Collaborative Research: Dispersion of Particles Within and Above Plant Canopies

所支持的研究将确定与植物冠层相互作用的近地表气流所特有的大气湍流特征，并进而确定控制这些冠层内小颗粒（如花粉粒、孢子、种子等）释放和运输的机制。动态相互作用将由现场观测、实验室水道实验和高分辨率数值模拟相结合来表示，这将超越当前模型对边界层中粒子输运的预测，目前模型通过稳定、均匀的扩散系数来表示湍流输运。通过这种方式，将定量地确定单个相干流结构在释放、捕获和运输颗粒中的作用。这项研究将结合水槽实验和人工冠层实验，在受控的实验室条件下，在实际作物的背景下进行实地实验（由宾夕法尼亚州立大学的岩石泉农场研究设施提供便利），以及使用大涡模拟（LES）模型的数值实验。这项工作的智力价值来自于对美国中西部典型农作物产生的湍流过程中植被-大气相互作用的更好理解，这与植物冠层内的大气行为和生物过程都有关。这项研究的更广泛的影响将集中在改善植物冠层内部和上方产生的大气湍流模式的表示和预测上，并将涉及大气科学和生物科学界面的强烈跨学科工作。各种各样的研究生和本科生教育机会将在不同的实地实验，实验室和数值分析设置中提供，并将包括学生参与在PSU实地研究设施进行的空气生物学实地课程。

The supported research will determine characteristics of atmospheric turbulence unique to near-surface airflow interaction with plant canopies, and in-turn identify mechanisms controlling the release and transport of small particles (e.g., pollen grains, spores, seeds, etc.) within such canopies. Dynamic interactions will be represented by a combination of field-observations, laboratory water-channel experiments and high-resolution numerical simulations advance the prediction of particle transport in boundary layers beyond current models, which represent turbulent transport via steady, homogenous diffusion coefficients. In this way, the role of individual coherent flow structures in releasing, capturing and transporting particles will be quantitatively determined. This research will combine flume experiments with artificial canopies under controlled laboratory conditions, field experiments in the context of actual crops (as facilitated by Pennsylvania State University's Rock Springs Farm research facility), and numerical experiments using large-eddy simulation (LES) models.The Intellectual Merit of this effort derives from improved understanding of vegetation-atmosphere interactions involving turbulent processes generated by agricultural crops typical of those across the Midwestern U.S., which has relevance both to atmospheric behavior and biological processes within plant canopies. Broader impacts of this research will center on improved representation and prediction of modes of atmospheric turbulence generated within and above plant canopies, and will involve strongly interdisciplinary work at the interface of the atmospheric and biological sciences. A variety of graduate and undergraduate educational opportunities will be provided within diverse field-experiment, laboratory and numerical analysis settings, and will include student participation in an Aerobiology Field Course to be conducted at the PSU field research facility.