Top-Down Constraints on North American Biogenic Volatile Organic Compounds (VOC) Emissions From Tall Tower Measurements and Lagrangian Particle Dispersion Modeling

大气挥发性有机化合物(VOCs)是对流层臭氧、一氧化碳(CO)、甲醛和有机气溶胶的前体，在氢氧化物(Hox)和氮氧化物(NOY)循环中起着核心作用。陆地生态系统是全球大气中挥发性有机化合物的主要来源。这项研究将通过解决以下核心问题来促进对生物源VOC(BVOC)排放及其大气影响的科学理解：BVOC通量在区域尺度上的分布是什么，以及它们如何响应环境强迫和物候？BVOCs对CO和其他主要大气物种的季节性影响是什么？在春季和秋季，BVOCs在推动臭氧生产的NOx和VOC限制制度之间的化学转变方面发挥了什么作用？该研究应用了一种新的测量模型方法，将高塔BVOC测量与拉格朗日和逆模型相结合。工作重点将集中在异戊二烯、甲醇和丙酮--三种最普遍和最重要的BVOCs上。具体任务将包括：1)在美国中西部的一座美国通量高塔(244米)测量BVOC和CO浓度。测量将跨越两个完整的年度周期。2)分析VOC浓度及其与上游源、地表覆盖和季节的关系。这一独特的数据集将为控制大气VOC丰度和从几分钟到几年的时间尺度上的化学影响提供新的见解。3)利用随机时间反转拉格朗日运输(STILT)模型和国家科学排放清单，将测量结果与区域来源定量联系起来。4)应用正式的贝叶斯反分析对景观到区域尺度(约100-1000公里)的BVOC源施加新的约束。5)探讨排放的季节性相关性以及由此产生的对CO和其他关键物种的光化学效应。这项工作的广泛影响和推广部分包括：1)通过与McNair学者计划的伙伴关系，扩大未被充分代表的学生对地球科学研究的参与；2)培训研究生使用尖端大气化学测量和建模工具；3)开发一种新的模型测量工具，应对科学界广泛有用；4)通过会议演讲和科学出版物积极传播科学发现。最后确定的数据将公之于众，并可在网上随时查阅。

Atmospheric volatile organic compounds (VOCs) are precursors of tropospheric ozone, carbon monoxide (CO), formaldehyde, and organic aerosol, and play a central role in hydrogen oxides (HOx) and nitrogen oxides (NOy) cycling. Terrestrial ecosystems are the dominant source of VOCs to the global atmosphere. This research will advance scientific understanding of biogenic VOC (BVOC) emissions and their atmospheric effects by addressing the following core questions: What is the landscape to regional-scale distribution of BVOC fluxes, and how do they respond to environmental forcing and phenology? What is the seasonal impact of BVOCs on CO and other key atmospheric species? What roles do BVOCs play during spring and fall in driving a chemical transition between NOx and VOC-limited regimes for ozone production? The research applies a new measurement-model approach linking tall tower BVOC measurements with Lagrangian and inverse modeling. Work will focus on isoprene, methanol, and acetone - three of the most ubiquitous and important BVOCs. Specific tasks will include: 1) Measure BVOC and CO concentrations at an Ameriflux tall tower (244 m) in the US Midwest. Measurements will span two full annual cycles. 2) Analyze the VOC concentrations and variability in relation to upstream sources, landcover, and season. This unique dataset will yield new insights into the controls on atmospheric VOC abundance and chemical impacts on timescales from minutes to years. 3) Relate the measurements quantitatively to regional sources using the Stochastic Time- Inverted Lagrangian Transport (STILT) model and state-of-science emission inventories. 4) Apply a formal Bayesian inverse analysis to place new constraints on landscape-to-regional scale (~ 100 - 1,000 km) BVOC sources. 5) Explore the seasonal dependence of emissions and the resulting photochemical effects on CO and other key species.Broader impact and outreach components of the work include: 1) Broadening the participation of underrepresented students in Earth Science research through a partnership with the McNair Scholars program; 2) Training graduate students in cutting-edge atmospheric chemistry measurement and modeling tools; 3) Developing a new model-measurement tool that should be broadly useful to the scientific community; 4) Active dissemination of scientific findings through conference presentations and scientific publications. Finalized data will be made public and readily available online.