoiding dangerous climate change and the most obvious way to do this is by减少CO2和CH4的排放。我们如何知道缓解排放政策是否有效？哪些国家或地区符合其排放量的减少目标？天然二氧化碳和CH4通量将如何应对极端天气事件？碳循环的哪些方面尚未解决？例如，尽管进行了数十年的研究，但科学家仍然不确定为什么CH4排放目前正在上升。要回答这些问题，我们需要能够测量和量化CO2和CH4排放和浓度，并具有分别量化自然和人造来源的能力。我们目前这样做的能力受到严重限制，尤其是对于CH4，它具有各种自然和人造资源。如果我们无法确定缓解政策的有效性，那么我们预测气候变化影响的能力将受到大型不确定性的损害。“聚生物学家”是区分不同源排放的一种非常有希望的新工具。构成CO2和CH4分子（碳（C），氧（O）和氢（H））的化学元素可以具有不同的质量，称为同位素。不同的源可以具有不同的同位素“指纹”或“特征”（因为源反应过程可能有利于更轻或更重的分子），因此测量同位素特征是一种有用的方法，可以洞悉源头。同位素测量已定期进行数十年。而该项目开发的最先进技术将使我们能够测量具有多种同位素的分子。例如，大多数C的相对原子质量为12和h质量为1。稀有的同位素分别为13和2。通常测量的CH4的同位素包括12CH4、13CH4和12CH3D（其中'd'代表具有质量2的重h原子）。 Whereas polyisotopologues of CH4 include 13CH3D and 12CH2D2 - these are far more challenging to measure, yet could provide invaluable insight into source emissions and sinks.POLYGRAM (POLYisotopologues of GReenhouse gases: Analysis and Modelling) will push the frontiers for both CO2 and CH4 polyisotopologue measurement capability using the latest advances in laser spectroscopic analysis and very high-resolution isotope比率质谱法。除了这些具有挑战性的技术发展外，我们还将建立一个全球小型大气抽样网络，以检查多分辨力学的纬度和纵向变化，这将帮助我们限制CO2和CH4的总体全球预算。我们将开展现场运动，以确定湿地，牛和垃圾填埋场的CH4，以及植物光合作用和呼吸以及化石燃料的二氧化碳，以及二氧化碳的二氧化碳。我们将进行实验室实验，以估计CH4同位素学在大气中被氧化和破坏时的反应速率。最后，我们将对两种气体进行大气传输建模，以更好地解释和理解测量值。