Channel Filtering Generates Multifractal Solute Signals
Channel Filtering Generates Multifractal Solute Signals
复制标题
通道过滤生成多重分形溶质信号
DOI：
10.1029/2018gl079864
复制
发表时间：
2018
影响因子：
5.2
通讯作者：
J. Jawitz
中科院分区：
文献类型：
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作者：
R. Hensley;M. Cohen;J. Jawitz
集水区作为一系列分层过滤器，衰减输入信号，并产生较少的变量流量和流溶质浓度输出信号。对各种溶质和集水区的光谱分析揭示了~1/f标度行为（即，频谱功率与频率成反比），时间跨度从数小时到数十年，这归因于山坡滤波。我们假设，额外的过滤流通道过程应该发生。然而，大多数集水区，其中溶质的缩放行为已经解决了通道的旅行时间太短，这是显而易见的，从相对较低的采样率利用。我们在较大的集水区（高达3 × 106 km 2）使用高频（1-4 hr−1）采样，以表明溶质信号确实是多重分形的，从低频的~1/f光谱到高频的~1/f 2光谱变陡。在保守的，反应性的，和气态溶质，我们证明了偏离1/f标度发生在频率对应的集水大小的度量。
Catchments act as a sequence of hierarchical filters, damping input signals and generating less variable streamflow and stream solute concentration output signals. Spectral analysis across a wide array of solutes and catchments has revealed ~1/f scaling behavior (i.e., spectral power inversely proportional to frequency) spanning periods of hours to decades, attributed to hillslope filtering. We hypothesize that additional filtering by stream channel processes should occur. However, most catchments in which solute scaling behavior has been resolved have channel travel times too short for this to be evident from the relatively low sampling rates utilized. We use high‐frequency (1–4 hr−1) sampling in larger catchments (up to 3 × 106 km2) to show that solute signals are indeed multifractal, steepening from ~1/f spectral at low frequencies to ~1/f 2 at higher frequencies. Across conservative, reactive, and gaseous solutes we demonstrate that departure from 1/f scaling occurs at frequencies that correspond with metrics of catchment size.