Investigating Key Uncertainties in Models of Tropospheric Photochemistry

研究对流层光化学模型中的关键不确定性

• 批准号: NE/F00060X/1
• 负责人: Steve Arnold
• 金额: $ 11.23万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF00060X%2F1
• 关键词: Investigating; Key; Uncertainties; Models; Tropospheric

Our understanding of the impacts of atmospheric composition on climate and air quality relies on simulations from numerical models of atmospheric chemistry and transport. The photochemical components of such models are uncertain, due to the reductions of detailed chemical mechanisms introduced to meet computing demands, and also due to uncertainties in empirically-derived kinetic parameters used in their representations of photochemistry. Validation of the ozone photochemistry component of models by comparison with observations is difficult, since the long lifetime of ozone in the free troposphere (~20 days), means that variability in its concentration at a given point in the atmosphere is generally dominated by transport rather than photochemistry. However, validation of our understanding of ozone photochemistry is critical to our predictions of future climate and air quality, particularly under future changes to ozone precursor sources, and any changes to other parts of the tropospheric ozone budget, such as stratospheric input and surface deposition. This proposal exploits a unique set of observations made during the ITCT Lagrangian-2K4 (Intercontinental Transport and Chemical Transformation) experiment. These provide measurements of a suite of trace gases and aerosol in single air masses at multiple stages during their advection across the North Atlantic from North America to Europe. These linked observations allow ozone photochemistry to be examined in a 'flow-relative', pseudo-Lagrangian frame of reference, removing the influence of advection on the observed ozone change. Simulations of ozone change within the observed air masses using a Lagrangian chemical transport model (CTM) will for the first time allow uncertainties in model photochemistry to be assessed over a timescale of several days. Comparison of Monte-Carlo type model simulations, perturbed by model uncertainties, with observed composition changes within air masses, will test the consistency of model photochemistry with observations. Information will be gained on which uncertainties have the largest impacts on ozone photochemistry. Recommendations will then be made of where effort should be focused in reducing uncertainties in laboratory or atmospheric measurement. The proposal envisages a short 1-year project, using existing tools to investigate these issues, which are of central importance to our confidence in models of air quality and climate. The model framework has already been developed to run locally in Leeds, and the full set of observations is available for use immediately. The project will benefit from expertise from one of the leading atmospheric modelling groups in the UK, in addition to local expertise in kinetic uncertainties and parameterisations from close links with groups in the School of Chemistry.

我们对大气成分对气候和空气质量影响的理解依赖于大气化学和运输数值模型的模拟。此类模型的光化学成分是不确定的，因为减少了为满足计算需求而引入的详细化学机制，并且还由于在光化学表示中使用的经验推导的动力学参数的不确定性。通过与观测结果进行比较来验证模型中的臭氧光化学成分是很困难的，因为臭氧在自由对流层中的寿命很长（约 20 天），这意味着大气中给定点的臭氧浓度变化通常主要是由传输决定的，而不是由迁移决定的。比光化学。然而，验证我们对臭氧光化学的理解对于我们预测未来气候和空气质量至关重要，特别是在未来臭氧前体来源发生变化以及对流层臭氧预算其他部分（例如平流层输入和表面沉积）发生任何变化的情况下。该提案利用了 ITCT Lagrangian-2K4（洲际传输和化学转化）实验期间进行的一组独特的观察结果。这些仪器可以在单一气团从北美到欧洲平流穿过北大西洋的过程中，在多个阶段对一系列微量气体和气溶胶进行测量。这些相关的观测结果允许在“相对流动”的伪拉格朗日参考系中检查臭氧光化学，消除平流对观测到的臭氧变化的影响。使用拉格朗日化学输运模型（CTM）模拟观测到的气团内的臭氧变化将首次允许在几天的时间尺度内评估模型光化学的不确定性。受模型不确定性干扰的蒙特卡罗模型模拟与观测到的气团内成分变化的比较，将测试模型光化学与观测结果的一致性。将获得有关哪些不确定性对臭氧光化学影响最大的信息。然后将就减少实验室或大气测量中的不确定性应重点努力的方面提出建议。该提案设想了一个为期一年的短期项目，利用现有工具来调查这些问题，这对于我们对空气质量和气候模型的信心至关重要。该模型框架已经开发出来，可以在利兹本地运行，并且全套观测数据可以立即使用。该项目将受益于英国领先的大气建模小组之一的专业知识，以及与化学学院小组密切联系的动力学不确定性和参数化方面的当地专业知识。

项目成果

Sensitivity of tropospheric ozone to chemical kinetic uncertainties in air masses influenced by anthropogenic and biomass burning emissions

对流层臭氧对受人为和生物质燃烧排放影响的气团中化学动力学不确定性的敏感性

• DOI: 10.1002/2017gl073802
• 发表时间: 2017
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Ridley D