Forests cover nearly a third of the Earth's land area and exchange mass, momentum, and energy with the atmosphere. Most studies of these exchanges, particularly using numerical models, consider forests whose structure has been heavily simplified. In many landscapes, these simplifications are unrealistic. Inhomogeneous landscapes and unsteady weather conditions generate fluid dynamical features that cause observations to be inaccurately interpreted, biased, or over-generalized. In Part I, we discuss experimental, theoretical, and numerical progress in the understanding of turbulent exchange over realistic forests. Scalar transport does not necessarily follow the flow in realistic settings, meaning scalar quantities are rarely at equilibrium around patchy forests, and significant scalar fluxes may form in the lee of forested hills. Gaps and patchiness generate significant spatial fluxes that current models and observations neglect. Atmospheric instability increases the distance over which fluxes adjust at forest edges. In deciduous forests, the effects of patchiness differ between seasons; counter intuitively, eddies reach further into leafy canopies (because they are rougher aerodynamically). Air parcel residence times are likely much lower in patchy forests than homogeneous ones, especially around edges. In Part II, we set out practical ways to make numerical models of forest-atmosphere more realistic, including by accounting for reconfiguration and realistic canopy structure and beginning to include more chemical and physical processes in turbulence resolving models. Future challenges include: (a) customizing numerical models to real study sites, (b) connecting space and time scales, and (c) incorporating a greater range of weather conditions in numerical models.

中文翻译：

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现实森林与森林-大气交换模型

森林覆盖了地球陆地面积的近三分之一，并与大气交换质量、动量和能量。大多数对这些交流的研究，特别是使用数值模型，都考虑了结构被大大简化的森林。在许多情况下，这些简化是不现实的。不均匀的景观和不稳定的天气条件会产生流体动力学特征，导致观测结果被不准确地解释、有偏差或过度概括。在第一部分中，我们讨论了在理解现实森林中的湍流交换方面的实验、理论和数值进展。标量传输不一定跟随现实环境中的流动，这意味着标量很少在斑块森林周围达到平衡，并且在森林覆盖的山丘的背风处可能会形成显着的标量通量。间隙和斑块产生了当前模型和观测忽略的显着空间通量。大气不稳定性增加了森林边缘通量调整的距离。在落叶林中，斑块的影响因季节而异；与直觉相反，涡流更深入地进入绿叶树冠（因为它们在空气动力学上更粗糙）。在斑驳的森林中，空气包裹的停留时间可能比同质森林中的要短得多，尤其是在边缘附近。在第二部分中，我们提出了使森林大气数值模型更加真实的实用方法，包括考虑重新配置和真实的树冠结构，并开始在湍流解析模型中包含更多的化学和物理过程。未来的挑战包括：（a）根据实际研究地点定制数值模型，