Source variability of WSOC in atmospheric precipitation

大气降水中 WSOC 的来源变异性

• 批准号: NE/H010327/1
• 负责人: Robert Upstill-Goddard
• 金额: $ 5.75万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH010327%2F1
• 关键词: Source; variability; WSOC; atmospheric; precipitation

A wide range of organic (carbon containing) compounds produced both naturally by biological and chemical processes but also by mans activities (fires, vehicle and industrial emissions etc.) readily dissolve in water. Together these compounds are termed 'water soluble organic carbon', or WSOC for short. In some senses WSOC can be considered as a somewhat vague and all-encompassing term because it is a complex mixture of organic molecules which vary in their contributions to the total and are extremely difficult to isolate and analyse individually. Nevertheless, as a so-called 'bulk' component, WSOC is an important constituent of atmospheric water and is reactive. Its constituent molecules undergo sunlight-induced (photochemical) reactions that result in a range of reactive products which influence atmospheric chemical processes, influencing the climate on both local and global scales. WSOC can be an important source of cloud condensation nuclei (CCN) which are required for cloud formation, it contributes to rainwater acidity, and it can be a nutrient source to lakes, rivers and the ocean. Recent trends of increasing rainfall in the UK and worldwide mean that the need for detailed study of WSOC will become ever more important. In order to predict its impact on the environment, its various individual sources need to be better identified and characterised in terms of their composition and variabilty in time and space. Detailed chemical analysis of WSOC is costly, not readily accesible and in any case does not provide a high level of identification; rather only 'average compositions'. Recently a large fraction of WSOC was found to be fluorescent, which means that it emits electromagnetic radiation, especially visible light, if stimulated by the absorption of incident radiation from some source. The wavelength spectrum emitted can be analysed and used as a 'fingerprint' to characterise WSOC (and other forms of dissolved organic matter) of different 'types' (so-called 'flourophores') that enable a means to deduce information about different WSOC sources contributing to a sample and provide a measure of their relative importance (from their fluorescence intensities). The advantages of fluorescence are its relative simplicity and low cost. The idea of this work is to collect rainwater samples from specific rainfall 'events' and analyse these by fluorecence to identify the fluorophores present and their intensities. Using these measurements along with meteorological data from an adjacent meteorological mast and software that uses these data to predict areas from which air masses have originated, it will be possible to determine the regions in which the various source 'types' identified originated. This will be an important first step towards a better understanding of the origin and subsequent fate of WSOC in the environment. The results from this short-duration study will be used to help formulate a more detailed programme of WSOC research in the near future.

生物学和化学过程自然产生了各种有机（含碳）化合物，也是由人类活动（火灾，车辆和工业排放等）很容易溶解在水中。这些化合物一起称为“水溶性有机碳”或WSOC。从某种意义上说，WSOC可以被认为是一个模糊且无所不包的术语，因为它是有机分子的复杂混合物，它们对总体的贡献有所不同，并且非常难以分离和分析。然而，作为所谓的“大量”组件，WSOC是大气水的重要组成部分，是反应性的。它的组成分子经历了阳光引起的（光化学）反应，从而导致一系列影响大气化学过程的反应性产物，从而影响局部和全球尺度的气候。 WSOC可能是云形成所需的云凝结核（CCN）的重要来源，它有助于雨水酸度，并且可以成为湖泊，河流和海洋的营养来源。英国和全球降雨量增加的最新趋势意味着对WSOC进行详细研究的需求将变得越来越重要。为了预测其对环境的影响，需要更好地识别和特征其各个单个来源的成分和时间和空间的变化。 WSOC的详细化学分析是昂贵的，不容易获得，并且在任何情况下都不会提供高水平的识别；而是只有“平均成分”。最近，发现大量的WSOC是荧光的，这意味着如果通过从某些来源吸收入射辐射的情况下，它会发出电磁辐射，尤其是可见光。可以分析和用作不同“类型”（所谓的“粉酚”）的WSOC（以及其他形式的溶解有机物）（溶解有机物）的“指纹”的波长光谱，以推导有关不同WSOC的信息，以推导有关不同WSOC的信息，以促进其样本并提供相对重要性（从其荧光强度）。荧光的优点是其相对简单性和低成本。这项工作的想法是从特定的降雨“事件”中收集雨水样本，并通过荧光症分析这些样本，以鉴定存在的荧光团及其强度。使用这些测量值以及来自相邻气象桅杆和软件的气象数据，这些数据使用这些数据来预测空气质量起源的领域，可以确定确定所确定的各种源“类型”所起源的区域。这将是对环境中WSOC的起源和随后命运的更好理解的重要第一步。这项短期研究的结果将用于帮助制定更详细的WSOC研究计划。