Observation, Analysis, and Modeling of Nearshore Dynamics

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Coastal Engineering".

Deadline for manuscript submissions: closed (15 October 2020) | Viewed by 38373

Special Issue Editors

Graduate School of Engineering, University of Tokyo, Tokyo 113-8654, Japan
Interests: nearshore hydrodynamics; sediment transport; numerical modeling; nearshore monitoring
Special Issues, Collections and Topics in MDPI journals
Water Resources Engineering, Lund University, 221 00 Lund, Sweden
Interests: nearshore hydrodynamics; sediment transport; coastal morphology; mathematical modeling
Special Issues, Collections and Topics in MDPI journals
National Research and Development Agency, Kanagawa, Japan
Grad. School of Eng., The University of Tokyo, Tokyo, Japan
Interests: coastal engineering; nearshore dynamics; coastal processes
Special Issues, Collections and Topics in MDPI journals
Graduate School of Engineering, University of Tokyo, Tokyo 113-8654, Japan
Interests: coastal hydrodynamics; coastal sediment transport; coastal disaster prevention
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Understanding the characteristics of nearshore dynamics and coastal processes is one of the essential tasks for sustainable coastal development, conservation, and protection. The coast exhibits varying dynamic characteristics over a broad range of spatial and temporal scales. Wind waves, for example, can determine instantaneous sediment transport and cause short-term cross-shore morphology change, while nearshore currents induced by waves and tides may determine long-term and large-scale morphology change, causing chronic coastal erosion. Such nearshore dynamics at different spatiotemporal scales typically interact with each other and are also affected by other factors such as human activities and climate change. Observation, analysis, and modeling of nearshore dynamics are, thus, inevitable not only for establishing the present conditions of the coast, but also for the evaluation and projection of the future evolution under the impact of a wide range of factors. This Special Issue, therefore, focuses on, but is not limited to the following:

  • Observations, analysis, and modeling of nearshore hydrodynamics
  • Observations, analysis, and modeling of nearshore sediment transport, including aeolian transport
  • Observations, analysis, and modeling of long-term and/or short-term nearshore morphology change
  • Development of monitoring techniques for nearshore dynamics at various spatiotemporal scales

We look forward to contributions of exciting new research in the form of research papers, reviews, and short communications to this Special Issue.

Prof. Yoshimitsu Tajima
Prof. Magnus Larson
Prof. Yoshiaki Kuriyama
Dr. Takenori Shimozono
Guest Editors

Manuscript Submission Information

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Keywords

  • Nearshore dynamics
  • nearshore monitoring
  • nearshore waves and currents
  • sediment transport
  • coastal processes
  • mathematical and numerical modeling

Published Papers (13 papers)

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Research

24 pages, 16434 KiB  
Article
Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics
by Bart Roest, Sierd de Vries, Matthieu de Schipper and Stefan Aarninkhof
J. Mar. Sci. Eng. 2021, 9(1), 37; https://doi.org/10.3390/jmse9010037 - 01 Jan 2021
Cited by 11 | Viewed by 3528
Abstract
Recently, mega feeder nourishments have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to [...] Read more.
Recently, mega feeder nourishments have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to spread the sediment alongshore over the course of years to decades. This article presents the morphological development of the first full-scale implementation of this strategy, examining the 20 × 106 m3“Sand Engine” feeder nourishment and its impact on adjacent coastal sections. The analysis is based on 37 high-resolution topographical surveys, executed in a 17 km coastal cell. These unique data describe the alongshore spreading in the first five years and the response at different elevations of the coastal profile. The analysis shows rapid transformation of the nourishment’s planform shape, changing rapidly into a smooth (Gaussian-like) shape which is gradually extending alongshore over time. Within five years, sediment has been distributed to a 5.8 km stretch of coast from the initial 2.2 km peninsula footprint. Changes in cross-shore and alongshore extent varied strongly over depth, with the strongest morphological response at the mean sea level (MSL) isobath and limited morphodynamic activity at deeper water, below −8 m MSL. This depth-dependent response has resulted in decreasing subtidal slopes in eroding areas, accretive areas contrastingly show a slope increment. These results yield important insights in nourished sediment mobility at different depths near the coast and distribution over a larger coastal cell. However, this single-design assessment cannot address the wide range of mega nourishment design parameters essential for morphological development of its coastal cell. This work suggests limiting cross-shore extent, since it is uncertain whether nourished sediment at deeper water will become active in the coastal system. A continuation of the current monitoring and future research might shed more light on this. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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23 pages, 3931 KiB  
Article
Estimation of Irregular Wave Runup on Intermediate and Reflective Beaches Using a Phase-Resolving Numerical Model
by Jonas Pinault, Denis Morichon and Volker Roeber
J. Mar. Sci. Eng. 2020, 8(12), 993; https://doi.org/10.3390/jmse8120993 - 05 Dec 2020
Cited by 8 | Viewed by 2424
Abstract
Accurate wave runup estimations are of great interest for coastal risk assessment and engineering design. Phase-resolving depth-integrated numerical models offer a promising alternative to commonly used empirical formulae at relatively low computational cost. Several operational models are currently freely available and have been [...] Read more.
Accurate wave runup estimations are of great interest for coastal risk assessment and engineering design. Phase-resolving depth-integrated numerical models offer a promising alternative to commonly used empirical formulae at relatively low computational cost. Several operational models are currently freely available and have been extensively used in recent years for the computation of nearshore wave transformations and runup. However, recommendations for best practices on how to correctly utilize these models in computations of runup processes are still sparse. In this work, the Boussinesq-type model BOSZ is applied to calculate runup from irregular waves on intermediate and reflective beaches. The results are compared to an extensive laboratory data set of LiDAR measurements from wave transformation and shoreline elevation oscillations. The physical processes within the surf and swash zones such as the transfer from gravity to infragravity energy and dissipation are accurately accounted for. In addition, time series of the shoreline oscillations are well captured by the model. Comparisons of statistical values such as R2% show relative errors of less than 6%. The sensitivity of the results to various model parameters is investigated to allow for recommendations of best practices for modeling runup with phase-resolving depth-integrated models. While the breaking index is not found to be a key parameter for the examined cases, the grid size and the threshold depth, at which the runup is computed, are found to have significant influence on the results. The use of a time series, which includes both amplitude and phase information, is required for an accurate modeling of swash processes, as shown by computations with different sets of random waves, displaying a high variability and decreasing the agreement between the experiment and the model results substantially. The infragravity swash SIG is found to be sensitive to the initial phase distribution, likely because it is related to the short wave envelope. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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22 pages, 3450 KiB  
Article
Modeling Impact of Intertidal Foreshore Evolution on Gravel Barrier Erosion and Wave Runup with XBeach-X
by Benjamin T. Phillips, Jennifer M. Brown and Andrew J. Plater
J. Mar. Sci. Eng. 2020, 8(11), 914; https://doi.org/10.3390/jmse8110914 - 12 Nov 2020
Cited by 6 | Viewed by 2740
Abstract
This paper provides a sensitivity analysis around how characterizing sandy, intertidal foreshore evolution in XBeach-X impacts on wave runup and morphological change of a vulnerable, composite gravel beach. The study is motivated by a need for confidence in storm-impact modeling outputs to inform [...] Read more.
This paper provides a sensitivity analysis around how characterizing sandy, intertidal foreshore evolution in XBeach-X impacts on wave runup and morphological change of a vulnerable, composite gravel beach. The study is motivated by a need for confidence in storm-impact modeling outputs to inform coastal management policy for composite beaches worldwide. First, the model is run with the sandy settings applied to capture changes in the intertidal foreshore, with the gravel barrier assigned as a non-erodible surface. Model runs were then repeated with the gravel settings applied to obtain wave runup and erosion of the barrier crest, updating the intertidal foreshore from the previous model outputs every 5, 10 and 15 min, and comparing this with a temporally static foreshore. Results show that the scenario with no foreshore evolution led to the highest wave runup and barrier erosion. The applied foreshore evolution setting update is shown to be a large control on the distribution of freeboard values indicative of overwash hazard and barrier erosion by causing an increase (with 5 min foreshore updates applied) or a decrease (with no applied foreshore updating) in the Iribarren number. Therefore, the sandy, intertidal component should not be neglected in gravel barrier modeling applications given the risk of over- or under-predicting the wave runup and barrier erosion. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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25 pages, 3317 KiB  
Article
From Ripples to Large-Scale Sand Transport: The Effects of Bedform-Related Roughness on Hydrodynamics and Sediment Transport Patterns in Delft3D
by Laura Brakenhoff, Reinier Schrijvershof, Jebbe van der Werf, Bart Grasmeijer, Gerben Ruessink and Maarten van der Vegt
J. Mar. Sci. Eng. 2020, 8(11), 892; https://doi.org/10.3390/jmse8110892 - 08 Nov 2020
Cited by 27 | Viewed by 4839
Abstract
Bedform-related roughness affects both water movement and sediment transport, so it is important that it is represented correctly in numerical morphodynamic models. The main objective of the present study is to quantify for the first time the importance of ripple- and megaripple-related roughness [...] Read more.
Bedform-related roughness affects both water movement and sediment transport, so it is important that it is represented correctly in numerical morphodynamic models. The main objective of the present study is to quantify for the first time the importance of ripple- and megaripple-related roughness for modelled hydrodynamics and sediment transport on the wave- and tide-dominated Ameland ebb-tidal delta in the north of the Netherlands. To do so, a sensitivity analysis was performed, in which several types of bedform-related roughness predictors were evaluated using a Delft3D model. Also, modelled ripple roughness was compared to data of ripple heights observed in a six-week field campaign on the Ameland ebb-tidal delta. The present study improves our understanding of how choices in model set-up influence model results. By comparing the results of the model scenarios, it was found that the ripple and megaripple-related roughness affect the depth-averaged current velocity, mainly over the shallow areas of the delta. The small-scale ripples are also important for the suspended load sediment transport, both indirectly through the affected flow and directly. While the current magnitude changes by 10–20% through changes in bedform roughness, the sediment transport magnitude changes by more than 100%. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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23 pages, 5674 KiB  
Article
Hydrodynamic Modeling of a Reef-Fringed Pocket Beach Using a Phase-Resolved Non-Hydrostatic Model
by Johan Risandi, Dirk P. Rijnsdorp, Jeff E. Hansen and Ryan J. Lowe
J. Mar. Sci. Eng. 2020, 8(11), 877; https://doi.org/10.3390/jmse8110877 - 04 Nov 2020
Cited by 13 | Viewed by 2458
Abstract
The non-hydrostatic wave-flow model SWASH was used to investigate the hydrodynamic processes at a reef fringed pocket beach in southwestern Australia (Gnarabup Beach). Gnarabup Beach is a ~1.5 km long beach with highly variable bathymetry that is bounded by rocky headlands. The site [...] Read more.
The non-hydrostatic wave-flow model SWASH was used to investigate the hydrodynamic processes at a reef fringed pocket beach in southwestern Australia (Gnarabup Beach). Gnarabup Beach is a ~1.5 km long beach with highly variable bathymetry that is bounded by rocky headlands. The site is also exposed to large waves from the Southern Ocean. The model performance was evaluated using observations collected during a field program measuring waves, currents and water levels between June and July 2017. Modeled sea-swell wave heights (periods 5–25 s), infragravity wave heights (periods 25–600 s), and wave-induced setup exhibited moderate to good agreement with the observations throughout the model domain. The mean currents, which were highly-spatially variable across the study site, were less accurately predicted at most sites. Model agreement with the observations tended to be the worst in the areas with the most uncertain bathymetry (i.e., areas where high resolution survey data was not available). The nearshore sea-swell wave heights, infragravity wave heights and setup were strongly modulated by the offshore waves. The headlands and offshore reefs also had a strong impact on the hydrodynamics within the lagoon (bordered by the reefs) by dissipating much of the offshore sea-swell wave energy and modifying the pattern of the nearshore flows (magnitude and direction). Wave breaking on the reef platforms drove strong onshore directed mean currents over the reefs, resulting in off-shore flow through channels between the reefs and headlands where water exchanges from the lagoon to ocean. Our results demonstrate that the SWASH model is able to produce realistic predictions of the hydrodynamic processes within bathymetrically-complex nearshore systems. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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17 pages, 3427 KiB  
Article
Long-Term Observations of Beach Variability at Hasaki, Japan
by Masayuki Banno, Satoshi Nakamura, Taichi Kosako, Yasuyuki Nakagawa, Shin-ichi Yanagishima and Yoshiaki Kuriyama
J. Mar. Sci. Eng. 2020, 8(11), 871; https://doi.org/10.3390/jmse8110871 - 02 Nov 2020
Cited by 15 | Viewed by 3066
Abstract
Long-term beach observation data for several decades are essential to validate beach morphodynamic models that are used to predict coastal responses to sea-level rise and wave climate changes. At the Hasaki coast, Japan, the beach profile has been measured for 34 years at [...] Read more.
Long-term beach observation data for several decades are essential to validate beach morphodynamic models that are used to predict coastal responses to sea-level rise and wave climate changes. At the Hasaki coast, Japan, the beach profile has been measured for 34 years at a daily to weekly time interval. This beach morphological dataset is one of the longest and most high-frequency measurements of the beach morphological change worldwide. The profile data, with more than 6800 records, reflect short- to long-term beach morphological change, showing coastal dune development, foreshore morphological change and longshore bar movement. We investigated the temporal beach variability from the decadal and monthly variations in elevation. Extremely high waves and tidal anomalies from an extratropical cyclone caused a significant change in the long-term bar behavior and foreshore slope. The berm and bar variability were also affected by seasonal wave and water level variations. The variabilities identified here from the long-term observations contribute to our understanding of various coastal phenomena. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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23 pages, 11614 KiB  
Article
Cross-Shore Intertidal Bar Behavior along the Dutch Coast: Laser Measurements and Conceptual Model
by Sander Vos, Lennard Spaans, Ad Reniers, Rob Holman, Robert Mccall and Sierd de Vries
J. Mar. Sci. Eng. 2020, 8(11), 864; https://doi.org/10.3390/jmse8110864 - 31 Oct 2020
Cited by 5 | Viewed by 2752
Abstract
Intertidal bars are naturally occurring morphological features along the waterline of sandy beaches. Present quantitative knowledge on intertidal bar behavior is limited, due to the scarcity of data resources and the limitations of traditional survey techniques. To investigate and quantify the cross-shore morphologic [...] Read more.
Intertidal bars are naturally occurring morphological features along the waterline of sandy beaches. Present quantitative knowledge on intertidal bar behavior is limited, due to the scarcity of data resources and the limitations of traditional survey techniques. To investigate and quantify the cross-shore morphologic behavior of intertidal bars, hourly terrestrial laser scans of Kijkduin beach (The Netherlands) are used and a conceptual evolution intertidal bar model is constructed. In a six-week period in January and February 2017, a pronounced intertidal bar formed at Kijkduin beach and migrated onshore during mild wave conditions and eroded again during storm conditions. The observed maximum shoreward migration was 30 m horizontally with a maximum growth of about 1 m in the vertical direction. Onshore sediment transport fluxes peaked around 2 m3 per m width per day. In the conceptual model proposed here, run-up and overwash processes are dominant for shoreward growth and migration of the bar and submersion processes are responsible for bar destruction. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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23 pages, 4647 KiB  
Article
Measurements and Analysis of Primary Ship Waves in the Stockholm Archipelago, Sweden
by Björn Almström and Magnus Larson
J. Mar. Sci. Eng. 2020, 8(10), 743; https://doi.org/10.3390/jmse8100743 - 25 Sep 2020
Cited by 14 | Viewed by 2349
Abstract
Primary ship waves generated by conventional marine vessels were investigated in the Furusund fairway located in the Stockholm archipelago, Sweden. Continuous water level measurements at two locations in the fairway were analyzed. In total, 466 such events were extracted during two months of [...] Read more.
Primary ship waves generated by conventional marine vessels were investigated in the Furusund fairway located in the Stockholm archipelago, Sweden. Continuous water level measurements at two locations in the fairway were analyzed. In total, 466 such events were extracted during two months of measurements. The collected data were used to evaluate 13 existing predictive equations for drawdown height or squat. However, none of the equations were able to satisfactorily predict the drawdown height. Instead, a new equation for drawdown height and period was derived based on simplified descriptions of the main physical processes together with field measurements, employing multiple regression analysis to derive coefficients in the equation. The proposed equation for drawdown height performed better than the existing equations with an R2 value of 0.65, whereas the equation for the drawdown period was R2 = 0.64. The main conclusion from this study is that an empirical equation can satisfactorily predict primary ship waves for a large data set. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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20 pages, 4938 KiB  
Article
Numerical Simulation of Volume Change of the Backshore Induced by Cross-Shore Aeolian Sediment Transport
by Masato Yokobori, Yoshiaki Kuriyama, Takenori Shimozono and Yoshimitsu Tajima
J. Mar. Sci. Eng. 2020, 8(6), 438; https://doi.org/10.3390/jmse8060438 - 15 Jun 2020
Cited by 4 | Viewed by 2012
Abstract
Predicting the morphological changes of the backshore is vital for appropriate beach management because the backshore plays a significant role in the ecosystem and disaster prevention. In this study, a one-dimensional model was developed and applied to the Hasaki Coast in Japan to [...] Read more.
Predicting the morphological changes of the backshore is vital for appropriate beach management because the backshore plays a significant role in the ecosystem and disaster prevention. In this study, a one-dimensional model was developed and applied to the Hasaki Coast in Japan to predict changes in backshore volume. The volume change was estimated from the difference between the aeolian sediment transport rates at the seaward and landward boundaries of the investigation area, considering the wind velocity and direction, sediment size, precipitation, and vegetation in the process. The model was calibrated and validated using the first and second halves of beach profile data obtained weekly at the Hasaki Coast over a 28-year period from 1987 to 2014. The validation suggests that the model can reasonably reproduce the cumulative volume change, which is the amount of volume change from the initial value, but it underestimates the time-varying fluctuations of the weekly averaged volume-change rate. This can be attributed to the presence of small-scale features, such as dense vegetation and wrack, which are not taken into account in the model. Although the model performance for the cumulative volume change was good, it overpredicted the values in the second half of the validation process. This can be attributed to the fact that the model is not able to predict reductions in the aeolian sediment transport rate caused by an increase in beach steepness. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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18 pages, 3900 KiB  
Article
Long-Wave Penetration through a Laterally Periodic Continental Shelf
by Jeffrey Knowles and Harry Yeh
J. Mar. Sci. Eng. 2020, 8(4), 241; https://doi.org/10.3390/jmse8040241 - 01 Apr 2020
Viewed by 1515
Abstract
The transformation of long waves—such as tsunamis and storm surges—evolving over a continental shelf is investigated. We approach this problem numerically using a pseudo-spectral method for a higher-order Euler formulation. Solitary waves and undular bores are considered as models for the long waves. [...] Read more.
The transformation of long waves—such as tsunamis and storm surges—evolving over a continental shelf is investigated. We approach this problem numerically using a pseudo-spectral method for a higher-order Euler formulation. Solitary waves and undular bores are considered as models for the long waves. The bathymetry possesses a periodic ridge-valley configuration in the alongshore direction which facilitates a means by which we may observe the effects of refraction, diffraction, focusing, and shoaling. In this scenario, the effects of wave focusing and shoaling enhance the wave amplitude and phase speed in the shallower regions of the domain. The combination of these effects leads to a wave pattern that is atypical of the usual behavior seen in linear shallow-water theory. A reciprocating behavior in the amplitude on the ridge and valley for the wave propagation causes wave radiation behind the leading waves, hence, the amplitude approaches a smaller asymptotic value than the equivalent case with no lateral variation. For an undular bore propagating in one dimension over a smooth step, we find that the water surface resolves into five different mean water levels. The physical mechanisms for this phenomenon are provided. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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22 pages, 11556 KiB  
Article
Using Video Monitoring to Test a Fetch-Based Aeolian Sand Transport Model
by Pam Hage, Gerben Ruessink, Zilla van Aartrijk and Jasper Donker
J. Mar. Sci. Eng. 2020, 8(2), 110; https://doi.org/10.3390/jmse8020110 - 12 Feb 2020
Cited by 9 | Viewed by 2320
Abstract
Transport of beach sand to the foredune by wind is essential for dunes to grow. The aeolian sand transport rate is related to wind velocity, but wind-based models often overpredict this transport for narrow beaches (<100 m). To better predict aeolian sand transport, [...] Read more.
Transport of beach sand to the foredune by wind is essential for dunes to grow. The aeolian sand transport rate is related to wind velocity, but wind-based models often overpredict this transport for narrow beaches (<100 m). To better predict aeolian sand transport, the fetch-based Aeolus model was developed. Here, we qualitatively test this model by comparing its transport-rate output to visual signs of aeolian transport on video imagery collected at Egmond aan Zee, the Netherlands, during a six-month winter period. The Aeolus model and the Argus images often agree on the timing of aeolian transport days, except when transport is small; that is not always visible on the Argus images. Consistent with the imagery (minimal signs of aeolian activity in strong winds), the Aeolus model sometimes predicts the actual transport to be smaller than the potential transport. This difference is largest when wind velocity is large, and its direction is cross-shore. Although transport limitations are not predicted to be common, the results suggest that their effect on the total transport in the study period was substantial. This indicates that the fetch distance should be taken into account when calculating aeolian transport for narrow beaches on longer timescales (>weeks). Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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19 pages, 9884 KiB  
Article
Circulation in the Gulf of Khambhat—A Lagrangian Perspective
by Aditi Mitra, V. Sanil Kumar and V. Simhadri Naidu
J. Mar. Sci. Eng. 2020, 8(1), 25; https://doi.org/10.3390/jmse8010025 - 06 Jan 2020
Cited by 7 | Viewed by 4054
Abstract
The circulation of the Gulf of Khambhat (GoK) is studied from a Lagrangian point of view using a 2D numerical model. The model-predicted tide elevation and current speed are in agreement with the observations. Seasonal variations of advection of particles are simulated by [...] Read more.
The circulation of the Gulf of Khambhat (GoK) is studied from a Lagrangian point of view using a 2D numerical model. The model-predicted tide elevation and current speed are in agreement with the observations. Seasonal variations of advection of particles are simulated by releasing 237 particles homogeneously distributed over the Gulf. After one month of simulation, no particles escaped from the GoK except a few from the southern GoK during southwest monsoon (June–September), and the advection of particles was at its maximum in the northern part. Residual eddies are present inside the GoK during the northeast (October–January) and southwest monsoon seasons. Gulf circulation is studied with the combined forcing of tide and wind for different tidal conditions, which had noticeable seasonal difference. The maximum simulated current speeds of 3.4 and 2.8 m/s are noticed during southwest monsoon near to Bhavnagar and Dahej respectively, where the tide elevations are maximum indicating that GoK is a tide-dominated system. A seasonal barrier could be found in the southern Gulf, which not only makes the Gulf circulation distinct from that of the Arabian Sea (AS), but also restricts water-mass exchange between the Gulf and AS during ebb condition. As the Gulf is a dump yard for anthropogenic wastes, the present study puts forward an effort to determine the fate of the waste from a hydrodynamic point of view. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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21 pages, 20287 KiB  
Article
Nearshore Dynamics of Storm Surges and Waves Induced by the 2018 Typhoons Jebi and Trami Based on the Analysis of Video Footage Recorded on the Coasts of Wakayama, Japan
by Yusuke Yamanaka, Yoshinao Matsuba, Yoshimitsu Tajima, Ryotaro Shibata, Naohiro Hattori, Lianhui Wu and Naoko Okami
J. Mar. Sci. Eng. 2019, 7(11), 413; https://doi.org/10.3390/jmse7110413 - 13 Nov 2019
Cited by 8 | Viewed by 3538
Abstract
In this study, field surveys along the coasts of Wakayama Prefecture, Japan, were first conducted to investigate the coastal damage due to storm surges and storm-induced waves caused by the 2018 Typhoons Jebi and Trami. Special focus was placed on the characteristic behavior [...] Read more.
In this study, field surveys along the coasts of Wakayama Prefecture, Japan, were first conducted to investigate the coastal damage due to storm surges and storm-induced waves caused by the 2018 Typhoons Jebi and Trami. Special focus was placed on the characteristic behavior of nearshore waves through investigation of observed data, numerical simulations, and image analysis of video footage recorded on the coasts. The survey results indicated that inundation, wave overtopping, and drift debris caused by violent storm-induced waves were the dominant factors causing coastal damage. Results of numerical simulations showed that heights of storm-induced waves were predominantly greater than storm surge heights along the entire coast of Wakayama in both typhoons. However, computed gradual alongshore variations in wave and surge heights did not explain locally-concentrated inundation and run-up heights observed along the coasts. These results indicate that complex nearshore hydrodynamics induced by local nearshore bathymetry might have played a significant role in inducing such local wave characteristics and the associated coastal damage. Analysis of video footage recorded during Typhoon Jebi, for example, clearly showed evidence of amplified infragravity wave components, which could enhance inundation and wave run-up. Full article
(This article belongs to the Special Issue Observation, Analysis, and Modeling of Nearshore Dynamics)
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