Monitoring Tidal Bores using Acoustic Tomography System
Monitoring Tidal Bores using Acoustic Tomography System
复制标题
使用声学断层扫描系统监测潮汐孔
DOI：
10.2112/jcoastres-d-15-00172.1
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发表时间：
2017
影响因子：
--
通讯作者：
Nistor Ioan
中科院分区：
文献类型：
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作者：
Kawanisi Kiyosi;Zhu Xiao-Hua;Fan Xiaopeng;Nistor Ioan
摘要卡瓦尼西，K.；朱X.-H.； Fan, X. 和 Nistor, I.，2017。使用声学断层扫描系统监测潮汐孔。在极端潮汐条件下的钱塘江（中国）进行了流速和悬浮沉积物的连续测量。河流和海岸声学断层扫描系统（FATS/CATS）与声学多普勒电流剖面仪（ADCP）和光学反向散射（OBS）设备同时用于现场研究。在河口上游约 90 公里处沿对角线安装了几个宽带传感器。声音传输线长度为3050 m。 FATS/CATS 收集的横截面平均速度 (V) 使作者能够估计潮汐孔的重要特征（潮汐孔高度和速度）。钻孔向上游运动期间记录的 V 变化范围为 1.35 至 1.76 ms−1。钻孔的高度和速度分别从 1.0 到 1.32 m 和 7.59 到 8.29 ms−1 变化。由于点/垂直测量无法代表河流的横截面，因此河岸附近的流速和水位（压力）的 ADCP 数据分别低估了钻孔高度 22% 和 16%。据观察，最大悬浮沉积物浓度 (SSC) 出现在钻孔到达后约 1 小时；最大SSC和钻孔前缘之间的时间滞后比以前的工作中的时间滞后要大得多。在较大孔径的情况下，截面平均 SSC（从 FATS/CATS 由于悬浮沉积物引起的声音衰减中推导出来）似乎是合适的。由 ADCP 测量的速度时程在钻孔通过期间偏离正常速度剖面，即，在钻孔到达后几分钟的弛豫时间内，速度大小随着床上方高度的增加而减小。
ABSTRACT Kawanisi, K.; Zhu, X.-H.; Fan, X., and Nistor, I., 2017. Monitoring tidal bores using acoustic tomography system. Continuous measurements of flow velocities and suspended sediments were carried out in the Qiantang River (China) with extreme tidal bore conditions. Fluvial and coastal acoustic tomography systems (FATS/CATS) were used in the field studies simultaneously with acoustic Doppler current profilers (ADCPs) and optical backscatter (OBS) equipment. A couple of broadband transducers were installed diagonally across the river around 90 km upstream of the mouth. The length of the sound transmission line was 3050 m. Cross-sectional averaged velocities (V) collected by FATS/CATS enabled the authors to estimate important characteristics of the tidal bores (bore height and celerity). The changes in V recorded during the upstream movement of the bore ranged from 1.35 to 1.76 ms−1. The height and celerity of the bore varied from 1.0 to 1.32 m and 7.59 to 8.29 ms−1, respectively. Since a point/vertical measurement cannot represent a river's cross section, the ADCP data for velocity and water level (pressure) near the riverbank underestimated the bore height by 22% and 16%, respectively. The maximum suspended sediment concentration (SSC) was observed to have occurred approximately 1 h after the bore's arrival; the time lag between the maximum SSC and the bore front is considerably larger than the time lags in previous works. In the case of larger bores, the section mean SSCs, which were deduced from the sound attenuation of FATS/CATS due to suspended sediment, appeared to be appropriate. The time history of the velocity, measured by ADCPs, during the passage of the bore deviated from the normal velocity profile, i.e. the velocity magnitude decreased with an increasing height above the bed for the relaxation time of a few minutes following the arrival of the bore.