Simulating and Simplifying the Physicochemical Complexity of Gas-Aerosol Systems to Promote Development of the Next Generation of Atmospheric 3-D Models

模拟和简化气体气溶胶系统的物理化学复杂性，促进下一代大气 3D 模型的开发

• 批准号: RGPIN-2014-04315
• 负责人: Zuend, Andreas
• 金额: $ 2.55万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708269
• 关键词: Simulating; Simplifying; Physicochemical; Complexity; Gas

Aerosol particles are important constituents of the atmosphere affecting clouds, air quality and Earth's climate. The amounts and distribution of these tiny particles in the surface layers of the atmosphere are important indicators of air quality, often reported in terms of particulate matter mass concentrations (PM10, PM2.5) alongside with ozone and nitrous oxide concentrations. Fine and ultrafine particles can easily enter the lungs and may affect adversely the health of humans. Aerosol particles play a crucial role in the formation of clouds and influence the microphysical properties of liquid water and ice clouds. The recent, comprehensive fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) highlights that aerosols remain poorly constrained climate agents of considerable importance: "There is high confidence that aerosols and their interactions with clouds have offset a substantial portion of global mean forcing from well-mixed greenhouse gases. They continue to contribute the largest uncertainty to the total radiative forcing (RF) estimate." Observed levels of aerosols globally show that organic compounds typically contribute 30% to 80% of the aerosol mass in the troposphere. The major part of this organic aerosol fraction is so-called secondary organic aerosol (SOA) formed from the oxidation of volatile organic compounds and subsequent gas-particle partitioning. It is of central importance for actions targeting the improvement of urban and regional air quality, as well as the critical assessment of climate sensitivity, to understand how chemical reactions and partitioning of volatile organic and inorganic species influences mass concentrations, chemical composition, and size distribution of atmospheric aerosols. Current atmospheric 3-D models implement such physicochemical processes by means of highly simplified schemes only. Most of the 3-D models substantially underpredict observed aerosol levels, constituting one of the main uncertainties in current assessments of air quality and global climate. It is a long-term goal of our research program to develop and utilize methods to translate process-level knowledge from laboratory aerosol experiments, field studies, theory, and box models into practical and justified process parameterizations for use in 3-D chemical transport and chemistry-climate models. Accordingly, our short-term objectives for the next five years include the development of a novel physicochemical modeling framework enabling simplified simulations of aerosol formation and chemical evolution and the evaluation and design of smog chamber experiments. The fundamental insights gained from a box model comprising key physicochemical processes of organic aerosol formation and chemical aging will provide a sound basis from which to assess the feasibility of different levels of simplifications, such as the number and classes of organic surrogate compounds required for process parameterizations in 3-D models. The influence of relative humidity on gas-particle partitioning is one of several questions we propose to study for a wide variety of secondary organic aerosol types. Model simulations in turn will allow us to establish a series of constraints and recommendations for the development of simplified yet improved parameterizations for applications in 3-D models, which largely depend on computationally efficient schemes. New parameterizations will be implemented and tested in an atmospheric chemical transport model. The proposed research offers excellent opportunities for the training of graduate students at McGill University. Our research and training efforts will be supported by mutually beneficial scientific collaborations with leading research groups from Europe and North America.

气溶胶颗粒是影响云，空气质量和地球气候的大气的重要组成部分。这些微小颗粒在大气表面层中的量和分布是空气质量的重要指标，通常与颗粒物质质量浓度（PM10，PM2.5）一起报告，并与臭氧和一氧化二氮浓度一起报告。细和超细颗粒可以轻松进入肺部，并可能对人类的健康不利。气溶胶颗粒在云的形成中起着至关重要的作用，并影响液态水和冰云的微物理特性。政府间互易人间小组（IPCC）的最新全面的第五次评估报告（AR5）强调，气溶胶仍然很限制，其重要性的气候受到了很大的重要性：“空气质量及其与云的相互作用具有很高的信心，即它们与云的相互作用具有很大的相互作用，从而占据了良好的全球性强迫（他们的总体上都有很大的贡献）。 估计。” 观察到的气溶胶水平在全球范围内表明，有机化合物通常在对流层中贡献30％至80％的气溶胶质量。该有机气溶胶馏分的主要部分是由挥发性有机化合物的氧化和随后的气体粒子分配形成的所谓二次有机气溶胶（SOA）。对于针对城市和区域空气质量改善的行动以及对气候敏感性的批判性评估，了解化学反应和挥发性有机和无机物种的分配如何影响质量浓度，化学成分以及大气气溶胶的大小分布，这是至关重要的。当前的大气3-D模型仅通过高度简化的方案实施了这种理化过程。大多数3-D模型大大低估了气溶胶水平，这是当前对空气质量和全球气候评估的主要不确定性之一。 我们的研究计划的长期目标是开发和利用方法将实验室气溶胶实验，现场研究，理论和框模型的过程级知识转化为实用和合理的过程参数，以用于3-D化学运输和化学气候模型。因此，我们接下来的五年中的短期目标包括开发一种新型的理化建模框架，从而实现了气溶胶形成和化学演化的简化模拟以及烟雾室实验的评估和设计。从包含有机气溶胶形成和化学老化的关键物理化学过程的框模型中获得的基本见解将提供一个合理的基础，以评估不同级别的简化水平的可行性，例如3-D模型中有机替代化合物的数量和类别。相对湿度对气体粒子分配的影响是我们提出的几个问题之一，用于研究各种二次有机气溶胶类型。模型仿真反过来将使我们能够建立一系列约束和建议，以开发简化但改进的3-D模型应用程序的参数化，这在很大程度上取决于计算高效的方案。将在大气化学转运模型中实施和测试新的参数化。 拟议的研究为麦吉尔大学的研究生培训提供了绝佳的机会。我们的研究和培训工作将得到与欧洲和北美领先的研究小组的互惠科学合作的支持。