Tidal level response to sea-level rise in the yangtze estuary

2012 ◽  
Vol 26 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Zheng Gong ◽  
Chang-kuan Zhang ◽  
Li-ming Wan ◽  
Jun-cheng Zuo
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Yangtze Estuary ◽  
Tidal Level ◽  
The Yangtze Estuary

Sensitivity of tides and net water transport in an estuarine network to river discharge, network geometry and sea level rise

2020 ◽  
Author(s):  
Jinyang Wang ◽  
Huib de Swart
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Water Transport ◽  
River Discharge ◽  
Yangtze Estuary ◽  
Dry Season ◽  
Sea Level Changes ◽  
Wet Season ◽  
The Yangtze Estuary ◽  
And Sea Level

<div> <div> <div> <p>Quite a number of estuaries are characterised by a complex network of branching channels, in which the water motion is primarily driven by tides and river discharge. Examples are the Berau estuary (Indonesia), the Pearl estuary (China) and the Yangtze estuary (China). Knowledge about tides are required for construction of dikes/harbours, while knowledge about net water transport is important for agriculture, fresh water supply to cities and for quantifying transport of sediment, nutrients and etc.</p> <p>In this contribution, we present a generic, weakly nonlinear 2DV estuarine network model to study tides and net water transport and to understand the dependence of their along-channel and vertical structure on geometric characteristics and sea level changes. The model will be applied to the Yangtze Estuary for different situations, such as the wet and dry season, with and without a shortcut channel and sea level rise for scenarios for the coming 50 to 100 years.</p> <p>It will be demonstrated that, for the current conditions, the model results are in good agreement with observations. Both tidal amplitude and current are weaker during the wet season than that during the dry season and the reason for these changes will be explained in terms of river-tide interactions. Effects of local changes in geometry are investigated by creation of a shortcut channel between two main channels. Results show that changes in tides are merely local, but they can be rather strong. Sea level rise (up to 2 meters) causes tides to increase, mainly as a consequence of less friction resulting from larger water depth. Net water transport turns out to be less sensitive to geometry and sea level rise compared to tides.</p> </div> </div> </div>

scholarly journals Impact of climate change on New York City’s coastal flood hazard: Increasing flood heights from the preindustrial to 2300 CE

2017 ◽  
Vol 114 (45) ◽  
pp. 11861-11866 ◽  
Author(s):  
Andra J. Garner ◽  
Michael E. Mann ◽  
Kerry A. Emanuel ◽  
Robert E. Kopp ◽  
Ning Lin ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
Sea Level Rise ◽  
Sea Level ◽  
Tropical Cyclones ◽  
York City ◽  
Flood Hazard ◽  
Storm Surges ◽  
Cmip5 Models ◽  
Tidal Level

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the preindustrial era through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP8.5 simulations from three CMIP5 models. The sea-level rise projections account for potential partial collapse of the Antarctic ice sheet in assessing future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights. For the various sea-level rise scenarios we consider, the 1-in-500-y flood event increases from 3.4 m above mean tidal level during 1970–2005 to 4.0–5.1 m above mean tidal level by 2080–2100 and ranges from 5.0–15.4 m above mean tidal level by 2280–2300. Further, we find that the return period of a 2.25-m flood has decreased from ∼500 y before 1800 to ∼25 y during 1970–2005 and further decreases to ∼5 y by 2030–2045 in 95% of our simulations. The 2.25-m flood height is permanently exceeded by 2280–2300 for scenarios that include Antarctica’s potential partial collapse.

Effect of decreasing sediment supply and sea level rise on the long-term morphodynamics of a large estuary

2021 ◽  
Author(s):  
Bing Yuan ◽  
Jian Sun ◽  
Binliang Lin ◽  
Fanyi Zhang
Keyword(s):  
Equilibrium State ◽  
Sea Level Rise ◽  
Sea Level ◽  
Yangtze Estuary ◽  
Sediment Supply ◽  
Bed Erosion ◽  
Adjustment Time ◽  
Riverine Sediment ◽  
And Sea Level

<p>Globally the riverine sediment supply to estuaries is decreasing and the mean sea level is rising, while the effects of these changes on the long-term estuarine morphodynamics have not been fully investigated. An idealized numerical model was used to explore the long-term morphodynamics of a large estuary subject to these changes. In the model, a funnel-shaped channel with fixed banks, constant riverine water and sediment fluxes, a single grain size and a semi-diurnal tide were used. A range of values of changes in the sediment supply (50-90% reduction) and sea level (1-5~mm/yr increase) were considered. Starting from an equilibrium state for an initial sediment supply, the estuary shifts to a new equilibrium for the considered changes on a timescale of millennia. Half of the bed level change occurs within several hundreds of years. A larger decrease in the sediment supply leads to a stronger bed erosion, while the corresponding adjustment time has minor changes in its range for the considered settings. When combined with sea level rise, the erosion is weakened and the adjustment time is shortened. The equilibrium state under sea level rise is characterized by a bed level keeping pace with the sea level and a significant amount of sediment being trapped in the estuary. Additional numerical experiments that use more realistic geometry and forcing of the Yangtze Estuary show that overall erosion of the estuary is expected for centuries.</p>

scholarly journals Influence Mechanism of Geomorphological Evolution in a Tidal Lagoon with Rising Sea Level

2022 ◽  
Vol 10 (1) ◽  
pp. 108
Author(s):  
Cuiping Kuang ◽  
Jiadong Fan ◽  
Zhichao Dong ◽  
Qingping Zou ◽  
Xin Cong ◽  
...  
Keyword(s):  
Shear Stress ◽  
Sea Level Rise ◽  
Sea Level ◽  
Settling Velocity ◽  
Sediment Supply ◽  
Tidal Level ◽  
Economic Implications ◽  
Bed Elevation ◽  
Geomorphological Evolution ◽  
Sediment Settling

A tidal lagoon system has multiple environmental, societal, and economic implications. To investigate the mechanism of influence of the geomorphological evolution of a tidal lagoon, the effect of critical erosion shear stress, critical deposition shear stress, sediment settling velocity, and initial bed elevation were assessed by applying the MIKE hydro- and morpho-dynamic model to a typical tidal lagoon, Qilihai Lagoon. According to the simulation results, without sediment supply, an increase of critical erosion, deposition shear stress, or sediment settling velocity gives rise to tidal networks with a stable terrain. Such an equilibrium state can be defined as when the change of net erosion has little variation, which can be achieved due to counter actions between the erosion and deposition effect. Moreover, the influence of the initial bed elevation depends on the lowest tidal level. When the initial bed elevation is below the lowest tidal level, the tidal networks tend to be fully developed. A Spearman correlation analysis indicated that the geomorphological evolution is more sensitive to critical erosion or deposition shear stress than sediment settling velocity and initial bed elevation. Exponential sea level rise contributes to more intensive erosion than the linear or the parabolic sea level rise in the long-term evolution of a tidal lagoon.

Glacial Contributions to 21st Century Sea Level Rise

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Kate Wheeling
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
Mass Change ◽  
Sources Of Uncertainty

Researchers identify the main sources of uncertainty in projections of global glacier mass change, which is expected to add about 8–16 centimeters to sea level, through this century.

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