期刊
OCEAN SCIENCE
卷 17, 期 6, 页码 1605-1621出版社
COPERNICUS GESELLSCHAFT MBH
DOI: 10.5194/os-17-1605-2021
关键词
-
资金
- Portuguese Foundation for Science and Technology (FCT) [UID/MAR/00350/2020]
- National Natural Science Foundation of China [51979296]
Observations show that fortnightly fluctuations in mean water level amplitude increase upstream along a tide-dominated lower estuary with low river discharge, while remaining constant further upstream. Analytical solutions reveal that these patterns are due to reflection effects at the estuary head, causing the phase difference between velocity and depth to increase as water levels approach slack water. As a result, tidal asymmetry in discharge decreases in the upstream direction.
Observations indicate that the fortnightly fluctuations in the mean amplitude of water level increase in the upstream direction along the lower half of a tide-dominated estuary (the Guadiana Estuary), with negligible river discharge, but remain constant upstream. Analytical solutions reproducing the semi-diurnal wave propagation shows that this pattern results from reflection effects at the estuary head. The phase difference between velocity and elevation increases from the mouth to the head (where the wave has a standing nature) as the timing of high and low water levels come progressively closer to slack water. Thus, the tidal (flood-ebb) asymmetry in discharge is reduced in the upstream direction. It becomes negligible along the upper estuary half as the mean sea level remains constant despite increased friction due to wave shoaling. Observations of a flat mean water level along a significant portion of an upper estuary suggest a standing wave character and, thus, indicate significant reflection of the propagating semi-diurnal wave at the head. Details of the analytical model show that changes in the mean depth or length of semi-arid estuaries, in particular for macrotidal locations, affect the fortnightly tide amplitude and, thus, the upstream mass transport and inundation regime. This has significant potential impacts on the estuarine environment in terms of ecosystem management.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据