Chair acoustics, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands.
J Acoust Soc Am. 2013 Aug;134(2):959-70. doi: 10.1121/1.4812858.
This contribution presents sediment classification results derived from different sources of data collected at the Dordtse Kil river, the Netherlands. The first source is a multi-beam echo-sounder (MBES). The second source is measurements taken with a gamma-ray scintillation detector, i.e., the Multi-Element Detection System for Underwater Sediment Activity (Medusa), towed over the sediments and measuring sediment natural radioactivity. Two analysis methods are employed for sediment classification based on the MBES data. The first is a Bayesian estimation method that uses the average backscatter data per beam and, therefore, is independent of the quality of the MBES calibration. The second is a model-based method that matches the measured backscatter curves to theoretical curves, predicted by a physics-based model. Medusa provides estimates for the concentrations of potassium, uranium, thorium, and cesium, known to be indicative for sediment properties, viz. mean grain size, silt content, and the presence of organic matter. In addition, a hydrophone attached to the Medusa system provides information regarding the sediment roughness. This paper presents an inter-comparison between the sediment classification results using the above-mentioned methods. It is shown that although originating from completely different sources, the MBES and Medusa provide similar information, revealing the same sediment distribution.
本研究报告介绍了从荷兰多德雷赫特河（Dordtse Kil）采集的不同数据源得出的沉积物分类结果。第一个来源是多波束回声测深仪（MBES）。第二个来源是使用伽马射线闪烁探测器（Multi-Element Detection System for Underwater Sediment Activity，Medusa）进行的测量，该探测器拖曳在沉积物上方并测量沉积物天然放射性。基于 MBES 数据，采用了两种分析方法进行沉积物分类。第一种是贝叶斯估计方法，该方法使用每个波束的平均反向散射数据，因此独立于 MBES 校准的质量。第二种是基于模型的方法，该方法将测量的反向散射曲线与由物理模型预测的理论曲线相匹配。Medusa 提供了钾、铀、钍和铯浓度的估计值，这些元素已知是指示沉积物特性的指标，例如平均粒径、淤泥含量和有机质含量。此外，附在 Medusa 系统上的水听器提供了有关沉积物粗糙度的信息。本文对使用上述方法进行的沉积物分类结果进行了比较。结果表明，尽管源自完全不同的数据源，但 MBES 和 Medusa 提供了相似的信息，揭示了相同的沉积物分布。
