Determination of Roughness Lengths for Heat and Momentum Over Boreal Forests
Determination of Roughness Lengths for Heat and Momentum Over Boreal Forests
复制标题
确定北方森林热量和动量的粗糙度长度
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Friedl
中科院分区：
文献类型：
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作者：
Rongqian Yang;M. Friedl
动量粗糙度（z 0 m）、零面位移高度（d）和热量粗糙度（z 0 h）是估算陆-气能量交换的重要参数。虽然已经开发了许多不同的方法来parameterizmomentum和热传递，现有的参数化通常利用高度简化的植被结构的表示。此外，用于动量和热交换的处理与用于辐射能量交换的处理之间存在不匹配。在本文中，参数化估计z 0 m，d，和z 0 h的森林制度，使用相关的信息，树冠密度和结构。参数化提供了现实的representationfor树冠内的树叶的垂直分布，并包括明确的治疗树冠粗糙度子层和叶阻力动量交换的影响。建议parameterizations是能够现实地考虑到站点间的差异，所产生的冠层结构properties.模型预测和实地测量之间的比较显示出良好的一致性，这表明，建议的parameterizations捕获的最重要的因素影响湍流交换的momentumand heat over forests。
The roughness length for momentum (z0m), zero-plane displacementheight (d), and roughness length for heat (z0h) are importantparameters used to estimate land-atmosphere energy exchange. Although many different approaches have been developed to parameterizemomentum and heat transfer, existing parameterizations generally utilizehighly simplified representations of vegetation structure. Further, a mismatch exists between the treatments used for momentum and heat exchange and those used for radiative energy exchanges. In this paper, parameterizations are developed to estimate z0m, d, and z0h for forested regimes using information related to tree crown density and structure. The parameterizations provide realistic representationfor the vertical distribution of foliage within canopies, and include explicit treatment for the effects of the canopy roughness sublayer and leaf drag on momentum exchange. The proposed parameterizationsare able to realistically account for site-to-site differences in roughness lengths that arise from canopy structural properties.Comparisons between model predictions and field measurements show good agreement, suggesting that the proposed parameterizations capture the most important factors influencing turbulent exchange of momentumand heat over forests.