Scalar Concentration Profiles in the Canopy and Roughness Sublayer
Scalar Concentration Profiles in the Canopy and Roughness Sublayer
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DOI：
10.1007/s10546-008-9328-4
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发表时间：
2008-10
影响因子：
4.3
通讯作者：
I. Harman;J. Finnigan
中科院分区：
文献类型：
--
作者：
I. Harman;J. Finnigan
众所周知，高树冠内部和上方的平均流量和标量浓度分布违反了标准边界层通量梯度关系。我们提出了一种标量浓度分布理论，该理论由与修正的表面层模型耦合的冠层交换模型组成。两个组件之间的耦合以及对表面层轮廓的修改是通过冠层顶部流动的混合层类比来制定的。这种类比提供了轮廓所依赖的额外长度尺度（涡度厚度）和一组标准，可以减少与文献中早期形式相关的经验主义。平均标量浓度分布的预测与潜在温度和水蒸气的各种非绝热稳定性的观测结果相匹配。
The mean flow and scalar concentration profiles within and above a tall canopy are well known to violate the standard boundary-layer flux-gradient relationships. We present a theory for the scalar concentration profile that is comprised of a canopy exchange model coupled to a modified surface-layer model. The coupling between the two components and the modifications to the surface-layer profiles are formulated through the mixing-layer analogy for the flow at canopy top. This analogy provides an additional length scale—the vorticity thickness—upon which the profiles depend and a set of criteria that allows a reduction in the empiricism associated with earlier forms in the literature. Predictions of the mean scalar concentration profiles are shown to match observations over a wide range of diabatic stabilities for both potential temperature and water vapour.