scholarly journals UNDULATED BOTTOM PROFILES AND ONSHORE-OFFSHORE TRANSPORT

1978 ◽  
Vol 1 (16) ◽  
pp. 86
Author(s):  
Madhav Manhohar
Keyword(s):  
Nile Delta ◽  
Break Point ◽  
Wave Climate ◽  
Coastal Processes ◽  
Wave Characteristics ◽  
Longshore Transport ◽  
Transport Direction ◽  
Characteristic Features ◽  
Offshore Transport ◽  
Hydrodynamic Reaction

Underwater bars, the characteristic features of oceans and lakes occur singly or in a series along the coast. Nearest bar to the shore, namely the break-point bar moves shoreward in summer, joins the coast and is replaced by another bar in its original place. The other seaward bars are storm bars, more or less permanent though they may shift slightly in orientation, position and shape depending upon the wave climate and state of the coastal processes. With the sediment and bottom profiles changing constantly with differing wave characteristics and beach exposure, a rigorous mathematical analysis for long range variability of profiles and therefore coastal processes in not possible. Therefore, the concept of medium depth and steepness characteristics is introduced to distinguish the profiles and their major dimensions. Onshore-offshore sediment motion is sometimes far in excess of longshore transport mostly confined in the breaker zone. When submarine bars are present, such motion is considerable mainly as a result of the hydrodynamic reaction between the rotating eddies generated over the bars and the bar surface. By means of dimensional analysis, it is possible to relate the quantity of onshore-offshore motion to the bar dimensions, wave period, water depth and transport direction by profile steepness characteristics. The above two concepts are then applied to the Nile Delta coastal processes with satisfactory results.

scholarly journals Multimodel Ensemble Projections of Wave Climate in the Western North Pacific Using CMIP6 Marine Surface Winds

2021 ◽  
Vol 9 (8) ◽  
pp. 835
Author(s):  
Mochamad Riam Badriana ◽  
Han Soo Lee
Keyword(s):  
North Pacific ◽  
General Circulation ◽  
Western North Pacific ◽  
Wave Climate ◽  
Coastal Development ◽  
Climate Projections ◽  
Surface Winds ◽  
Time Step ◽  
Wave Characteristics ◽  
Marine Surface

For decades, the western North Pacific (WNP) has been commonly indicated as a region with high vulnerability to oceanic and atmospheric hazards. This phenomenon can be observed through general circulation model (GCM) output from the Coupled Model Intercomparison Project (CMIP). The CMIP consists of a collection of ensemble data as well as marine surface winds for the projection of the wave climate. Wave climate projections based on the CMIP dataset are necessary for ocean studies, marine forecasts, and coastal development over the WNP region. Numerous studies with earlier phases of CMIP are abundant, but studies using CMIP6 as the recent dataset for wave projection is still limited. Thus, in this study, wave climate projections with WAVEWATCH III are conducted to investigate how wave characteristics in the WNP will have changed in 2050 and 2100 compared to those in 2000 with atmospheric forcings from CMIP6 marine surface winds. The wave model runs with a 0.5° × 0.5° spatial resolution in spherical coordinates and a 10-min time step. A total of eight GCMs from the CMIP6 dataset are used for the marine surface winds modelled over 3 hours for 2050 and 2100. The simulated average wave characteristics for 2000 are validated with the ERA5 Reanalysis wave data showing good consistency. The wave characteristics in 2050 and 2100 show that significant decreases in wave height, a clockwise shift in wave direction, and the mean wave period becomes shorter relative to those in 2000.

Projected changes in wind wave directional spectra and their impact on coastal processes

2021 ◽  
Author(s):  
Hector Lobeto ◽  
Melisa Menendez ◽  
Iñigo J. Losada ◽  
Ottavio Mazzaretto
Keyword(s):  
Wave Energy ◽  
Wind Wave ◽  
Wave Climate ◽  
Wave Period ◽  
Standard Approach ◽  
Coastal Processes ◽  
Full Spectrum ◽  
Wave Parameters ◽  
Future Behavior ◽  
Projected Changes

<p>The assessment of the projected changes in wave climate due to climate change has been subject of study during the last two decades (Morim et al., 2018), largely due to the severe impacts these changes may have on coastal processes such as flooding and erosion. The wind wave climate is fully described by the sea surface elevation spectrum, which represents the distribution of energy resulting from the contributions of several superimposed waves with different periods and directions. Nevertheless, to this day the standard approach to address the future behavior of wind waves is based on the use of integrated wave parameters (e.g. significant wave height, mean wave period, mean wave direction) as a representation of the full spectrum. In this study, we analyze the changes in wave energy from directional spectra discretized in 24 directions and 32 frequencies in a number of locations distributed across all ocean basins, shedding light on the added value that an assessment based on the full spectrum offers with respect to the standard approach. In addition, the ESTELA method (Pérez et al., 2014) is applied to ease the understanding of the changes obtained in wave energy at the locations of study.</p><p>The spectral approach helps to assess the projected change in the energy of each wave system that reach a specific location. Results demonstrate that the use of integrated wave parameters can mask important information about the sign, magnitude and uncertainty of the actual projected changes in mean wave climate due to the offset of the expected variations in the different wave systems that integrate the spectrum. It is especially relevant at locations where an increase in the wave period or wave energy is hidden by the application of the standard approach, as these parameters are proven to play a key role in coastal processes. In addition, we reach relevant conclusions about the future behavior of swell systems. For instance, a robust increase in the energy carried by swells generated below 40°S can be observed in every ocean basin and both hemispheres, even beyond 30°N. Similarly, a decrease in the energy carried by northern swells can be observed close to the equator.</p>

scholarly journals A SCHEMATIZATION OF ONSHORE-OFFSHORE TRANSPORT

1974 ◽  
Vol 1 (14) ◽  
pp. 51 ◽  
Author(s):  
D.H. Swart
Keyword(s):  
Sediment Transport ◽  
Sandy Beaches ◽  
Full Scale ◽  
Scale Model ◽  
Small Scale ◽  
Coastal Processes ◽  
Schematic Model ◽  
Empirical Relationships ◽  
Physically Based ◽  
Offshore Transport

The investigation reported herein covers two aspects of the schematization of coastal processes on sandy beaches in a direction perpendicular to the coastline, viz.: (1) the prediction of equilibrium beach profiles and (2) the corresponding offshore sediment transport due to wave action. A physically-based schematic model of the onshore-offshore profile development was tested on available small-scale and full-scale model tests and physically-based empirical relationships were derived to enable the application of the model to both small-scale and prototype conditions.

scholarly journals Complete Proceedings - Single PDF Download

1988 ◽  
Vol 1 (21) ◽  
Author(s):  
Billy L. Edge
Keyword(s):  
Civil Engineer ◽  
Case Studies ◽  
Wind Waves ◽  
Coastal Engineering ◽  
Coastal Processes ◽  
Ship Motions ◽  
Coastal Structures ◽  
Wave Characteristics ◽  
The Individual ◽  
Engineering Projects

This book contains over 220 papers presented at the 21st International Conference on Coastal Engineering. The book is divided into six parts: theoretical and observed wave characteristics; coastal processes and sediment transport; coastal structures and related problems; coastal, estuarine and environmental problems; case studies; and ship motions. The individual papers include such topics as the effects of wind, waves, storms and currents, erosion, sedimentation, and beach nourishment. Special emphasis is given to case studies of completed engineering projects. With the inclusion of both the theoretical and the practical, these papers provide the civil engineer with a broad range of information on coastal engineering.

scholarly journals Wave refraction and longshore transport patterns along the southern Santa Catarina coast

2007 ◽  
Vol 55 (2) ◽  
pp. 109-120 ◽  
Author(s):  
Eduardo Siegle ◽  
Nils Edvin Asp
Keyword(s):  
Wave Climate ◽  
Transport Processes ◽  
Brazilian Coast ◽  
Santa Catarina ◽  
Wave Refraction ◽  
The North ◽  
Longshore Transport ◽  
Longshore Drift ◽  
Northern Portion ◽  
Transport Patterns

Based on the wave climate for the southern Brazilian coast, wave refraction has been modelled in order to obtain the refracted wave heights and directions along the southern Santa Catarina coast, providing the needed information for potential longshore drift estimates. According to its coastline orientation, different sectors of the coast present varying longshore drift patterns. Estimates have been made for the yearly-averaged wave climate as well as for each season, showing thereby the longshore drift patterns along the year. Based on the results of the potential longshore drift intensities and directions and on the shoreline outline in plan, it has been possible to identify a strongly drift-dominated coast in the south turning to a mixed drift and swash dominated coast towards the north of the studied area. Contrasting patterns of longshore drift between the southern and northern portion of the coastline indicate a sediment surplus in the central portion, making sediment available for cross-shore transport processes, either on- or offshore. Considering long-term aspects, the longshore drift patterns are in agreement with the coastal infilling process which has mainly been driven by persistent surplus from littoral sediment drift.

scholarly journals DESCRIPTION OF BEACH CHANGES USING AN EMPIRICAL PREDICTIVE MODEL OF BEACH PROFILE CHANGES

1982 ◽  
Vol 1 (18) ◽  
pp. 86 ◽  
Author(s):  
Takaaki Uda ◽  
Hiroshi Hashimoto
Keyword(s):  
Predictive Model ◽  
Sand Transport ◽  
Coastal Structures ◽  
Beach Profile ◽  
Profile Data ◽  
Longshore Transport ◽  
Profile Changes ◽  
Offshore Transport ◽  
Eigenfunction Method ◽  
Profile Change

In order to analyze beach profile changes due to longshore and onshore-offshore sand transport, here is proposed a new model named the "empirical predictive model of beach profile change", which is an application of the empirical eigenfunction method. The analysis of the profile data obtained at the Misawa fishery port in Ogawarako Coast over five years from 1973 to 1977 indicates that profile changes due to longshore transport and to onshore-offshore transport can be separated. The model is shown to be effective in the analysis of profile changes near coastal structures.

scholarly journals LONGSHORE TRANSPORT DETERMINED BY AN EFFICIENT TRAP

1982 ◽  
Vol 1 (18) ◽  
pp. 60 ◽  
Author(s):  
R.G. Dean ◽  
E.P. Berek ◽  
C.G. Gable ◽  
R.J. Seymour
Keyword(s):  
Sediment Transport ◽  
Field Component ◽  
Santa Barbara ◽  
Wave Characteristics ◽  
Nearshore Sediment Transport ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Correlation Constant ◽  
The Relationship ◽  
Best Fit

The Nearshore Sediment Transport Study (NSTS), sponsored by the National Sea Grant Office included a field component to quantify the total longshore sediment transport relationship. This component was conducted at Santa Barbara, California and encompassed a period of eighteen months during which ten surveys were conducted. To date, eight of these surveys have been analyzed, yielding seven intersurvey periods. A total of 288,600 m3 of net sediment transport was documented by these eight surveys. The wave characteristics are based on one of two Sxy gages located in a water depth of 7 m. The most widely used correlation constant, K, in the relationship I = KP, is 0.77. The values found from the data were 0.93 and 1.23 for linear and log best-fit values, respectively. The corresponding values of K4 relating I and S are 2.60 and 2.63 m/s, respectively.

scholarly journals Complete Proceedings - Single PDF Download

1986 ◽  
Vol 1 (20) ◽  
Author(s):  
Billy L. Edge
Keyword(s):  
Sediment Transport ◽  
Case Reports ◽  
Field Studies ◽  
Coastal Engineering ◽  
Coastal Processes ◽  
Ship Motions ◽  
Theoretical Studies ◽  
Coastal Structures ◽  
Wave Characteristics ◽  
Wind Storms

This book contains over 200 papers presented at the 20th International Conference on Coastal Engineering. The book is divided into five parts: theoretical and observed wave characteristics; coastal processes and sediment transport; coastal structures and related problems; coastal, estuarine and environmental problems; and ship motions. Reports include the effects of wind, storms, and currents. Erosion, sedimentation and beach nourishment are covered. The papers approach these topics with theoretical studies, case reports, models, and field studies.

Wave Climate and Large-Scale Coastal Processes in Terms of Boundary Conditions

2000 ◽  
Vol 42 (1) ◽  
pp. 31-56 ◽  
Author(s):  
Zbigniew Pruszak ◽  
Rafal Ostrowski ◽  
Marek Skaja ◽  
Marek Szmytkiewicz
Keyword(s):  
Boundary Conditions ◽  
Large Scale ◽  
Wave Climate ◽  
Coastal Processes
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