Leaf-level to Canopy NOx and Ozone Exchanges at University of Michigan Biological Station (UMBS) during PHotochemistry, Emissions, and Transport (PROPHET) 2016

这个项目是夏季野外研究的一部分，目的是更好地了解森林环境中大气中的反应化学。在这个项目中，将研究叶片水平上氮化合物的交换，以更好地预测臭氧、二次有机气溶胶的产生以及大气和生物圈之间氮的循环。提高对森林环境中反应化学的认识，将有助于预测森林演替和气候的未来变化如何影响未来的大气成分。本研究的具体目标是：(1)在密歇根大学生物站（UMBS）的氧化剂研究计划：光化学、排放和运输（PROPHET）站点，确定优势树种的NO、NO2、NOy和臭氧的叶片交换；(2)确定叶片水平气体交换对光合作用、气孔导度、光照、温度和湿度等生理环境因子的依赖；(3)确定叶级气体交换对环境NOx和臭氧混合比的依赖关系；(4)研究叶片氮氧化物交换与生物源性挥发性有机碳排放之间的潜在联系；(5)利用高分辨率温度梯度测量重新研究了多层冠层化学交换（MLC-CHEM）模型中夜间和白天的冠层下湍流输送表征；(6)纳入、重新审视并进一步改进UMBS森林氧化模型。

This project is part of a summer field study to gain a better understanding of reactive chemistry in the atmosphere of a forested environment. In this project, the exchange of nitrogen compounds at the leaf-level will be investigated to better predict the production of ozone, secondary organic aerosols and the cycling of nitrogen between the atmosphere and the biosphere. Improving the understanding of reactive chemistry in forest environments will improve projections of how future changes in forest succession and climate might affect the future composition of the atmosphere. The specific objectives of this study are to: (1) determine leaf exchanges of NO, NO2, NOy, and ozone for the dominant tree species at the University of Michigan Biological Station's (UMBS) Program for Research on Oxidants: PHotochemistry, Emissions, and Transport (PROPHET) site; (2) determine the dependency of the leaf-level gas exchanges on the physiological and environmental factors including photosynthesis, stomatal conductance, light, temperature, and humidity; (3) determine the dependency of the leaf-level gas exchanges on the ambient NOx and ozone mixing ratio; (4) Investigate potential connections between leaf-level NOx exchanges and emission of biogenic volatile organic carbon; (5) re-examine nocturnal and daytime below-canopy turbulent transport representation in the Multi-layer Canopy Chemical Exchange (MLC-CHEM) model using high resolution temperature gradient measurements; and (6) incorporate, revisit, and further improve the modeling of the UMBS forest oxidation.