The effects of spatial and temporal variability at the sediment surface on aquatic eddy correlation flux measurements
The effects of spatial and temporal variability at the sediment surface on aquatic eddy correlation flux measurements
复制标题
沉积物表面时空变化对水生涡相关通量测量的影响
DOI：
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复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
P. Berg
中科院分区：
文献类型：
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作者：
J. Rheuban;P. Berg
涡动相关技术已成为一种广泛使用的方法来测量生态系统尺度通量在水生底栖环境，然而，有一些理论研究旨在指导部署规划，通量变化的表征，或如何正确地解释测量通量。在这里，近底层水湍流输送和混合的三维数值模型被用来检查如何以及由于底栖生物群落的不均匀性的垂直通量的变化被集成在涡动相关测量。结果表明，适当选择测量高度以上的沉积物表面是至关重要的，以获得准确的平均值的垂直通量从异质底栖生物群落。通过对模拟结果的回归分析，推导出了一组简单的解析表达式，该阈值测量高度作为两个参数的函数：异质斑块大小和沉积物表面粗糙度。同一模型也被用来检查当垂直通量的变化发生在沉积物表面时，当它到达测量点之间的时间滞后。结果表明，这种响应时间变化的几个数量级取决于流速，沉积物表面粗糙度，和测量高度。简单的解析表达式也得到了响应时间。总体而言，研究结果表明，无论是在底栖生物群落的空间变异性和对时间变化的反应是重要的因素，应考虑在规划涡动相关测量和解释涡动相关通量。
The eddy correlation technique has become a widely used approach to measure ecosystem scale fluxes in aquatic benthic environments; however, there are few theoretical studies designed to guide deployment planning, the characterization of flux variability, or how to correctly interpret measured fluxes. Here, a three‐dimensional numerical model for the turbulent transport and mixing in the near‐bottom water was used to examine how well variations in vertical flux due to heterogeneities in the benthic community are integrated in eddy correlation measurements. The results showed that an appropriate choice of measuring height above the sediment surface is crucial to obtain an accurate average of the vertical flux from heterogeneous benthic communities. Through regression analysis of modeling results, a set of simple analytical expressions were derived for this threshold measuring height as a function of two parameters: heterogeneity patch size and sediment surface roughness. The same model was also used to examine the time lag between when a change in vertical flux occurs at the sediment surface and when it reaches the measuring point. The results showed that this response time varies by several orders of magnitude depending on flow velocity, sediment surface roughness, and measuring height. Simple analytical expressions were also derived for the response time. Overall, the findings indicate that both the spatial variability in benthic communities and the response to temporal changes are important factors that should be considered in planning eddy correlation measurements and interpreting eddy correlation fluxes.
影响因子：
2.7
作者：
Berg, Peter;Glud, Ronnie N.;Kitazato, Hiroshi
通讯作者：
Kitazato, Hiroshi
影响因子：
2.5
作者：
Glud, Ronnie N.;Berg, Peter;Rysgaard, Soren
通讯作者：
Rysgaard, Soren