New Seasonal Shift in In-Stream Diurnal Nitrate Cycles Identified by Mining High-Frequency Data.
New Seasonal Shift in In-Stream Diurnal Nitrate Cycles Identified by Mining High-Frequency Data.
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DOI：
10.1371/journal.pone.0153138
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Breuer L
中科院分区：
文献类型：
--
作者：
Aubert AH;Breuer L
最近发展的原位监测装置，如紫外光谱仪，使短期流化学变化的研究相关，特别是研究的昼夜周期，这还没有完全理解。我们的研究是基于高频率的数据，从农业集水区（Schenenlandschaft Schwingbachtal，德国）。提出了一种新的方法，即聚类分析和线性判别分析相结合，从这些数据中挖掘硝酸盐行为模式。因此，我们观察到的季节性硝酸盐昼夜循环，这不同于文献中描述的最常见的周期季节性，即黎明前的高峰在春天。我们的周期出现在夏季，最大值和最小值在夏末/秋季转移到较晚的时间。这是观察到的水和能源有限的年份，从而可能强调蒸散的作用。通过数据挖掘得到的蒸散对硝酸盐流浓度的作用的结论性假设，拓宽了流硝酸盐浓度的日循环的视角。
The recent development of in-situ monitoring devices, such as UV-spectrometers, makes the study of short-term stream chemistry variation relevant, especially the study of diurnal cycles, which are not yet fully understood. Our study is based on high-frequency data from an agricultural catchment (Studienlandschaft Schwingbachtal, Germany). We propose a novel approach, i.e. the combination of cluster analysis and Linear Discriminant Analysis, to mine from these data nitrate behavior patterns. As a result, we observe a seasonality of nitrate diurnal cycles, that differs from the most common cycle seasonality described in the literature, i.e. pre-dawn peaks in spring. Our cycles appear in summer and the maximum and minimum shift to a later time in late summer/autumn. This is observed both for water- and energy-limited years, thus potentially stressing the role of evapotranspiration. This concluding hypothesis on the role of evapotranspiration on nitrate stream concentration, which was obtained through data mining, broadens the perspective on the diurnal cycling of stream nitrate concentrations.