In situ and high frequency monitoring of suspended sediment properties using a spectrophotometric sensor
In situ and high frequency monitoring of suspended sediment properties using a spectrophotometric sensor
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DOI：
10.1002/hyp.10858
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发表时间：
2016-09
影响因子：
3.2
通讯作者：
N. Martínez‐Carreras;Michael Schwab;J. Klaus;C. Hissler
中科院分区：
文献类型：
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作者：
N. Martínez‐Carreras;Michael Schwab;J. Klaus;C. Hissler
众所周知，沉积物特性，包括沉积物相关的化学成分和沉积物物理特性，在暴雨径流事件内和暴雨径流事件之间可能表现出显着的变化。然而，悬浮沉积物研究中包含的样本数量通常受到溪流水采样后耗时且昂贵的实验室程序的限制。这将高频采样活动限制在有限数量的事件中，并且在估计与沉积物相关的化学成分的通量和负荷时降低了准确性。在这项研究中，我们探讨了便携式紫外可见分光光度计（220-730 nm）以资源有效方式估计悬浮沉积物特性的潜力。目前有几种可现场部署的分光光度计可用于高时间分辨率的环境变量的流内测量。这些仪器主要开发并用于量化溶质浓度（例如溶解的有机碳和 NO3-N）、溶解和颗粒形式的总浓度（例如总有机碳）和浊度。在这里，我们认为可以校准光吸光度值来估计沉积物特性。我们提供了 2013 年 12 月至 2015 年 1 月在韦尔巴赫流域（卢森堡西北部，0.45 平方公里）每隔 15 分钟收集的吸光度数据。在这项概念验证研究中，我们使用悬浮沉积物烧失量 (LOI) 测量值作为悬浮沉积物特性的示例进行了局部校准。我们评估了几种将光吸光度测量与重量百分比 LOI 相关联的回归模型的性能。 MM 稳健回归方法具有最低的预测标准误差 (0.48%)，并被选择进行校准（在观察值和预测值之间调整 r2 = 0.76）。该模型随后用于预测 2014 年 12 月风暴径流事件期间的 LOI。这项研究表明，分光光度计可用于以简单、非破坏性且经济实惠的方式在高时间分辨率和长时间跨度下估计悬浮沉积物特性。版权所有 © 2016 约翰·威利父子有限公司
It is well known that sediment properties, including sediment‐associated chemical constituents and sediment physical properties, can exhibit significant variations within and between storm runoff events. However, the number of samples included in suspended sediment studies is often limited by time‐consuming and expensive laboratory procedures after stream water sampling. This restricts high frequency sampling campaigns to a limited number of events and reduces accuracy when aiming to estimate fluxes and loads of sediment‐associated chemical constituents. In this study, we address the potential of a portable ultraviolet–visible spectrophotometer (220–730 nm) to estimate suspended sediment properties in a resource efficient way. Several field deployable spectrophotometers are currently available for in‐stream measurements of environmental variables at high temporal resolution. These instruments have primarily been developed and used to quantify solute concentrations (e.g. dissolved organic carbon and NO3‐N), total concentrations of dissolved and particulate forms (e.g. total organic carbon) and turbidity. Here we argue that light absorbance values can be calibrated to estimate sediment properties. We present light absorbance data collected at 15‐min intervals in the Weierbach catchment (NW Luxembourg, 0.45 km2) from December 2013 to January 2015. In this proof‐of‐concept study, we performed a local calibration using suspended sediment loss‐on‐ignition (LOI) measurements as an example of suspended sediment property. We assessed the performance of several regression models that relate light absorbance measurements with the percentage weight LOI. The MM‐robust regression method presented the lowest standard error of prediction (0.48%) and was selected for calibration (adjusted r2 = 0.76 between observed and predicted values). The model was then used to predict LOI during a storm runoff event in December 2014. This study demonstrates that spectrophotometers can be used to estimate suspended sediment properties at high temporal resolution and for long‐time spans in a simple, non‐destructive and affordable manner. Copyright © 2016 John Wiley & Sons, Ltd.