scholarly journals IMPACT OF SEA LEVEL RISE ON HYDRODYNAMICS OF ESTUARIES WITH RESTRICTED ENTRANCES

2020 ◽  
pp. 3
Author(s):  
Danial Khojasteh ◽  
Steve Hottinger ◽  
Stefan Felder ◽  
Giovanni De Cesare ◽  
Valentin Heimhuber ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Case Studies ◽  
Sea Level ◽  
Potential Solution ◽  
Tidal Dynamics ◽  
Large Ensemble ◽  
Clustering Techniques ◽  
Tidal Forcing ◽  
Tidal Amplification ◽  
Static Models

Worldwide, hundreds of millions of people who live on or near estuarine environments are vulnerable to sea level rise (SLR). Using clustering techniques and moving beyond static models and case studies, this study used a large ensemble of idealised estuary models of varying scale, geometry, level of entrance constriction, and SLR scenarios. It was found that tidal forcing, degree of entrance restriction, and estuarine length can primarily control the tidal dynamics of prismatic estuaries under SLR. Further, restricting an entrance can be presented as a potential solution to offset SLR induced tidal amplification if the associated impacts on entrance stability, navigation, and flooding are considered.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vOptOAbqN3U

scholarly journals Coupling of Sea Level Rise, Tidal Amplification, and Inundation

2014 ◽  
Vol 44 (5) ◽  
pp. 1439-1455 ◽  
Author(s):  
Rusty C. Holleman ◽  
Mark T. Stacey
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
San Francisco ◽  
High Water ◽  
Progressive Wave ◽  
Tidal Dynamics ◽  
Tidal Amplification ◽  
Tidal Estuaries ◽  
Tidal Characteristics ◽  
Frictional Effects

Abstract With the global sea level rising, it is imperative to quantify how the dynamics of tidal estuaries and embayments will respond to increased depth and newly inundated perimeter regions. With increased depth comes a decrease in frictional effects in the basin interior and altered tidal amplification. Inundation due to higher sea level also causes an increase in planform area, tidal prism, and frictional effects in the newly inundated areas. To investigate the coupling between ocean forcing, tidal dynamics, and inundation, the authors employ a high-resolution hydrodynamic model of San Francisco Bay, California, comprising two basins with distinct tidal characteristics. Multiple shoreline scenarios are simulated, ranging from a leveed scenario, in which tidal flows are limited to present-day shorelines, to a simulation in which all topography is allowed to flood. Simulating increased mean sea level, while preserving original shorelines, produces additional tidal amplification. However, flooding of adjacent low-lying areas introduces frictional, intertidal regions that serve as energy sinks for the incident tidal wave. Net tidal amplification in most areas is predicted to be lower in the sea level rise scenarios. Tidal dynamics show a shift to a more progressive wave, dissipative environment with perimeter sloughs becoming major energy sinks. The standing wave southern reach of the bay couples more strongly back to the central portion of the bay, in contrast to the progressive wave northern reach of the bay. Generation of the M4 overtide is also found to vary between scenarios and is a nonnegligible contributor to net changes in high water elevation.

Vulnerability of Zostera noltei to Sea Level Rise: the Use of Clustering Techniques in Climate Change Studies

2020 ◽  
Vol 43 (8) ◽  
pp. 2063-2075
Author(s):  
Bárbara Ondiviela ◽  
Cristina Galván ◽  
María Recio ◽  
Mirian Jiménez ◽  
José Antonio Juanes ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Clustering Techniques ◽  
Zostera Noltei

scholarly journals WITHDRAWN: Sea level rise and estuarine tidal dynamics: A review

2020 ◽  
pp. 103166 ◽  
Author(s):  
Danial Khojasteh ◽  
William Glamore ◽  
Valentin Heimhuber ◽  
Stefan Felder
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tidal Dynamics

scholarly journals The significance of coastal bathymetry representation for modelling the tidal response to mean sea level rise in the German Bight

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Caroline Rasquin ◽  
Rita Seiffert ◽  
Benno Wachler ◽  
Norbert Winkel
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
North Sea ◽  
German Bight ◽  
Coastal Areas ◽  
Tidal Dynamics ◽  
Mean Sea Level ◽  
The North ◽  
The North Sea ◽  
The Impact

Abstract. Due to climate change an accelerated mean sea level rise is expected. One key question for the development of adaptation measures is how mean sea level rise affects tidal dynamics in shelf seas such as the North Sea. Owing to its low-lying coastal areas, the German Bight (located in the southeast of the North Sea) will be especially affected. Numerical hydrodynamic models help to understand how mean sea level rise changes tidal dynamics. Models cannot adequately represent all processes in overall detail. One limiting factor is the resolution of the model grid. In this study we investigate which role the representation of the coastal bathymetry plays when analysing the response of tidal dynamics to mean sea level rise. Using a shelf model including the whole North Sea and a high-resolution hydrodynamic model of the German Bight we investigate the changes in M2 amplitude due to a mean sea level rise of 0.8 and 10 m. The shelf model and the German Bight Model react in different ways. In the simulations with a mean sea level rise of 0.8 m the M2 amplitude in the shelf model generally increases in the region of the German Bight. In contrast, the M2 amplitude in the German Bight Model increases only in some coastal areas and decreases in the northern part of the German Bight. In the simulations with a mean sea level rise of 10 m the M2 amplitude increases in both models with largely similar spatial patterns. In two case studies we adjust the German Bight Model in order to more closely resemble the shelf model. We find that a different resolution of the bathymetry results in different energy dissipation changes in response to mean sea level rise. Our results show that the resolution of the bathymetry especially in flat intertidal areas plays a crucial role for modelling the impact of mean sea level rise.

Viscoelastic modeling results of the 79°N Glacier, Greenland

2020 ◽  
Author(s):  
Julia Christmann ◽  
Martin Rückamp ◽  
Ole Zeising ◽  
Daniel Steinhage ◽  
Niklas Neckel ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Greenland Ice Sheet ◽  
Material Model ◽  
Outlet Glacier ◽  
Tidal Forcing ◽  
North East ◽  
Periodic Movement ◽  
Grounding Line ◽  
Horizontal Displacements

<p>Grounding line/zone dynamics of floating-tongue glaciers is of major importance for changes in their contribution to sea-level rise. For floating-tongue glaciers, thermal forcing of oceanic heat and tidal forcing are the major processes acting in that zone. Here we deal with the response to tidal forcing. The 79°N Glacier, an outlet glacier of the North East Greenland Ice Stream, is the focus of the Greenland Ice Sheet Ocean Interaction project (GROCE) funded by the German Ministry of Education and Research. We present a study of this region considering the deformation of the glacier in response to ocean tidal forcing by means of observations and modeling. GPS measurements realized in 2017-2018 are analyzed for vertical and horizontal displacements of the glacier and its floating tongue. Observations on fully-grounded ice reveal a periodic horizontal displacement in response to ocean tidal forcing in a distance of more than 35 km upstream from the grounding line. In the hinge zone, i.e. the transition between grounded and floating ice, the tidal forcing leads to a measurable vertical bending of the ice and a periodic movement of the grounding line. Understanding the mechanisms of grounding line migration is important to better evaluate the contribution of grounded ice discharge to sea-level rise.</p><p>In order to model the measured displacements, a viscoelastic material model is required using the observed vertical displacements at the floating ice tongue as external forcing. Geometries obtained from AWI’s new ultrawideband radar form the basis for finite-element simulations in COMSOL. With the viscoelastic Maxwell material model, the response of the ice to ocean tidal forcing can successfully be modeled. Results obtained with a nonlinear Glen-type viscosity agree very well with the observed bending near the grounding line. The expected phase shift of the horizontal displacements upstream from the grounding line is well reproduced in the model.</p>

scholarly journals Large ensemble modeling of last deglacial retreat of the West Antarctic Ice Sheet: comparison of simple and advanced statistical techniques

2015 ◽  
Vol 8 (11) ◽  
pp. 9925-9963 ◽  
Author(s):  
D. Pollard ◽  
W. Chang ◽  
M. Haran ◽  
P. Applegate ◽  
R. DeConto
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Large Ensemble ◽  
The West ◽  
West Antarctic Ice Sheet ◽  
West Antarctic ◽  
Parameter Ranges ◽  
Best Fit ◽  
Last Deglacial

Abstract. A 3-D hybrid ice-sheet model is applied to the last deglacial retreat of the West Antarctic Ice Sheet over the last ~ 20 000 years. A large ensemble of 625 model runs is used to calibrate the model to modern and geologic data, including reconstructed grounding lines, relative sea-level records, elevation-age data and uplift rates, with an aggregate score computed for each run that measures overall model-data misfit. Two types of statistical methods are used to analyze the large-ensemble results: simple averaging weighted by the aggregate score, and more advanced Bayesian techniques involving Gaussian process-based emulation and calibration, and Markov chain Monte Carlo. Results for best-fit parameter ranges and envelopes of equivalent sea-level rise with the simple averaging method agree quite well with the more advanced techniques, but only for a large ensemble with full factorial parameter sampling. Best-fit parameter ranges confirm earlier values expected from prior model tuning, including large basal sliding coefficients on modern ocean beds. Each run is extended 5000 years into the "future" with idealized ramped climate warming. In the majority of runs with reasonable scores, this produces grounding-line retreat deep into the West Antarctic interior, and the analysis provides sea-level-rise envelopes with well defined parametric uncertainty bounds.

Variations in physiography, tidal forcing, and bottom shear stress in palaeo-seas: lessons learned from numerical modelling.

2021 ◽  
Author(s):  
Valentin Zuchuat ◽  
Elisabeth Steel ◽  
Ryan Mulligan ◽  
Daniel Collins ◽  
J.A. Mattias Green
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Sedimentary Facies ◽  
Upper Jurassic ◽  
Tidal Dynamics ◽  
Relative Sea Level ◽  
Level Change ◽  
Tidal Harmonics ◽  
Tidal Amplification ◽  
The Impact

<p>The physiography (geometry and bathymetry) of a basin and its latitude are the primary parameters that dictate the tidal dynamics in shoreline–shelf systems. Understanding the impact that changes in physiography have on tides allows researchers to 1) improve interpretations of historical sedimentary processes in shallow-marine basins, and 2) better predict potential variations in tidal dynamics in response to an anthropogenic-driven relative sea level change.</p><p>Here, we present an analysis of numerical modelling of tidal propagation in the Upper Jurassic Sundance and Curtis Seas demontrating that basin-scale amplification and dampening of tides occurred in different palaeophysiographic configurations, and more localised amplification relating to tidal harmonics occurred in certain physiographic scenarios. Consequently, palaeophysiography was the primary control on both the magnitude and location of tidal amplification, flow speed, and bed shear stress, whereas secondary controls were initial tidal forcing and bottom drag coefficient.</p><p>Simulation results for the palaeophysiography with a 600 m depth at the mouth of the system suggest a distribution of sedimentary facies comparable to those documented in the Upper Jurassic lower Curtis Formation, apart from the innermost Curtis Sea, near to the palaeoshoreline. Sediments potentially supplied by aeolian processes during regression and increased aridity were likely reworked by tides during a subsequent a transgression as the climate became more humid. The palaeophysiography with a 600 m depth at the mouth of the system can therefore be considered a realistic palaeophysiographic configuration for the Sundance and Curtis Seas given the similarities that exist between the predicted distribution of sedimentary facies and their actual distribution in the lower Curtis Formation. In this palaeophysiography, the Sundance Sea and the Curtis Sea would have thus attained a maximum depth of ~240 m and 40-45 m, respectively. In this context, the simulated tidal range in the Curtis Sea would have reached 2.60 m, which would classify the Curtis Sea as a meso-tidal system (2x 1.30 m tidal amplitude).</p><p>Finally, using change in palaeophysiographic configuration as a proxy for relative sea-level variations revealed the non-uniqueness (sensu Burgess & Prince, 2015) of sedimentary successions deposited in tide-dominated basin, given that tidal amplification in the system was controlled by palaeophysiographic configuration: one specific succession could be the product of several, equally-valid relative sea-level histories. Reciprocally, the impact of relative sea-level change on different successions is non-unique, since local tidal harmonics and the characteristics of coeval deposition may vary significantly during relative sea level changes.</p>

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