Bedform dynamics and net sediment transport paths over a flood-ebb tidal cycle in the Grådyb channel (Denmark), determined by high-resolution multi-beam echosounding
Bedform dynamics and net sediment transport paths over a flood-ebb tidal cycle in the Grådyb channel (Denmark), determined by high-resolution multi-beam echosounding
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由高分辨率多波束回声测深确定的 Grådyb 海峡（丹麦）洪水-落潮潮汐周期中的底床动态和净沉积物输送路径
DOI：
10.1080/00167223.2004.10649503
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发表时间：
2004
影响因子：
2.3
通讯作者：
J. Bartholdy
中科院分区：
文献类型：
--
作者：
A. Bartholomä;V. Ernstsen;B. Flemming;J. Bartholdy
摘要利用高频(455 KHz)多波束回声测深仪(MBES)进行了高分辨率的水深测量，以确定丹麦西海岸潮汐航道在一个潮汐周期内的总体积泥沙输移量。由于MBE的高重复率和高精度，通过对以短时间间隔记录的形态变化的简单比较，可以准确地计算沙丘高度和迁移率，这是现实地近似潮汐水道流量预算所需的主要参数。在一个潮汐周期内，泥沙净输出量为0.061 m~3/m~2，这意味着年净输沙量为44.5m m−2年−1。大型复合沙丘系统的总输沙量以落潮为导向的输出趋势与“活跃区”的洪水导向输移形成鲜明对比，在小沙丘上的输沙量为0.6m~2，在坡面和谷地上的输沙量为0.15m~2。由此推算出落潮的平均体积输沙率为0.7697×105m2 S−1，洪水的平均体积输沙率为1.059×105m2 S−1，与早先计算的输沙率有较大偏差。
Abstract High-resolution bathymetric surveys were carried out by means of a high-frequency (455 kHz) multibeam-echosounder (MBES) to determine the total volumetric sediment transport over a tidal period in a tidal channel at the Danish west coast. With the high repetition rate and high accuracy of the MBES, a simple comparison of morphological changes recorded at short time intervals allows an accurate calculation of dune heights and migration rates, the main parameters required for realistic approximations of volume budgets in tidal channels. The net sediment volume of 0.061 m3 per m2 over one tidal period is ebb-orientated, which means an annual net volume export of 44.5 m3 m−2 year−1. The general ebb-oriented export trend recorded for the large, compound dune system is contrasted by a net flood-oriented transport in the ‘active zone’ involving smaller superimposed dunes, which amounts to 0.6 m2 per flow phase on top of the large dunes, and 0.15 m2 per flow phase on the slopes and in the troughs. This gives a mean volumetric sediment transport rate of 0.7697×105 m2 s−1 for the ebb flow, and 1.059×105 m2 s−1 for the flood flow, strongly deviating from earlier calculated transport rates.