Another Simple Method of Spectral Correction to Obtain Robust Eddy-Covariance Results
Another Simple Method of Spectral Correction to Obtain Robust Eddy-Covariance Results
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DOI：
10.1007/s10546-008-9295-9
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发表时间：
2008-07
影响因子：
4.3
通讯作者：
U. Spank;C. Bernhofer
中科院分区：
文献类型：
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作者：
U. Spank;C. Bernhofer
涡协方差方法是测量质量和能量通量的最先进的工具，尽管许多测量系统（特别是闭路系统）显示出强烈的光谱衰减，导致实际质量通量的显着低估。纠正这些低估的标准方法是使用理论上推导的传递函数。实际实施表明，即使考虑了附加的管阻尼，这种方法也会低估衰减，尤其是闭路系统的衰减。本文介绍并测试了三种基于光谱分析的替代现场特定和硬件特定校正方法，除了经典校正之外，这些方法通常会增强基于闭路分析仪计算的质量通量，因为它们不可避免的管道和所使用的过滤器会导致额外的流量衰减。三种方法中的两种基于特定于站点和特定于硬件的传输函数，第三种使用 cospectra 的直接比较。主要是，基于传递函数的方法一旦针对特定设置和测量站点建立起来，就被证明很容易处理。它们代表了校正光谱衰减的实用且稳健的方法。
The eddy-covariance method is the state-of-the-art tool to measure mass and energy fluxes, though many measuring systems (particularly closed-path systems) show strong spectral attenuation that causes significant underestimates of actual mass fluxes. The standard way to correct these underestimates is to use theoretically derived transfer functions. Practical implementation has shown that the attenuation, especially of closed-path systems, is underestimated by this method, even when the additional tube damping is considered. This paper introduces and tests three alternative site-specific and hardware specific correction methods based on spectral analysis, which typically enhance—additionally to the classical correction—the calculated mass fluxes based on closed-path analysers, as their inevitable tubing and the filters used cause additional flow attenuation. Two of the three methods are based on a site-specific and hardware specific transfer functions, the third uses direct comparison of cospectra. Primarily the methods based on transfer functions proved to be easy-to-handle once established for the specific set-up and measurement site. They represent practical and robust methods to correct for spectral attenuation.