Collaborative Research: Up-scaling from Leaf to Canopy the Aerosol-sized Particle Collection Mechanism Within a Non-uniform Canopy Medium

合作研究：将不均匀冠层介质中气溶胶大小的颗粒收集机制从叶子扩大到冠层

• 批准号: 1102227
• 负责人: Gabriel Katul
• 金额: $ 20.1万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1102227&HistoricalAwards=false
• 关键词: Collaborative; Research; Up; scaling; Leaf

Atmospheric aerosol particle concentrations represent one the largest uncertainties in understanding of both historical and possible future climate forcing, and even regional atmospheric chemistry models exhibit considerable discrepancies with in situ observations of particle size distribution and composition in part because of the complexities of particle dynamics, including dry deposition. Given the expansive forest cover and relatively high particle deposition velocities over forests, the role of forested ecosystems in removing aerosol particles is drawing increased attention in a number of scientific disciplines and regulatory agencies. However, significant uncertainties remain due to: (1) difficulties associated with field measurements of particle size resolved fluxes and mean concentrations, (2) lack of detailed and simultaneous measurements of the canopy medium and, more importantly, foliage surface characteristics, and (3) challenges in describing all the main features of the transporting agent (turbulence) within and immediately above the canopy. This project will address three key aspects of particle deposition onto forested surfaces using a combined experimental and modeling approach at multiple hierarchical scales (leaf-to-canopy) by exploring: (1) the relative importance of, and correct descriptions of, the foliage collection mechanisms at the leaf scale, (2) deposition flux partitioning between foliar and non-foliar elements, and (3) up-scaling results from aspects [1] and [2] to the entire ecosystem.Canopy scale size-resolved particle fluxes and mean concentration profiles will be measured in a diverse array of forested sites (conifers and broadleaf) endowed with "idealized" micrometeorological conditions and in controlled experiments in an environmental chamber. Findings from these experiments will guide the development of new particle collection schemes at the leaf level by accounting for leaf surface properties, turbo- and thermophoretic components. Also, how to upscale these results to the canopy level from measurements that can now be acquired from remote sensing platforms (e.g. leaf area density) using multi-level and particle size-resolved canopy turbulence closure models will be explored. The model results will be evaluated at three forested sites using size-resolved mean particle concentration profiles and two-level eddy-covariance particle flux systems positioned above the canopy and in the understory.This project will provide improvements in process-level understanding of particle dry deposition and for mechanistic descriptions suitable for application in a range of numerical models from earth system models to regional scale air quality models. To facilitate maximal use of the research products derived, the data sets and the models will be made publically accessible via a project website. The project will support one post-doctoral scholar and one graduate student, who will have opportunity to engage with the broader scientific community via interaction with the BEACHON (Biosphere-atmosphere Exchange of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen) research team and European collaborators. Opportunities for undergraduate students will be offered within the BSES (Bachelor of Science in Environmental Science, http://www.indiana.edu/~bses/) program to undertake their capstone research experiences.

大气气溶胶颗粒浓度是理解历史和可能未来气候强迫的最大不确定性，甚至区域大气化学模型也表现出相当大的差异，与现场观察到粒度分布和部分组成部分，部分原因是粒子动力学的复杂性，包括干燥的沉积。鉴于森林上宽阔的森林覆盖率和相对较高的颗粒沉积速度，森林生态系统在去除气溶胶颗粒中的作用在许多科学学科和调节机构中引起了人们的注意。但是，由于：（1）与粒径分辨率和平均浓度的现场测量相关的困难仍然存在，（2）缺乏对冠层培养基的详细和同时测量，更重要的是，叶子表面特征，以及（3）在描述运输剂（湍流式）的所有主要特征（3）挑战。 This project will address three key aspects of particle deposition onto forested surfaces using a combined experimental and modeling approach at multiple hierarchical scales (leaf-to-canopy) by exploring: (1) the relative importance of, and correct descriptions of, the foliage collection mechanisms at the leaf scale, (2) deposition flux partitioning between foliar and non-foliar elements, and (3) up-scaling results from aspects [1] and [2] to整个生态系统。将在具有“理想化的”微量气候条件的各种林地（针叶树和阔叶）中测量覆盖量表大小分辨的粒子通量和平均浓度曲线。这些实验的发现将通过考虑叶表面特性，涡轮和嗜热成分来指导叶片水平的新颗粒收集方案的开发。同样，如何从遥感平台（例如叶面积密度）使用多级别和粒度分辨的冠层湍流闭合模型从遥感平台（例如叶面积密度）获取这些结果。该模型结果将在三个森林地点进行评估，使用尺寸分辨的平均颗粒浓度概况以及位于冠层和林里的两级涡流粒子通量系统。该项目将改善对粒子干燥量的过程级别的理解，以改进适用于地球系统模型中的数字模型模型的机械描述，以适用于机械描述。为了促进最大程度地使用衍生的研究产品，将通过项目网站公开访问数据集和模型。该项目将支持一名博士后学者和一名研究生，他们将有机会通过与Beachon（生物圈 - 大气交换能源，气溶胶，碳，H2O，Organics＆Nitrogen和Nitrogen）研究团队和欧洲合作者的互动来与更广泛的科学界互动。 BSES（环境科学学士学位，http：//www.indiana.edu/~bses/）计划将提供本科生的机会，以实现其顶峰研究经验。