Effects of leaf area index and density on ultrafine particle deposition onto forest canopies: A LES study
Effects of leaf area index and density on ultrafine particle deposition onto forest canopies: A LES study
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DOI：
10.1016/j.atmosenv.2018.06.048
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发表时间：
2018-09
影响因子：
5
通讯作者：
Xinlu Lin;M. Chamecki;G. Katul;Xiping Yu
中科院分区：
文献类型：
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作者：
Xinlu Lin;M. Chamecki;G. Katul;Xiping Yu
提出了一种利用大涡模拟（LES）来描述森林中超细颗粒（UFP）迁移和沉积的框架。与芬兰南部苏格兰松林内部和上方收集的测量数据进行比较，用于探索模拟的合理性。然后利用数值模型量化了冠层形态（叶面积指数和叶面积密度）、湍流强度和粒径对冠层上、下沉积分配和总体沉积速度的影响。结果表明，冠层形态与湍流之间存在复杂的相互作用，这反映在冠层内的颗粒通量分布上。然而，冠层顶部的平均颗粒浓度曲线、总沉降量和沉降速度对叶面积密度曲线不敏感，而主要依赖于叶面积指数、湍流水平和颗粒大小。最后，为了了解沉积速度对所有这些参数的敏感性，我们开发了一个分析模型，该模型在所有模拟条件下都与LES结果吻合良好（在±20%以内）。
A framework to describe transport and deposition of ultrafine particles (UFP) within forests using large eddy simulation (LES) is presented. Comparison with measurements collected within and above a Scots pine stand in Southern Finland are used to explore the plausibility of the simulations. The numerical model is then employed to quantify the effects of canopy morphology (leaf area index and leaf area density), turbulence intensity, and particle size on the partitioning between upper canopy and subcanopy deposition and the overall deposition velocities. Results show a complex interplay between canopy morphology and turbulence, which is reflected on the particle flux profiles within the canopy. However, mean particle concentration profiles, total deposition, and deposition velocities at the canopy top are insensitive to the leaf area density profile but show dependence mostly on leaf area index, turbulence levels, and particle size. Finally, with the goal of understanding the sensitivity of the deposition velocity to all these parameters, an analytical model is developed that shows good agreement with LES results (within±20%) for all conditions simulated here.