A combination of quality assessment tools for eddy covariance measurements with footprint modelling for the characterisation of complex sites
A combination of quality assessment tools for eddy covariance measurements with footprint modelling for the characterisation of complex sites
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DOI：
10.1016/j.agrformet.2004.07.012
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发表时间：
2004-12-25
影响因子：
6.2
通讯作者：
Foken, T
中科院分区：
文献类型：
--
作者：
Göckede, M;Rebmann, C;Foken, T
采用涡旋相关方差技术估算地表交换是建立在一定气象条件有效的前提下。其中最重要的是水平均匀性、稳态和非平流条件。由于在复杂的地形条件下，例如在森林上的通量监测点，常常违反这些条件，因此本研究旨在评估地表异质性的影响，以便对测量结果作出正确的解释。涡流相关方差测量的质量评估工具已与足迹模型相结合。这使得确定通量的空间背景成为可能，并在分析中纳入周围地形的土地利用特征。还确定了不同风段和不同气象条件下通量数据的质量，以便确定最适合收集高质量数据集的情况。此外，还计算了足迹区内不同土地利用类型的通量贡献。结果以二维图形的形式显示了不同通量质量的空间分布。这些图确定了影响通量数据质量的地形影响。这种评价对于检查一个地点的测量通量在多大程度上代表一种特定类型的土地利用特别有用。(C) 2004 Elsevier B.V.版权所有
The adoption of the eddy covariance technique to estimate surface exchange is based on the assumption that certain meteorological conditions are valid. The most important of these are horizontal homogeneity, steady-state, and non-advective conditions. Since such conditions are often violated under complex terrain conditions, e.g. at flux monitoring sites over forests, this study aims to evaluate the influence of surface heterogeneity to permit a correct interpretation of the measurement results.Quality assessment tools for eddy covariance measurements have been combined with footprint modelling. This makes it possible to define the spatial context of the fluxes, and to include land use features of the surrounding terrain in the analysis. The quality of the flux data for different wind sectors and varying meteorological conditions is also determined, so that the most suitable situations for the collection of high-quality data sets can be identified. Additionally, the flux contribution of the different land use types present in the footprint area is calculated. The results are presented as two-dimensional graphs, which show the spatial distribution of the quality of different fluxes. These graphs identify terrain influences affecting the flux data quality. The evaluation is especially useful for checking to what extent the measured fluxes at a site are representative of a specific type of land use. (C) 2004 Elsevier B.V. All rights reserved.