The "shallow-waterness" of the wave climate in European coastal regions

Science.gov (United States)

Håkon Christensen, Kai; Carrasco, Ana; Bidlot, Jean-Raymond; Breivik, Øyvind

2017-07-01

In contrast to deep water waves, shallow water waves are influenced by bottom topography, which has consequences for the propagation of wave energy as well as for the energy and momentum exchange between the waves and the mean flow. The ERA-Interim reanalysis is used to assess the fraction of wave energy associated with shallow water waves in coastal regions in Europe. We show maps of the distribution of this fraction as well as time series statistics from eight selected stations. There is a strong seasonal dependence and high values are typically associated with winter storms, indicating that shallow water wave effects can occasionally be important even in the deeper parts of the shelf seas otherwise dominated by deep water waves.

Coastal vulnerability across the Pacific dominated by El Niño-Southern Oscillation

Science.gov (United States)

Barnard, Patrick L.; Short, Andrew D.; Harley, Mitchell D.; Splinter, Kristen D.; Vitousek, Sean; Turner, Ian L.; Allan, Jonathan; Banno, Masayuki; Bryan, Karin R.; Doria, André; Hansen, Jeff E.; Kato, Shigeru; Kuriyama, Yoshiaki; Randall-Goodwin, Evan; Ruggiero, Peter; Walker, Ian J.; Heathfield, Derek K.

2015-01-01

To predict future coastal hazards, it is important to quantify any links between climate drivers and spatial patterns of coastal change. However, most studies of future coastal vulnerability do not account for the dynamic components of coastal water levels during storms, notably wave-driven processes, storm surges and seasonal water level anomalies, although these components can add metres to water levels during extreme events. Here we synthesize multi-decadal, co-located data assimilated between 1979 and 2012 that describe wave climate, local water levels and coastal change for 48 beaches throughout the Pacific Ocean basin. We find that observed coastal erosion across the Pacific varies most closely with El Niño/Southern Oscillation, with a smaller influence from the Southern Annular Mode and the Pacific North American pattern. In the northern and southern Pacific Ocean, regional wave and water level anomalies are significantly correlated to a suite of climate indices, particularly during boreal winter; conditions in the northeast Pacific Ocean are often opposite to those in the western and southern Pacific. We conclude that, if projections for an increasing frequency of extreme El Niño and La Niña events over the twenty-first century are confirmed, then populated regions on opposite sides of the Pacific Ocean basin could be alternately exposed to extreme coastal erosion and flooding, independent of sea-level rise.

Towards high fidelity numerical wave tanks for modelling coastal and ocean engineering processes

Science.gov (United States)

Cozzuto, G.; Dimakopoulos, A.; de Lataillade, T.; Kees, C. E.

2017-12-01

With the increasing availability of computational resources, the engineering and research community is gradually moving towards using high fidelity Comutational Fluid Mechanics (CFD) models to perform numerical tests for improving the understanding of physical processes pertaining to wave propapagation and interaction with the coastal environment and morphology, either physical or man-made. It is therefore important to be able to reproduce in these models the conditions that drive these processes. So far, in CFD models the norm is to use regular (linear or nonlinear) waves for performing numerical tests, however, only random waves exist in nature. In this work, we will initially present the verification and validation of numerical wave tanks based on Proteus, an open-soruce computational toolkit based on finite element analysis, with respect to the generation, propagation and absorption of random sea states comprising of long non-repeating wave sequences. Statistical and spectral processing of results demonstrate that the methodologies employed (including relaxation zone methods and moving wave paddles) are capable of producing results of similar quality to the wave tanks used in laboratories (Figure 1). Subsequently cases studies of modelling complex process relevant to coastal defences and floating structures such as sliding and overturning of composite breakwaters, heave and roll response of floating caissons are presented. Figure 1: Wave spectra in the numerical wave tank (coloured symbols), compared against the JONSWAP distribution

The “shallow-waterness” of the wave climate in European coastal regions

Directory of Open Access Journals (Sweden)

K. H. Christensen

2017-07-01

Full Text Available In contrast to deep water waves, shallow water waves are influenced by bottom topography, which has consequences for the propagation of wave energy as well as for the energy and momentum exchange between the waves and the mean flow. The ERA-Interim reanalysis is used to assess the fraction of wave energy associated with shallow water waves in coastal regions in Europe. We show maps of the distribution of this fraction as well as time series statistics from eight selected stations. There is a strong seasonal dependence and high values are typically associated with winter storms, indicating that shallow water wave effects can occasionally be important even in the deeper parts of the shelf seas otherwise dominated by deep water waves.

On the use of wave parameterizations and a storm impact scaling model in National Weather Service Coastal Flood and decision support operations

Science.gov (United States)

Mignone, Anthony; Stockdon, H.; Willis, M.; Cannon, J.W.; Thompson, R.

2012-01-01

National Weather Service (NWS) Weather Forecast Offices (WFO) are responsible for issuing coastal flood watches, warnings, advisories, and local statements to alert decision makers and the general public when rising water levels may lead to coastal impacts such as inundation, erosion, and wave battery. Both extratropical and tropical cyclones can generate the prerequisite rise in water level to set the stage for a coastal impact event. Forecasters use a variety of tools including computer model guidance and local studies to help predict the potential severity of coastal flooding. However, a key missing component has been the incorporation of the effects of waves in the prediction of total water level and the associated coastal impacts. Several recent studies have demonstrated the importance of incorporating wave action into the NWS coastal flood program. To follow up on these studies, this paper looks at the potential of applying recently developed empirical parameterizations of wave setup, swash, and runup to the NWS forecast process. Additionally, the wave parameterizations are incorporated into a storm impact scaling model that compares extreme water levels to beach elevation data to determine the mode of coastal change at predetermined “hotspots” of interest. Specifically, the storm impact model compares the approximate storm-induced still water level, which includes contributions from tides, storm surge, and wave setup, to dune crest elevation to determine inundation potential. The model also compares the combined effects of tides, storm surge, and the 2 % exceedance level for vertical wave runup (including both wave setup and swash) to dune toe and crest elevations to determine if erosion and/or ocean overwash may occur. The wave parameterizations and storm impact model are applied to two cases in 2009 that led to significant coastal impacts and unique forecast challenges in North Carolina: the extratropical “Nor'Ida” event during 11-14 November and

NODC Standard Format NOS Coastal Wave Program (F182) Data (1979-1983) (NODC Accession 0014203)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data type was designed for analyzed wave data originating from the National Ocean Service (NOS) Coastal Wave Program. The data are organized into 3 record...

Implications of Sea Level Rise on Coastal Flood Hazards

Science.gov (United States)

Roeber, V.; Li, N.; Cheung, K.; Lane, P.; Evans, R. L.; Donnelly, J. P.; Ashton, A. D.

2012-12-01

Recent global and local projections suggest the sea level will be on the order of 1 m or higher than the current level by the end of the century. Coastal communities and ecosystems in low-lying areas are vulnerable to impacts resulting from hurricane or large swell events in combination with sea-level rise. This study presents the implementation and results of an integrated numerical modeling package to delineate coastal inundation due to storm landfalls at future sea levels. The modeling package utilizes a suite of numerical models to capture both large-scale phenomena in the open ocean and small-scale processes in coastal areas. It contains four components to simulate (1) meteorological conditions, (2) astronomical tides and surge, (3) wave generation, propagation, and nearshore transformation, and (4) surf-zone processes and inundation onto dry land associated with a storm event. Important aspects of this package are the two-way coupling of a spectral wave model and a storm surge model as well as a detailed representation of surf and swash zone dynamics by a higher-order Boussinesq-type wave model. The package was validated with field data from Hurricane Ivan of 2005 on the US Gulf coast and applied to tropical and extratropical storm scenarios respectively at Eglin, Florida and Camp Lejeune, North Carolina. The results show a nonlinear increase of storm surge level and nearshore wave energy with a rising sea level. The exacerbated flood hazard can have major consequences for coastal communities with respect to erosion and damage to infrastructure.

The challenges of coastal oceanography. Prediction limits and new applications based on Sentinel data

Science.gov (United States)

Sánchez-Arcilla, Agustín; Carniel, Sandro; Badger, Merete; Bidlot, Jean; Boye Hansen, Lars; Bolaños-Sanchez, Rodolfo; Cipollini, Paolo; Espino, Manuel; Marcello Miglietta, Mario; Saulter, Andy; Staneva, Joanna

2017-04-01

The increasing quality and quantity (resolution in space, coverage in time, combinations of sensors in the Sentinel family) of information provided by Copernicus offer the possibility to analyse and predict coastal meteo-oceanography at an unprecedented level. This is a unique opportunity to develop the Copernicus coastal dimension to tackle the pressures of increasing population and activities. The combination of ocean/atmosphere/land observations from the Sentinel (S) 1/2/3, aligned with the availability of an increasing number of high-resolution numerical simulations (e.g. wave and current fields) in the Copernicus Marine Environment Monitoring Service (CMEMS) catalogue, should allow users to access proven representations of the coastal environment at a new level of understanding (e.g. wave diffraction at coastal "obstacles"), coupling (e.g. incorporating the land discharge into the coastal sea) and reliability for applications (e.g. hazards for coastal navigation). By adding periodic bathymetric up-dating and incorporating new assimilation routines it will be possible to achieve a new level of analysis for coastal seas. In the paper we shall present the CEASELESS project that addresses the multiple scales coexisting in littoral areas by developing new shallow water parameterizations, introducing them into coupled model suites (wind-wave-surge-current-land discharge) and producing new standards for coastal simulations and analyses. This will demonstrate the technical feasibility of an operational coastal service. The set of derived products will be ingested into the users' work routines, proving the economic feasibility of such a coastal extension. The level of conflicts in squeezed coastal zones, expected to grow in the face of climate change, will, thus, benefit directly from CEASELESS, establishing tangible contributions for a wide range of economic sectors. The mutual validation of satellite data, numerical results and in-situ observations will generate

Input reduction for long-term morphodynamic simulations in wave-dominated coastal settings

NARCIS (Netherlands)

Walstra, D.J.R.; Hoekstra, R.; Tonnon, P.K.; Ruessink, B.G.

2013-01-01

Input reduction is imperative to long-term (> years) morphodynamic simulations to avoid excessive computation times. Here, we introduce an input-reduction framework for wave-dominated coastal settings. Our framework comprises 4 steps, viz. (1) the selection of the duration of the original (full)

Application of State of Art Modeling Techniques to Predict Flooding and Waves for an Exposed Coastal Area

Directory of Open Access Journals (Sweden)

Malcolm L. Spaulding

2017-02-01

Full Text Available Flood Insurance Rate Maps (FIRMs are developed by the Federal Emergency Management Agency (FEMA to provide guidance in establishing the risk to structures and infrastructure in the coastal zone from storm surge and coincidental waves. The maps are used by state agencies and municipalities to help guide coastal planning and establish the minimum elevation standard for new or substantially improved structures. A summary of the methods used and results of 2012 FIRM mapping are presented for Charlestown, RI; a coastal community located along the exposed, southern shoreline of the state. Concerns with the methods used in the 2012 analysis are put in context with the National Research Council’s (NRC 2009 review of the FEMA coastal mapping program. New mapping is then performed using state of the art, fully coupled surge and wave modeling and data analysis methods to address the concerns in the NRC review. The new maps and methodologies are in compliance with FEMA regulations and guidelines. The approach makes extensive use of the numerical modeling results from the recent US Army Corp of Engineers (USACE, North Atlantic Coast Comprehensive Study (NACCS 2015. Revised flood maps are presented and compared with the 2012 FIRM map to provide insight into the differences. The new maps highlight the importance of developing better estimates of offshore surge dynamics and its coupling to waves, dune erosion based on local observations, and the advancement in nearshore mapping of waves in flood inundated areas by the use of state of the art, two-dimensional wave transformation models.

Coastal flooding: impact of waves on storm surge during extremes – a case study for the German Bight

Directory of Open Access Journals (Sweden)

J. Staneva

2016-11-01

Full Text Available This study addresses the impact of wind, waves, tidal forcing and baroclinicity on the sea level of the German Bight during extreme storm events. The role of wave-induced processes, tides and baroclinicity is quantified, and the results are compared with in situ measurements and satellite data. A coupled high-resolution modelling system is used to simulate wind waves, the water level and the three-dimensional hydrodynamics. The models used are the wave model WAM and the circulation model GETM. The two-way coupling is performed via the OASIS3-MCT coupler. The effects of wind waves on sea level variability are studied, accounting for wave-dependent stress, wave-breaking parameterization and wave-induced effects on vertical mixing. The analyses of the coupled model results reveal a closer match with observations than for the stand-alone circulation model, especially during the extreme storm Xaver in December 2013. The predicted surge of the coupled model is significantly enhanced during extreme storm events when considering wave–current interaction processes. This wave-dependent approach yields a contribution of more than 30 % in some coastal areas during extreme storm events. The contribution of a fully three-dimensional model compared with a two-dimensional barotropic model showed up to 20 % differences in the water level of the coastal areas of the German Bight during Xaver. The improved skill resulting from the new developments justifies further use of the coupled-wave and three-dimensional circulation models in coastal flooding predictions.

Study of dispersive and nonlinear effects of coastal wave dynamics with a fully nonlinear potential flow model

Science.gov (United States)

Benoit, Michel; Yates, Marissa L.; Raoult, Cécile

2017-04-01

Efficient and accurate numerical models simulating wave propagation are required for a variety of engineering projects including the evaluation of coastal risks, the design of protective coastal structures, and the estimation of the potential for marine renewable energy devices. Nonlinear and dispersive effects are particularly significant in the coastal zone where waves interact with the bottom, the shoreline, and coastal structures. The main challenge in developing a numerical models is finding a compromise between computational efficiency and the required accuracy of the simulated wave field. Here, a potential approach is selected and the (fully nonlinear) water wave problem is formulated using the Euler-Zakharov equations (Zakharov, 1968) describing the temporal evolution of the free surface elevation and velocity potential. The proposed model (Yates and Benoit, 2015) uses a spectral approach in the vertical (i.e. the vertical variation of the potential is approximated by a linear combination of the first NT+1 Chebyshev polynomials, following the work of Tian and Sato (2008)). The Zakharov equations are integrated in time using a fourth-order Runge-Kutta scheme with a constant time step. At each sub-timestep, the Laplace Boundary Value Problem (BVP) is solved to estimate the free surface vertical velocity using the spectral approach, with typical values of NT between 5 to 8 for practical applications. The 1DH version of the code is validated with comparisons to the experimental data set of Becq-Girard et al. (1999), which studied the propagation of irregular waves over a beach profile with a submerged bar. The nonlinear and dispersive capacities of the model are verified with the correct representation of wave-wave interactions, in particular the transfer of energy between different harmonic components during wave propagation (analysis of the transformation of the variance spectrum along the channel). Evolution of wave skewness, asymmetry and kurtosis along the

An integrated wave modelling framework for extreme and rare events for climate change in coastal areas – the case of Rethymno, Crete

Directory of Open Access Journals (Sweden)

Vasiliki K. Tsoukala

2016-04-01

Full Text Available Coastal floods are regarded as among the most dangerous and harmful of all natural disasters affecting urban areas adjacent to the shorelines. Rapid urbanization combined with climate change and poor governance often results in significant increase of flood risk, especially for coastal communities. Wave overtopping and wave run-up are the key mechanisms for monitoring the results of coastal flooding and as such, significant efforts are currently focusing on their predicting. In this paper, an integrated methodology is proposed, accounting for wave overtopping and wave run-up under extreme wave scenarios caused by storm surges. By taking advantage of past and future climatic projections of wind data, a downscaling approach is proposed, utilizing a number of appropriate numerical models than can simulate the wave propagation from offshore up to the swash zone. The coastal zone of Rethymno in Greece is selected as a case study area and simulations of wave characteristics with the model SWAN for the period 1960–2100 in the offshore region are presented. These data are given as boundary conditions to further numerical models (MIKE21 PMS and HD in order to investigate the spatial evolution of the wave and the hydrodynamic field in intermediate and shallow waters. Finally, the calculated wave height serves as input to empirical formulas and time dependent wave propagation models (MIKE21 BW to estimate the wave run-up and wave overtopping (EurOtop. It is suggested that the proposed procedure is generic enough to be applicable to any similar region.

Analytical characterization of selective benthic flux components in estuarine and coastal waters

Science.gov (United States)

King, Jeffrey N.

2011-01-01

Benthic flux is the rate of flow across the bed of a water body, per unit area of bed. It is forced by component mechanisms, which interact. For example, pressure gradients across the bed, forced by tide, surface gravity waves, density gradients, bed–current interaction, turbulence, and terrestrial hydraulic gradients, drive an advective benthic flux of water and constituents between estuarine and coastal waters, and surficial aquifers. Other mechanisms also force benthic flux, such as chemical gradients, bioturbation, and dispersion. A suite of component mechanisms force a total benthic flux at any given location, where each member of the suite contributes a component benthic flux. Currently, the types and characteristics of component interactions are not fully understood. For example, components may interact linearly or nonlinearly, and the interaction may be constructive or destructive. Benthic flux is a surface water–groundwater interaction process. Its discharge component to a marine water body is referred to, in some literature, as submarine groundwater discharge. Benthic flux is important in characterizing water and constituent budgets of estuarine and coastal systems. Analytical models to characterize selective benthic flux components are reviewed. Specifically, these mechanisms are for the component associated with the groundwater tidal prism, and forced by surface gravity wave setup, surface gravity waves on a plane bed, and the terrestrial hydraulic gradient. Analytical models are applied to the Indian River Lagoon, Florida; Great South Bay, New York; and the South Atlantic Bight in South Carolina and portions of North Carolina.

A New International Standard for "Actions from Waves and Currents on Coastal Structures"

DEFF Research Database (Denmark)

Tørum, Alf; Burcharth, Hans F.; Goda, Yoshimi

2007-01-01

The International Organization for Standardization (ISO) is going to issue a new standard concerning "Actions from Waves and Currents on Coastal Structures," which becomes the first international standard in coastal engineering. It is composed of a normative part (29 pages), an informative part (80...... pages) and Bibliography ( 17 pages). The normative part describes what is considered as the norm of the matters in concern, while the informative part provides the information on recommended practice. The paper introduces the main points of the normative part and discusses the influence of the new...

Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

Science.gov (United States)

Goslin, Jérôme; Clemmensen, Lars B.

2017-10-01

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

Does vegetation prevent wave erosion of salt marsh edges?

Science.gov (United States)

Feagin, R A; Lozada-Bernard, S M; Ravens, T M; Möller, I; Yeager, K M; Baird, A H

2009-06-23

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves.

The Effect of Breaking Waves on CO_2 Air-Sea Fluxes in the Coastal Zone

Science.gov (United States)

Gutiérrez-Loza, Lucía; Ocampo-Torres, Francisco J.; García-Nava, Héctor

2018-03-01

The influence of wave-associated parameters controlling turbulent CO_2 fluxes through the air-sea interface is investigated in a coastal region. A full year of high-quality data of direct estimates of air-sea CO_2 fluxes based on eddy-covariance measurements is presented. The study area located in Todos Santos Bay, Baja California, Mexico, is a net sink of CO_2 with a mean flux of -1.3 μmol m^{-2}s^{-1} (-41.6 mol m^{-2}yr^{-1} ). The results of a quantile-regression analysis computed between the CO_2 flux and, (1) wind speed, (2) significant wave height, (3) wave steepness, and (4) water temperature, suggest that the significant wave height is the most correlated parameter with the magnitude of the flux but the behaviour of the relation varies along the probability distribution function, with the slopes of the regression lines presenting both positive and negative values. These results imply that the presence of surface waves in coastal areas is the key factor that promotes the increase of the flux from and into the ocean. Further analysis suggests that the local characteristics of the aqueous and atmospheric layers might determine the direction of the flux.

Coastal Engineering

NARCIS (Netherlands)

Van der Velden, E.T.J.M.

1989-01-01

Introduction, waves, sediment transport, littoral transport, lonshore sediment transport, onshore-offshore sediment transport, coastal changes, dune erosion and storm surges, sedimentation in channels and trenches, coastal engineering in practice.

Innovative wave energy device applied to coastal observatory systems

Science.gov (United States)

Marcelli, Marco; Bonamano, Simone; Piermattei, Viviana; Scanu, Sergio; Paladini de Mendoza, Francesco; Martellucci, Riccardo; Maximo, Peviani

2017-04-01

Marine environment is one of the most promising sources of renewable energy, whose exploitation could have an effect on several application fields. This work presents the design of an innovative device based on the Oscillating Water Column (OWC), that allows to convert wave energy into electricity, suitable for the typical Mediterranean wave climate. The flexibility of the device permits its installation either in deep or shallow waters, with reduced costs of deployment, maintenance and connection to the grid. Furthermore, the replicability of the design allows the device to be installed in array of several number of similar units. The technical concept is to convey the sea water within a vertical pipe, in which the water movements activate a rotor connected to a generator that transforms the energy of the water motion into electricity. The hydrodynamic design of the pipe is built to minimize the losses due to friction and turbulence and to exploit the maximum possible energy from wave motion. The wave energy is directly absorbed by the rotational movement of the turbine blades located in the water itself allowing a further reduction of the energy losses associated with the transformation of the linear water motion into electrical generation in the air phase (typical configuration of the OWC devices). In this work the device components are described considering two possible configurations that use a Wells turbine or a Bulb type turbine. The system can be realized at a low cost, because of the modularity of the device project, which allows large freedom of sizes and placements, being able to be installed both individually and in arrays. The modularity, associated with the fact that the main elements of the system are available on the market, makes the device particularly attractive from the economic point of view. Finally, it is realized with a high constructive flexibility: the proposed system can be transported floating and moored to existing coastal structures or

Application of State of the Art Modeling Techniques to Predict Flooding and Waves for a Coastal Area within a Protected Bay

Directory of Open Access Journals (Sweden)

Malcolm L. Spaulding

2017-03-01

Full Text Available Flood Insurance Rate Maps (FIRMs are developed by the Federal Emergency Management Agency (FEMA to provide guidance in establishing the risk to structures and infrastructure from storm surge sand associated waves in the coastal zone. The maps are used by state agencies and municipalities to help guide coastal planning and establish the minimum elevation and construction standards for new or substantially improved structures. A summary of the methods used and a comparison with the results of 2013 FIRM mapping are presented for Warwick, Rhode Island (RI, a coastal community located within Narragansett Bay. Because of its location, Warwick is protected from significant coastal erosion and wave attacks, but is subject to surge amplification. Concerns surrounding the FEMA methods used in the 2013 FIRM analysis are put in context with the National Research Council’s (NRC 2009 review of the FEMA coastal mapping program. New mapping is then performed using state of the art, fully coupled surge and wave modeling, and data analysis methods, to address the NRC concerns. The new maps and methodologies are in compliance with FEMA regulations and guidelines. This new approach makes extensive use of the numerical modeling results from the recent US Army Corp of Engineers, North Atlantic Coast Comprehensive Study (NACCS, 2015. Revised flooding maps are presented and compared to the 2013 FIRM maps, to provide insight into the differences. The new maps highlight the importance of developing better estimates of surge dynamics and the advancement in nearshore mapping of waves in flood inundated areas by the use of state of the art, two-dimensional, wave transformation models.

Implementation and test of a coastal forecasting system for wind waves in the Mediterranean Sea

Science.gov (United States)

Inghilesi, R.; Catini, F.; Orasi, A.; Corsini, S.

2010-09-01

A coastal forecasting system has been implemented in order to provide a coverage of the whole Mediterranean Sea and of several enclosed coastal areas as well. The problem is to achieve a good definition of the small scale coastal processes which affect the propagation of waves toward the shores while retaining the possibility of selecting any of the possible coastal areas in the whole Mediterranean Sea. The system is built on a very high resolution parallel implementation of the WAM and SWAN models, one-way chain-nested in key areas. The system will shortly be part of the ISPRA SIMM forecasting system which has been operative since 2001. The SIMM sistem makes available the high resolution wind fields (0.1/0.1 deg) used in the coastal system. The coastal system is being tested on several Italian coastal areas (Ligurian Sea, Lower Tyrrenian Sea, Sicily Channel, Lower Adriatic Sea) in order to optimise the numerics of the coastal processes and to verify the results in shallow waters and complex bathymetries. The results of the comparison between hindcast and buoy data in very shallow (14m depth) and deep sea (150m depth) will be shown for several episodes in the upper Tyrrenian Sea.

Potential Hydrodynamic Loads on Coastal Bridges in the Greater New York Area due to Extreme Storm Surge and Wave

Science.gov (United States)

2018-04-18

This project makes a computer modeling study on vulnerability of coastal bridges in New York City (NYC) metropolitan region to storm surges and waves. Prediction is made for potential surges and waves in the region and consequent hydrodynamic load an...

A numerical study of tsunami wave impact and run-up on coastal cliffs using a CIP-based model

Science.gov (United States)

Zhao, Xizeng; Chen, Yong; Huang, Zhenhua; Hu, Zijun; Gao, Yangyang

2017-05-01

There is a general lack of understanding of tsunami wave interaction with complex geographies, especially the process of inundation. Numerical simulations are performed to understand the effects of several factors on tsunami wave impact and run-up in the presence of gentle submarine slopes and coastal cliffs, using an in-house code, a constrained interpolation profile (CIP)-based model. The model employs a high-order finite difference method, the CIP method, as the flow solver; utilizes a VOF-type method, the tangent of hyperbola for interface capturing/slope weighting (THINC/SW) scheme, to capture the free surface; and treats the solid boundary by an immersed boundary method. A series of incident waves are arranged to interact with varying coastal geographies. Numerical results are compared with experimental data and good agreement is obtained. The influences of gentle submarine slope, coastal cliff and incident wave height are discussed. It is found that the tsunami amplification factor varying with incident wave is affected by gradient of cliff slope, and the critical value is about 45°. The run-up on a toe-erosion cliff is smaller than that on a normal cliff. The run-up is also related to the length of a gentle submarine slope with a critical value of about 2.292 m in the present model for most cases. The impact pressure on the cliff is extremely large and concentrated, and the backflow effect is non-negligible. Results of our work are highly precise and helpful in inverting tsunami source and forecasting disaster.

Ecological traps in shallow coastal waters-Potential effect of heat-waves in tropical and temperate organisms.

Directory of Open Access Journals (Sweden)

Catarina Vinagre

Full Text Available Mortality of fish has been reported in tide pools during warm days. That means that tide pools are potential ecological traps for coastal organisms, which happen when environmental changes cause maladaptive habitat selection. Heat-waves are predicted to increase in intensity, duration and frequency, making it relevant to investigate the role of tide pools as traps for coastal organisms. However, heat waves can also lead to acclimatization. If organisms undergo acclimatization prior to being trapped in tide pools, their survival chances may increase. Common tide pool species (46 species in total were collected at a tropical and a temperate area and their upper thermal limits estimated. They were maintained for 10 days at their mean summer sea surface temperature +3°C, mimicking a heat-wave. Their upper thermal limits were estimated again, after this acclimation period, to calculate each species' acclimation response. The upper thermal limits of the organisms were compared to the temperatures attained by tide pool waters to investigate if 1 tide pools could be considered ecological traps and 2 if the increase in upper thermal limits elicited by the acclimation period could make the organisms less vulnerable to this threat. Tropical tide pools were found to be ecological traps for an important number of common coastal species, given that they can attain temperatures higher than the upper thermal limits of most of those species. Tide pools are not ecological traps in temperate zones. Tropical species have higher thermal limits than temperate species, but lower acclimation response, that does not allow them to survive the maximum habitat temperature of tropical tide pools. This way, tropical coastal organisms seem to be, not only more vulnerable to climate warming per se, but also to an increase in the ecological trap effect of tide pools.

Numerical Modeling of Coastal Inundation and Sedimentation by Storm Surge, Tides, and Waves at Norfolk, Virginia, USA

Science.gov (United States)

2012-07-01

hurricanes (tropical) with a 50-year and a 100-year return period, and one winter storm ( extratropical ) occurred in October 1982. There are a total of 15...under the 0-m and 2-m SLR scenarios, respectively. • Tropical and extratropical storms induce extensive coastal inundation around the military...1 NUMERICAL MODELING OF COASTAL INUNDATION AND SEDIMENTATION BY STORM SURGE, TIDES, AND WAVES AT NORFOLK, VIRGINIA, USA Honghai Li 1 , Lihwa Lin 1

Operational wave now- and forecast in the German Bight as a basis for the assessment of wave-induced hydrodynamic loads on coastal dikes

Science.gov (United States)

Dreier, Norman; Fröhle, Peter

2017-12-01

The knowledge of the wave-induced hydrodynamic loads on coastal dikes including their temporal and spatial resolution on the dike in combination with actual water levels is of crucial importance of any risk-based early warning system. As a basis for the assessment of the wave-induced hydrodynamic loads, an operational wave now- and forecast system is set up that consists of i) available field measurements from the federal and local authorities and ii) data from numerical simulation of waves in the German Bight using the SWAN wave model. In this study, results of the hindcast of deep water wave conditions during the winter storm on 5-6 December, 2013 (German name `Xaver') are shown and compared with available measurements. Moreover field measurements of wave run-up from the local authorities at a sea dike on the German North Sea Island of Pellworm are presented and compared against calculated wave run-up using the EurOtop (2016) approach.

Correction factors for assessing immersion suits under harsh conditions.

Science.gov (United States)

Power, Jonathan; Tikuisis, Peter; Ré, António Simões; Barwood, Martin; Tipton, Michael

2016-03-01

Many immersion suit standards require testing of thermal protective properties in calm, circulating water while these suits are typically used in harsher environments where they often underperform. Yet it can be expensive and logistically challenging to test immersion suits in realistic conditions. The goal of this work was to develop a set of correction factors that would allow suits to be tested in calm water yet ensure they will offer sufficient protection in harsher conditions. Two immersion studies, one dry and the other with 500 mL of water within the suit, were conducted in wind and waves to measure the change in suit insulation. In both studies, wind and waves resulted in a significantly lower immersed insulation value compared to calm water. The minimum required thermal insulation for maintaining heat balance can be calculated for a given mean skin temperature, metabolic heat production, and water temperature. Combining the physiological limits of sustainable cold water immersion and actual suit insulation, correction factors can be deduced for harsh conditions compared to calm. The minimum in-situ suit insulation to maintain thermal balance is 1.553-0.0624·TW + 0.00018·TW(2) for a dry calm condition. Multiplicative correction factors to the above equation are 1.37, 1.25, and 1.72 for wind + waves, 500 mL suit wetness, and both combined, respectively. Calm water certification tests of suit insulation should meet or exceed the minimum in-situ requirements to maintain thermal balance, and correction factors should be applied for a more realistic determination of minimum insulation for harsh conditions. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Effect of Coastal Waves on Hydrodynamics in One-Inlet Coastal Nador Lagoon, Morocco

Directory of Open Access Journals (Sweden)

Jeyar Mohammed

2015-01-01

Full Text Available Nador lagoon is a coastal system connected to the sea through a narrow and shallow inlet; understanding its hydraulic performance is required for its design and operation. This paper investigates the hydrodynamic impacts of the whole lagoon due to tidal waves using a numerical approach. In this study we use a two-dimensional, depth-averaged hydrodynamic model based on so-called shallow water equations solved within triangular mesh by a developed efficient finite volume method. The method was calibrated and validated against observed data and applied to analyze and predict water levels, tidal currents, and wind effects within the lagoon. Two typical idealized scenarios were investigated: tide only and tide with wind forcing. The predicted sea surface elevations and current speeds have been presented during a typical tidal period and show correct physics in different scenarios.

Spatio-temporal variability of internal waves in the northern Gulf of Mexico studied with the Navy Coastal Ocean Model, NCOM

Science.gov (United States)

Cambazoglu, M. K.; Jacobs, G. A.; Howden, S. D.; Book, J. W.; Arnone, R.; Soto Ramos, I. M.; Vandermeulen, R. A.; Greer, A. T.; Miles, T. N.

2016-02-01

Internal waves enhance mixing in the upper ocean, transport nutrients and plankton over the water column and across the shelf from deeper waters to shallower coastal areas, and could also transport pollutants such as hydrocarbons onshore during an oil spill event. This study aims to characterize internal waves in the northern Gulf of Mexico (nGoM) and investigate the possible generation and dissipation mechanisms using a high-resolution (1-km) application of the Navy Coastal Ocean Model (NCOM). Three dimensional model products are used to detect the propagation patterns of internal waves. The vertical structure of internal waves is studied and the role of stratification is analyzed by looking at the temperature, salinity and velocity variations along the water column. The model predictions suggest the generation of internal waves on the continental shelf, therefore the role of ocean bottom topography interacting with tides and general circulation features such as the Loop Current Eddy front, on the internal wave generation will be discussed. The time periods of internal wave occurrences are identified from model predictions and compared to satellite ocean color imagery. Further data analysis, e.g. Fourier analysis, is implemented to determine internal wavelengths and frequencies and to determine if the response of internal waves are at tidal periods or at different frequencies. The atmospheric forcing provided to NCOM and meteorological data records are analyzed to define the interaction between wind forcing and internal wave generation. Wavelet analysis characterizes the ocean response to atmospheric events with periodic frequencies. Ocean color satellite imagery was used to visualize the location of the Mississippi river plume (and other oceanic features) and compared to the model predictions because the enhanced stratification from freshwater plumes which propagate across the Mississippi Bight can provide favorable conditions in coastal waters for internal wave

Impacts of severe wave event to the coastal environment, east Taiwan: a case study of 2015 Typhoon Soudelor

Science.gov (United States)

Huang, Shao-Yi; Yen, Jiun-Yee; Wu, Bo-Lin; Kao, Yu-Hsuan; Chang, Ting-Yi

2017-04-01

As an island surrounded by open water bodies, Taiwan faces associated challenges of oceanic events such as tidal, current and seasonsal wave cycles. In addition to the secular variations of the adjacent oceans, researchers have raised public awareness toward extreme wave events such as tsunamis and storm surges that may cause great damage to coastal infrastructures and loss of valuable lives. The east coast of Taiwan is prone to suffer from typhoons every year and records have shown that more than 30% of the low-pressure centers took the east coastline as their landing point. In year 2015, Typhoon Soudelor attacked the east coast of Taiwan and resulted in a great number of casualties and severe damage to the infrastructures all over the island. Soudelor is not the greatest typhoon of the year yet still brought in significant influences to the coastal topography due to its path and robust structure. In order to understand the impacts of typhoons like Soudelor, we investigated the coastal areas of Hualien, east Taiwan, to document how sediments and debris are transported along the shoreline under the extreme wave condition. Four coastal areas were surveyed to extract applicable information such as local relief profiles, grain size distribution of drifted sediments/debris, maximum inundation limit and so forth. Field observation suggests that the waves displayed great capability of transporting the sediments and redistributing the beach morphology. For instance, the beach of Qixing Lake (Chishingtan) has astonishing records like maximum volume of transported boulder around 3,000,000 cm3, maximum long axis of transported boulder around 144 cm, maximum distance of boulder transportation of 70 m, and maximum inundation distance of ca. 180 m. The composition and distribution of the drifted sediments in every areas vary with local geological conditions but in general all suggest similar characteristics: 1. the transported materials size down toward inland; 2. The sediments

The Framework of a Coastal Hazards Model - A Tool for Predicting the Impact of Severe Storms

Science.gov (United States)

Barnard, Patrick L.; O'Reilly, Bill; van Ormondt, Maarten; Elias, Edwin; Ruggiero, Peter; Erikson, Li H.; Hapke, Cheryl; Collins, Brian D.; Guza, Robert T.; Adams, Peter N.; Thomas, Julie

2009-01-01

The U.S. Geological Survey (USGS) Multi-Hazards Demonstration Project in Southern California (Jones and others, 2007) is a five-year project (FY2007-FY2011) integrating multiple USGS research activities with the needs of external partners, such as emergency managers and land-use planners, to produce products and information that can be used to create more disaster-resilient communities. The hazards being evaluated include earthquakes, landslides, floods, tsunamis, wildfires, and coastal hazards. For the Coastal Hazards Task of the Multi-Hazards Demonstration Project in Southern California, the USGS is leading the development of a modeling system for forecasting the impact of winter storms threatening the entire Southern California shoreline from Pt. Conception to the Mexican border. The modeling system, run in real-time or with prescribed scenarios, will incorporate atmospheric information (that is, wind and pressure fields) with a suite of state-of-the-art physical process models (that is, tide, surge, and wave) to enable detailed prediction of currents, wave height, wave runup, and total water levels. Additional research-grade predictions of coastal flooding, inundation, erosion, and cliff failure will also be performed. Initial model testing, performance evaluation, and product development will be focused on a severe winter-storm scenario developed in collaboration with the Winter Storm Working Group of the USGS Multi-Hazards Demonstration Project in Southern California. Additional offline model runs and products will include coastal-hazard hindcasts of selected historical winter storms, as well as additional severe winter-storm simulations based on statistical analyses of historical wave and water-level data. The coastal-hazards model design will also be appropriate for simulating the impact of storms under various sea level rise and climate-change scenarios. The operational capabilities of this modeling system are designed to provide emergency planners with

The June 2016 Australian East Coast Low: Importance of Wave Direction for Coastal Erosion Assessment

Directory of Open Access Journals (Sweden)

Thomas R. Mortlock

2017-02-01

Full Text Available In June 2016, an unusual East Coast Low storm affected some 2000 km of the eastern seaboard of Australia bringing heavy rain, strong winds and powerful wave conditions. While wave heights offshore of Sydney were not exceptional, nearshore wave conditions were such that beaches experienced some of the worst erosion in 40 years. Hydrodynamic modelling of wave and current behaviour as well as contemporaneous sand transport shows the east to north-east storm wave direction to be the major determinant of erosion magnitude. This arises because of reduced energy attenuation across the continental shelf and the focussing of wave energy on coastal sections not equilibrated with such wave exposure under the prevailing south-easterly wave climate. Narrabeen–Collaroy, a well-known erosion hot spot on Sydney’s Northern Beaches, is shown to be particularly vulnerable to storms from this direction because the destructive erosion potential is amplified by the influence of the local embayment geometry. We demonstrate the magnified erosion response that occurs when there is bi-directionality between an extreme wave event and preceding modal conditions and the importance of considering wave direction in extreme value analyses.

Feedbacks Between Wave Energy And Declining Coral Reef Structure: Implications For Coastal Morphodynamics

Science.gov (United States)

Grady, A. E.; Jenkins, C. J.; Moore, L. J.; Potts, D. C.; Burgess, P. M.; Storlazzi, C. D.; Elias, E.; Reidenbach, M. A.

2013-12-01

The incident wave energy dissipated by the structural complexity and bottom roughness of coral reef ecosystems, and the carbonate sediment produced by framework-building corals, provide natural shoreline protection and nourishment, respectively. Globally, coral reef ecosystems are in decline as a result of ocean warming and acidification, which is exacerbated by chronic regional stressors such as pollution and disease. As a consequence of declining reef health, many reef ecosystems are experiencing reduced coral cover and shifts to dominance by macroalgae, resulting in a loss of rugosity and thus hydrodynamic roughness. As coral reef architecture is compromised and carbonate skeletons are eroded, wave energy dissipation and sediment transport patterns--along with the carbonate sediment budget of the coastal environment--may be altered. Using a Delft3D numerical model of the south-central Molokai, Hawaii, fringing reef, we simulate the effects of changing reef states on wave energy and sediment transport. To determine the temporally-varying effects of biotic and abiotic stressors such as storms and bleaching on the reef structure and carbonate production, we couple Delft3D with CarboLOT, a model that simulates growth and competition of carbonate-producing organisms. CarboLOT is driven by the Lotka-Volterra population ecology equations and niche suitability principles, and accesses the CarboKB database for region-specific, carbonate-producing species information on growth rates, reproduction patterns, habitat suitability, as well as organism geometries. Simulations assess how changing reef states--which alter carbonate sediment production and reef morphology and thus hydrodynamic roughness--impact wave attenuation and sediment transport gradients along reef-fronted beaches. Initial results suggest that along fringing reefs having characteristics similar to the Molokai fringing reef, projected sea level rise will likely outpace coral reef accretion, and the increased

Azimuth cut-off model for significant wave height investigation along coastal water of Kuala Terengganu, Malaysia

Science.gov (United States)

Marghany, Maged; Ibrahim, Zelina; Van Genderen, Johan

2002-11-01

The present work is used to operationalize the azimuth cut-off concept in the study of significant wave height. Three ERS-1 images have been used along the coastal waters of Terengganu, Malaysia. The quasi-linear transform was applied to map the SAR wave spectra into real ocean wave spectra. The azimuth cut-off was then used to model the significant wave height. The results show that azimuth cut-off varied with the different period of the ERS-1 images. This is because of the fact that the azimuth cut-off is a function of wind speed and significant wave height. It is of interest to find that the significant wave height modeled from azimuth cut-off is in good relation with ground wave conditions. It can be concluded that ERS-1 can be used as a monitoring tool in detecting the significant wave height variation. The azimuth cut-off can be used to model the significant wave height. This means that the quasi-linear transform could be a good application to significant wave height variation during different seasons.

STS-93 Commander Collins waves after suiting up before launch

Science.gov (United States)

1999-01-01

During final launch preparations in the Operations and Checkout Building, STS-93 Commander Eileen M. Collins waves after donning her launch and entry suit. After Space Shuttle Columbia's July 20 launch attempt was scrubbed at the T-7 second mark in the countdown, the launch was rescheduled for Thursday, July 22, at 12:28 a.m. EDT. The target landing date is July 26, 1999, at 11:24 p.m. EDT. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected unlock the secrets of supernovae, quasars and black holes. The STS-93 crew numbers five: Commander Collins, Pilot Jeffrey S. Ashby, and Mission Specialists Stephen A. Hawley (Ph.D.), Catherine G. Coleman (Ph.D.) and Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES). Collins is the first woman to serve as commander of a shuttle mission.

The Impact of Sea Ice Loss on Wave Dynamics and Coastal Erosion Along the Arctic Coast

Science.gov (United States)

Overeem, I.; Anderson, R. S.; Wobus, C. W.; Matell, N.; Urban, F. E.; Clow, G. D.; Stanton, T. P.

2010-12-01

The extent of Arctic sea ice has been shrinking rapidly over the past few decades, and attendant acceleration of erosion is now occurring along the Arctic coast. This both brings coastal infrastructure into harm’s way and promotes a complex response of the adjacent landscape to global change. We quantify the effects of declining sea ice extent on coastal erosion rates along a 75-km stretch of coastal permafrost bluffs adjacent to the Beaufort Sea, Alaska, where present-day erosion rates are among the highest in the world at ~14 m yr-1. Our own observations reinforce those of others, and suggest that the rate-limiting process is thermal erosion at the base of the several-meter tall bluffs. Here we focus on the interaction between the nearshore sea ice concentration, the location of the sea ice margin, and the fetch-limited, shallow water wave field, since these parameters ultimately control both sea surface temperatures and the height to which these waters can bathe the frozen bluffs. Thirty years of daily or bi-daily passive microwave data from Nimbus-7 SMMR and DMSP SSM/I satellites reveal that the nearshore open water season lengthened ~54 days over 1979-2009. The open water season, centered in August, expands more rapidly into the fall (September and October~0.92 day yr-1) than into the early summer (July~0.71 days yr-1). Average fetch, defined for our purposes as the distance from the sea ice margin to the coast over which the wind is blowing, increased by a factor 1.7 over the same time-span. Given these time series, we modeled daily nearshore wave heights during the open water season for each year, which we integrated to provide a quantitative metric for the annual exposure of the coastal bluffs to thermal erosion. This “annual wave exposure” increased by 250% during 1979-2009. In the same interval, coastal erosion rates reconstructed from satellite and aerial photo records show less acceleration. We attribute this to a disproportionate extension of the

ABRASION WAVE OBSTRUCTS TOURISM DEVELOPMENT IN COASTAL REGIONS OF BINUANGEUN, LEBAK - BANTEN

Directory of Open Access Journals (Sweden)

Delyuzar Ilahude

2017-07-01

Full Text Available Geographically, the study area is located in the southern coast of Java and also exposed to the influence of wave energy from the southeast, south and southwest. The energy flux of waves generated by surface wind components that affect the coastline and the surrounding waters of Binuangeun. The impact of the wave coming from southeast direction caused a continuous abrasion process in Binuangeun coast and its adjacent areas, included the tourism area in the eastern part of Binuangeun coast towards the center of the study area. The current movement along the coast was accompanied by sediments deposition which tends to westward. The value of sediments supply (Vq in sample area point number 9 was bigger than the sample area number 4 about 33.703 m3/year within the same direction tendency of sediments deposition. Western part of Binuangeun coastal area would presumably become the sediment accumulation point throughout the year, while the erosion process in the central part of the study area were expanding and occured seasonally.

Predicting coastal cliff erosion using a Bayesian probabilistic model

Science.gov (United States)

Hapke, Cheryl J.; Plant, Nathaniel G.

2010-01-01

Regional coastal cliff retreat is difficult to model due to the episodic nature of failures and the along-shore variability of retreat events. There is a growing demand, however, for predictive models that can be used to forecast areas vulnerable to coastal erosion hazards. Increasingly, probabilistic models are being employed that require data sets of high temporal density to define the joint probability density function that relates forcing variables (e.g. wave conditions) and initial conditions (e.g. cliff geometry) to erosion events. In this study we use a multi-parameter Bayesian network to investigate correlations between key variables that control and influence variations in cliff retreat processes. The network uses Bayesian statistical methods to estimate event probabilities using existing observations. Within this framework, we forecast the spatial distribution of cliff retreat along two stretches of cliffed coast in Southern California. The input parameters are the height and slope of the cliff, a descriptor of material strength based on the dominant cliff-forming lithology, and the long-term cliff erosion rate that represents prior behavior. The model is forced using predicted wave impact hours. Results demonstrate that the Bayesian approach is well-suited to the forward modeling of coastal cliff retreat, with the correct outcomes forecast in 70–90% of the modeled transects. The model also performs well in identifying specific locations of high cliff erosion, thus providing a foundation for hazard mapping. This approach can be employed to predict cliff erosion at time-scales ranging from storm events to the impacts of sea-level rise at the century-scale.

Synchronization of Long Ocean Waves by Coastal Relief on the Southeast Shelf of Sakhalin Island

Science.gov (United States)

Kovalev, Dmitry P.; Kovalev, Peter D.

2017-12-01

The phenomenon of synchronization (trapping) of coming waves by the resonant water area in a coastal zone of the sea found from the observed data is considered in the paper. Edge waves with the period of about 10.7 minutes are visually observed in sea level fluctuations near the village of Okhotskoye and the cape Ostri on the southeast coast of Sakhalin Island. These waves are synchronized with the resonance water area. It becomes apparent from the unlimited increase of a phase between the bottom stations installed at distance of about 7.5km. In relation to the phenomenon found, the problem of weak and periodic impact on regular self-oscillatory system — Van der Paul’s oscillator — is considered. Good compliance between theoretical model and data of experiments is obtained.

The 14th international workshop on wave hindcasting and forecasting and the 5th coastal hazards symposium

Science.gov (United States)

Breivik, Øyvind; Alves, Jose Henrique; Greenslade, Diana; Horsburgh, Kevin; Swail, Val

2017-04-01

Following the 14th International Workshop on Wave Hindcasting and Forecasting and 5th Coastal Hazards Symposium in November 2014 in Key West, Florida, a topical collection has appeared in recent issues of Ocean Dynamics. Here, we give a brief overview of the 16 papers published in this topical collection as well as an overview of the widening scope of the conference in recent years. A general trend in the field has been towards closer integration between the wave and ocean modelling communities. This is also seen in this topical collection, with several papers exploring the interaction between surface waves and mixed layer dynamics and sea ice.

Coastal Risk Management in a Changing Climate

DEFF Research Database (Denmark)

Burcharth, Hans F.; Zanuttigh, Barbara; Andersen, Thomas Lykke

2014-01-01

Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, Coastal Risk...... Management in a Changing Climate provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments...

Particle Tracking Model (PTM) with Coastal Modeling System (CMS)

Science.gov (United States)

2015-11-04

Coastal Inlets Research Program Particle Tracking Model (PTM) with Coastal Modeling System ( CMS ) The Particle Tracking Model (PTM) is a Lagrangian...currents and waves. The Coastal Inlets Research Program (CIRP) supports the PTM with the Coastal Modeling System ( CMS ), which provides coupled wave...and current forcing for PTM simulations. CMS -PTM is implemented in the Surface-water Modeling System, a GUI environment for input development

A multimodal wave spectrum-based approach for statistical downscaling of local wave climate

Science.gov (United States)

Hegermiller, Christie; Antolinez, Jose A A; Rueda, Ana C.; Camus, Paula; Perez, Jorge; Erikson, Li; Barnard, Patrick; Mendez, Fernando J.

2017-01-01

Characterization of wave climate by bulk wave parameters is insufficient for many coastal studies, including those focused on assessing coastal hazards and long-term wave climate influences on coastal evolution. This issue is particularly relevant for studies using statistical downscaling of atmospheric fields to local wave conditions, which are often multimodal in large ocean basins (e.g. the Pacific). Swell may be generated in vastly different wave generation regions, yielding complex wave spectra that are inadequately represented by a single set of bulk wave parameters. Furthermore, the relationship between atmospheric systems and local wave conditions is complicated by variations in arrival time of wave groups from different parts of the basin. Here, we address these two challenges by improving upon the spatiotemporal definition of the atmospheric predictor used in statistical downscaling of local wave climate. The improved methodology separates the local wave spectrum into “wave families,” defined by spectral peaks and discrete generation regions, and relates atmospheric conditions in distant regions of the ocean basin to local wave conditions by incorporating travel times computed from effective energy flux across the ocean basin. When applied to locations with multimodal wave spectra, including Southern California and Trujillo, Peru, the new methodology improves the ability of the statistical model to project significant wave height, peak period, and direction for each wave family, retaining more information from the full wave spectrum. This work is the base of statistical downscaling by weather types, which has recently been applied to coastal flooding and morphodynamic applications.

Coastal knickpoints and the competition between fluvial and wave-driven erosion on rocky coastlines

Science.gov (United States)

Limber, Patrick; Barnard, Patrick

2018-01-01

Active margin coastlines are distinguished by rock erosion that acts in two different directions: waves erode the coast horizontally or landwards, a process that creates sea cliffs; and rivers and streams erode the landscape vertically via channel incision. The relative rates of each process exert a dominant control on coastline morphology. Using a model of river channel incision and sea-cliff retreat, we explore how terrestrial and marine erosion compete to shape coastal topography, and specifically what conditions encourage the development of coastal knickpoints (i.e., a river or stream channels that end at a raised sea-cliff edge). We then compare results to actual landscapes. Model results and observations show that coastal knickpoint development is strongly dependent on drainage basin area, where knickpoints typically occur in drainage basins smaller than 5 × 105–6 × 106 m2, as well as channel geometry and sea-cliff retreat rate. In our study area, coastal knickpoints with persistent flow (waterfalls) are uncommon and form only within a small morphological window when 1) drainage basin area is large enough to sustain steady stream discharge, but not large enough to out-compete sea-cliff formation, 2) sea-cliff retreat is rapid, and 3) channel concavity is low so that channel slopes at the coast are high. This particular geomorphic combination can sustain sea-cliff formation even when streams tap into larger drainage basins with greater discharge and more stream power, and provides an initial explanation of why persistent coastal waterfalls are, along many coastlines, relatively rare features.

Coastal knickpoints and the competition between fluvial and wave-driven erosion on rocky coastlines

Science.gov (United States)

Limber, Patrick W.; Barnard, Patrick L.

2018-04-01

Active margin coastlines are distinguished by rock erosion that acts in two different directions: waves erode the coast horizontally or landwards, a process that creates sea cliffs; and rivers and streams erode the landscape vertically via channel incision. The relative rates of each process exert a dominant control on coastline morphology. Using a model of river channel incision and sea-cliff retreat, we explore how terrestrial and marine erosion compete to shape coastal topography, and specifically what conditions encourage the development of coastal knickpoints (i.e., a river or stream channels that end at a raised sea-cliff edge). We then compare results to actual landscapes. Model results and observations show that coastal knickpoint development is strongly dependent on drainage basin area, where knickpoints typically occur in drainage basins smaller than 5 × 105-6 × 106 m2, as well as channel geometry and sea-cliff retreat rate. In our study area, coastal knickpoints with persistent flow (waterfalls) are uncommon and form only within a small morphological window when 1) drainage basin area is large enough to sustain steady stream discharge, but not large enough to out-compete sea-cliff formation, 2) sea-cliff retreat is rapid, and 3) channel concavity is low so that channel slopes at the coast are high. This particular geomorphic combination can sustain sea-cliff formation even when streams tap into larger drainage basins with greater discharge and more stream power, and provides an initial explanation of why persistent coastal waterfalls are, along many coastlines, relatively rare features.

Wave Dragon Wave Energy Converters Used as Coastal Protection

DEFF Research Database (Denmark)

Nørgaard, Jørgen Harck; Andersen, Thomas Lykke; Kofoed, Jens Peter

2011-01-01

This paper deals with wave energy converters used to reduce the wave height along shorelines. For this study the Wave Dragon wave energy converter is chosen. The wave height reduction from a single device has been evaluated from physical model tests in scale 1:51.8 of the 260 x 150 m, 24 kW/m model...... Spain, to evaluate the potential for reducing wave heights close the shore by means of Wave Dragons....

An Integrated Numerical Model for the Design of Coastal Protection Structures

Directory of Open Access Journals (Sweden)

Theophanis V. Karambas

2017-10-01

Full Text Available In the present work, an integrated coastal engineering numerical model is presented. The model simulates the linear wave propagation, wave-induced circulation, and sediment transport and bed morphology evolution. It consists of three main modules: WAVE_L, WICIR, and SEDTR. The nearshore wave transformation module WAVE_L (WAVE_Linear is based on the hyperbolic-type mild slope equation and is valid for a compound linear wave field near coastal structures where the waves are subjected to the combined effects of shoaling, refraction, diffraction, reflection (total and partial, and breaking. Radiation stress components (calculated from WAVE_L drive the depth averaged circulation module WICIR (Wave Induced CIRculation for the description of the nearshore wave-induced currents. Sediment transport and bed morphology evolution in the nearshore, surf, and swash zone are simulated by the SEDTR (SEDiment TRansport module. The model is tested against experimental data to study the effect of representative coastal protection structures and is applied to a real case study of a coastal engineering project in North Greece, producing accurate and consistent results for a versatile range of layouts.

WAVE DIRECTION and Other Data from FIXED STATIONS From Coastal Waters of California from 19750313 to 19750525 (NODC Accession 9400044)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The accession contains Wave Surface Data collected in Coastal Waters of California between March 13, 1975 and May 25, 1975. Water surface elevation data was...

Development of wave and surge atlas for the design and protection of coastal bridges in south Louisiana : [tech summary].

Science.gov (United States)

2015-02-01

The failures of highway bridges on the Gulf Coast seen in the aftermath of Hurricane Katrina in 2005 were unprecedented. : In the past four decades, wind waves accompanied by high surges from hurricanes have damaged a number of coastal : bridges alon...

A hydrodynamic model of nearshore waves and wave-induced currents

Directory of Open Access Journals (Sweden)

Ahmed Khaled Seif

2011-09-01

Full Text Available In This study develops a quasi-three dimensional numerical model of wave driven coastal currents with accounting the effects of the wave-current interaction and the surface rollers. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. The surface roller associated with wave breaking was modeled based on a modification of the equations by Dally and Brown (1995 and Larson and Kraus (2002. Furthermore, the quasi-three dimensional model, which based on Navier-Stokes equations, was modified in association with the surface roller effect, and solved using frictional step method. The model was validated by data sets obtained during experiments on the Large Scale Sediment Transport Facility (LSTF basin and the Hazaki Oceanographical Research Station (HORS. Then, a model test against detached breakwater was carried out to investigate the performance of the model around coastal structures. Finally, the model was applied to Akasaki port to verify the hydrodynamics around coastal structures. Good agreements between computations and measurements were obtained with regard to the cross-shore variation in waves and currents in nearshore and surf zone.

Hurricane Ike: Observations and Analysis of Coastal Change

Science.gov (United States)

Doran, Kara S.; Plant, Nathaniel G.; Stockdon, Hilary F.; Sallenger, Asbury H.; Serafin, Katherine A.

2009-01-01

Understanding storm-induced coastal change and forecasting these changes require knowledge of the physical processes associated with the storm and the geomorphology of the impacted coastline. The primary physical processes of interest are the wind field, storm surge, and wave climate. Not only does wind cause direct damage to structures along the coast, but it is ultimately responsible for much of the energy that is transferred to the ocean and expressed as storm surge, mean currents, and large waves. Waves and currents are the processes most responsible for moving sediments in the coastal zone during extreme storm events. Storm surge, the rise in water level due to the wind, barometric pressure, and other factors, allows both waves and currents to attack parts of the coast not normally exposed to those processes. Coastal geomorphology, including shapes of the shoreline, beaches, and dunes, is equally important to the coastal change observed during extreme storm events. Relevant geomorphic variables include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach slope. These variables, in addition to hydrodynamic processes, can be used to predict coastal vulnerability to storms The U.S. Geological Survey's (USGS) National Assessment of Coastal Change Hazards Project (http://coastal.er.usgs.gov/hurricanes), strives to provide hazard information to those interested in the Nation's coastlines, including residents of coastal areas, government agencies responsible for coastal management, and coastal researchers. As part of the National Assessment, observations were collected to measure coastal changes associated with Hurricane Ike, which made landfall near Galveston, Texas, on September 13, 2008. Methods of observation included aerial photography and airborne topographic surveys. This report documents these data-collection efforts and presents qualitative and quantitative descriptions of hurricane-induced changes to the shoreline

Why the coastal plain of Paraiba do Sul river not be denominated the classical model of wave dominated delta

International Nuclear Information System (INIS)

Martin, L.

1987-01-01

Existing coastal sedimentation models have not properly incorporated the fundamental role of Holocene sea-level history in the development of modern coastal regions. For example the classical work by COLEMAN and WRIGHT (1975), although analyzing the influence of as many as 400 parameters on the geometry of deltaic sand bodies, did not address the effects of Holocene sea-level oscillations. Previous work on the central portion of the Brazilian coastline indicated that the relative construction of the coastal plains. Detailed mapping and radiocarbon dating have allowed us to establish the different phases involved in the depositional history of the plain situated at the Paraiba do Sul river mouth. This history is not in keeping with the classical model of wave dominated delta. (author)

CMS-Wave

Science.gov (United States)

2015-10-30

Coastal Inlets Research Program CMS -Wave CMS -Wave is a two-dimensional spectral wind-wave generation and transformation model that employs a forward...marching, finite-difference method to solve the wave action conservation equation. Capabilities of CMS -Wave include wave shoaling, refraction... CMS -Wave can be used in either on a half- or full-plane mode, with primary waves propagating from the seaward boundary toward shore. It can

HIGH WAVE AND COASTAL INUNDATION IN SOUTH OF JAVA AND WEST OF SUMATERA (CASE STUDIES ON 7-10 JUNE 2016

Directory of Open Access Journals (Sweden)

Roni Kurniawan

2017-10-01

Full Text Available The high wave and spring tide occurred on June 7 to 10, 2016 had led to storm tide and coastal inundation at a number of coastal areas in south of Java and west of Sumatera, this incident caused substantial losses to coastal communities. The aim of this study is to understand the cause of storm tide, so it can be serve as a strategic contribution to assess, evaluate and mitigate the impact. The output of Wavewatch-III (WW3 model and Aviso Altimetry indicates the occurrence high wave in Indian Ocean reach more than 6 meters, this wave triggered by high wind speed around the Mascarene high event in Western Australia. Further analysis based on the output resulted by WW3 showed that the extreme wave in west Sumatera and south of Java (7-10 June, 2016 was dominated by swell waves generated by Mascarene High superposed with the highest diurnal tide as well as sea surface height anomaly, triggers the storm tide that consequentially costed more damaging impact in the south of Java and west of Sumatera. Gelombang tinggi dan pasang air laut yang terjadi pada tanggal 7 -10 Juni 2016 menyebabkan sejumlah wilayah pesisir di selatan Jawa dan Barat Sumatera mengalami gelombang pasang dan banjir rob, yang mengakibatkan kerugian cukup besar bagi masyarakat pesisir. Kajian ini bertujuan untuk mengetahui penyebab terjadinya gelombang pasang tersebut, sehingga dapat bermanfaat sebagai evaluasi dan mitigasi kedepan. Data luaran model Wavewatch-III (WW3 dan Aviso-Satellite altimetry menunjukkan adanya gelombang tinggi lebih dari 6 meter di Samudera Hindia yang dipicu oleh angin kencang di sekitar wilayah kejadian Mascarene High di sebelah barat Australia. Analisis lebih lanjut berdasarkan output yang dihasilkan oleh WW3 menunjukkan bahwa gelombang ekstrim di selatan Jawa dan barat Sumatera (tanggal 7 – 10 Juni 2016 lebih didominasi oleh swell yang dihasilkan oleh kejadian Mascarene High. Terjadinya swell ini bersuperposisi dengan pasang tertinggi dan anomali tinggi

Modeling the mitigation effect of coastal forests on tsunami

Science.gov (United States)

Kh'ng, Xin Yi; Teh, Su Yean; Koh, Hock Lye

2017-08-01

As we have learned from the 26 Dec 2004 mega Andaman tsunami that killed 250, 000 lives worldwide, tsunami is a devastating natural disaster that can cause severe impacts including immense loss of human lives and extensive destruction of properties. The wave energy can be dissipated by the presence of coastal mangrove forests, which provide some degree of protection against tsunami waves. On the other hand, costly artificial structures such as reinforced walls can substantially diminish the aesthetic value and may cause environmental problems. To quantify the effectiveness of coastal forests in mitigating tsunami waves, an in-house 2-D model TUNA-RP is developed and used to quantify the reduction in wave heights and velocities due to the presence of coastal forests. The degree of reduction varies significantly depending on forest flow-resistant properties such as vegetation characteristics, forest density and forest width. The ability of coastal forest in reducing tsunami wave heights along the west coast of Penang Island is quantified by means of model simulations. Comparison between measured tsunami wave heights for the 2004 Andaman tsunami and 2-D TUNA-RP model simulated values demonstrated good agreement.

Integrated sedimentological and ichnological characteristics of a wave-dominated, macrotidal coast: a case study from the intertidal shoreface of the Dongho coast, southwest Korea

Science.gov (United States)

Yang, Byong Cheon; Chang, Tae Soo

2018-04-01

Generalized coastal facies models invariably assume that tidal flats and intertidally exposed shorefaces along macrotidal coasts are tide-dominated. Recent advances in coastal sedimentology, however, have revealed that wave-dominated macrotidal flats also occur in a wide range of coastal settings, in particular where tidal modulation forces the lateral translation of the wave-affected zone across the tidally exposed shoreface with the rising tide. Despite tidal modulation, the depositional character in the latter case (abundant storm deposits) exhibits a high degree of similarity with conventional subtidal shorefaces, implying that it is inherently difficult to distinguish between the two coastal systems in the rock record. In the present study, integrated sedimentological and ichnological data from the Dongho coast, which is located along the southwest coast of Korea, provide valuable information for the establishment of facies criteria that can assist in the recognition of such coastal deposits. In fact, the sedimentary character of the study area, which is dominated by an abundance of wave-formed structures, resembles that generally associated with subtidal shorefaces. In addition, the depositional processes responsible for sediment accumulation are, in the present case, also strongly influenced by pronounced seasonal variations in wave energy. In this context, the study has revealed a number of major features that appear to be characteristic of wave-dominated intertidal flats and shorefaces: (1) firmground muds may be encountered on the beach face, where intense swash-backwash motions are dominant; (2) the thickness of storm deposits decreases landward, reflecting the progressive decrease in wave energy; (3) ichnologically, there is an offshore shift in the dominance of trace fossils from the Skolithos ichnofacies, including Ophiomorpha, Thalassinoides and Psilonichnus, to a proximal expression of the Cruziana ichnofacies, which includes Siphonichnus and

Towards improved management of coastal submersion crises – CRISMA-WAVE solution as an example of CRISMA Framework application

Directory of Open Access Journals (Sweden)

Erlich Marc

2016-01-01

Full Text Available Coping with various types of natural or man-made hazards the FP7 SECURITY CRISMA project (http://www.crismaproject.eu has designed and developed an experimental software framework allowing building crisis management simulation application. One of the five pilot applications of CRISMA dealing with preparedness to the coastal submersions was developed and implemented using return of experience of the reference Xynthia storm surge event in the Charente Maritime County in France. The paper addresses the generic CRISMA Framework applicability to simulate mitigation effects of a coastal submersion through CRISMA-Wave implementation of a full modelling cycle. The CRISMA-Wave paradigm reflects user needs for simulation of “what-if” scenarios for short and long-term actions and the paper describes in particular its different components : *Simulation of submersion effects at a range of temporal and spatial scales, *Preparedness Planning, *Assessment of impacts depending on scenarios based on options for managing the inundation risks, *Cascading effects and *Evaluation of damages with comparison of submersion defence scenarios based on cost-benefit and multi criteria analysis.

Sele coastal plain flood risk due to wave storm and river flow interaction

Science.gov (United States)

Benassai, Guido; Aucelli, Pietro; Di Paola, Gianluigi; Della Morte, Renata; Cozzolino, Luca; Rizzo, Angela

2016-04-01

Wind waves, elevated water levels and river discharge can cause flooding in low-lying coastal areas, where the water level is the interaction between wave storm elevated water levels and river flow interaction. The factors driving the potential flood risk include weather conditions, river water stage and storm surge. These data are required to obtain inputs to run the hydrological model used to evaluate the water surface level during ordinary and extreme events regarding both the fluvial overflow and storm surge at the river mouth. In this paper we studied the interaction between the sea level variation and the river hydraulics in order to assess the location of the river floods in the Sele coastal plain. The wave data were acquired from the wave buoy of Ponza, while the water level data needed to assess the sea level variation were recorded by the tide gauge of Salerno. The water stages, river discharges and rating curves for Sele river were provided by Italian Hydrographic Service (Servizio Idrografico e Mareografico Nazionale, SIMN).We used the dataset of Albanella station (40°29'34.30"N, 15°00'44.30"E), located around 7 km from the river mouth. The extreme river discharges were evaluated through the Weibull equation, which were associated with their return period (TR). The steady state river water levels were evaluated through HEC-RAS 4.0 model, developed by Hydrologic Engineering Center (HEC) of the United States Army Corps of Engineers Hydrologic Engineering Center (USACE,2006). It is a well-known 1D model that computes water surface elevation (WSE) and velocity at discrete cross-sections by solving continuity, energy and flow resistance (e.g., Manning) equation. Data requirements for HEC-RAS include topographic information in the form of a series of cross-sections, friction parameter in the form of Manning's n values across each cross-section, and flow data including flow rates, flow change locations, and boundary conditions. For a steady state sub

Diurnal tidal currents attributed to free baroclinic coastal-trapped waves on the Pacific shelf off the southeastern coast of Hokkaido, Japan

Science.gov (United States)

Kuroda, Hiroshi; Kusaka, Akira; Isoda, Yutaka; Honda, Satoshi; Ito, Sayaka; Onitsuka, Toshihiro

2018-04-01

To understand the properties of tides and tidal currents on the Pacific shelf off the southeastern coast of Hokkaido, Japan, we analyzed time series of 9 current meters that were moored on the shelf for 1 month to 2 years. Diurnal tidal currents such as the K1 and O1 constituents were more dominant than semi-diurnal ones by an order of magnitude. The diurnal tidal currents clearly propagated westward along the coast with a typical phase velocity of 2 m s-1 and wavelength of 200 km. Moreover, the shape and phase of the diurnal currents measured by a bottom-mounted ADCP were vertically homogeneous, except in the vicinity of the bottom boundary layer. These features were very consistent with theoretically estimated properties of free baroclinic coastal-trapped waves of the first mode. An annual (semi-annual) variation was apparent for the phase (amplitude) of the O1 tidal current, which was correlated with density stratification (intensity of an along-shelf current called the Coastal Oyashio). These possible causes are discussed in terms of the propagation and generation of coastal-trapped waves.

STORMTOOLS: Coastal Environmental Risk Index (CERI

Directory of Open Access Journals (Sweden)

Malcolm L. Spaulding

2016-08-01

Full Text Available One of the challenges facing coastal zone managers and municipal planners is the development of an objective, quantitative assessment of the risk to structures, infrastructure, and public safety that coastal communities face from storm surge in the presence of changing climatic conditions, particularly sea level rise and coastal erosion. Here we use state of the art modeling tool (ADCIRC and STWAVE to predict storm surge and wave, combined with shoreline change maps (erosion, and damage functions to construct a Coastal Environmental Risk Index (CERI. Access to the state emergency data base (E-911 provides information on structure characteristics and the ability to perform analyses for individual structures. CERI has been designed as an on line Geographic Information System (GIS based tool, and hence is fully compatible with current flooding maps, including those from FEMA. The basic framework and associated GIS methods can be readily applied to any coastal area. The approach can be used by local and state planners to objectively evaluate different policy options for effectiveness and cost/benefit. In this study, CERI is applied to RI two communities; Charlestown representing a typical coastal barrier system directly exposed to ocean waves and high erosion rates, with predominantly low density single family residences and Warwick located within Narragansett Bay, with more limited wave exposure, lower erosion rates, and higher residential housing density. Results of these applications are highlighted herein.

Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Jesbin, G.

–885, 2016 www.ann-geophys.net/34/871/2016/ doi:10.5194/angeo-34-871-2016 © Author(s) 2016. CC Attribution 3.0 License. Influence of Indian summer monsoon variability on the surface waves in the coastal regions of eastern Arabian Sea V. Sanil Kumar and Jesbin... of the period. The annual average value is ∼ 1.5 m (Anoop et al., 2015). During the non-monsoon period, the land and sea breeze has a signif- icant influence on the wave climate of eastern AS (Glejin Ann. Geophys., 34, 871–885, 2016 www.ann-geophys.net/34...

Coastal Risk Management in a Changing Climate

DEFF Research Database (Denmark)

Existing coastal management and defense approaches are not well suited to meet the challenges of climate change and related uncertanities. Professionals in this field need a more dynamic, systematic and multidisciplinary approach. Written by an international group of experts, "Coastal Risk...... Management in a Changing Climate" provides innovative, multidisciplinary best practices for mitigating the effects of climate change on coastal structures. Based on the Theseus program, the book includes eight study sites across Europe, with specific attention to the most vulnerable coastal environments...... such as deltas, estuaries and wetlands, where many large cities and industrial areas are located. Integrated risk assessment tools for considering the effects of climate change and related uncertainties. Presents latest insights on coastal engineering defenses. Provides integrated guidelines for setting up...

Evaluation and adjustment of altimeter measurement and numerical hindcast in wave height trend estimation in China's coastal seas

Science.gov (United States)

Li, Shuiqing; Guan, Shoude; Hou, Yijun; Liu, Yahao; Bi, Fan

2018-05-01

A long-term trend of significant wave height (SWH) in China's coastal seas was examined based on three datasets derived from satellite measurements and numerical hindcasts. One set of altimeter data were obtained from the GlobWave, while the other two datasets of numerical hindcasts were obtained from the third-generation wind wave model, WAVEWATCH III, forced by wind fields from the Cross-Calibrated Multi-Platform (CCMP) and NCEP's Climate Forecast System Reanalysis (CFSR). The mean and extreme wave trends were estimated for the period 1992-2010 with respect to the annual mean and the 99th-percentile values of SWH, respectively. The altimeter wave trend estimates feature considerable uncertainties owing to the sparse sampling rate. Furthermore, the extreme wave trend tends to be overestimated because of the increasing sampling rate over time. Numerical wave trends strongly depend on the quality of the wind fields, as the CCMP waves significantly overestimate the wave trend, whereas the CFSR waves tend to underestimate the trend. Corresponding adjustments were applied which effectively improved the trend estimates from the altimeter and numerical data. The adjusted results show generally increasing mean wave trends, while the extreme wave trends are more spatially-varied, from decreasing trends prevailing in the South China Sea to significant increasing trends mainly in the East China Sea.

Visualizing Coastal Erosion, Overwash and Coastal Flooding in New England

Science.gov (United States)

Young Morse, R.; Shyka, T.

2017-12-01

Powerful East Coast storms and their associated storm tides and large, battering waves can lead to severe coastal change through erosion and re-deposition of beach sediment. The United States Geological Survey (USGS) has modeled such potential for geological response using a storm-impact scale that compares predicted elevations of hurricane-induced water levels and associated wave action to known elevations of coastal topography. The resulting storm surge and wave run-up hindcasts calculate dynamic surf zone collisions with dune structures using discrete regime categories of; "collision" (dune erosion), "overwash" and "inundation". The National Weather Service (NWS) recently began prototyping this empirical technique under the auspices of the North Atlantic Regional Team (NART). Real-time erosion and inundation forecasts were expanded to include both tropical and extra-tropical cyclones along vulnerable beaches (hotspots) on the New England coast. Preliminary results showed successful predictions of impact during hurricane Sandy and several intense Nor'easters. The forecasts were verified using observational datasets, including "ground truth" reports from Emergency Managers and storm-based, dune profile measurements organized through a Maine Sea Grant partnership. In an effort to produce real-time visualizations of this forecast output, the Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS) and the Gulf of Maine Research Institute (GMRI) partnered with NART to create graphical products of wave run-up levels for each New England "hotspot". The resulting prototype system updates the forecasts twice daily and allows users the ability to adjust atmospheric and sea state input into the calculations to account for model errors and forecast uncertainty. This talk will provide an overview of the empirical wave run-up calculations, the system used to produce forecast output and a demonstration of the new web based tool.

Hurricane Gustav: Observations and Analysis of Coastal Change

Science.gov (United States)

Doran, Kara S.; Stockdon, Hilary F.; Plant, Nathaniel G.; Sallenger, Asbury H.; Guy, Kristy K.; Serafin, Katherine A.

2009-01-01

Understanding storm-induced coastal change and forecasting these changes require knowledge of the physical processes associated with a storm and the geomorphology of the impacted coastline. The primary physical processes of interest are the wind field, storm surge, currents, and wave field. Not only does wind cause direct damage to structures along the coast, but it is ultimately responsible for much of the energy that is transferred to the ocean and expressed as storm surge, mean currents, and surface waves. Waves and currents are the processes most responsible for moving sediments in the coastal zone during extreme storm events. Storm surge, which is the rise in water level due to the wind, barometric pressure, and other factors, allows both waves and currents to attack parts of the coast not normally exposed to these processes. Coastal geomorphology, including shapes of the shoreline, beaches, and dunes, is also a significant aspect of the coastal change observed during extreme storms. Relevant geomorphic variables include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach slope. These variables, in addition to hydrodynamic processes, can be used to predict coastal vulnerability to storms. The U.S. Geological Survey (USGS) National Assessment of Coastal Change Hazards project (http://coastal.er.usgs.gov/hurricanes) strives to provide hazard information to those concerned about the Nation's coastlines, including residents of coastal areas, government agencies responsible for coastal management, and coastal researchers. As part of the National Assessment, observations were collected to measure morphological changes associated with Hurricane Gustav, which made landfall near Cocodrie, Louisiana, on September 1, 2008. Methods of observation included oblique aerial photography, airborne topographic surveys, and ground-based topographic surveys. This report documents these data-collection efforts and presents qualitative and

Assessment of current effect on waves in a semi-enclosed basin

Science.gov (United States)

Benetazzo, A.; Carniel, S.; Sclavo, M.; Bergamasco, A.

2012-04-01

considered. During intense storms, the effect of coupling on wave heights is resulting in variations of the wave heights up to 15%, with some areas experiencing increase or decrease of wave spectral energy for opposite and following currents respectively. The study is part of the activities developed in the European Union (EU) funded FIELD_AC project (Fluxes, Interactions and Environment at the Land-ocean boundary. Downscaling, Assimilation and Coupling), which is conceived with the goal to better identify the most significant natural processes in coastal areas, and to address their impact on the coastal and nearshore dynamics by including them in a complete numerical prediction suite.

Types and Functions of Coastal Structures

DEFF Research Database (Denmark)

Burcharth, H. F.; A. Hughes, Steven

2003-01-01

Coastal structures are used in coastal defence schemes with the objective of preventing shoreline erosion and flooding of the hinterland. Other objectives include sheltering of harbour basins and harbour entrances against waves, stabilization of navigation channels at inlets, and protection...

Bottom friction. A practical approach to modelling coastal oceanography

Science.gov (United States)

Bolanos, Rodolfo; Jensen, Palle; Kofoed-Hansen, Henrik; Tornsfeldt Sørensen, Jacob

2017-04-01

Coastal processes imply the interaction of the atmosphere, the sea, the coastline and the bottom. The spatial gradients in this area are normally large, induced by orographic and bathymetric features. Although nowadays it is possible to obtain high-resolution bathymetry, the details of the seabed, e.g. sediment type, presence of biological material and living organisms are not available. Additionally, these properties as well as bathymetry can also be highly dynamic. These bottom characteristics are very important to describe the boundary layer of currents and waves and control to a large degree the dissipation of flows. The bottom friction is thus typically a calibration parameter in numerical modelling of coastal processes. In this work, we assess this process and put it into context of other physical processes uncertainties influencing wind-waves and currents in the coastal areas. A case study in the North Sea is used, particularly the west coast of Denmark, where water depth of less than 30 m cover a wide fringe along the coast, where several offshore wind farm developments are being carried out. We use the hydrodynamic model MIKE 21 HD and the spectral wave model MIKE 21 SW to simulate atmosphere and tidal induced flows and the wind wave generation and propagation. Both models represent state of the art and have been developed for flexible meshes, ideal for coastal oceanography as they can better represent coastlines and allow a variable spatial resolution within the domain. Sensitivity tests to bottom friction formulations are carried out into context of other processes (e.g. model forcing uncertainties, wind and wave interactions, wind drag coefficient). Additionally, a map of varying bottom properties is generated based on a literature survey to explore the impact of the spatial variability. Assessment of different approaches is made in order to establish a best practice regarding bottom friction and coastal oceanographic modelling. Its contribution is also

Multiscale climate emulator of multimodal wave spectra: MUSCLE-spectra

Science.gov (United States)

Rueda, Ana; Hegermiller, Christie A.; Antolinez, Jose A. A.; Camus, Paula; Vitousek, Sean; Ruggiero, Peter; Barnard, Patrick L.; Erikson, Li H.; Tomás, Antonio; Mendez, Fernando J.

2017-02-01

Characterization of multimodal directional wave spectra is important for many offshore and coastal applications, such as marine forecasting, coastal hazard assessment, and design of offshore wave energy farms and coastal structures. However, the multivariate and multiscale nature of wave climate variability makes this complex problem tractable using computationally expensive numerical models. So far, the skill of statistical-downscaling model-based parametric (unimodal) wave conditions is limited in large ocean basins such as the Pacific. The recent availability of long-term directional spectral data from buoys and wave hindcast models allows for development of stochastic models that include multimodal sea-state parameters. This work introduces a statistical downscaling framework based on weather types to predict multimodal wave spectra (e.g., significant wave height, mean wave period, and mean wave direction from different storm systems, including sea and swells) from large-scale atmospheric pressure fields. For each weather type, variables of interest are modeled using the categorical distribution for the sea-state type, the Generalized Extreme Value (GEV) distribution for wave height and wave period, a multivariate Gaussian copula for the interdependence between variables, and a Markov chain model for the chronology of daily weather types. We apply the model to the southern California coast, where local seas and swells from both the Northern and Southern Hemispheres contribute to the multimodal wave spectrum. This work allows attribution of particular extreme multimodal wave events to specific atmospheric conditions, expanding knowledge of time-dependent, climate-driven offshore and coastal sea-state conditions that have a significant influence on local nearshore processes, coastal morphology, and flood hazards.

Oceanography at coastal scales: Introduction to the special issue on results from the EU FP7 FIELD_AC project

Science.gov (United States)

Sánchez-Arcilla, Agustín; Wolf, Judith; Monbaliu, Jaak

2014-09-01

The high-resolution and coupled forecasting of wind, waves and currents, in restricted coastal domains, offer a number of important challenges; these limit the quality of predictions, in the present state-of-the-art. This paper presents the main results obtained for such coastal domains, with reference to a variety of modelling suites and observing networks for: a) Liverpool Bay; b) German Bight; c) Gulf of Venice; and d) the Catalan coast. All of these areas are restricted domains, where boundary effects play a significant role in the resulting inner dynamics. This contribution addresses also the themes of the other papers in this Special Issue, ranging from observations to simulations. Emphasis is placed upon the physics controlling such restricted areas. The text deals also with the transfer to end-users and other interested parties, since the requirements on resolution, accuracy and robustness must be linked to their applications. Finally, some remarks are included on the way forward for coastal oceanography and the synergetic combination of in-situ and remote measurements, with high-resolution 3D simulations.

NODC Standard Format Coastal Ocean Wave and Current (F181) Data from the Atlantic Remote Sensing Land/Ocean Experiment (ARSLOE) (1980) (NODC Accession 0014202)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains time series coastal ocean wave and current data collected during the Atlantic Remote Sensing Land/Ocean Experiment (ARSLOE). ARSLOE was...

Modeling Coastal Vulnerability through Space and Time.

Science.gov (United States)

Hopper, Thomas; Meixler, Marcia S

2016-01-01

Coastal ecosystems experience a wide range of stressors including wave forces, storm surge, sea-level rise, and anthropogenic modification and are thus vulnerable to erosion. Urban coastal ecosystems are especially important due to the large populations these limited ecosystems serve. However, few studies have addressed the issue of urban coastal vulnerability at the landscape scale with spatial data that are finely resolved. The purpose of this study was to model and map coastal vulnerability and the role of natural habitats in reducing vulnerability in Jamaica Bay, New York, in terms of nine coastal vulnerability metrics (relief, wave exposure, geomorphology, natural habitats, exposure, exposure with no habitat, habitat role, erodible shoreline, and surge) under past (1609), current (2015), and future (2080) scenarios using InVEST 3.2.0. We analyzed vulnerability results both spatially and across all time periods, by stakeholder (ownership) and by distance to damage from Hurricane Sandy. We found significant differences in vulnerability metrics between past, current and future scenarios for all nine metrics except relief and wave exposure. The marsh islands in the center of the bay are currently vulnerable. In the future, these islands will likely be inundated, placing additional areas of the shoreline increasingly at risk. Significant differences in vulnerability exist between stakeholders; the Breezy Point Cooperative and Gateway National Recreation Area had the largest erodible shoreline segments. Significant correlations exist for all vulnerability (exposure/surge) and storm damage combinations except for exposure and distance to artificial debris. Coastal protective features, ranging from storm surge barriers and levees to natural features (e.g. wetlands), have been promoted to decrease future flood risk to communities in coastal areas around the world. Our methods of combining coastal vulnerability results with additional data and across multiple time

Modeling wave trains in coastal regions; Modelagem de trens de ondas em regioes costeiras

Energy Technology Data Exchange (ETDEWEB)

Luz, Ana M.S.; Nachbin, A. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Matematica Pura e Aplicada (IMPA)

2008-07-01

Our goal is to present a model that captures how the sea bottom topography or submarine structures can influence the evolution of water wave trains over a varying topography at intermediate depth. To obtain such a model, we consider Euler equations for inviscid fluids and we perform the asymptotic simplification of the nonlinear potential theory equations together with the method of multiple scales to get a reduced model. Such a model is called reduced because it simplifies nonlinear potential theory from two spatial dimensions to one dimension along the free boundary. We consider a varying topography at the bottom and/or the presence of submarine structures together with a free boundary at the surface of the sea. For modeling such a geometry we transform our Cartesian system into curvilinear coordinates through a conformal mapping that maps the original physical domain into a simpler domain (a strip). This modeling strategy allows us to capture and understand the dynamics of water waves in regions where offshore exploration activity already exists or not. Through an efficient model we can get important information regarding the dynamics of waves in coastal regions and also questions on the viability of oil and gas recovery in these regions. (author)

Coastal Amplification Laws for the French Tsunami Warning Center: Numerical Modeling and Fast Estimate of Tsunami Wave Heights Along the French Riviera

Science.gov (United States)

Gailler, A.; Hébert, H.; Schindelé, F.; Reymond, D.

2018-04-01

Tsunami modeling tools in the French tsunami Warning Center operational context provide rapidly derived warning levels with a dimensionless variable at basin scale. A new forecast method based on coastal amplification laws has been tested to estimate the tsunami onshore height, with a focus on the French Riviera test-site (Nice area). This fast prediction tool provides a coastal tsunami height distribution, calculated from the numerical simulation of the deep ocean tsunami amplitude and using a transfer function derived from the Green's law. Due to a lack of tsunami observations in the western Mediterranean basin, coastal amplification parameters are here defined regarding high resolution nested grids simulations. The preliminary results for the Nice test site on the basis of nine historical and synthetic sources show a good agreement with the time-consuming high resolution modeling: the linear approximation is obtained within 1 min in general and provides estimates within a factor of two in amplitude, although the resonance effects in harbors and bays are not reproduced. In Nice harbor especially, variation in tsunami amplitude is something that cannot be really assessed because of the magnitude range and maximum energy azimuth of possible events to account for. However, this method is well suited for a fast first estimate of the coastal tsunami threat forecast.

West India coastal current and Lakshadweep High/Low

Digital Repository Service at National Institute of Oceanography (India)

Shetye, S.R.

basin is driven by seasonal monsoon winds. As a result, its wind-dirven near-surface circulation consists primarily of annual and semi-annual long, equatorially-trapped Kelvin and Rossby waves, and coastally-trapped Kelvin waves. In terms of these waves...

Surf Wave Hydrodynamics in the Coastal Environment

NARCIS (Netherlands)

Salmon, J.E.

2016-01-01

Stochastic wave models play a central role in our present-day wave modelling capabilities. They are frequently used to compute wave statistics, to generate boundary conditions and to include wave effects in coupled model systems. Historically, such models were developed to predict the wave field

The Record Los Angeles Heat Event of September 2010: 1. Synoptic-Scale-Meso-β-Scale Analyses of Interactive Planetary Wave Breaking, Terrain- and Coastal-Induced Circulations

Science.gov (United States)

Kaplan, Michael L.; Tilley, Jeffrey S.; Hatchett, Benjamin J.; Smith, Craig M.; Walston, Joshua M.; Shourd, Kacie N.; Lewis, John M.

2017-10-01

On 27 September 2010 the Los Angeles Civic Center reached its all-time record maximum temperature of 45°C before 1330 local daylight time with several other regional stations observing all-time record breaking heat early in that afternoon. This record event is associated with a general circulation pattern predisposed to hemispheric wave breaking. Three days before the event, wave breaking organizes complex terrain- and coastal-induced processes that lead to isentropic surface folding into the Los Angeles Basin. The first wave break occurs over the western two thirds of North America leading to trough elongation across the southwestern U.S. Collocated with this trough is an isentropic potential vorticity filament that is the locus of a thermally indirect circulation central to warming and associated thickness increases and ridging westward across the Great Basin. In response to this circulation, two subsynoptic wave breaks are triggered along the Pacific coast. The isentropic potential vorticity filament is coupled to the breaking waves and the interaction produces a subsynoptic low-pressure center and a deep vortex aloft over the southeastern California desert. This coupling leads to advection of an elevated mixed layer over Point Conception the night before the record-breaking heat that creates a coastally trapped low-pressure area southwest of Los Angeles. The two low-pressure centers create a low-level pressure gradient and east-southeasterly jet directed offshore over the Los Angeles Basin by sunrise on 27 September. This allows the advection of low-level warm air from the inland terrain toward the coastally trapped disturbance and descending circulation resulting in record heating.

Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

Science.gov (United States)

Cheriton, Olivia; Storlazzi, Curt; Rosenberger, Kurt

2016-01-01

Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04–0.004 Hz) and very low frequency (0.004–0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

Science.gov (United States)

Cheriton, Olivia M.; Storlazzi, Curt D.; Rosenberger, Kurt J.

2016-05-01

Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04-0.004 Hz) and very low frequency (0.004-0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Yasuo; Mayer, D.W.; Argo, R.S.

1982-01-01

Models are presented to estimate the migration of toxic contaminants in coastal waters. Ocean current is simulated by the vertically-averaged, finite element, two-demensional model known as CAFE-I with the Galerkin weighted residual technique. The refraction of locally generated waves or swells is simulated by the wave refraction model, LO3D. Using computed current, depth, and wave characteristics, the finite element model, FETRA, simulated sediment and contaminant transport in coastal waters, estuaries and rivers. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interaction, and the mechanism governing the transport, deposition, and resuspension of contaminated sediment. Several simple equations such as the unsteady, advection-diffusion equation, the equation for noncohesive-sediment load due to wind-induced waves in offshore and surf zones, and the equation for sediment-radionuclide transport simulation were solved during the preliminary testing of the model. (Kato, T.)

Wave hindcast experiments in the Indian Ocean using MIKE 21 SW ...

Indian Academy of Sciences (India)

Wave prediction and hindcast studies are important in ocean engineering, coastal ... wave data can be used for the assessment of wave climate in offshore and coastal areas. In the .... for the change in performance during SW monsoon.

Wave-induced current considering wave-tide interaction in Haeundae

Science.gov (United States)

Lim, Hak Soo

2017-04-01

The Haeundae, located at the south eastern end of the Korean Peninsula, is a famous beach, which has an approximately 1.6 km long and 70 m wide coastline. The beach has been repeatedly eroded by the swell waves caused by typhoons in summer and high waves originating in the East Sea in winter. The Korean government conducted beach restoration projects including beach nourishment (620,000 m3) and construction of two submerged breakwaters near both ends of the beach. To prevent the beach erosion and to support the beach restoration project, the Korean government initiated a R&D project, the development of coastal erosion control technology since 2013. As a part of the project, we have been measuring waves and currents at a water depth of 22 m, 1.8 km away from the beach using an acoustic wave and current meter (AWAC) continuously for more than three years; we have also measured waves and currents intensively near the surf-zone in summer and winter. In this study, a numerical simulation using a wave and current coupled model (ROMS-SWAN) was conducted for determining the wave-induced current considering seasonal swell waves (Hs : 2.5 m, Tp: 12 s) and for better understanding of the coastal process near the surf-zone in Haeundae. By comparing the measured and simulated results, we found that cross-shore current during summer is mainly caused by the eddy produced by the wave-induced current near the beach, which in turn, is generated by the strong waves coming from the SSW and S directions. During other seasons, longshore wave-induced current is produced by the swell waves coming from the E and ESE directions. The longshore current heading west toward Dong-Back Island, west end of the beach, during all the seasons and eddy current toward Mipo-Port, east end of the beach, in summer which is well matched with the observed residual current. The wave-induced current with long-term measurement data is incorporated in simulation of sediment transport modeling for developing

Generating synthetic wave climates for coastal modelling: a linear mixed modelling approach

Science.gov (United States)

Thomas, C.; Lark, R. M.

2013-12-01

Numerical coastline morphological evolution models require wave climate properties to drive morphological change through time. Wave climate properties (typically wave height, period and direction) may be temporally fixed, culled from real wave buoy data, or allowed to vary in some way defined by a Gaussian or other pdf. However, to examine sensitivity of coastline morphologies to wave climate change, it seems desirable to be able to modify wave climate time series from a current to some new state along a trajectory, but in a way consistent with, or initially conditioned by, the properties of existing data, or to generate fully synthetic data sets with realistic time series properties. For example, mean or significant wave height time series may have underlying periodicities, as revealed in numerous analyses of wave data. Our motivation is to develop a simple methodology to generate synthetic wave climate time series that can change in some stochastic way through time. We wish to use such time series in a coastline evolution model to test sensitivities of coastal landforms to changes in wave climate over decadal and centennial scales. We have worked initially on time series of significant wave height, based on data from a Waverider III buoy located off the coast of Yorkshire, England. The statistical framework for the simulation is the linear mixed model. The target variable, perhaps after transformation (Box-Cox), is modelled as a multivariate Gaussian, the mean modelled as a function of a fixed effect, and two random components, one of which is independently and identically distributed (iid) and the second of which is temporally correlated. The model was fitted to the data by likelihood methods. We considered the option of a periodic mean, the period either fixed (e.g. at 12 months) or estimated from the data. We considered two possible correlation structures for the second random effect. In one the correlation decays exponentially with time. In the second

The use of mangroves in coastal protection

NARCIS (Netherlands)

Loi, T.T.; Verhagen, H.J.

2012-01-01

Apart from many ecological advantages, mangroves in front of a coastal defence may lower the construction and maintenance costs of the defence. Although mangroves have hardly any reducing effect on water levels (and on tsunami impact) mangroves may significantly reduce wave attack on a coastal dike,

Study of storm surge trends in typhoon-prone coastal areas based on observations and surge-wave coupled simulations

Science.gov (United States)

Feng, Xingru; Li, Mingjie; Yin, Baoshu; Yang, Dezhou; Yang, Hongwei

2018-06-01

This is a study of the storm surge trends in some of the typhoon-prone coastal areas of China. An unstructured-grid, storm surge-wave-tide coupled model was established for the coastal areas of Zhejiang, Fujian and Guangdong provinces. The coupled model has a high resolution in coastal areas, and the simulated results compared well with the in situ observations and satellite altimeter data. The typhoon-induced storm surges along the coast of the study areas were simulated based on the established coupled model for the past 20 years (1997-2016). The simulated results were used to analyze the trends of the storm surges in the study area. The extreme storm surge trends along the central coast of Fujian Province reached up to 0.06 m/y, significant at the 90% confidence level. The duration of the storm surges greater than 1.0 and 0.7 m had an increasing trend along the coastal area of northern Fujian Province, significant at confidence levels of 70%-91%. The simulated trends of the extreme storm surges were also validated by observations from two tide gauge stations. Further studies show that the correlation coefficient (RTE) between the duration of the storm surge greater than 1 m and the annual ENSO index can reach as high as 0.62, significant at the 99% confidence level. This occurred in a location where the storm surge trend was not significant. For the areas with significant increasing storm surge trends, RTE was small and not significant. This study identified the storm surge trends for the full complex coastline of the study area. These results are useful both for coastal management by the government and for coastal engineering design.

Coastal Inlets Research Program

Science.gov (United States)

2013-03-01

Geomorphic  Evolution • ADCP Currents  • ADCP Backscatter • Total Suspended  Solids • Turbidity  Sensor  Array • Wave Array • Light Attenuation • Surface...shore for both East and West Coastal and Hydraulics Laboratory 38 Coast Applications Summary and New Initiatives http://cirp.usace.army.milCIRP...Nearshore Berm Target Date: Sep FY15- Sep FY17 • Coastal experiments on Atlantic • Estuary experiments in Currituck Sound • Overland

Coping with Higher Sea Levels and Increased Coastal Flooding in New York City. Chapter 13

Science.gov (United States)

Gornitz, Vivien; Horton, Radley; Bader, Daniel A.; Orton, Philip; Rosenzweig, Cynthia

2017-01-01

The 837 km New York City shoreline is lined by significant economic assets and dense population vulnerable to sea level rise and coastal flooding. After Hurricane Sandy in 2012, New York City developed a comprehensive plan to mitigate future climate risks, drawing upon the scientific expertise of the New York City Panel on Climate Change (NPCC), a special advisory group comprised of university and private-sector experts. This paper highlights current NPCC findings regarding sea level rise and coastal flooding, with some of the City's ongoing and planned responses. Twentieth century sea level rise in New York City (2.8 cm/decade) exceeded the global average (1.7 cm/decade), underscoring the enhanced regional risk to coastal hazards. NPCC (2015) projects future sea level rise at the Battery of 28 - 53 cm by the 2050s and 46 - 99 cm by the 2080s, relative to 2000 - 2004 (mid-range, 25th - 75th percentile). High-end SLR estimates (90th percentile) reach 76 cm by the 2050s, and 1.9 m by 2100. Combining these projections with updated FEMA flood return period curves, assuming static flood dynamics and storm behavior, flood heights for the 100-year storm (excluding waves) attain 3.9-4.5 m (mid-range), relative to the NAVD88 tidal datum, and 4.9 m (high end) by the 2080s, up from 3.4 m in the 2000s. Flood heights with a 1% annual chance of occurrence in the 2000s increase to 2.0 - 5.4% (mid-range) and 12.7% per year (high-end), by the 2080s. Guided by NPCC (2013, 2015) findings, New York City has embarked on a suite of initiatives to strengthen coastal defenses, employing various approaches tailored to specific neighborhood needs. NPCC continues its collaboration with the city to investigate vulnerability to extreme climate events, including heat waves, inland floods and coastal storms. Current research entails higher-resolution neighborhood-level coastal flood mapping, changes in storm characteristics, surge height interactions with sea level rise, and stronger engagement

Design wave estimation considering directional distribution of waves

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Deo, M.C

.elsevier.com/locate/oceaneng Technical Note Design wave estimation considering directional distribution of waves V. Sanil Kumar a,C3 , M.C. Deo b a OceanEngineeringDivision,NationalInstituteofOceanography,Donapaula,Goa-403004,India b Civil... of Physical Oceanography Norway, Report method for the routine 18, 1020–1034. ocean waves. Division of No. UR-80-09, 187 p. analysis of pitch and roll Conference on Coastal Engineering, 1. ASCE, Taiwan, pp. 136–149. Deo, M.C., Burrows, R., 1986. Extreme wave...

Hurricane Isaac: observations and analysis of coastal change

Science.gov (United States)

Guy, Kristy K.; Stockdon, Hilary F.; Plant, Nathaniel G.; Doran, Kara S.; Morgan, Karen L.M.

2013-01-01

Understanding storm-induced coastal change and forecasting these changes require knowledge of the physical processes associated with a storm and the geomorphology of the impacted coastline. The primary physical process of interest is sediment transport that is driven by waves, currents, and storm surge associated with storms. Storm surge, which is the rise in water level due to the wind, barometric pressure, and other factors, allows both waves and currents to impact parts of the coast not normally exposed to these processes. Coastal geomorphology reflects the coastal changes associated with extreme-storm processes. Relevant geomorphic variables that are observable before and after storms include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach slope. These variables, in addition to hydrodynamic processes, can be used to quantify coastal change and are used to predict coastal vulnerability to storms (Stockdon and others, 2007). The U.S. Geological Survey (USGS) National Assessment of Coastal Change Hazards (NACCH) project (http://coastal.er.usgs.gov/national-assessment/) provides hazard information to those concerned about the Nation’s coastlines, including residents of coastal areas, government agencies responsible for coastal management, and coastal researchers. Extreme-storm research is a component of the NACCH project (http://coastal.er.usgs.gov/hurricanes/) that includes development of predictive understanding, vulnerability assessments using models, and updated observations in response to specific storm events. In particular, observations were made to determine morphological changes associated with Hurricane Isaac, which made landfall in the United States first at Southwest Pass, at the mouth of the Mississippi River, at 0000 August 29, 2012 UTC (Coordinated Universal Time) and again, 8 hours later, west of Port Fourchon, Louisiana (Berg, 2013). Methods of observation included oblique aerial photography

Predicting location-specific extreme coastal floods in the future climate by introducing a probabilistic method to calculate maximum elevation of the continuous water mass caused by a combination of water level variations and wind waves

Science.gov (United States)

Leijala, Ulpu; Björkqvist, Jan-Victor; Johansson, Milla M.; Pellikka, Havu

2017-04-01

Future coastal management continuously strives for more location-exact and precise methods to investigate possible extreme sea level events and to face flooding hazards in the most appropriate way. Evaluating future flooding risks by understanding the behaviour of the joint effect of sea level variations and wind waves is one of the means to make more comprehensive flooding hazard analysis, and may at first seem like a straightforward task to solve. Nevertheless, challenges and limitations such as availability of time series of the sea level and wave height components, the quality of data, significant locational variability of coastal wave height, as well as assumptions to be made depending on the study location, make the task more complicated. In this study, we present a statistical method for combining location-specific probability distributions of water level variations (including local sea level observations and global mean sea level rise) and wave run-up (based on wave buoy measurements). The goal of our method is to obtain a more accurate way to account for the waves when making flooding hazard analysis on the coast compared to the approach of adding a separate fixed wave action height on top of sea level -based flood risk estimates. As a result of our new method, we gain maximum elevation heights with different return periods of the continuous water mass caused by a combination of both phenomena, "the green water". We also introduce a sensitivity analysis to evaluate the properties and functioning of our method. The sensitivity test is based on using theoretical wave distributions representing different alternatives of wave behaviour in relation to sea level variations. As these wave distributions are merged with the sea level distribution, we get information on how the different wave height conditions and shape of the wave height distribution influence the joint results. Our method presented here can be used as an advanced tool to minimize over- and

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

OpenAIRE

O'Boyle, Louise; Elsäßer, Björn; Whittaker, Trevor

2017-01-01

Wave energy converters (WECs) inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An ...

Doubling of coastal flooding frequency within decades due to sea-level rise

Science.gov (United States)

Vitousek, Sean; Barnard, Patrick L.; Fletcher, Charles H.; Frazer, Neil; Erikson, Li; Storlazzi, Curt D.

2017-01-01

Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

Doubling of coastal flooding frequency within decades due to sea-level rise.

Science.gov (United States)

Vitousek, Sean; Barnard, Patrick L; Fletcher, Charles H; Frazer, Neil; Erikson, Li; Storlazzi, Curt D

2017-05-18

Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

The simulation of Typhoon-induced coastal inundation in Busan, South Korea applying the downscaling technique

Science.gov (United States)

Jang, Dongmin; Park, Junghyun; Yuk, Jin-Hee; Joh, MinSu

2017-04-01

Due to typhoons, the south coastal cities including Busan in South Korea coastal are very vulnerable to a surge, wave and corresponding coastal inundation, and are affected every year. In 2016, South Korea suffered tremendous damage by typhoon 'Chaba', which was developed near east-north of Guam on Sep. 28 and had maximum 10-minute sustained wind speed of about 50 m/s, 1-minute sustained wind speed of 75 m/s and a minimum central pressure of 905 hpa. As 'Chaba', which is the strongest since typhoon 'Maemi' in 2003, hit South Korea on Oct. 5, it caused a massive economic and casualty damage to Ulsan, Gyeongju and Busan in South Korea. In particular, the damage of typhoon-induced coastal inundation in Busan, where many high-rise buildings and residential areas are concentrated near coast, was serious. The coastal inundation could be more affected by strong wind-induced wave than surge. In fact, it was observed that the surge height was about 1 m averagely and a significant wave height was about 8 m at coastal sea nearby Busan on Oct. 5 due to 'Chaba'. Even though the typhoon-induced surge elevated the sea level, the typhoon-induced long period wave with wave period of more than 15s could play more important role in the inundation. The present work simulated the coastal inundation induced by 'Chaba' in Busan, South Korea considering the effects of typhoon-induced surge and wave. For 'Chaba' hindcast, high resolution Weather Research and Forecasting model (WRF) was applied using a reanalysis data produced by NCEP (FNL 0.25 degree) on the boundary and initial conditions, and was validated by the observation of wind speed, direction and pressure. The typhoon-induced coastal inundation was simulated by an unstructured gird model, Finite Volume Community Ocean Model (FVCOM), which is fully current-wave coupled model. To simulate the wave-induced inundation, 1-way downscaling technique of multi domain was applied. Firstly, a mother's domain including Korean peninsula was

Comparison between the Coastal Impacts of Cyclone Nargis and the Indian Ocean Tsunami

Science.gov (United States)

Fritz, H. M.; Blount, C.

2009-12-01

On 26 December 2004 a great earthquake with a moment magnitude of 9.3 occurred off the North tip of Sumatra, Indonesia. The Indian Ocean tsunami claimed 230,000 lives making it the deadliest in recorded history. Less than 4 years later tropical cyclone Nargis (Cat. 4) made landfall in Myanmar’s Ayeyarwady delta on 2 May 2008 causing the worst natural disaster in Myanmar’s recorded history. Official death toll estimates exceed 138,000 fatalities making it the 7th deadliest cyclone ever recorded worldwide. The Bay of Bengal counts seven tropical cyclones with death tolls in excess of 100,000 striking India and Bangladesh in the past 425 years, which highlights the difference in return periods between extreme cyclones and tsunamis. Damage estimates at over $10 billion made Nargis the most damaging cyclone ever recorded in the Indian Ocean. Although the two natural disasters are completely different in their generation mechanisms they both share massive coastal inundations as primary damage and death cause. While the damage patterns exhibit similarities the forcing differs. The primary tsunami impact is dominated by the runup of a few main waves washing rapidly ashore and inducing high lateral forces. On the contrary the tropical cyclone storm surge damage is the result of numerous storm waves continuously hitting the flooded structures on the elevated storm tide level. While coastal vegetation such as mangroves may be effective at reducing superimposed storm waves they are limited at reducing storm surge. Unfortunately, mangroves have been significantly cut for charcoal and land use as rice paddies in Myanmar due to rapid population growth and economic reasons, thereby increasing coastal vulnerability and land loss due to erosion (Figure 1). The period of a storm surge is typically an order of magnitude longer than the period of a tsunami resulting in significantly larger inundation distances along coastal plains and river deltas. The storm surge of cyclone Nargis

First results of the research project MIRAMAR, Innovative Methodologies for Coastal Environmental Monitoring and Analysis

Science.gov (United States)

Rovere, A.; Casella, E.; Vacchi, M.; Mucerino, L.; Pedroncini, A.; Ferrari, M.; Firpo, M.

2013-12-01

A large part of the Mediterranean coastlines are strongly affected by coastal erosion. This is mainly due to human impact, natural hazards and their mutual interaction. All along the Regione Liguria coastlines (Northwestern Mediterranean), significant problems of coastal erosion are reported since the '60s. In this study, we focus on the coastal area between Albenga and Savona, where dramatic coastal retreat of ~2 m y-1 has been inferred from comparison of historic maps and older aerial pictures. Beach monitoring is essential in order to understand the mechanisms of evolution of soft coasts, and the rates of erosion. Traditional beach monitoring techniques involve topographic and bathymetric surveys of the emerged and submerged beach, and/or aerial photos repeated in time and compared through geographical information systems. A major problem of this kind of approach is the high economic cost. This often leads to increase the time lag between successive monitoring campaigns to reduce survey costs, with the consequence of fragmenting the information available for coastal zone management. MIRAMar is a project funded by Regione Liguria through the PO CRO European Social Fund, and it has two main objectives: i) to study and develop an innovative technique, relatively low-cost, to monitor the evolution of the shoreline using low-altitude Unmanned Aerial Vehicle (UAV) photos; ii) to study the impact of different type of storm events on a vulnerable coastal tract subject to coastal erosion using also the data collected by the UAV instrument. To achieve these aims we use a drone with its hardware and software suit, traditional survey techniques (bathymetric surveys, topographic GPS surveys and GIS techniques) and we implement a numerical modeling chain (coupling hydrodynamic, wave and sand transport modules) in order to study the impact of different type of storm events on a vulnerable coastal tract subject to coastal erosion. Aerial picture of one of the beaches studied

Diffusion in coastal and harbour zones, effects of Waves,Wind and Currents

Science.gov (United States)

Diez, M.; Redondo, J. M.

2009-04-01

As there are multiple processes at different scales that produce turbulent mixing in the ocean, thus giving a large variation of horizontal eddy diffusivities, we use a direct method to evaluate the influence of different ambient parameters such as wave height and wind on coastal dispersion. Measurements of the diffusivity are made by digital processing of images taken from from video recordings of the sea surface near the coast. The use of image analysis allows to estimate both spatial and temporal characteristics of wave fields, surface circulation and mixing in the surf zone, near Wave breakers and inside Harbours. The study of near-shore dispersion [1], with the added complexity of the interaction between wave fields, longshore currents, turbulence and beach morphology, needs detailed measurements of simple mixing processes to compare the respective influences of forcings at different scales. The measurements include simultaneous time series of waves, currents, wind velocities from the studied area. Cuantitative information from the video images is accomplished using the DigImage video processing system [3], and a frame grabber. The video may be controlled by the computer, allowing, remote control of the processing. Spectral analysis on the images has also used n order to estimate dominant wave periods as well as the dispersion relations of dominant instabilities. The measurements presented here consist mostly on the comarison of difussion coeficients measured by evaluating the spread of blobs of dye (milk) as well as by measuring the separation between different buoys released at the same time. We have used a techniques, developed by Bahia(1997), Diez(1998) and Bezerra(2000)[1-3] to study turbulent diffusion by means of digital processing of images taken from remote sensing and video recordings of the sea surface. The use of image analysis allows to measure variations of several decades in horizontal diffusivity values, the comparison of the diffusivities

Wave measurement in severe ocean currents

Digital Repository Service at National Institute of Oceanography (India)

Diwan, S.G.; Suryavanshi, A.K.; Nayak, B.U.

The measurement of ocean waves has been of particular interest, as wave data and understanding of wave phenomena are essential to ocean engineering, coastal engineering and to many marine operations. The National Institute of Oceanography, Goa...

An Improved Ocean Observing System for Coastal Louisiana: WAVCIS (WAVE-CURRENT-SURGE Information System )

Science.gov (United States)

Zhang, X.; Stone, G. W.; Gibson, W. J.; Braud, D.

2005-05-01

WAVCIS is a regional ocean observing and forecasting system. It was designed to measure, process, forecast, and distribute oceanographic and meteorological information. WAVCIS was developed and is maintained by the Coastal Studies Institute at Louisiana State University. The in-situ observing stations are distributed along the central Louisiana and Mississippi coast. The forecast region covers the entire Gulf of Mexico with emphasis on offshore Louisiana. By using state-of-the-art instrumentation, WAVCIS measures directional waves, currents, temperature, water level, conductivity, turbidity, salinity, dissolved oxygen, chlorophyll, Meteorological parameters include wind speed and direction, air pressure and temperature visibility and humidity. Through satellite communication links, the measured data are transmitted to the WAVCIS laboratory. After processing, they are available to the public via the internet on a near real-time basis. WAVCIS also includes a forecasting capability. Waves, tides, currents, and winds are forecast daily for up to 80 hours in advance. There are a number of numerical wave and surge models that can be used for forecasts. WAM and SWAN are used for operational purposes to forecast sea state. Tides at each station are predicted based on the harmonic constants calculated from past in-situ observations at respective sites. Interpolated winds from the ETA model are used as input forcing for waves. Both in-situ and forecast information are available online to the users through WWW. Interactive GIS web mapping is implemented on the WAVCIS webpage to visualize the model output and in-situ observational data. WAVCIS data can be queried, retrieved, downloaded, and analyzed through the web page. Near real-time numerical model skill assessment can also be performed by using the data from in-situ observing stations.

The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

Science.gov (United States)

Narayan, Siddharth; Beck, Michael W; Reguero, Borja G; Losada, Iñigo J; van Wesenbeeck, Bregje; Pontee, Nigel; Sanchirico, James N; Ingram, Jane Carter; Lange, Glenn-Marie; Burks-Copes, Kelly A

2016-01-01

There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost

The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

Directory of Open Access Journals (Sweden)

Siddharth Narayan

Full Text Available There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences and (ii analyses of the effectiveness of coastal habitats (natural defences in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become

Summit to Sea Characterization of Coastal Watersheds - Puerto Rico 2004

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This Characterization of Coastal Watershed for Puerto Rico, Culebra Island and Vieques Island, is a GIS products suite consisting of layers derived from diverse...

Evolution of Cross-Shore Profile Models for Sustainable Coastal Design

Science.gov (United States)

Ismail, Nabil; El-Sayed, Mohamed

2014-05-01

Selection and evaluation of coastal structures are correlated with environmental wave and current parameters as well as cross shore profiles. The coupling between the environmental conditions and cross shore profiles necessitates the ability to predict reasonably the cross shore profiles. Results obtained from the validation of a cross-shore profile evolution model, Uniform Beach Sediment Transport-Time-Averaged Cross-Shore (UNIBEST-TC), were examined and further analyzed to reveal the reasons for the discrepancy between the model predictions of the field data at the surf zone of the Duck Beach in North Carolina, USA. The UNIBEST model was developed to predict the main cross shore parameters of wave height, direction, cross shore and long shore currents. However, the results of the model predictions are generally satisfactory for wave height and direction but not satisfactory for the remaining parameters. This research is focused on exploring the discrepancy between the model predictions and the field data of the Duck site, and conducting further analyses to recommend model refinements. The discrepancy is partially attributed due to the fact that the measured values, were taken close to the seabed, while the predicted values are the depth-averaged velocity. Further examination indicated that UNIBEST-TC model runs consider the RMS of the wave height spectrum with a constant gamma-value from the offshore wave spectrum at 8.0m depth. To confirm this argument, a Wavelet Analysis was applied to the time series of wave height and longshore current velocity parameters at the Duck site. The significant wave height ranged between 0.6m and 4.0m while the frequencies ranged between 0.08 to 0.2Hz at 8.0m water depth. Four cases corresponding to events of both high water level and low water level at Duck site were considered in this study. The results show that linear and non-linear interaction between wave height and long-shore current occur over the range of frequencies

Modern sedimentation processes in a wave-dominated coastal embayment: Espírito Santo Bay, southeast Brazil

Science.gov (United States)

Bastos, Alex Cardoso; Costa Moscon, Daphnne Moraes; Carmo, Dannilo; Neto, José Antonio Baptista; da Silva Quaresma, Valéria

2015-02-01

Sediment dynamics in wave-dominated coastal embayments are generally controlled by seasonal meteorological conditions, storms having a particularly strong influence. In the present study, such hydrodynamic processes and associated deposits have been investigated in a coastal embayment located along the southeast coast of Brazil, i.e. Espírito Santo Bay, in the winter (June/July) of 2008. The bay has undergone a series of human interventions that have altered the local hydrodynamic processes and, consequently, the sediment transport patterns. Facies distribution and sediment dynamics were examined by acoustic seabed mapping, sediment and core sampling, hydrodynamic measurements and sand transport modelling. The results show that sediment distribution can be described in terms of nearshore and offshore zones. The offshore bay sector is predominantly composed of "palimpsest" lithoclastic medium-coarse sands deposited in the course of the early Holocene transgression that peaked about 5,000 years ago. In the inner bay or nearshore zone (up to depths of 4-8 m), these older transgressive deposits are today overlain by a thin (up to 30-cm-thick) and partly patchy blanket of younger regressive fine sand/muddy fine sands. Both coarse- and fine-grained facies are being reworked during high-energy events (Hs>1.5 m) when fine sediment is resuspended, weak tide-induced drift currents causing the sand patches to be displaced. The coarser sediment, by contrast, is mobilized as bedload to produce wave ripples with spacings of up to 1.2 m. These processes lead to a sharp spatial delimitation between a fine sand/mud facies and a rippled coarse sand facies. The fine sand patches have a relief of about 20-30 cm and reveal a typical internal tempestite depositional sequence. Fair-weather wave-induced sediment transport (Hs<1 m), supported by weak tidal currents, seems to only affect the fine sediment facies. Sediment dynamics in Espírito Santo Bay is thus essentially controlled by

Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Kofoed, Jens Peter; Friis-Madsen, Erik

2013-01-01

An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration....... An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection...... of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon...

The new Euskalmet coastal-maritime warning system

Science.gov (United States)

Gaztelumendi, Santiago; Egaña, Joseba; Liria, Pedro; Gonzalez, Manuel; Aranda, José Antonio; Anitua, Pedro

2016-06-01

This work presents the main characteristics of the Basque Meteorology Agency (Euskalmet) maritime-coastal risk warning system, with special emphasis on the latest updates, including a clear differentiation on specific warning messages addressing sea conditions for navigation purposes in the first 2 nautical miles, and expected coastal impacts. Some details of the warning bulletin for maritime and coastal risk situations are also presented, together with other communication products and strategies used in coastal and maritime severe episodes at the Basque coast. Today, three different aspects are included in the coastal-maritime risk warning system in Basque Country, related to the main potential severe events that affecting coastal activities. - "Galerna" risk relates to a sudden wind reversal that can severely affect coastal navigation and recreational activities. - "Navigation" risk relates to severe sea state conditions for 0-2 miles, affecting different navigation activities. - "Coastal impact" risk relates to adverse wave characteristics and tidal surges that induce flooding events and different impacts in littoral areas.

Coastal morphology and dynamics of two beaches of Favignana

International Nuclear Information System (INIS)

Pasanisi, Francesco; Tebano, Carlo; Grauso, Sergio

2015-01-01

Results of an investigation on the coastal morphology and dynamics of two pocket beaches of Favignana, Cala Azzurra and Lido Burrone, are presented. Four detailed hydrographic surveys were performed using multibeam echo sounder with sidescan sonar and differential marine GPS. Surveys were repeated in different periods following the same navigation project. Moreover, incident wave climate and coastal hydrodynamics were investigated using state-of-the-art numerical models. Results of in-situ activities indicate little bathymetric variations among different surveys and suggest a substantial stability of submerged beach profiles limited to surveyed area. Slightly greater bathymetric changes and a generally more intense coastal dynamics were observed at Cala Azzurra compared to Lido Burrone. Simulations of wave propagation and nearshore circulation currents provided results consistent with field observations [it

Rogue waves in shallow water

Science.gov (United States)

Soomere, T.

2010-07-01

Most of the processes resulting in the formation of unexpectedly high surface waves in deep water (such as dispersive and geometrical focusing, interactions with currents and internal waves, reflection from caustic areas, etc.) are active also in shallow areas. Only the mechanism of modulational instability is not active in finite depth conditions. Instead, wave amplification along certain coastal profiles and the drastic dependence of the run-up height on the incident wave shape may substantially contribute to the formation of rogue waves in the nearshore. A unique source of long-living rogue waves (that has no analogues in the deep ocean) is the nonlinear interaction of obliquely propagating solitary shallow-water waves and an equivalent mechanism of Mach reflection of waves from the coast. The characteristic features of these processes are (i) extreme amplification of the steepness of the wave fronts, (ii) change in the orientation of the largest wave crests compared with that of the counterparts and (iii) rapid displacement of the location of the extreme wave humps along the crests of the interacting waves. The presence of coasts raises a number of related questions such as the possibility of conversion of rogue waves into sneaker waves with extremely high run-up. Also, the reaction of bottom sediments and the entire coastal zone to the rogue waves may be drastic.

Coastal flooding hazard related to storms and coastal evolution in Valdelagrana spit (Cadiz Bay Natural Park, SW Spain)

Science.gov (United States)

Benavente, J.; Del Río, L.; Gracia, F. J.; Martínez-del-Pozo, J. A.

2006-06-01

Mapping of coastal inundation hazard related to storms requires the combination of multiple sources of information regarding meteorological, morphological and dynamic characteristics of both the area at risk and the studied phenomena. Variables such as beach slope, storm wave height or wind speed have traditionally been used, but detailed geomorphological features of the area as well as long-term shoreline evolution trends must also be taken into account in order to achieve more realistic results. This work presents an evaluation of storm flooding hazard in Valdelagrana spit and marshes (SW Spain), considering two types of storm that are characteristic of the area: a modal storm with 1 year of recurrence interval (maximum wave height of 3.3 m), and an extreme storm with 6-10 years of recurrence interval (maximum wave height of 10.6 m), both approaching the coast perpendicularly. After calculating theoretical storm surge elevation, a digital terrain model was made by adjusting topographic data to field work and detailed geomorphological analysis. A model of flooding extent was subsequently developed for each storm type, and then corrected according to the rates of shoreline change in the last decades, which were assessed by means of aerial photographs taking the dune toe as shoreline indicator. Results show that long-term coastline trend represents an important factor in the prediction of flooding extent, since shoreline retreat causes the deterioration of natural coastal defences as dune ridges, thus increasing coastal exposure to high-energy waves. This way, it has been stated that the lack of sedimentary supply plays an important role in spatial variability of inundation extent in Valdelagrana spit. Finally, a hazard map is presented, where calculated coastal retreat rates are employed in order to predict the areas that could be affected by future inundation events.

Wave Monitoring with Wireless Sensor Networks

NARCIS (Netherlands)

Marin Perianu, Mihai; Chatterjea, Supriyo; Marin Perianu, Raluca; Bosch, S.; Dulman, S.O.; Kininmonth, Stuart; Havinga, Paul J.M.

2008-01-01

Real-time collection of wave information is required for short and long term investigations of natural coastal processes. Current wave monitoring techniques use only point-measurements, which are practical where the bathymetry is relatively uniform. We propose a wave monitoring method that is

Maximizing effectiveness of adaptation action in Pacific Island communities using coastal wave attenuation models

Science.gov (United States)

Jung, H.; Carruthers, T.; Allison, M. A.; Weathers, D.; Moss, L.; Timmermans, H.

2017-12-01

Pacific Island communities are highly vulnerable to the effects of climate change, specifically accelerating rates of sea level rise, changes to storm intensity and associated rainfall patterns resulting in flooding and shoreline erosion. Nature-based adaptation is being planned not only to reduce the risk from shoreline erosion, but also to support benefits of a healthy ecosystem (e.g., supporting fisheries or coral reefs). In order to assess potential effectiveness of the nature-based actions to dissipate wave energy, two-dimensional X-Beach models were developed to predict the wave attenuation effect of coastal adaptation actions at the pilot sites—the villages of Naselesele and Somosomo on Taveuni island, Fiji. Both sites are experiencing serious shoreline erosion due to sea level rise and storm wave. The water depth (single-beam bathymetry), land elevation (truck-based LiDAR), and vegetation data including stem density and height were collected in both locations in a June 2017 field experiment. Wave height and water velocity were also measured for the model setup and calibration using a series of bottom-mounted instruments deployed in the 0-15 m water depth portions of the study grid. The calibrated model will be used to evaluate a range of possible adaptation actions identified by the community members of Naselesele and Somosomo. Particularly, multiple storm scenario runs with management-relevant shoreline restoration/adaptation options will be implemented to evaluate efficiencies of each adaptation action (e.g., no action, with additional planted trees, with sand mining, with seawalls constructed with natural materials, etc.). These model results will help to better understand how proposed adaption actions may influence future shoreline change and maximize benefits to communities in island nations across the SW Pacific.

Modeling of Nonlinear Hydrodynamics of the Coastal Areas of the Black Sea by the Chain of the Proprietary and Open Source Models

Science.gov (United States)

Kantardgi, Igor; Zheleznyak, Mark; Demchenko, Raisa; Dykyi, Pavlo; Kivva, Sergei; Kolomiets, Pavlo; Sorokin, Maxim

2014-05-01

The nearshore hydrodynamic fields are produced by the nonlinear interactions of the shoaling waves of different time scales and currents. To simulate the wind wave and swells propagated to the coasts, wave generated near shore currents, nonlinear-dispersive wave transformation and wave diffraction in interaction with coastal and port structure, sediment transport and coastal erosion the chains of the models should be used. The objective of this presentation is to provide an overview of the results of the application of the model chains for the assessment of the wave impacts on new construction designed at the Black Sea coasts and the impacts of these constructions on the coastal erosion/ accretion processes to demonstrate needs for further development of the nonlinear models for the coastal engineering applications. The open source models Wave Watch III and SWAN has been used to simulate wave statistics of the dedicated areas of the Black Sea in high resolution to calculated the statistical parameters of the extreme wave approaching coastal zone construction in accordance with coastal engineering standards. As the main tool for the costal hydrodynamic simulations the modeling system COASTOX-MORPHO has been used, that includes the following models. HWAVE -code based on hyperbolic version of mild slope equations., HWAVE-S - spectral version of HWAVE., BOUSS-FNL - fully nonlinear system of Boussinesq equations for simulation wave nonlinear -dispersive wave transformation in coastal areas. COASTOX-CUR - the code provided the numerical solution of the Nonlinear Shallow Water Equations (NLSWE) by finite-volume methods on the unstructured grid describing the long wave transformation in the coastal zone with the efficient drying -wetting algorithms to simulate the inundation of the coastal areas including tsunami wave runup. Coastox -Cur equations with the radiation stress term calculated via near shore wave fields simulate the wave generated nearhore currents. COASTOX

Wave transmission in mangrove forests

NARCIS (Netherlands)

Schiereck, G.J.; Booij, N.

1995-01-01

There is an increasing awareness of the role of mangrove forests in coastal ecosystems and coastal protection. At the transition between ocean and land, they have to absorb the energy that comes from the motion of the water. Little quantitative in formation is available, however, on wave

Generation and Analysis of Random Waves

DEFF Research Database (Denmark)

Liu, Zhou; Frigaard, Peter

applied to hydrology, wind mechanics, ice mechanics, etc., not to mention the fact that spectral analysis comes originally from optics and electronics. The book intents to be a textbook for senior and graduate students who have interest in coastal and offshore structures. The only pre......Sea waves are the most important phenomenon to be considered in the design of coastal and offshore structures. It should be stressed that, even though all contents in the book are related to sea waves, they have a broader application in practice. For example, the extreme theory has also been......-requirement for the book is the knowledge of linear wave theory....

Numerical modeling of wave overwash on low-crested sand barriers

NARCIS (Netherlands)

Tuan, T.Q.; Verhagen, H.J.; Visser, P.J.; Stive, M.

2006-01-01

For management of coastal breaching hazards it is critical to be able to assess the potential of coastal barrier breaching as a result of wave actions during storm surges (wave overwash). This phenomenon is known as the breach initiation phase; the mechanisms behind this are not very well

Gabor Wave Packet Method to Solve Plasma Wave Equations

International Nuclear Information System (INIS)

Pletzer, A.; Phillips, C.K.; Smithe, D.N.

2003-01-01

A numerical method for solving plasma wave equations arising in the context of mode conversion between the fast magnetosonic and the slow (e.g ion Bernstein) wave is presented. The numerical algorithm relies on the expansion of the solution in Gaussian wave packets known as Gabor functions, which have good resolution properties in both real and Fourier space. The wave packets are ideally suited to capture both the large and small wavelength features that characterize mode conversion problems. The accuracy of the scheme is compared with a standard finite element approach

State of the Art in the Design of Coastal Structures

DEFF Research Database (Denmark)

Burcharth, H. F.

1997-01-01

Coastal structures are used in coastal defence schemes with the objective of preventing shoreline erosion and flooding of the hinterland. Other objectives are sheltering of harbour basins and entrances against waves, stabilization of navigation channels at inlets, and protection of water intakes ...

State of the Art in the Design of Coastal Structures

DEFF Research Database (Denmark)

Burcharth, Hans F.

1998-01-01

Coastal structures are used in coastal defence schemes with the objective of preventing shoreline erosion and flooding of the hinterland. Other objectives are sheltering of harbour basins and entrances against waves, stabilization of navigation channels at inlets and protection of water intakes a...

Relative role of subinertial and superinertial modes in the coastal long wave response forced by the landfall of a tropical cyclone

Science.gov (United States)

Ke, Ziming; Yankovsky, Alexander E.

2011-06-01

A set of numerical experiments has been performed in order to analyze the long-wave response of the coastal ocean to a translating mesoscale atmospheric cyclone approaching the coastline at a normal angle. An idealized two-slope shelf topography is chosen. The model is forced by a radially symmetric atmospheric pressure perturbation with a corresponding gradient wind field. The cyclone's translation speed, radius, and the continental shelf width are considered as parameters whose impact on the long wave period, modal structure, and amplitude is studied. Subinertial continental shelf waves (CSW) dominate the response under typical forcing conditions and on the narrower shelves. They propagate in the downstream (in the sense of Kelvin wave propagation) direction. Superinertial edge wave modes have higher free surface amplitudes and faster phase speeds than the CSW modes. While potentially more dangerous, edge waves are not as common as subinertial shelf waves because their generation requires a wide, gently sloping shelf and a storm system translating at a relatively high (˜10 m s -1 or faster) speed. A relatively smaller size of an atmospheric cyclone also favors edge wave generation. Edge waves with the highest amplitude (up to 60% of the forced storm surge) propagate upstream. They are produced by a storm system with an Eulerian time scale equal to the period of a zero-mode edge wave with the wavelength of the storm spatial scale. Large amplitude edge waves were generated during Hurricane Wilma's landfall (2005) on the West Florida shelf with particularly severe flooding occurring upstream of the landfall site.

Intraseasonal response of the northern Indian Ocean coastal waveguide to the Madden-Julian Oscillation

Digital Repository Service at National Institute of Oceanography (India)

Vialard, J.; Shenoi, S.S.C.; Mc; Shankar, D.; Durand, F.; Fernando, V.; Shetye, S.R.

Author version: Geophys. Res. Lett.: 36(14); 2009; doi:10.1029/2009GL038450; 5 pp Intraseasonal response of Northern Indian Ocean coastal waveguide to the Madden-Julian Oscillation J. Vialard 1 2 , S.S.C Shenoi 2 , J.P. McCreary 3 , D. Shankar 2... involving both equatorial wave dynamics and coastal wave propagation around the perimeter of the northern Indian Ocean [McCreary et al., 1993]. The East India Coastal Current (EICC), for example, is strongly influenced by remote wind forcing from...

Coastal zone

International Nuclear Information System (INIS)

2002-01-01

The report entitled Climate Change Impacts and Adaptation : A Canadian Perspective, presents a summary of research regarding the impacts of climate change on key sectors over the past five years as it relates to Canada. This chapter on the coastal zone focuses on the impact of climate change on Canada's marine and Great Lakes coasts with tips on how to deal with the impacts associated with climate change in sensitive environments. This report is aimed at the sectors that will be most affected by adaptation decisions in the coastal zone, including fisheries, tourism, transportation and water resources. The impact of climate change in the coastal zone may include changes in water levels, wave patterns, storm surges, and thickness of seasonal ice cover. The Intergovernmental Panel on Climate Change projects global average sea level will rise between 9 and 88 centimetres between 1990 to 2100, but not all areas of Canada will experience the same rate of future sea level change. The main physical impact would be shoreline change that could result in a range of biophysical and socio-economic impacts, some beneficial, some negative. The report focuses on issues related to infrastructure and communities in coastal regions. It is noted that appropriate human adaptation will play a vital role in reducing the extent of potential impacts by decreasing the vulnerability of average zone to climate change. The 3 main trends in coastal adaptation include: (1) increase in soft protection, retreat and accommodation, (2) reliance on technology such as geographic information systems to manage information, and (3) awareness of the need for coastal adaptation that is appropriate for local conditions. 61 refs., 7 figs

Summit to Sea Characterization of Coastal Watersheds - US Virgin Islands 2005

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This Characterization of Coastal Watershed for St Croix, St. John and St Thomas, US Virgin Islands, is a GIS products suite consisting of layers derived from diverse...

Hindcast of breaking waves and its impact at an island sheltered coast, Karwar

Science.gov (United States)

Dora, G. Udhaba; Kumar, V. Sanil

2018-01-01

Variability in the characteristics of depth-induced wave breakers along a non-uniform coastal topography and its impact on the morpho-sedimentary processes is examined at the island sheltered wave-dominated micro-tidal coast, Karwar, west coast of India. Waves are simulated using the coupled wind wave model, SWAN nested in WAVEWATCH III, forced by the reanalysis winds from different sources (NCEP/NCAR, ECMWF, and NCEP/CFSR). Impact of the wave breakers is evaluated through mean longshore current and sediment transport for various wave energy conditions across different coastal morphology. Study revealed that the NCEP/CFSR wind is comparatively reasonable in simulation of nearshore waves using the SWAN model nested by 2D wave spectra generated from WAVEWATCH III. The Galvin formula for estimating mean longshore current using the crest wave period and the Kamphuis approximation for longshore sediment transport is observed realistically at the sheltered coastal environment while the coast interacts with spilling and plunging breakers.

A socioeconomic assessment of climate change-enhanced coastal storm hazards in the U.S. Pacific Northwest

Science.gov (United States)

Baron, H. M.; Ruggiero, P.; Harris, E.

2010-12-01

Every winter, coastal communities in the U.S. Pacific Northwest are at risk to coastal change hazards caused by extreme storm events. These storms have the potential to erode large portions of the primary foredune that may be a community’s only barrier from the ocean. Furthermore, the frequency and magnitude of significant erosion events appears to be increasing, likely due to climate-related processes such as sea level rise and increases in storm wave heights. To reduce risks posed by winter storms, it is not only important to determine the impending physical impacts but it is also necessary to explore the vulnerability of the social-ecological system in the context of these hazards. Here we assess the exposure to both annually occurring and extreme storm events at various planning timelines using a methodology that incorporates the effect of a variable and changing climate on future total water levels. To do this, we have developed a suite of climate change scenarios involving a range of projections for the wave climate, global sea level rise, and the occurrence of El Niño events through 2100. Simple geometric models are then used to conservatively determine the extent of erosion that may occur for a given combination of these climatic factors. We integrate the physical hazards with socioeconomic data using a geographic information system (GIS) in order to quantify societal vulnerability, characterized by the exposure and sensitivity of a community, which is based on the distribution of people, property, and resources. Here we focus on a 14 km stretch of dune-backed coast in northwest Oregon, from Cascade Head to Cape Kiwanda—the location of two communities that, historically, have experienced problematic storm-induced coastal change, Pacific City and Neskowin. Although both of these communities have similar exposure to coastal change hazards at the present, Neskowin is more than twice as sensitive to erosion because almost all of its residents and community

Marine natural hazards in coastal zone: observations, analysis and modelling (Plinius Medal Lecture)

Science.gov (United States)

Didenkulova, Ira

2010-05-01

Giant surface waves approaching the coast frequently cause extensive coastal flooding, destruction of coastal constructions and loss of lives. Such waves can be generated by various phenomena: strong storms and cyclones, underwater earthquakes, high-speed ferries, aerial and submarine landslides. The most famous examples of such events are the catastrophic tsunami in the Indian Ocean, which occurred on 26 December 2004 and hurricane Katrina (28 August 2005) in the Atlantic Ocean. The huge storm in the Baltic Sea on 9 January 2005, which produced unexpectedly long waves in many areas of the Baltic Sea and the influence of unusually high surge created by long waves from high-speed ferries, should also be mentioned as examples of regional marine natural hazards connected with extensive runup of certain types of waves. The processes of wave shoaling and runup for all these different marine natural hazards (tsunami, coastal freak waves, ship waves) are studied based on rigorous solutions of nonlinear shallow-water theory. The key and novel results presented here are: i) parameterization of basic formulas for extreme runup characteristics for bell-shape waves, showing that they weakly depend on the initial wave shape, which is usually unknown in real sea conditions; ii) runup analysis of periodic asymmetric waves with a steep front, as such waves are penetrating inland over large distances and with larger velocities than symmetric waves; iii) statistical analysis of irregular wave runup demonstrating that wave nonlinearity nearshore does not influence on the probability distribution of the velocity of the moving shoreline and its moments, and influences on the vertical displacement of the moving shoreline (runup). Wave runup on convex beaches and in narrow bays, which allow abnormal wave amplification is also discussed. Described analytical results are used for explanation of observed extreme runup of tsunami, freak (sneaker) waves and ship waves on different coasts

DIOPS: A PC-Based Wave, Tide and Surf Prediction System

National Research Council Canada - National Science Library

Allard, Richard; Dykes, James; Kaihatu, James; Wakeham, Dean

2005-01-01

.... Regional and coastal wave predictions are made by the Simulating Waves Nearshore (SWAN) wave module that is typically initialized by offshore directional wave spectra from the Fleet Numerical Meteorological and Oceanography Center (FNMOC...

Evaluation of Tsunami Run-Up on Coastal Areas at Regional Scale

Science.gov (United States)

González, M.; Aniel-Quiroga, Í.; Gutiérrez, O.

2017-12-01

Tsunami hazard assessment is tackled by means of numerical simulations, giving as a result, the areas flooded by tsunami wave inland. To get this, some input data is required, i.e., the high resolution topobathymetry of the study area, the earthquake focal mechanism parameters, etc. The computational cost of these kinds of simulations are still excessive. An important restriction for the elaboration of large scale maps at National or regional scale is the reconstruction of high resolution topobathymetry on the coastal zone. An alternative and traditional method consists of the application of empirical-analytical formulations to calculate run-up at several coastal profiles (i.e. Synolakis, 1987), combined with numerical simulations offshore without including coastal inundation. In this case, the numerical simulations are faster but some limitations are added as the coastal bathymetric profiles are very simply idealized. In this work, we present a complementary methodology based on a hybrid numerical model, formed by 2 models that were coupled ad hoc for this work: a non-linear shallow water equations model (NLSWE) for the offshore part of the propagation and a Volume of Fluid model (VOF) for the areas near the coast and inland, applying each numerical scheme where they better reproduce the tsunami wave. The run-up of a tsunami scenario is obtained by applying the coupled model to an ad-hoc numerical flume. To design this methodology, hundreds of worldwide topobathymetric profiles have been parameterized, using 5 parameters (2 depths and 3 slopes). In addition, tsunami waves have been also parameterized by their height and period. As an application of the numerical flume methodology, the coastal parameterized profiles and tsunami waves have been combined to build a populated database of run-up calculations. The combination was tackled by means of numerical simulations in the numerical flume The result is a tsunami run-up database that considers real profiles shape

SUIT

DEFF Research Database (Denmark)

Algreen-Ussing, Gregers; Wedebrunn, Ola

2003-01-01

Leaflet om project SUIT udgivet af European Commission. Tryksagen forklarer i korte ord resultatet af projektet SUIT. Kulturværdier i Miljøspørgsmål. Vurdering af projekter og indvirkning på miljø....

User's Manual for the Simulating Waves Nearshore Model (SWAN)

National Research Council Canada - National Science Library

Allard, Richard

2002-01-01

The Simulating WAves Nearshore (SWAN) model is a numerical wave model used to obtain realistic estimates of wave parameters in coastal areas, lakes, and estuaries from given wind, bottom, and current conditions...

The relevance of the whitecapping term in wave forecasting. An analysis for the wave period of the Catalan coast.

Science.gov (United States)

Pallares, Elena; Espino, Manuel; Sánchez-Arcilla, Agustín

2013-04-01

The Catalan Coast is located in the North Western Mediterranean Sea. It is a region with highly heterogeneous wind and wave conditions, characterized by a microtidal environment, and economically very dependent from the sea and the coastal zone activities. Because some of the main coastal conflicts and management problems occur within a few kilometers of the land-ocean boundary, the level of resolution and accuracy from meteo-oceanographic predictions required is not currently available. The current work is focused on improving high resolution wave forecasting very near the coast. The SWAN wave model is used to simulate the waves in the area, and various buoy data and field campaigns are used to validate the results. The simulations are structured in four different domains covering all the North Western Mediterranean Sea, with a grid resolution from 9 km to 250 meters in coastal areas. Previous results show that the significant wave height is almost always underpredicted in this area, and the underprediction is higher during storm events. However, the error in the peak period and the mean period is almost always constantly under predicted with a bias between one and two seconds, plus some residual error. This systematic error represents 40% of the total error. To improve the initial results, the whiteccaping dissipation term is studied and modified. In the SWAN model, the whitecapping is mainly controlled by the steepness of the waves. Although the by default parameter is not depending on the wave number, there is a new formulation in the last SWAN version (40.81) to include it in the calculations. Previous investigations show that adjusting the dependence for the wave number improved the predictions for the wave energy at lower frequencies, solving the underprediction of the period mentioned before. In the present work different simulations are developed to calibrate the new formulation, obtaining important improvements in the results. For the significant wave

Quantification of risks to coastal areas and development: wave run-up and erosion

CSIR Research Space (South Africa)

Theron, A

2010-09-01

Full Text Available In support of the effective implementation of the Integrated Coastal Management Act (Act No 24 of 2008), a review is presented of coastal hazard assessment methods. In particular the ICM Act legislates the establishment or change of coastal setback...

The present and future role of coastal wetland vegetation in protecting shorelines: Answering recent challenges to the paradigm

Science.gov (United States)

Gedan, Keryn B.; Kirwan, Matthew L.; Wolanski, Eric; Barbier, Edward B.; Silliman, Brian R.

2011-01-01

For more than a century, coastal wetlands have been recognized for their ability to stabilize shorelines and protect coastal communities. However, this paradigm has recently been called into question by small-scale experimental evidence. Here, we conduct a literature review and a small meta-analysis of wave attenuation data, and we find overwhelming evidence in support of established theory. Our review suggests that mangrove and salt marsh vegetation afford context-dependent protection from erosion, storm surge, and potentially small tsunami waves. In biophysical models, field tests, and natural experiments, the presence of wetlands reduces wave heights, property damage, and human deaths. Meta-analysis of wave attenuation by vegetated and unvegetated wetland sites highlights the critical role of vegetation in attenuating waves. Although we find coastal wetland vegetation to be an effective shoreline buffer, wetlands cannot protect shorelines in all locations or scenarios; indeed large-scale regional erosion, river meandering, and large tsunami waves and storm surges can overwhelm the attenuation effect of vegetation. However, due to a nonlinear relationship between wave attenuation and wetland size, even small wetlands afford substantial protection from waves. Combining man-made structures with wetlands in ways that mimic nature is likely to increase coastal protection. Oyster domes, for example, can be used in combination with natural wetlands to protect shorelines and restore critical fishery habitat. Finally, coastal wetland vegetation modifies shorelines in ways (e.g. peat accretion) that increase shoreline integrity over long timescales and thus provides a lasting coastal adaptation measure that can protect shorelines against accelerated sea level rise and more frequent storm inundation. We conclude that the shoreline protection paradigm still stands, but that gaps remain in our knowledge about the mechanistic and context-dependent aspects of shoreline

Experiments on the WavePiston, Wave Energy Converter

DEFF Research Database (Denmark)

Angelelli, E.; Zanuttigh, B.; Kofoed, Jens Peter

2011-01-01

This paper analyses the performance of a new Wave Energy Converter (WEC) of the Oscillating Water Column type (OWC), named WavePiston. This near-shore floating device is composed of plates (i.e. energy collectors) sliding around a cylinder, that is placed perpendicular to the shore. Tests...... in the wave basin at Aalborg University allowed to investigate power production in the North Sea typical wave climate, with varying design parameters such as plate dimensions and their mutual distance. The power produced per meter by each collector is about the 5% of the available wave power. Experimental...... results and survivability considerations suggest that the WavePiston would be particularly suited for installations in milder seas. An example application is therefore presented in the Mediterranean Sea, off-shore the island of Sicily. In this case, each collector harvests the 10% of the available wave...

Characteristics of phase-averaged equations for modulated wave groups

NARCIS (Netherlands)

Klopman, G.; Petit, H.A.H.; Battjes, J.A.

2000-01-01

The project concerns the influence of long waves on coastal morphology. The modelling of the combined motion of the long waves and short waves in the horizontal plane is done by phase-averaging over the short wave motion and using intra-wave modelling for the long waves, see e.g. Roelvink (1993).

A numerical study on the effects of wave-current-surge interactions on the height and propagation of sea surface waves in Charleston Harbor during Hurricane Hugo 1989

Science.gov (United States)

Liu, Huiqing; Xie, Lian

2009-06-01

The effects of wave-current interactions on ocean surface waves induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal waters are examined by using a three-dimensional (3D) wave-current coupled modeling system. The 3D storm surge modeling component of the coupled system is based on the Princeton Ocean Model (POM), the wave modeling component is based on the third generation wave model, Simulating WAves Nearshore (SWAN), and the inundation model is adopted from [Xie, L., Pietrafesa, L. J., Peng, M., 2004. Incorporation of a mass-conserving inundation scheme into a three-dimensional storm surge model. J. Coastal Res., 20, 1209-1223]. The results indicate that the change of water level associated with the storm surge is the primary cause for wave height changes due to wave-surge interaction. Meanwhile, waves propagating on top of surge cause a feedback effect on the surge height by modulating the surface wind stress and bottom stress. This effect is significant in shallow coastal waters, but relatively small in offshore deep waters. The influence of wave-current interaction on wave propagation is relatively insignificant, since waves generally propagate in the direction of the surface currents driven by winds. Wave-current interactions also affect the surface waves as a result of inundation and drying induced by the storm. Waves break as waters retreat in regions of drying, whereas waves are generated in flooded regions where no waves would have occurred without the flood water.

South Baltic representative coastal field surveys, including monitoring at the Coastal Research Station in Lubiatowo, Poland

Science.gov (United States)

Ostrowski, Rafał; Schönhofer, Jan; Szmytkiewicz, Piotr

2016-10-01

The paper contains a brief description of selected investigations carried out in the south Baltic coastal zone, with the particular focus on the history and recent activities conducted at the Coastal Research Station in Lubiatowo (CRS Lubiatowo), Poland. These activities comprise field investigations of nearshore hydrodynamic, lithodynamic, and morphodynamic processes. The study area is a sandy multi-bar shore with a mild slope, much exposed to the impact of waves approaching from NW-NE sector. The shore has a dissipative character which means that the wave energy is subject to gradual dissipation in the nearshore zone and only a small part of this energy is reflected by the shore. Due to the big wind fetch in N-NNE direction, the location of CRS Lubiatowo is favourable to registration of the maximum values of parameters of hydrodynamic and morphodynamic processes which occur in the Baltic during extreme storms.

Development of a coastal information system for the management of Jeddah coastal waters in Saudi Arabia

Science.gov (United States)

Mayerle, R.; Al-Subhi, A.; Fernández Jaramillo, J.; Salama, A.; Bruss, G.; Zubier, K.; Runte, K.; Turki, A.; Hesse, K.; Jastania, H.; Ladwig, N.; Mudarris, M.

2016-04-01

This paper presents results of the development and application of a web-based information system, Jeddah CIS, for assisting decision makers in the management of Jeddah coastal waters, in Saudi Arabia. The system will support coastal planning, management of navigation and tackle pollution due to accidents. The system was developed primarily to nowcast in quasi-real time and to deliver short-term forecasts of water levels, current velocities and waves with high spatial and temporal resolution for the area near Jeddah. Therefor it will hasten response when adverse weather conditions prevail. The Jeddah-CIS integrates sensors transmitting in real time, meteorological, oceanographic and water quality parameters and operational models for flow and waves. It also provides interactive tools using advanced visualization techniques to facilitate dissemination of information. The system relies on open source software and has been designed to facilitate the integration of additional components for enhanced information processing, data evaluation and generation of higher water level, current velocity and wave for the general public. Jeddah-CIS has been operational since 2013. Extensions of the system to speed operations and improving the accuracy of the predictions to the public are currently underway.

Design basis flood for nuclear power plants on coastal sites

International Nuclear Information System (INIS)

1983-01-01

This Guide discusses the phenomena causing coastal floods (storm surge, seiche, tsunami and wind-wave) and gives a general description of the methods used and the critical factors involved in the evaluation of such floods and of their associated effects. In addition, some treatment is presented of the possible combinations of two or more of these phenomena to produce a DBF. Methods are also provided for evaluating the reference water levels, taking into account the effect of tides, sea level anomalies and changes in lake level and river flow. Sites vulnerable to coastal flooding are located on open coastal regions, semi-enclosed bodies of water and enclosed bodies of water. Open coastal regions are those portions of land directly exposed to and having a shore on a major body of water. Semi-enclosed bodies of water are lagoons, river estuaries, gulfs, fjords and rias. Enclosed bodies of water are lakes and reservoirs. The phenomena of the lowering of the water level at coastal sites caused by offshore winds, low tides, wave effects or of drawdown caused by tsunamis are discussed. The static and dynamic effects of floods resulting from the various combinations (independent and interdependent) of surface waves of varying frequency are also discussed. Consideration is also given to shoreline instabilities and to the effects of erosion. Estimated flood levels and related effects on the nuclear power plant, which will vary according to the method of analysis and the type of flooding considered, shall be compared with available historical data where this is relevant, to check the conservativeness of the evaluated results

Wave reflections from breakwaters

OpenAIRE

Dickson, William S.

1994-01-01

A new method is presented for estimating the reflection of a random, multi-directional sea from a coastal structure. The technique is applicable to an array of wave gauges of arbitrary geometry deployed seaward of the reflector. An expansion for small oblique wave incidence angles is used to derive an approximate relationship between measured array cross-spectra and a small number of parameters that describe the incident wave properties and the reflectivity of the structure. Model tests with ...

Z-2 Suit Support Stand and MKIII Suit Center of Gravity Test

Science.gov (United States)

Nguyen, Tuan Q.

2014-01-01

NASA's next generation spacesuits are the Z-Series suits, made for a range of possible exploration missions in the near future. The prototype Z-1 suit has been developed and assembled to incorporate new technologies that has never been utilized before in the Apollo suits and the Extravehicular Mobility Unit (EMU). NASA engineers tested the Z-1 suit extensively in order to developed design requirements for the new Z-2 suit. At the end of 2014, NASA will be receiving the new Z-2 suit to perform more testing and to further develop the new technologies of the suit. In order to do so, a suit support stand will be designed and fabricated to support the Z-2 suit during maintenance, sizing, and structural leakage testing. The Z-2 Suit Support Stand (Z2SSS) will be utilized for these purposes in the early testing stages of the Z-2 suit.

Origins of wind-driven intraseasonal sea level variations in the North Indian Ocean coastal waveguide

Digital Repository Service at National Institute of Oceanography (India)

Suresh, I.; Vialard, J.; Lengaigne, M.; Han, W.; Mc; Durand, F.; Muraleedharan, P.M.

version: Geophys. Res. Lett., vol.40(21); 2013; 5740-5744 Origins of wind-driven intraseasonal sea level variations in the North Indian Ocean coastal waveguide I. Suresh1, J. Vialard2, M. Lengaigne2, W. Han3, J. McCreary4, F. Durand5, P.M. Muraleedharan1... reversing winds. These wind variations drive seasonal equatorial Kelvin and Rossby wave responses. The seasonal equatorial Kelvin waves propagate into the North Indian Ocean (hereafter NIO) as coastal Kelvin waves [McCreary et al., 1993]. As a result...

Modeling the SAR Signature of Nonlinear Internal Waves

National Research Council Canada - National Science Library

Lettvin, Ellen E

2008-01-01

Nonlinear Internal Waves are pervasive globally, particularly in coastal waters. The currents and displacements associated with internal waves influence acoustic propagation and underwater navigation, as well as ocean transport and mixing...

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean

International Nuclear Information System (INIS)

1990-01-01

The proposed COPS (Coastal Ocean Prediction Systems) program is concerned with combining numerical models with observations (through data assimilation) to improve our predictive knowledge of the coastal ocean. It is oriented toward applied research and development and depends upon the continued pursuit of basic research in programs like COOP (Coastal Ocean Processes); i.e., to a significant degree it is involved with ''technology transfer'' from basic knowledge to operational and management applications. This predictive knowledge is intended to address a variety of societal problems: (1) ship routing, (2) trajectories for search and rescue operations, (3) oil spill trajectory simulations, (4) pollution assessments, (5) fisheries management guidance, (6) simulation of the coastal ocean's response to climate variability, (7) calculation of sediment transport, (8) calculation of forces on structures, and so forth. The initial concern is with physical models and observations in order to provide a capability for the estimation of physical forces and transports in the coastal ocean. For all these applications, there are common needs for physical field estimates: waves, tides, currents, temperature, and salinity, including mixed layers, thermoclines, fronts, jets, etc. However, the intent is to work with biologists, chemists, and geologists in developing integrated multidisciplinary prediction systems as it becomes feasible to do so. From another perspective, by combining observations with models through data assimilation, a modern approach to monitoring is provided through whole-field estimation

Coupling atmospheric and ocean wave models for storm simulation

DEFF Research Database (Denmark)

Du, Jianting

the atmosphere must, by conservation, result in the generation of the surface waves and currents. The physics-based methods are sensitive to the choice of wind-input source function (Sin), parameterization of high-frequency wave spectra tail, and numerical cut-off frequencies. Unfortunately, literature survey......This thesis studies the wind-wave interactions through the coupling between the atmospheric model and ocean surface wave models. Special attention is put on storm simulations in the North Sea for wind energy applications in the coastal zones. The two aspects, namely storm conditions and coastal...... shows that in most wind-wave coupling systems, either the Sin in the wave model is different from the one used for the momentum flux estimation in the atmospheric model, or the methods are too sensitive to the parameterization of high-frequency spectra tail and numerical cut-off frequencies. To confront...

Wave Runup on a Frozen Beach Under High Energy Conditions

Science.gov (United States)

Didier, D.; Bernatchez, P.; Dumont, D.; Corriveau, M.

2017-12-01

High and mid-latitude beaches have typical morphological characteristics influenced by nearshore processes prevailing under ice conditions during cold season. Nearshore ice complexes (NIC) offer a natural coastal protection by covering beach sediments, while offshore ice-infested waters dissipate incoming waves. Climate change contributes to sea ice shrinking therefore reducing its protection against erosion and flooding. In the Estuary and Gulf of the St. Lawrence (ESL, GSL) (eastern Canada), sea ice cover undergoes an overall shrinking and simulated future projections tend toward a negligible effect on wave climate by 2100. Quantifying the effect of nearshore dynamics on frozen beaches is therefore imperative for coastal management as more wave energy at the coast is expected in the future. To measure the effect of a frozen beach on wave runup elevations, this study employs a continuous video recording of the swash motion at 4Hz. Video-derived wave runup statistics have been extracted during a tidal cycle on a frozen beach, using the Pointe-Lebel beach (ESL) as a test case. Timestack analysis was combined with offshore water levels and wave measurements. A comparison of runup under icy conditions (Dec. 30 2016) with a runup distribution during summer was made under similar high energy wave conditions. Results indicate high runup excursions potentially caused by lowered sediment permeability due to high pore-ice saturation in the swash zone, accentuating the overwash of the eroding coastline and thus the risk of flooding. With projected reduction in coastal sea ice cover and thus higher wave energy, this study suggests that episodes of degradation and weakening could influence the coastal flood risk in mid- and high-latitude cold environments.

75 FR 28593 - Board on Coastal Engineering Research

Science.gov (United States)

2010-05-21

...-Level Changes along the U.S. Atlantic Coast, Atlantic Region Coastal Storms, Overview of Climatic Variation Effects on Extratropical and Tropical Storms, Evidence for a Changing North Pacific Wave Climate...

Coastal and Riverine Flood Forecast Model powered by ADCIRC

Science.gov (United States)

Khalid, A.; Ferreira, C.

2017-12-01

Coastal flooding is becoming a major threat to increased population in the coastal areas. To protect coastal communities from tropical storms & hurricane damages, early warning systems are being developed. These systems have the capability of real time flood forecasting to identify hazardous coastal areas and aid coastal communities in rescue operations. State of the art hydrodynamic models forced by atmospheric forcing have given modelers the ability to forecast storm surge, water levels and currents. This helps to identify the areas threatened by intense storms. Study on Chesapeake Bay area has gained national importance because of its combined riverine and coastal phenomenon, which leads to greater uncertainty in flood predictions. This study presents an automated flood forecast system developed by following Advanced Circulation (ADCIRC) Surge Guidance System (ASGS) guidelines and tailored to take in riverine and coastal boundary forcing, thus includes all the hydrodynamic processes to forecast total water in the Potomac River. As studies on tidal and riverine flow interaction are very scarce in number, our forecast system would be a scientific tool to examine such area and fill the gaps with precise prediction for Potomac River. Real-time observations from National Oceanic and Atmospheric Administration (NOAA) and field measurements have been used as model boundary feeding. The model performance has been validated by using major historical riverine and coastal flooding events. Hydrodynamic model ADCIRC produced promising predictions for flood inundation areas. As better forecasts can be achieved by using coupled models, this system is developed to take boundary conditions from Global WaveWatchIII for the research purposes. Wave and swell propagation will be fed through Global WavewatchIII model to take into account the effects of swells and currents. This automated forecast system is currently undergoing rigorous testing to include any missing parameters which

Wave Dissipation on Low- to Super-Energy Coral Reefs

Science.gov (United States)

Harris, D. L.

2016-02-01

Coral reefs are valuable, complex and bio-diverse ecosystems and are also known to be one of the most effective barriers to swell events in coastal environments. Previous research has found coral reefs to be remarkably efficient in removing most of the wave energy during the initial breaking and transformation on the reef flats. The rate of dissipation is so rapid that coral reefs have been referred to as rougher than any known coastal barrier. The dissipation of wave energy across reef flats is crucial in maintaining the relatively low-energy conditions in the back reef and lagoonal environments providing vital protection to adjacent beach or coastal regions from cyclone and storm events. A shift in the regulation of wave energy by reef flats could have catastrophic consequences ecologically, socially, and economically. This study examined the dissipation of wave energy during two swell events in Tahiti and Moorea, French Polyesia. Field sites were chosen in varying degrees of exposure and geomorphology from low-energy protected sites (Tiahura, Moorea) to super-energy sites (Teahupo'o, Tahiti). Waves were measured during two moderate to large swell events in cross reef transects using short-term high-resolution pressure transducers. Wave conditions were found to be similar in all back reef locations despite the very different wave exposure at each reef site. However, wave conditions on the reef flats were different and mirrored the variation in wave exposure with depth over the reef flat the primary regulator of reef flat wave height. These results indicate that coral reef flats evolve morphodynamically with the wave climate, which creates coral reef geomorphologies capable of dissipating wave energy that results in similar back reef wave conditions regardless of the offshore wave climate.

The role of the reef–dune system in coastal protection in Puerto Morelos (Mexico

Directory of Open Access Journals (Sweden)

G. L. Franklin

2018-04-01

Full Text Available Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef–dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH. Wave hindcast information, tidal level, and a measured beach profile of the reef–dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore

The role of the reef-dune system in coastal protection in Puerto Morelos (Mexico)

Science.gov (United States)

Franklin, Gemma L.; Torres-Freyermuth, Alec; Medellin, Gabriela; Allende-Arandia, María Eugenia; Appendini, Christian M.

2018-04-01

Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef-dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH). Wave hindcast information, tidal level, and a measured beach profile of the reef-dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore reef slope) is warranted.

Proceedings of the conference days on 'Climate change impacts on coastal risks'

International Nuclear Information System (INIS)

Becker, M.; Meyssignac, B.; Llovel, W.; Cazenave, A.; Rogel, P.; Woppelmann, G.; Salas y Melia, D.; Morelatto, D.; Benoit, M.; Tiberi-Wadier, A.L.; Charles, E.; Thiebot, J.; Le Cozannet, G.; Pedreros, R.; Ardhuin, F.; Planton, S.; Balouin, Y.; Ferreira, O.; Ciavola, P.; Donato, V.; Walker, P.; Dubois, A.; Sedrati, M.; Menier, D.; Idier, D.; Balouin, Y.; Bohn Bertoldo, R.; Bouchette, F.; Boulahya, F.; Brivois, O.; Calvete, D.; Capo, S.; Castelle, B.; Certain, R.; Charles, E.; Chateauminois, E.; Delvallee, E.; Falques, A.; Fattal, P.; Larroude, P.; Lecacheux, S.; Garnier, R.; Hequette, A.; Maanan, M.; Mallet, C.; Maspataud, A.; Mays, C.; Oliveros, C.; Paillart, M.; Parisot, J.P.; Pedreros, R.; Poumadere, M.; Robin, N.; Ruz, M.H.; Robin, M.; Vinchon, C.; Capo, S.; Rihouey, D.; Howa, H.; Desmazes, F.; Fauque, L.; Maillet, G.; Vella, C.; Pelinovski, E.; Demory, F.; Canut, V.; Dussouillez, P.; Fleury, T.J.; Lecacheux, S.; Garcin, M.; Krien, Y.; Poisson, B.; Almar, R.; Senechal, N.; Bonneton, P.; Ennesser, Y.; Cataliotti, D.; Terrier, M.; Genovese, E.; Hallegatte, S.; Dumas, P.; Sauzeau, T.; Peret, J.; Zaninetti, J.M.; Vinchon, C.; Agenais, A.L.; Baron-Yelles, N.; Berthelier, E.; Garcin, M.; Herivaux, C.; Kuhfuss, L.; Maton, L.; Meur-Ferec, C.; Rey-Valette, H.; Charles, J.C.; Franquart, H.; Hellequin, A.P.; Marche, F.; Mazeiraud, V.; Nathan, F.; Romieu, E.; Rulleau, B.; Maton, L.; Rulleau, B.; Flanquart, H.; Balouin, Y.; Poumadere, M.; Deve, I.; Bouteau, F.; Aubie, S.; Mugica, J.; Hoareau, A.; Duvat, V.; Magnan, A.; Sergent, P.; Prevot, G.; Tissier, M.; Chazel, F.; Lannes, D.; Falques, A.; Ruessink, G.; Maspataud, A.; Ruz, M.H.; Vanhee, S.; Vanroye, C.; Elineau, S.; Duperret, A.; Mallet, P.; Caspar, R.; Bonnot-Courtois, C.; Perherin, C.; Roche, A.; Trmal, C.; Roux, I.; Pons, F.; Boura, C.; Devaux, E.; Desire, G.; Cayocca, F.; Le Hir, P.; Vinchon, C.; Andre, C.; Meur-Ferec, C.; Idier, D.; Rohmer, J.; Turpin, V.; Magnan, A.; Baillarin, F.; Galarraga, D.; Gardel, A.; Fromard, F.; Froidefond, J.M.; Lafon, V.; Proisy, C.; Walcker, R.; Mercier, F.; Pronier, O.; Dehouck, A.; Bertrand, F.; Goeldner-Gianella, L.

2011-01-01

This document gathers the articles of the presentations given during this conference about the climate change impacts on coastal risks: - Topic 1 - forcing changes: Regional sea level changes rebuilt for the last five decades; Sea level modeling in decennial and centennial experiments of the coupled CNRM-CERFACS model; Sea level state simulations in the Atlantic ocean between 1960 and 2100 for 3 climate change scenarios; Wave trends and characteristics variability in the Bay of Biscay from 1958 to 2001; Climate change impacts on storm events affecting the European coastline, the MICORE project; CECILE project: coastal environmental changes, impacts of sea level rise; Hydro-dynamism of a meso-tidal bay-shore in modal conditions and in storm conditions, Suscinio Bay, South-Brittany; - Topic 2 - impacts on unforeseen turns of events: VULSACO - vulnerability of sandy coastal systems in front of climate changes and anthropic pressures, methods, tools, results and lessons learnt; Climate change vulnerability with a 2DH modeling on 4 French beaches; Analysis of the 'Truc-Vert' beach (Gironde) evolution over a decennial period, link with the North Atlantic Oscillation (NAO); Impact of the reduction of the Rhone river solid fraction on the delta coastline mobility since the Little Ice Age; Mega-blocs of the eastern side of the Fos Gulf as markers of exceptional SW-oriented storms; Implementation of a multi-model approach to evaluate the Languedoc coast exposure to marine submersions in a climate change context; Continuous video observation of the littoral: multi-scales and multi-processes; - Topic 3 - Socio-economic impacts: Climate change and coastal risk evaluation in North Africa; Assessment of damage from storm surge and sea level rise to coastal cities: lessons from the Miami area; Construction and environmental protection of centre-west Atlantic coastal communities: contribution of geo-history; Consideration of climate change effects in new coastal protection schemes

Wave modelling south of the Danube Delta in the Black Sea

Science.gov (United States)

Rusu, Eugen; Butunoiu, Dorin

2015-04-01

A multilevel wave modelling system, based on SWAN (Simulating Waves Nearshore) spectral model, was implemented in the Black Sea and focused on the western coast. Model simulations have been performed for a 10-year time interval (1999-2008). Validations have been carried out against both satellite data and in situ measurements. A high resolution SWAN computational domain (100m x100m), which is focused on the coastal environment south of the Danube Delta, was also implemented. This coastal area includes Sacalin, which is a newly formed island in the Black Sea, south of the Saint George branch of the Danube. Initially, this was an island system, which consisted of two smaller islands, Greater Sacalin and Lesser Sacalin. In time, due to the enhanced sedimentary processes, the two islands merged into a single continuous landmass. The island has become the habitat of a great variety of rare species and for this reason it was declared an ecological reserve. In the high resolution computational domain, focused on the Sacalin Island, the effect of the currents induced by the Danube River outflow was also accounted in the model, together with some other processes specific to the coastal environment as diffraction, triad wave-wave interactions and wave induced set up. Considering the results of the ten-year SWAN model simulations with the modelling system covering the entire sea basin, the most relevant configurations of the environmental matrix, characteristic to this side of the sea, were defined. On this basis, by performing SWAN simulations in the high resolution coastal domain, the wave propagation patterns in the nearshore, together with some parameters related to the shoreline conditions, were evaluated. A great number of possible situations were analyzed. The most relevant correspond to different directions of the incoming waves (N, NE, E and SE, respectively) and significant wave energy conditions. The results provided by the modelling system indicate two different

Application of STORMTOOLS's simplified flood inundation model with sea level rise to assess impacts to RI coastal areas

Science.gov (United States)

Spaulding, M. L.

2015-12-01

The vision for STORMTOOLS is to provide access to a suite of coastal planning tools (numerical models et al), available as a web service, that allows wide spread accessibly and applicability at high resolution for user selected coastal areas of interest. The first product developed under this framework were flood inundation maps, with and without sea level rise, for varying return periods for RI coastal waters. The flood mapping methodology is based on using the water level vs return periods at a primary NOAA water level gauging station and then spatially scaling the values, based on the predictions of high resolution, storm and wave simulations performed by Army Corp of Engineers, North Atlantic Comprehensive Coastal Study (NACCS) for tropical and extratropical storms on an unstructured grid, to estimate inundation levels for varying return periods. The scaling for the RI application used Newport, RI water levels as the reference point. Predictions are provided for once in 25, 50, and 100 yr return periods (at the upper 95% confidence level), with sea level rises of 1, 2, 3, and 5 ft. Simulations have also been performed for historical hurricane events including 1938, Carol (1954), Bob (1991), and Sandy (2012) and nuisance flooding events with return periods of 1, 3, 5, and 10 yr. Access to the flooding maps is via a web based, map viewer that seamlessly covers all coastal waters of the state at one meter resolution. The GIS structure of the map viewer allows overlays of additional relevant data sets (roads and highways, wastewater treatment facilities, schools, hospitals, emergency evacuation routes, etc.) as desired by the user. The simplified flooding maps are publically available and are now being implemented for state and community resilience planning and vulnerability assessment activities in response to climate change impacts.

Communicating Coastal Risk Analysis in an Age of Climate Change

Science.gov (United States)

2011-10-01

extratropical storm systems); the geometry and geomorphology of the area (regional and local bathymetry and topography, including rivers, marshes, and...at risk from coastal hazards including storm surge inundation, precipitation driven flooding, waves, and coastal erosion. This population segment...will likely be exposed to increased risk as impacts of a changing climate are felt through elevated sea levels and potentially increased storm

Experimental Update of the Overtopping Model Used for the Wave Dragon Wave Energy Converter

Directory of Open Access Journals (Sweden)

Erik Friis-Madsen

2013-04-01

Full Text Available An overtopping model specifically suited for Wave Dragon is needed in order to improve the reliability of its performance estimates. The model shall be comprehensive of all relevant physical processes that affect overtopping and flexible to adapt to any local conditions and device configuration. An experimental investigation is carried out to update an existing formulation suited for 2D draft-limited, low-crested structures, in order to include the effects on the overtopping flow of the wave steepness, the 3D geometry of Wave Dragon, the wing reflectors, the device motions and the non-rigid connection between platform and reflectors. The study is carried out in four phases, each of them specifically targeted at quantifying one of these effects through a sensitivity analysis and at modeling it through custom-made parameters. These are depending on features of the wave or the device configuration, all of which can be measured in real-time. Instead of using new fitting coefficients, this approach allows a broader applicability of the model beyond the Wave Dragon case, to any overtopping WEC or structure within the range of tested conditions. Predictions reliability of overtopping over Wave Dragon increased, as the updated model allows improved accuracy and precision respect to the former version.

Coastal erosion problem, modelling and protection

Science.gov (United States)

Yılmaz, Nihal; Balas, Lale; İnan, Asu

2015-09-01

Göksu Delta, located in the south of Silifke County of Mersin on the coastal plain formed by Göksu River, is one of the Specially Protected Areas in Turkey. Along the coastal area of the Delta, coastline changes at significant rates are observed, concentrating especially at four regions; headland of İncekum, coast of Paradeniz Lagoon, river mouth of Göksu and coast of Altınkum. The coast of Paradeniz Lagoon is suffering significantly from erosion and the consequent coastal retreating problem. Therefore, the narrow barrier beach which separates Paradeniz Lagoon from the Mediterranean Sea is getting narrower, creating a risk of uniting with the sea, thus causing the disappearance of the Lagoon. The aim of this study was to understand the coastal transport processes along the coastal area of Göksu Delta to determine the coastal sediment transport rates, and accordingly, to propose solutions to prevent the loss of coastal lands in the Delta. To this end, field measurements of currents and sediment grain sizes were carried out, and wind climate, wave climate, circulation patterns and longshore sediment transport rates were numerically modeled by HYDROTAM-3D, which is a three dimensional hydrodynamic transport model. Finally, considering its special importance as an environmentally protected region, some coastal structures of gabions were proposed as solutions against the coastal erosion problems of the Delta. The effects of proposed structures on future coastline changes were also modeled, and the coastlines predicted for the year 2017 are presented and discussed in the paper.

L-Shaped Flume Wave Basin and 2-ft Flume Facility

Data.gov (United States)

Federal Laboratory Consortium — At the Engineer Research and Development Center, Coastal and Hydraulics Laboratory, two-dimensional wave flumes and three-dimensional stability wave basins are used...

Future Projection of Ocean Wave Climate: Analysis of SST Impacts on Wave Climate Changes in the Western North Pacific

OpenAIRE

Shimura, Tomoya; Mori, Nobuhito; Mase, Hajime

2015-01-01

Changes in ocean surface waves elicit a variety of impacts on coastal environments. To assess the future changes in the ocean surface wave climate, several future projections of global wave climate have been simulated in previous studies. However, previously there has been little discussion about the causes behind changes in the future wave climate and the differences between projections. The objective of this study is to estimate the future changes in mean wave climate and the sensitivity of...

Role of beach morphology in wave overtopping hazard assessment

Science.gov (United States)

Phillips, Benjamin; Brown, Jennifer; Bidlot, Jean-Raymond; Plater, Andrew

2017-04-01

Understanding the role of beach morphology in controlling wave overtopping volume will further minimise uncertainties in flood risk assessments at coastal locations defended by engineered structures worldwide. XBeach is used to model wave overtopping volume for a 1:200 yr joint probability distribution of waves and water levels with measured, pre- and post-storm beach profiles. The simulation with measured bathymetry is repeated with and without morphological evolution enabled during the modelled storm event. This research assesses the role of morphology in controlling wave overtopping volumes for hazardous events that meet the typical design level of coastal defence structures. Results show disabling storm-driven morphology under-represents modelled wave overtopping volumes by up to 39% under high Hs conditions, and has a greater impact on the wave overtopping rate than the variability applied within the boundary conditions due to the range of wave-water level combinations that meet the 1:200 yr joint probability criterion. Accounting for morphology in flood modelling is therefore critical for accurately predicting wave overtopping volumes and the resulting flood hazard and to assess economic losses.

Wave climate change, coastline response and hazard prediction in New South Wales, Australia

International Nuclear Information System (INIS)

Goodwin, Ian D.; Verdon, Danielle; Cowell, Peter

2007-01-01

Full text: Full text: Considerable research effort has been directed towards understanding and the gross prediction of shoreline response to sea level rise (eg. Cowell ef a/. 2003a, b). In contrast, synoptic prediction of changes in the planform configuration of shorelines in response to changes in wind and wave climates over many decades has been limited by the lack of geohistorical data on shoreline alignment evolution and long time series of wave climate. This paper presents new data sets on monthly mean wave direction variability based on: a. Waverider buoy data; b. a reconstruction of monthly mid-shelf wave direction, 1877 to 2002 AD from historical MSLP data (Goodwin 2005); and c. a multi-decadal reconstruction of wave direction, in association with the Interdecadal Pacific Oscillation and the Southern Annular Mode of climate variability, covering the past millennium. A model of coastline response to the wave climate variability is presented for northern and central New South Wales (NSW) for decadal to multi-decadal time scales, and is based on instrumental and geohistorical data. The sensitivity of the coastline position and alignment, and beach state to mean and extreme wave climate changes is demonstrated (e.g. Goodwin et al. 2006). State changes in geometric shoreline alignment rotation, sand volume (progradation/recession) for NSW and mean wave direction, are shown to be in agreement with the low-frequency change in Pacific-wide climate. Synoptic typing of climate patterns using Self Organised Mapping methods is used to downscale CSIRO GCM output for this century. The synoptic types are correlated to instrumental wave climate data and coastal behaviour. The shifts in downscaled synoptic types for 2030 and 2070 AD are then used as the basis for predicting mean wave climate changes, coastal behaviour and hazards along the NSW coastline. The associated coastal hazards relate to the definition of coastal land loss through rising sea levels and shoreline

Wind Stress Variability Observed Over Coastal Waters

Science.gov (United States)

Ortiz-Suslow, D. G.; Haus, B. K.; Laxague, N.; Williams, N. J.; Graber, H. C.

2016-02-01

The wind stress on the ocean surface generates waves, drives currents, and enhances gas exchange; and a significant amount of work has been done to characterize the air-sea momentum flux in terms of bulk oceanographic and atmospheric parameters. However, the majority of this work to develop operational algorithms has been focused on the deep ocean and the suitability of these methods in the coastal regime has not been evaluated. The findings from a two-part field campaign will be presented which highlight the divergence of nearshore wind stress observations from conventional, deep water results. The first set of data comes from a coastal region near a relatively small, natural tidal inlet. A high degree of spatial variability was observed in both the wind stress magnitude and direction, suggestive of coastal processes (e.g., depth-limited wave affects and horizontal current shear) modulating the momentum flux from the atmosphere to the ocean surface. These shallow-water processes are typically not accounted for in conventional parameterizations. Across the experimental domain and for a given wind speed, the stress magnitude was found to be nearly 2.5 times that predicted by conventional methods; also, a high propensity for stress steering off the mean azimuthal wind direction (up to ±70 degrees) was observed and linked to horizontal current gradients produced by the tidal inlet. The preliminary findings from a second data set taken in the vicinity of the macrotidal Columbia River Mouth will also be presented. Compared to the first data set, a similar degree of variability is observed here, but the processes responsible for this are present at a much larger scale. Specifically, the Columbia River Mouth observations were made in the presence of significant swell wave energy and during periods of very high estuarine discharge. The relative angle between the wind and swell direction is expected to be significant with regards to the observed momentum flux. Also, these

IMPORTANCE OF MANGROVE TO REDUCE THE TSUNAMI WAVE ENERGY

Directory of Open Access Journals (Sweden)

Anastasia Neni Candra Purnamasari

2017-09-01

Full Text Available Mangrove has a very important role to reduce the tsunami wave energy. It is shown that the coastal areas have no vegetation or in this case will have an impact Mangrove forests greater damage due to tsunami waves than the coastal areas of vegetation. The purpose of the Term Paper is proved the importance of Mangrove to reduce the tsunami wave energy by comparing the various methods that have been observed in some case studies on the impact of the tsunami that occurred in several Asian countries in 2004 and case studies on ocean waves on the Gulf coast of south Florida. Based on the research results that could dampen Mangrove Tsunami wave energy. Tsunami wave energy can be reduced by several factors, namely mangrove species, tree size, vast mangrove forest, nature tree structure, and the size limit Mangrove forest (as far as how much of the ocean to the surface.

The global coastal hazards data base

International Nuclear Information System (INIS)

Gornitz, V.; White, T.W.

1989-01-01

A rise of sea level between 0.5 and 1.5 m, caused by predicted climate warming in the next century, could jeopardize low-lying radioactive waste disposal sites near the coast, due to permanent and episodic inundation, increased shoreline retreat, and changes in the water table. The effects of global sea level rise on the shoreline will not be spatially uniform. Therefore, site selection will depend on assessment of these differential vulnerabilities, in order to avoid high-risk coasts. The coastal hazards data base described here could provide an appropriate framework. The coastal hazards data base integrates relevant topographic, geologic, geomorphologic, erosional and subsidence information in a Geographic Information System (GIS), to identify high-risk shorelines characterized by low coastal relief, an erodible substrate, present and past evidence of subsidence, extensive shoreline retreat, and high wave/tide energies. Data for seven variables relating to inundation and erosion hazards are incorporated into the ORNL ARC/INFO Geographic Information System (GIS). Data compilation has been completed for the US and is being extended to North America, and ultimately the world. A coastal vulnerability index (CVI) has been designed to flag high risk coastal segments. 17 refs., 2 figs., 2 tabs

Adapting Coastal State Indicators to end-users: the iCoast Project

Science.gov (United States)

Demarchi, Alessandro; Isotta Cristofori, Elena; Gracia, Vicente; Sairouní, Abdel; García-León, Manuel; Cámaro, Walther; Facello, Anna

2016-04-01

The extraordinary development of the built environment and of the population densities in the coastal areas are making coastal communities highly exposed. The sea level rise induced by climate change will worsen this coastal vulnerability scenario and a considerable amount of people are expected to be threatened by coastal flooding in the future. Due to the increasing number of catastrophic events, and the consequent increased number of damages and people affected, over the last decades coastal hazard management has become a fundamental activity in order to improve the resilience of coastal community. In this scenario, iCoast (integrated COastal Alert SysTem) project has been founded to develop a tool able to address coastal risks caused by extreme waves and high sea water levels in European coastal areas. In the framework of iCoast Project, a set of Coastal State Indicators (CSIs) has been developed in order to improve the forecasting and the assessment of coastal risks. CSIs are indeed parameters able to provide end-users with an essential information about coastal hazards and related impacts. Within the iCoast Project, following a comprehensive literature review about existing indicators concerning coastal risks, a list of CSIs have been chosen as parameters that can be derived from the meteorological and the hydrodynamic modules. They include both physical variables used as trigger for meteorological and flood warnings from the majority of the operational National/Regional warning systems and further essential parameters, so called 'storm integrated' coastal-storm indicators, able to describe the physical processes that drive coastal damages, such as erosion, accumulation, flooding, destructions. Nowadays, it is generally acknowledged that communities are not homogenous and hence their different vulnerable groups might need different warnings. Generally, even existing national EWS in developed countries are often ineffective to issue targeted warnings for

Impacts of wave energy conversion devices on local wave climate: observations and modelling from the Perth Wave Energy Project

Science.gov (United States)

Hoeke, Ron; Hemer, Mark; Contardo, Stephanie; Symonds, Graham; Mcinnes, Kathy

2016-04-01

As demonstrated by the Australian Wave Energy Atlas (AWavEA), the southern and western margins of the country possess considerable wave energy resources. The Australia Government has made notable investments in pre-commercial wave energy developments in these areas, however little is known about how this technology may impact local wave climate and subsequently affect neighbouring coastal environments, e.g. altering sediment transport, causing shoreline erosion or accretion. In this study, a network of in-situ wave measurement devices have been deployed surrounding the 3 wave energy converters of the Carnegie Wave Energy Limited's Perth Wave Energy Project. This data is being used to develop, calibrate and validate numerical simulations of the project site. Early stage results will be presented and potential simulation strategies for scaling-up the findings to larger arrays of wave energy converters will be discussed. The intended project outcomes are to establish zones of impact defined in terms of changes in local wave energy spectra and to initiate best practice guidelines for the establishment of wave energy conversion sites.

Experimental Measurement of Wave Field Variations around Wave Energy Converter Arrays

Directory of Open Access Journals (Sweden)

Louise O’Boyle

2017-01-01

Full Text Available Wave energy converters (WECs inherently extract energy from incident waves. For wave energy to become a significant power provider in the future, large farms of WECs will be required. This scale of energy extraction will increase the potential for changes in the local wave field and coastal environment. Assessment of these effects is necessary to inform decisions on the layout of wave farms for optimum power output and minimum environmental impact, as well as on potential site selection. An experimental campaign to map, at high resolution, the wave field variation around arrays of 5 oscillating water column WECs and a methodology for extracting scattered and radiated waves is presented. The results highlight the importance of accounting for the full extent of the WEC behavior when assessing impacts on the wave field. The effect of radiated waves on the wave field is not immediately apparent when considering changes to the entire wave spectrum, nor when observing changes in wave climate due to scattered and radiated waves superimposed together. The results show that radiated waves may account for up to 50% of the effects on wave climate in the near field in particular operating conditions.

Coherence between coastal and river flooding along the California coast

Science.gov (United States)

Odigie, Kingsley O.; Warrick, Jonathan

2018-01-01

Water levels around river mouths are intrinsically determined by sea level and river discharge. If storm-associated coastal water-level anomalies coincide with extreme river discharge, landscapes near river mouths will be flooded by the hydrodynamic interactions of these two water masses. Unfortunately, the temporal relationships between ocean and river water masses are not well understood. The coherence between extreme river discharge and coastal water levels at six California river mouths across different climatic and geographic regions was examined. Data from river gauges, wave buoys, and tide gauges from 2007 to 2014 were integrated to investigate the relationships between extreme river discharge and coastal water levels near the mouths of the Eel, Russian, San Lorenzo, Ventura, Arroyo Trabuco, and San Diego rivers. Results indicate that mean and extreme coastal water levels during extreme river discharge are significantly higher compared with background conditions. Elevated coastal water levels result from the combination of nontidal residuals (NTRs) and wave setups. Mean and extreme (>99th percentile of observations) NTRs are 3–20 cm and ∼30 cm higher during extreme river discharge conditions, respectively. Mean and extreme wave setups are up to 40 cm and ∼20–90 cm higher during extreme river discharge than typical conditions, respectively. These water-level anomalies were generally greatest for the northern rivers and least for the southern rivers. Time-series comparisons suggest that increases in NTRs are largely coherent with extreme river discharge, owing to the low atmospheric pressure systems associated with storms. The potential flooding risks of the concurrent timing of these water masses are tempered by the mixed, semidiurnal tides of the region that have amplitudes of 2–2.5 m. In summary, flooding hazard assessments for floodplains near California river mouths for current or future conditions with sea-level rise should include the temporal

A systems approach framework for coastal zones

DEFF Research Database (Denmark)

Hopkins, Tom Sawyer; Bailly, Denis; Støttrup, Josianne

2011-01-01

This Special Feature Volume examines the potential value of the Systems Approach Framework (SAF) as a methodological framework for the transition to sustainable development in coastal zones. This article provides insight on the Systems Approach, the theory behind it, and how its practical...... application to coastal zone systems (CZSs) was developed. The SAF is about information for management through a focus on how to generate a higher, dynamic level of information about complex CZSs and how to render this information more useful to end users through a participatory suite of communication methods....... The SAF is an open research methodology that investigates the function of systems in order to simulate specific issues or questions concerning their function. The research articles that are included in this Volume demonstrate examples of coupled multidisciplinary methods integrated into SAF simulations...

Evaluation and Numerical Simulation of Tsunami for Coastal Nuclear Power Plants of India

International Nuclear Information System (INIS)

Sharma, Pavan K.; Singh, R.K.; Ghosh, A.K.; Kushwaha, H.S.

2006-01-01

Recent tsunami generated on December 26, 2004 due to Sumatra earthquake of magnitude 9.3 resulted in inundation at the various coastal sites of India. The site selection and design of Indian nuclear power plants demand the evaluation of run up and the structural barriers for the coastal plants: Besides it is also desirable to evaluate the early warning system for tsunami-genic earthquakes. The tsunamis originate from submarine faults, underwater volcanic activities, sub-aerial landslides impinging on the sea and submarine landslides. In case of a submarine earthquake-induced tsunami the wave is generated in the fluid domain due to displacement of the seabed. There are three phases of tsunami: generation, propagation, and run-up. Reactor Safety Division (RSD) of Bhabha Atomic Research Centre (BARC), Trombay has initiated computational simulation for all the three phases of tsunami source generation, its propagation and finally run up evaluation for the protection of public life, property and various industrial infrastructures located on the coastal regions of India. These studies could be effectively utilized for design and implementation of early warning system for coastal region of the country apart from catering to the needs of Indian nuclear installations. This paper presents some results of tsunami waves based on different analytical/numerical approaches with shallow water wave theory. (authors)

Modelling coastal processes and morphological changes of the UK east coast in support of coastal decision-making

Science.gov (United States)

Li, Xiaorong; Leonardi, Nicoletta; Brown, Jennifer; Plater, Andy

2017-04-01

The coastline of Eastern England is home to about one quarter of the UK's coastal habitats, including intertidal salt marshes, tidal flats and sand dunes. These geomorphic features are of great importance to the local wildlife, global biodiversity, marine environment and human society and economy. Due to sea-level rise and the occurrence of extreme weather conditions, the coastline of Eastern England is under high risk of erosion and recession, which could lead to tidal inundation of sites such as the RSPB Minsmere Reserve and power generation infrastructure at Sizewell. This research responds to the need for sustainable shoreline management plans of the UK east coast through sensitivity studies at the Dunwich-Sizewell area, Suffolk, UK. Particular interest is on the long-term morphodynamic response of the study area to possible environmental variations associated with global climate change. Key coastal processes, i.e. current, waves and sediment transport, and morphological evolution are studied using a process-based numerical model under the following scenarios: current mean sea level + calm wave conditions, current mean sea level + storms, sea level rise + calm wave conditions, and sea level rise + storms, all with a 'do nothing' management plan which allows the coastal environment to exist and respond dynamically. As a further aspect of this research, rules will be generalized for reduced-complexity, system-based modelling. Alternative management plans, including 'managed realignment' and 'advance the line', are also investigated in this research under the same environmental forcing scenarios, for the purposes of protection of infrastructure of national importance and conservation of wetland habitats. Both 'hard' and 'soft' engineering options, such as groynes and beach nourishment respectively, are considered. A more ecohydrological option which utilizes aquatic plant communities for wave energy dissipation and sediment trapping is also studied. The last

Experimental Modeling of the Overtopping Flow on the Wave Dragon Wave Energy Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Kofoed, Jens Peter; Friis-Madsen, Erik

2011-01-01

The Wave Dragon Wave Energy Converter is currently facing a precommercial phase. At this stage of development a reliable overtopping model is highly required, in order to predict the performance of the device at possible deployment locations. A model formulation derived for an overtopping device...... with general geometry has been used so far. The paper presents an updated formulation drawn through the tank testing of a scaled model the Wave Dragon. The sensitivity analysis of the main features influencing the overtopping flow led to an updated model formulation which can be specifically suited...... for the Wave Dragon....

Simulation of morphodinamic processes in small coastal systems: application to the Aljezur coastal stream (Portugal)

Science.gov (United States)

Guerreiro, Martha; Fortunato, André B.; Oliveira, Anabela; Bertin, Xavier; Bruneau, Nicolas; Rodrigues, Marta

2010-05-01

In small and shallow coastal streams, morphological changes may have a dramatic effect on tidal propagation and distortion, on hydrodynamics and, ultimately, on the transport and fate of water-borne material. Hence, the ability to simulate the morphodynamic evolution of these dynamic and complex systems can be required for water quality studies. This work aimed at implementing, validating and exploring the morphodynamic modelling system MORSYS2D (Fortunato and Oliveira, 2004, Bertin et al., 2009) in the Aljezur stream, a small and dynamic coastal system located in south-west Portugal. Four extensive field campaigns were carried out in 2008 and 2009 to measure bathymetry, water levels, waves and currents, in both the estuary and the adjoining beach. Between the two 2009 campaigns, bathymetry was measured on a monthly basis. Data revealed significant morphological changes, including channel migration and the formation of sandbars. The morphodynamic modelling system MORSYS2D consists of a wave model (SWAN - Booij et al., 1999), a circulation model (ELCIRC - Zhang et al., 2004) and a sediment transport and bottom update model (SAND2D, Fortunato and Oliveira, 2004), and is controlled by a script that runs the models, manages the transfer of information between them and performs control checks. The model was shown to reproduce successfully the waves, the water levels and the velocities. Preliminary morphodynamic simulations revealed that the model is highly sensitive to small changes in the initial conditions, the parameterization of friction and the sediment transport formulation. This presentation will describe the calibration and validation of the morphodynamic modelling system and will investigate on the circumstances that can lead to the inlet closure (including wave action and river flow). Acknowledgements This work was sponsored by the Portuguese Science and Technology Foundation (FCT), project MADyCOS (PTDC/ECM/66484/2006). The authors thank the developers of the

Variational Boussinesq model for strongly nonlinear dispersive waves

NARCIS (Netherlands)

Lawrence, C.; Adytia, D.; van Groesen, E.

2018-01-01

For wave tank, coastal and oceanic applications, a fully nonlinear Variational Boussinesq model with optimized dispersion is derived and a simple Finite Element implementation is described. Improving a previous weakly nonlinear version, high waves over flat and varying bottom are shown to be

The numerical calculation of hydrological processes in the coastal zone of the Black Sea region in the city of Poti

Science.gov (United States)

Saghinadze, Ivane; Pkhakadze, Manana

2016-04-01

(The article was published with support of the Sh. Rustaveli National Science Foundation) The serious environmental problems started in Poti after transfer of the main flow of the river Rioni to the north. As a result the flooding of the city stopped, but the reduction of water consumption in the city channel, caused a decrease of the sediments carried away by the river, what leads to coastal erosion. The coast changes are connected with the movement of the waves and currents in the coastal part of the sea. In the paper, the three-dimensional mathematical model of sediment transport and coastal zone lithodynamics is developed. The finite element formulations for the problems of wave modes, coastal currents, sediment transport and evolution of the coastal zone of the sea, are given. The numerical algorithms, implemented in the form of software. Programs are allowing to bring the solutions of the tasks to numerical results. The numerical modeling was developed in three stages. In the first stage the topography of the coast and the initial geometry of the structures are considered as an input parameters. Then, coastal wave field is calculated for the conditions prescribed in the initial wave. In the second stage, the calculated wave field is used to estimate the spatial distribution of the radiation stresses near-bottom orbital velocity. In the third stage the coastal wave fields and flow fields are used in the sub-models of sediment transport and changes in the topography of the coast. In the numerical solution of basic equations of motion of the waves, coastal currents and changes in sea bottom topography we use: finite element, finite difference methods and the method of upper relaxation, Crank-Nicolson scheme. As an example, we are giving the results of research of the wave regime in the coastal area of the city of Poti (700X600m) adjacent to the port of Poti. The bottom profile, in this area is rather complicated. During the calculations of the average rise of

Coastal High-resolution Observations and Remote Sensing of Ecosystems (C-HORSE)

Science.gov (United States)

Guild, Liane

2016-01-01

Coastal benthic marine ecosystems, such as coral reefs, seagrass beds, and kelp forests are highly productive as well as ecologically and commercially important resources. These systems are vulnerable to degraded water quality due to coastal development, terrestrial run-off, and harmful algal blooms. Measurements of these features are important for understanding linkages with land-based sources of pollution and impacts to coastal ecosystems. Challenges for accurate remote sensing of coastal benthic (shallow water) ecosystems and water quality are complicated by atmospheric scattering/absorption (approximately 80+% of the signal), sun glint from the sea surface, and water column scattering (e.g., turbidity). Further, sensor challenges related to signal to noise (SNR) over optically dark targets as well as insufficient radiometric calibration thwart the value of coastal remotely-sensed data. Atmospheric correction of satellite and airborne remotely-sensed radiance data is crucial for deriving accurate water-leaving radiance in coastal waters. C-HORSE seeks to optimize coastal remote sensing measurements by using a novel airborne instrument suite that will bridge calibration, validation, and research capabilities of bio-optical measurements from the sea to the high altitude remote sensing platform. The primary goal of C-HORSE is to facilitate enhanced optical observations of coastal ecosystems using state of the art portable microradiometers with 19 targeted spectral channels and flight planning to optimize measurements further supporting current and future remote sensing missions.

A 35 year high-resolution wave atlas for nearshore energy production and economics at the Aegean Sea

OpenAIRE

Lavidas, George; Venugopal, Vengatesan

2017-01-01

The study enhances the coastal resource knowledge and discusses opportunities for wave energy in theAegean Sea. A fine-resolution numerical wave model is utilised to provide results for the Greek coastalregions. The model ran for 35 years (1980e2014) estimating wave characteristics, and quantifying thewave energy potential in coastal areas. The results deliver the energy potential, variability, and sitecharacterisation for the Aegean Sea.The dataset is coupled with wave energy converters powe...

Modelling of Performance of Caisson Type Breakwaters under Extreme Waves

Science.gov (United States)

Güney Doǧan, Gözde; Özyurt Tarakcıoǧlu, Gülizar; Baykal, Cüneyt

2016-04-01

Many coastal structures are designed without considering loads of tsunami-like waves or long waves although they are constructed in areas prone to encounter these waves. Performance of caisson type breakwaters under extreme swells is tested in Middle East Technical University (METU) Coastal and Ocean Engineering Laboratory. This paper presents the comparison of pressure measurements taken along the surface of caisson type breakwaters and obtained from numerical modelling of them using IH2VOF as well as damage behavior of the breakwater under the same extreme swells tested in a wave flume at METU. Experiments are conducted in the 1.5 m wide wave flume, which is divided into two parallel sections (0.74 m wide each). A piston type of wave maker is used to generate the long wave conditions located at one end of the wave basin. Water depth is determined as 0.4m and kept constant during the experiments. A caisson type breakwater is constructed to one side of the divided flume. The model scale, based on the Froude similitude law, is chosen as 1:50. 7 different wave conditions are applied in the tests as the wave period ranging from 14.6 s to 34.7 s, wave heights from 3.5 m to 7.5 m and steepness from 0.002 to 0.015 in prototype scale. The design wave parameters for the breakwater were 5m wave height and 9.5s wave period in prototype. To determine the damage of the breakwater which were designed according to this wave but tested under swell waves, video and photo analysis as well as breakwater profile measurements before and after each test are performed. Further investigations are carried out about the acting wave forces on the concrete blocks of the caisson structures via pressure measurements on the surfaces of these structures where the structures are fixed to the channel bottom minimizing. Finally, these pressure measurements will be compared with the results obtained from the numerical study using IH2VOF which is one of the RANS models that can be applied to simulate

Effect of transient wave forcing on the behavior of arsenic in a sandy nearshore aquifer

Science.gov (United States)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2016-12-01

Waves cause large quantities of coastal water to recirculate across the groundwater-coastal water interface in addition to inducing complex groundwater flows in the nearshore aquifer. Due to the distinct chemical composition of recirculating coastal water compared with discharging terrestrial groundwater, wave-induced recirculations and flows can alter geochemical gradients in the nearshore aquifer which may subsequently affect the mobilization and transport of reactive pollutants (e.g., arsenic). The impact of seasonal geochemical and hydrological variability on the occurrence and mobility of arsenic near the groundwater-surface water interface has been shown previously in riverine settings, however, the impact of high frequency geochemical variations (e.g., varying wave conditions) on arsenic mobility in groundwater-surface water environments is unclear. The objective of the study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer to determine the factors regulating its mobility and transport to receiving coastal waters. Field investigations were conducted at a permeable beach on the Great Lakes during a period of intensified wave conditions (wave event). High spatial resolution pore water sampling captured the geochemical conditions in the nearshore aquifer prior to the wave event, immediately after the wave event and over a recovery period of 3 weeks following the wave event. Shifts in pH and redox potential (ORP) gradients in response to varying wave conditions caused shifts in the iron and arsenic distributions in the aquifer. Sediment analysis was combined with the pore water distributions to assess the release of sediment-bound arsenic in response to the varying wave conditions. Insight into the effect of transient forcing on arsenic mobility and transport in groundwater-surface water environments is important for evaluating the potential risks associated with this toxic metalloid. The findings of this

Mangrove Cultivation For Dealing With Coastal Abrasion Case Study Of Karangsong

Science.gov (United States)

Fatimatuzzahroh, Feti; Hadi, Sudharto P.; Purnaweni, Hartuti

2018-02-01

Coastal abrasion is consequence from destructive waves and sea current. One of cause is human intervention. The effort to solve of abrasion is by mangrove cultivation. Mangroves are halophyte plant that can restrain the sea wave. Mangrove cultivation required participation community that give awareness the importance of mangrove in coastal sustainability. Mangroves in coastal Karangsong, Indramayu west java, in 2007 was through abrasion approximately 127.30 ha. Mangrove cultivation in Karangsong has been replanting since 1998 to 2003, but there was no maintenance and management. In 2007 until 2015 Karangsong replanting mangroves and has been succeed. Karangsong became the center of mangrove study for west java area in 2015. This achievement is result of cooperation between community, NGO, and local government. In addition, this effort made not only overcome the abrasion problem but also give community awareness about the importance of mangrove cultivation in preventing coastal abrasion throughout community development. This paper reviews abrasion in Karangsong and the impact for local community and empowerment in mangrove cultivation. To achieve the success mangrove cultivation required community development approach from planning process, planting, maintenance and management.

Wave data processing toolbox manual

Science.gov (United States)

Sullivan, Charlene M.; Warner, John C.; Martini, Marinna A.; Lightsom, Frances S.; Voulgaris, George; Work, Paul

2006-01-01

Researchers routinely deploy oceanographic equipment in estuaries, coastal nearshore environments, and shelf settings. These deployments usually include tripod-mounted instruments to measure a suite of physical parameters such as currents, waves, and pressure. Instruments such as the RD Instruments Acoustic Doppler Current Profiler (ADCP(tm)), the Sontek Argonaut, and the Nortek Aquadopp(tm) Profiler (AP) can measure these parameters. The data from these instruments must be processed using proprietary software unique to each instrument to convert measurements to real physical values. These processed files are then available for dissemination and scientific evaluation. For example, the proprietary processing program used to process data from the RD Instruments ADCP for wave information is called WavesMon. Depending on the length of the deployment, WavesMon will typically produce thousands of processed data files. These files are difficult to archive and further analysis of the data becomes cumbersome. More imperative is that these files alone do not include sufficient information pertinent to that deployment (metadata), which could hinder future scientific interpretation. This open-file report describes a toolbox developed to compile, archive, and disseminate the processed wave measurement data from an RD Instruments ADCP, a Sontek Argonaut, or a Nortek AP. This toolbox will be referred to as the Wave Data Processing Toolbox. The Wave Data Processing Toolbox congregates the processed files output from the proprietary software into two NetCDF files: one file contains the statistics of the burst data and the other file contains the raw burst data (additional details described below). One important advantage of this toolbox is that it converts the data into NetCDF format. Data in NetCDF format is easy to disseminate, is portable to any computer platform, and is viewable with public-domain freely-available software. Another important advantage is that a metadata

Transport processes near coastal ocean outfalls

Science.gov (United States)

Noble, M.A.; Sherwood, C.R.; Lee, Hooi-Ling; Xu, Jie; Dartnell, P.; Robertson, G.; Martini, M.

2001-01-01

The central Southern California Bight is an urbanized coastal ocean where complex topography and largescale atmospheric and oceanographic forcing has led to numerous sediment-distribution patterns. Two large embayments, Santa Monica and San Pedro Bays, are connected by the short, very narrow shelf off the Palos Verdes peninsula. Ocean-sewage outfalls are located in the middle of Santa Monica Bay, on the Palos Verdes shelf and at the southeastern edge of San Pedro Bay. In 1992, the US Geological Survey, together with allied agencies, began a series of programs to determine the dominant processes that transport sediment and associated pollutants near the three ocean outfalls. As part of these programs, arrays of instrumented moorings that monitor currents, waves, water clarity, water density and collect resuspended materials were deployed on the continental shelf and slope information was also collected on the sediment and contaminant distributions in the region. The data and models developed for the Palos Verdes shelf suggest that the large reservoir of DDT/DDE in the coastal ocean sediments will continue to be exhumed and transported along the shelf for a long time. On the Santa Monica shelf, very large internal waves, or bores, are generated at the shelf break. The near-bottom currents associated with these waves sweep sediments and the associated contaminants from the shelf onto the continental slope. A new program underway on the San Pedro shelf will determine if water and contaminants from a nearby ocean outfall are transported to the local beaches by coastal ocean processes. The large variety of processes found that transport sediments and contaminants in this small region of the continental margin suggest that in regions with complex topography, local processes change markedly over small spatial scales. One cannot necessarily infer that the dominant transport processes will be similar even in adjacent regions.

Freaque waves during Typhoon Krosa

Directory of Open Access Journals (Sweden)

P. C. Liu

2009-07-01

Full Text Available This paper presents a subjective search for North Sea Draupner-like freaque waves from wave measurement data available in the northeastern coastal waters of Taiwan during Typhoon Krosa, October 2007. Not knowing what to expect, we found rather astonishingly that there were more Draupner-like freaque wave types during the build-up of the storm than we ever anticipated. As the conventional approach of defining freaque waves as H_max/H_s>2 is ineffective to discern all the conspicuous cases we found, we also tentatively proposed two new indices based on different empirical wave grouping approaches which hopefully can be used for further development of effective indexing toward identifying freaque waves objectively.

Variability in Benthic Exchange Rate, Depth, and Residence Time Beneath a Shallow Coastal Estuary

Science.gov (United States)

Russoniello, Christopher J.; Heiss, James W.; Michael, Holly A.

2018-03-01

Hydrodynamically driven benthic exchange of water between the water column and shallow seabed aquifer is a significant and dynamic component of coastal and estuarine fluid budgets. Associated exchange of solutes promotes ecologically important chemical reactions, so quantifying benthic exchange rates, depths, and residence times constrains coastal chemical cycling estimates. We present the first combined field, numerical, and analytical modeling investigation of wave-induced exchange. Temporal variability of exchange was calculated with data collected by instruments deployed in a shallow estuary for 11 days. Differential pressure sensors recorded pressure gradients across the seabed, and up- and down-looking ADCPs recorded currents and pressures to determine wave parameters, surface-water currents, and water depth. Wave-induced exchange was calculated (1) directly from differential pressure measurements, and indirectly with an analytical model based on wave parameters from (2) ADCP and (3) wind data. Wave-induced exchange from pressure measurements and ADCP-measured wave parameters matched well, but both exceeded wind-based values. Exchange induced by tidal pumping and current-bed form interaction—the other primary drivers in shallow coastal waters were calculated from tidal stage variation and ADCP-measured currents. Exchange from waves (mean = 20.0 cm/d; range = 1.75-92.3 cm/d) greatly exceeded exchange due to tides (mean = 3.7 cm/d) and current-bed form interaction (mean = 6.5 × 10-2 cm/d). Groundwater flow models showed aquifer properties affect wave-driven benthic exchange: residence time and depth increased and exchange rates decreased with increasing hydraulic diffusivity (ratio of aquifer permeability to compressibility). This new understanding of benthic exchange will help managers assess its control over chemical fluxes to marine systems.

Depositional Architecture of Late Pleistocene-Holocene Coastal Alluvial-fan System in the Coastal Range, Taiwan

Science.gov (United States)

Chen, S. T.; Chen, W. S.

2016-12-01

Since late Pleistocene, the Coastal Range (Philippine Sea plate) collided and overridden on the Central Range (Eurasian Plate) along the Longitudinal Valley Fault. Therefore, the Coastal Range is exposed widely the late Pleistocene-Holocene marine and fluvial terraces caused by the tectonic uplift. Based on the estimation of paleosea-level elevations (Δh), depositional paleodepth, altitude distribution of Holocene deposits (D), altitude of outcrops (H), and 14C dating of marine deposits (t), the uplift rate (=(Δh+H +d-D)/t) is about 5-10 mm/yr in the southern Coastal Range. In this study, we suggest through field logging that the deposits can be divided into alluvial, foreshore (intertidal), shoreface, and offshore environments. In Dulan area in the southern Coastal Range, the uplift rate was 6-7 mm/yr during 16,380-10,000 cal yr BP and 3-4 mm/yr after 7,000 cal yr BP. Results from the Dulan Coastal alluvial-fan system can be divided into five depositional stages: (1) 16,380-14,300 cal yr BP: The rate of global sea level rise (SLR) has averaged about 6-7 mm/yr, similar to the tectonic uplift rate. In this stage, the bedrock was eroded and formed a wide wave-cut platform. (2) 14,300-10,000 cal yr BP: SLR of about 14 mm/yr that was faster than tectonic uplift rate of 6-7 mm/yr. As a result of transgression, the beach-lagoon deposits about 5 m thick were unconformably overlain on the wave-cut platform. (3) 10,000-8,200 cal yr BP: The ongoing sea level rise (SLR: 11 mm/yr), the lagoon deposits were overlain by an offshore slump deposits representing a gradual deepening of the depositional environment. (4) 8,200-7,930 cal yr BP (SLR: 6-7 mm/yr): The tectonic uplift rate may occur at similar SLR. The alluvial-fan deposits have prograded over the shallow marine deposits. (5) After 7,000 cal yr BP (SLR: 1-0 mm/yr): SLR was much slower than tectonic uplift rate of 3-4 mm/yr. Thus, Holocene marine terraces are extensively developed in the coastal region, showing that the

Toward a community coastal sediment transport modeling system: the second workshop

Science.gov (United States)

Sherwood, Christopher R.; Harris, Courtney K.; Geyer, W. Rockwell; Butman, Bradford

2002-01-01

Models for transport and the long-term fate of particles in coastal waters are essential for a variety of applications related to commerce, defense, public health, and the quality of the marine environment. Examples include: analysis of waste disposal and transport and the fate of contaminated materials; evaluation of burial rates for naval mines or archaeological artifacts; prediction of water-column optical properties; analysis of transport and the fate of biological particles; prediction of coastal flooding and coastal erosion; evaluation of impacts of sea-level or wave-climate changes and coastal development; planning for construction and maintenance of navigable waterways; evaluation of habitat for commercial fisheries; evaluation of impacts of natural or anthropogenic changes in coastal conditions on recreational activities; and design of intakes and outfalls for sewage treatment, cooling systems, and desalination plants.

Tsunamis effects at coastal sites due to offshore faulting

International Nuclear Information System (INIS)

Miloh, T.; Striem, H.L.

1976-07-01

Unusual waves (tsunamis) triggered by submarine tectonic activity such as a fault displacement in the sea bottom may have considerable effect on a coastal site. The possiblity of such phenomena to occur at the southern coast of Israel due to a series of shore-parallel faults, about twenty kilometers offshore, is examined in this paper. The analysis relates the energy or the momentum imparted to the body of water due to a fault displacement of the sea bottom to the energy or the momentum of he water waves thus created. The faults off the Ashdod coast may cause surface waves with amplitudes of about five metres and periods of about one third of an hour. It is also considered that because of the downward movement of the faulted blocks a recession of the sea level rather than a flooding would be the first and the predominant effect at the shore, and this is in agreement with some historical reports. The analysis here presented might be of interest to those designing coastal power plants. (author)

Morphodynamic modeling of low energy beaches under waves, tides and currents

Science.gov (United States)

Ruiz, G.; Marino-Tapia, I.

2013-05-01

Natural processes such as coastal erosion or sediment accretion on beaches are produced by the interaction of physical forces in the littoral zone; these coastal processes can attain equilibrium states in the mid- and long term at beaches. Elements that contribute to such behaviour are the cumulative effects of waves, tides and shelf currents, which generate flow, sediment and wave patterns that shape the beach. However, over recent decades, coastal erosion has been intensified by the accelerated growth of the human population, urbanization and land development on coastal boundaries, which modify natural processes. This study shows the results of hydro-morphological numerical modeling of the northern beaches of Yucatán, Mexico, in which erosion problems are identified. The 2D-numerical simulations were carried out using the WAVE, FLOW and MOR models of DELFT 3D. The forcing elements which were used in the simulations, such as wave, tide and wind data were determined from oceanographical equipment and meteorological instruments that were located at the Yucatan coast. A nested model was used in the simulations in order to incorporate a detailed grid with a spatial resolution of 3 m within an overall larger grid. The detailed grid had 27,000 cells and covered a littoral cell of 800 x 200 m. Subsequently, an analysis of kinetic energy was performed to evaluate the grid and WAVE+ FLOW model stability. On the other hand, the calibration and validation tests were carried out through the comparison of computed and measured volumetric changes; the measured data were obtained from two field surveys where the change in the volume sediments was calculated from the evolution of a beach profile, over a span of 55 days. As a result of the validation test, the error between data and model was of ±3%. In order to identify which forcing is the most relevant for the coastal processes of these beaches, various scenarios were tested. Furthermore, an arrangement of six control volume

Lecture Notes for the Course in Water Wave Mechanics

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Frigaard, Peter

knowledge. The course is at the same time an introduction to the course in coastal hydraulics on the 8th semester. The notes cover the following five lectures: 1. Definitions. Governing equations and boundary conditions. Derivation of velocity potential for linear waves. Dispersion relationship. 2. Particle...... paths, velocities, accelerations, pressure variation, deep and shallow water waves, wave energy and group velocity. 3. Shoaling, refraction, diffraction and wave breaking. 4. Irregular waves. Time domain analysis of waves. 5. Wave spectra. Frequency domain analysis of waves. The present notes are based...

Climate Change Impacts on Future Wave Climate around the UK

Directory of Open Access Journals (Sweden)

William G. Bennett

2016-11-01

Full Text Available Understanding the changes in future storm wave climate is crucial for coastal managers and planners to make informed decisions required for sustainable coastal management and for the renewable energy industry. To investigate potential future changes to storm climate around the UK, global wave model outputs of two time slice experiments were analysed with 1979–2009 representing present conditions and 2075–2100 representing the future climate. Three WaveNet buoy sites around the United Kingdom, which represent diverse site conditions and have long datasets, were chosen for this study. A storm event definition (Dissanayake et al., 2015 was used to separate meteorologically-independent storm events from wave data, which in turn allowed storm wave characteristics to be analysed. Model outputs were validated through a comparison of the modelled storm data with observed storm data for overlapping periods. Although no consistent trends across all future clusters were observed, there were no significant increases in storm wave height, storm count or storm power in the future, at least according to the global wave projection results provided by the chosen model.

Analysis of X-band radar images for the detection of the reflected and diffracted waves in coastal zones

Science.gov (United States)

Ludeno, Giovanni; Natale, Antonio; Soldovieri, Francesco; Vicinanza, Diego; Serafino, Francesco

2014-05-01

The observation of nearshore waves and the knowledge of the sea state parameters can play a crucial role for the safety of harbors and ocean engineering. In the last two decades, different algorithms for the estimation of sea state parameters, surface currents and bathymetry from X-band radar data have been developed and validated [1, 2]. The retrieval of ocean wave parameters such as significant height, period, direction and wavelength of the dominant wave is based on the spectral analysis of data sequences collected by nautical X-band radars [3]. In particular, the reconstruction of the wave motion is carried out through the inversion procedure explained in [1-3], which exploits the dispersion relationship to define a band pass filter used to separate the energy associated with the ocean waves from the background noise. It is worth to note that the shape of such a band pass filter depends upon the value of both the surface currents and bathymetry; in our reconstruction algorithm these parameters are estimated through the (Normalized Scalar Product) procedure [1], which outperforms other existing methods (e.g., the Least Squares) [4]. From the reconstructed wave elevation sequences we can get the directional spectrum that provides useful information (i.e., wavelength, period, direction and amplitude) relevant to the main waves contributing to the wave motion. Of course, in coastal zones a number of diffraction and reflection phenomena can be observed, due to sea-waves impinging obstacles as jetties, breakwaters and boats. In the present paper we want to show the capability to detect reflected and diffracted sea-waves offered by the processing of X-band radar data. Further details relevant to the obtained results will be provided in the full paper and at the conference time. References [1] F. Serafino, C. Lugni, F. Soldovieri, "A novel strategy for the surface current determination from marine X-Band radar data", IEEE Geosci. and Remote Sensing Letters, vol. 7, no

Journal and Wave Bearing Impedance Calculation Software

Science.gov (United States)

Hanford, Amanda; Campbell, Robert

2012-01-01

The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

Mapping Deep Low Velocity Zones in Alaskan Arctic Coastal Permafrost using Seismic Surface Waves

Science.gov (United States)

Dou, S.; Ajo Franklin, J. B.; Dreger, D. S.

2012-12-01

Permafrost degradation may be an important amplifier of climate change; Thawing of near-surface sediments holds the potential of increasing greenhouse gas emissions due to microbial decomposition of preserved organic carbon. Recently, the characterization of "deep" carbon pools (several meters below the surface) in circumpolar frozen ground has increased the estimated amount of soil carbon to three times higher than what was previously thought. It is therefore potentially important to include the characteristics and processes of deeper permafrost strata (on the orders of a few to tens of meters below surface) in climate models for improving future predictions of accessible carbon and climate feedbacks. This extension is particularly relevant if deeper formations are not completely frozen and may harbor on-going microbial activity despite sub-zero temperatures. Unfortunately, the characterization of deep permafrost systems is non-trivial; logistics and drilling constraints often limit direct characterization to relatively shallow units. Geophysical measurements, either surface or airborne, are often the most effective tools for evaluating these regions. Of the available geophysical techniques, the analysis of seismic surface waves (e.g. MASW) has several unique advantages, mainly the ability to provide field-scale information with good depth resolution as well as penetration (10s to 100s of m with small portable sources). Surface wave methods are also able to resolve low velocity regions, a class of features that is difficult to characterize using traditional P-wave refraction methods. As part of the Department of Energy (DOE) Next-Generation Ecosystem Experiments (NGEE-Arctic) project, we conducted a three-day seismic field survey (May 12 - 14, 2012) at the Barrow Environmental Observatory, which is located within the Alaskan Arctic Coastal Plain. Even though permafrost at the study site is continuous, ice-rich and thick (>= 350m), our Multichannel Analysis of

Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

Energy Technology Data Exchange (ETDEWEB)

Dunkin, Lauren McNeill [Texas A & M Univ., College Station, TX (United States)

2010-05-01

Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

Coastal defence solutions (approach of ComCoast)

NARCIS (Netherlands)

Verhagen, H.J.; Visser, P.J.

2007-01-01

Along the North Sea coast, water levels are rising and waves are intensifying due to climate change. The best scientific evidence suggests that both phenomena are likely to accelerate over the coming decades. In some North Sea coastal areas also land is sinking and tidal heights and rates of erosion

Catching the Right Wave: Evaluating Wave Energy Resources and Potential Compatibility with Existing Marine and Coastal Uses

Science.gov (United States)

Kim, Choong-Ki; Toft, Jodie E.; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D.; Ruckelshaus, Marry H.; Arkema, Katie K.; Guannel, Gregory; Wood, Spencer A.; Bernhardt, Joanna R.; Tallis, Heather; Plummer, Mark L.; Halpern, Benjamin S.; Pinsky, Malin L.; Beck, Michael W.; Chan, Francis; Chan, Kai M. A.; Levin, Phil S.; Polasky, Stephen

2012-01-01

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses. PMID:23144824

Catching the right wave: evaluating wave energy resources and potential compatibility with existing marine and coastal uses.

Science.gov (United States)

Kim, Choong-Ki; Toft, Jodie E; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D; Ruckelshaus, Marry H; Arkema, Katie K; Guannel, Gregory; Wood, Spencer A; Bernhardt, Joanna R; Tallis, Heather; Plummer, Mark L; Halpern, Benjamin S; Pinsky, Malin L; Beck, Michael W; Chan, Francis; Chan, Kai M A; Levin, Phil S; Polasky, Stephen

2012-01-01

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses.

Development and Application of Percent Annual Chance Coastal Inundation Maps to Support Decision-Making in the Northern Gulf of Mexico

Science.gov (United States)

Bilskie, M. V.; Hagen, S. C.; Irish, J. L.; Yoskowitz, D.; Del Angel, D. C.

2017-12-01

Rising sea levels increase the vulnerability, exposure, probability, and thus risk associated with hurricane storm surge flooding across low-gradient coastal landscapes. In the U.S., flood risk assessments commonly employ the delineation of the 1% annual chance flood (100-year return period) that guide coastal policy and planning. As many coastal communities now include climate change effects on future development activities, the need to provide scientifically sound and scenario-based data products are becoming increasingly essential. Implementing bio-geo-physical models to study the effects of sea level rise (SLR) on coastal flooding under a variety of scenarios can be a powerful tool. However, model results alone are not appropriate for use by the broader coastal management community and thus must be further refined. For example, developing return period inundations maps or examining the potential economic damages are vital to translate scientific finding and extend their practicality to coastal resources managers, stakeholders, and governmental agencies. This work employs a collection of high-resolution wind-wave and hurricane storm surge models forced by a suite of synthetic storms to derive the 1% and 0.2% annual chance floodplain under four SLR scenarios (0.2, m, 0.5 m, 1.2 m, and 2.0 m) across the northern Gulf of Mexico (NGOM) coast, which include Mississippi, Alabama, and the Florida panhandle. The models represent the potential outlook of the coastal landscape for each of the scenarios and contains changes to the salt marsh, barrier islands, shoreline position, dune elevations, and land use land cover. Simulated surge data are fed into a hazard assessment tool that provides estimates of potential future damages and costs for each SLR scenario. Results provide evidence that the present 500-year floodplain becomes the 100-year floodplain under the 0.5 m SLR scenario by the end of the century along the Alabama and the Florida panhandle coast. Across

Validation suite for MCNP

International Nuclear Information System (INIS)

Mosteller, Russell D.

2002-01-01

Two validation suites, one for criticality and another for radiation shielding, have been defined and tested for the MCNP Monte Carlo code. All of the cases in the validation suites are based on experiments so that calculated and measured results can be compared in a meaningful way. The cases in the validation suites are described, and results from those cases are discussed. For several years, the distribution package for the MCNP Monte Carlo code1 has included an installation test suite to verify that MCNP has been installed correctly. However, the cases in that suite have been constructed primarily to test options within the code and to execute quickly. Consequently, they do not produce well-converged answers, and many of them are physically unrealistic. To remedy these deficiencies, sets of validation suites are being defined and tested for specific types of applications. All of the cases in the validation suites are based on benchmark experiments. Consequently, the results from the measurements are reliable and quantifiable, and calculated results can be compared with them in a meaningful way. Currently, validation suites exist for criticality and radiation-shielding applications.

The Coastal Ocean Prediction Systems program: Understanding and managing our coastal ocean. Volume 1: Strategic summary

Energy Technology Data Exchange (ETDEWEB)

1990-05-15

The proposed COPS (Coastal Ocean Prediction Systems) program is concerned with combining numerical models with observations (through data assimilation) to improve our predictive knowledge of the coastal ocean. It is oriented toward applied research and development and depends upon the continued pursuit of basic research in programs like COOP (Coastal Ocean Processes); i.e., to a significant degree it is involved with ``technology transfer`` from basic knowledge to operational and management applications. This predictive knowledge is intended to address a variety of societal problems: (1) ship routing, (2) trajectories for search and rescue operations, (3) oil spill trajectory simulations, (4) pollution assessments, (5) fisheries management guidance, (6) simulation of the coastal ocean`s response to climate variability, (7) calculation of sediment transport, (8) calculation of forces on structures, and so forth. The initial concern is with physical models and observations in order to provide a capability for the estimation of physical forces and transports in the coastal ocean. For all these applications, there are common needs for physical field estimates: waves, tides, currents, temperature, and salinity, including mixed layers, thermoclines, fronts, jets, etc. However, the intent is to work with biologists, chemists, and geologists in developing integrated multidisciplinary prediction systems as it becomes feasible to do so. From another perspective, by combining observations with models through data assimilation, a modern approach to monitoring is provided through whole-field estimation.

Building Blocks: A Quantitative Approach for Evaluating Coastal Vulnerability

Directory of Open Access Journals (Sweden)

Komali Kantamaneni

2017-11-01

Full Text Available Climate change and associated factors such as global and regional sea-level rise; the upsurge in high-intensity flooding events; and coastal erosion are pulse and press disturbances that threaten to increase landslides in coastal regions. Under these circumstances; a rigorous framework is required to evaluate coastal vulnerability in order to plan for future climate change scenarios. A vast majority of coastal vulnerability assessments across the globe are evaluated at the macro level (city scale but not at the micro level (small town scale; particularly in the United Kingdom (UK. In order to fill this vital research gap; the current study established a coastal vulnerability index termed here as the Micro Town Coastal Vulnerability Index (MTCVI and then applied it to Barton-on-Sea; which is a small coastal town of the Hampshire region; England; UK. MTCVI was evaluated for Barton-on-Sea coastal vulnerability by integrating both novel and existing parameters. Results suggest that the entire shoreline frontage (2 km exhibits very high coastal vulnerability and is prone to various coastal hazards such as landslides; erosion; and wave intrusion. This suggests that Barton-on-Sea coastal amenities will require a substantial improvement in shoreline protection measures. In this study; GIS (geographic information system coastal vulnerability and landslide maps were generated; and these maps can be used by the local authorities; district councils; coastal engineers; and planners to improve and design coastal management strategies under the climate change scenarios. Meanwhile; the methodology used in this study could also be applied to any other suitable location in the world depending on the availability of the data.

Coastal wave measurements during passage of tropical storm Amy

Science.gov (United States)

Morris, W. D.

1977-01-01

Aerial photographic and laser profilometer data of waves generated by tropical storm Amy are presented. The data mission consisted primarily of two legs, one in the direction of the wind waves, and the second along the direction of swell propagation, using Jennette's Pier at Nags Head, North Carolina, as a focal point. At flight time, Amy's center was 512 nmi from shore and had maximum winds of 60 knots. The storm's history is presented, along with a satellite photograph, showing the extent of the storm on the day of the flight. Flight ground tracks are presented along with sample aerial photographs of the wave conditions showing approximate wavelength and direction. Sample wave energy spectra are presented both from the laser profilometer onboard the aircraft, and from the Corps of Engineers Research Center (CERC) shore gauge at Nags Head, North Carolina.

Performance of coastal sea-defense infrastructure at El Jadida (Morocco against tsunami threat: lessons learned from the Japanese 11 March 2011 tsunami

Directory of Open Access Journals (Sweden)

R. Omira

2013-07-01

Full Text Available This paper seeks to investigate the effectiveness of sea-defense structures in preventing/reducing the tsunami overtopping as well as evaluating the resulting tsunami impact at El Jadida, Morocco. Different tsunami wave conditions are generated by considering various earthquake scenarios of magnitudes ranging from Mw = 8.0 to Mw = 8.6. These scenarios represent the main active earthquake faults in the SW Iberia margin and are consistent with two past events that generated tsunamis along the Atlantic coast of Morocco. The behaviour of incident tsunami waves when interacting with coastal infrastructures is analysed on the basis of numerical simulations of near-shore tsunami waves' propagation. Tsunami impact at the affected site is assessed through computing inundation and current velocity using a high-resolution digital terrain model that incorporates bathymetric, topographic and coastal structures data. Results, in terms of near-shore tsunami propagation snapshots, waves' interaction with coastal barriers, and spatial distributions of flow depths and speeds, are presented and discussed in light of what was observed during the 2011 Tohoku-oki tsunami. Predicted results show different levels of impact that different tsunami wave conditions could generate in the region. Existing coastal barriers around the El Jadida harbour succeeded in reflecting relatively small waves generated by some scenarios, but failed in preventing the overtopping caused by waves from others. Considering the scenario highly impacting the El Jadida coast, significant inundations are computed at the sandy beach and unprotected areas. The modelled dramatic tsunami impact in the region shows the need for additional tsunami standards not only for sea-defense structures but also for the coastal dwellings and houses to provide potential in-place evacuation.

Modeling wave attenuation by salt marshes in Jamaica Bay, New York, using a new rapid wave model

Science.gov (United States)

Marsooli, Reza; Orton, Philip M.; Mellor, George

2017-07-01

Using a new rapid-computation wave model, improved and validated in the present study, we quantify the value of salt marshes in Jamaica Bay—a highly urbanized estuary located in New York City—as natural buffers against storm waves. We augment the MDO phase-averaged wave model by incorporating a vegetation-drag-induced energy dissipation term into its wave energy balance equation. We adopt an empirical formula from literature to determine the vegetation drag coefficient as a function of environmental conditions. Model evaluation using data from laboratory-scale experiments show that the improved MDO model accurately captures wave height attenuation due to submerged and emergent vegetation. We apply the validated model to Jamaica Bay to quantify the influence of coastal-scale salt marshes on storm waves. It is found that the impact of marsh islands is largest for storms with lower flood levels, due to wave breaking on the marsh island substrate. However, the role of the actual marsh plants, Spartina alterniflora, grows larger for storms with higher flood levels, when wave breaking does not occur and the vegetative drag becomes the main source of energy dissipation. For the latter case, seasonality of marsh height is important; at its maximum height in early fall, S. alterniflora causes twice the reduction as when it is at a shorter height in early summer. The model results also indicate that the vegetation drag coefficient varies 1 order of magnitude in the study area, and suggest exercising extra caution in using a constant drag coefficient in coastal wetlands.

A long record of extreme wave events in coastal Lake Hamana, Japan

Science.gov (United States)

Boes, Evelien; Yokoyama, Yusuke; Schmidt, Sabine; Riedesel, Svenja; Fujiwara, Osamu; Nakamura, Atsunori; Garrett, Ed; Heyvaert, Vanessa; Brückner, Helmut; De Batist, Marc

2017-04-01

Coastal Lake Hamana is located near the convergent tectonic boundary of the Nankai-Suruga Trough, along which the Philippine Sea slab is subducted underneath the Eurasian Plate, giving rise to repeated tsunamigenic megathrust earthquakes (Mw ≥ 8). A good understanding of the earthquake- and tsunami-triggering mechanisms is crucial in order to better estimate the complexity of seismic risks. Thanks to its accommodation space, Lake Hamana may represent a good archive for past events, such as tsunamis and tropical storms (typhoons), also referred to as "extreme wave" events. Characteristic event layers, consisting of sediment entrained by these extreme waves and their backwash, are witnesses of past marine incursions. By applying a broad range of surveying methods (reflection-seismic profiling, gravity coring, piston coring), sedimentological analyses (CT-scanning, XRF-scanning, multi-sensor core logging, grain size, microfossils etc.) and dating techniques (210Pb/137Cs, 14C, OSL, tephrochronology), we attempt to trace extreme wave event deposits in a multiproxy approach. Seismic imagery shows a vertical stacking of stronger reflectors, interpreted to be coarser-grained sheets deposited by highly energetic waves. Systematic sampling of lake bottom sediments along a transect from ocean-proximal to ocean-distal sites enables us to evaluate vertical and lateral changes in stratigraphy. Ocean-proximal, we observe a sequence of eight sandy units separated by silty background sediments, up to a depth of 8 m into the lake bottom. These sand layers quickly thin out and become finer-grained land-inward. Seismic-to-core correlations show a good fit between the occurrence of strong reflectors and sandy deposits, hence confirming presumptions based on acoustic imagery alone. Sand-rich intervals typically display a higher magnetic susceptibility, density and stronger X-ray attenuation. However, based on textural and structural differences, we can make the distinction between

Ocean acidification 2.0: Managing our Changing Coastal Ocean Chemistry

OpenAIRE

Strong, AL; Kroeker, KJ; Teneva, LT; Mease, LA; Kelly, RP

2014-01-01

Ocean acidification (OA) is rapidly emerging as a significant problem for organisms, ecosystems, and human societies. Globally, addressing OA and its impacts requires international agreements to reduce rising atmospheric carbon dioxide concentrations. However, the complex suite of drivers of changing carbonate chemistry in coastal environments also requires regional policy analysis, mitigation, and adaptation responses. In order to fundamentally address the threat of OA, environmental manager...

The numerics of hydrostatic structured-grid coastal ocean models: State of the art and future perspectives

Science.gov (United States)

Klingbeil, Knut; Lemarié, Florian; Debreu, Laurent; Burchard, Hans

2018-05-01

The state of the art of the numerics of hydrostatic structured-grid coastal ocean models is reviewed here. First, some fundamental differences in the hydrodynamics of the coastal ocean, such as the large surface elevation variation compared to the mean water depth, are contrasted against large scale ocean dynamics. Then the hydrodynamic equations as they are used in coastal ocean models as well as in large scale ocean models are presented, including parameterisations for turbulent transports. As steps towards discretisation, coordinate transformations and spatial discretisations based on a finite-volume approach are discussed with focus on the specific requirements for coastal ocean models. As in large scale ocean models, splitting of internal and external modes is essential also for coastal ocean models, but specific care is needed when drying & flooding of intertidal flats is included. As one obvious characteristic of coastal ocean models, open boundaries occur and need to be treated in a way that correct model forcing from outside is transmitted to the model domain without reflecting waves from the inside. Here, also new developments in two-way nesting are presented. Single processes such as internal inertia-gravity waves, advection and turbulence closure models are discussed with focus on the coastal scales. Some overview on existing hydrostatic structured-grid coastal ocean models is given, including their extensions towards non-hydrostatic models. Finally, an outlook on future perspectives is made.

Modeling sheet-flow sand transport under progressive surface waves

NARCIS (Netherlands)

Kranenburg, Wouter

2013-01-01

In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels.

The protective role of coastal marshes: a systematic review and meta-analysis.

Directory of Open Access Journals (Sweden)

Christine C Shepard

Full Text Available BACKGROUND: Salt marshes lie between many human communities and the coast and have been presumed to protect these communities from coastal hazards by providing important ecosystem services. However, previous characterizations of these ecosystem services have typically been based on a small number of historical studies, and the consistency and extent to which marshes provide these services has not been investigated. Here, we review the current evidence for the specific processes of wave attenuation, shoreline stabilization and floodwater attenuation to determine if and under what conditions salt marshes offer these coastal protection services. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a thorough search and synthesis of the literature with reference to these processes. Seventy-five publications met our selection criteria, and we conducted meta-analyses for publications with sufficient data available for quantitative analysis. We found that combined across all studies (n = 7, salt marsh vegetation had a significant positive effect on wave attenuation as measured by reductions in wave height per unit distance across marsh vegetation. Salt marsh vegetation also had a significant positive effect on shoreline stabilization as measured by accretion, lateral erosion reduction, and marsh surface elevation change (n = 30. Salt marsh characteristics that were positively correlated to both wave attenuation and shoreline stabilization were vegetation density, biomass production, and marsh size. Although we could not find studies quantitatively evaluating floodwater attenuation within salt marshes, there are several studies noting the negative effects of wetland alteration on water quantity regulation within coastal areas. CONCLUSIONS/SIGNIFICANCE: Our results show that salt marshes have value for coastal hazard mitigation and climate change adaptation. Because we do not yet fully understand the magnitude of this value, we propose that decision

The effectiveness of coral reefs for coastal hazard risk reduction and adaptation

Science.gov (United States)

Ferrario, Filippo; Beck, Michael W.; Storlazzi, Curt D.; Micheli, Fiorenza; Shepard, Christine C.; Airoldi, Laura

2014-01-01

The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97%. Reef crests alone dissipate most of this energy (86%). There are 100 million or more people who may receive risk reduction benefits from reefs or bear hazard mitigation and adaptation costs if reefs are degraded. We show that coral reefs can provide comparable wave attenuation benefits to artificial defences such as breakwaters, and reef defences can be enhanced cost effectively. Reefs face growing threats yet there is opportunity to guide adaptation and hazard mitigation investments towards reef restoration to strengthen this first line of coastal defence.

The influence of wave action on coastal erosion along Monwabisi ...

African Journals Online (AJOL)

Microsoft account

commonly recognised effect of this warming is the eustatic rise of sea level (Allen ... 100km of the coastline and could be affected by future sea-level rise (SLR)- ..... Douglas, BC 2000, 'Sea Level Rise Shown to Drive Coastal Erosion', Florida.

Risk Analysis of Coastal hazard Considering Sea-level Rise and Local Environment in Coastal Area

Science.gov (United States)

Sangjin, P.; Lee, D. K.; KIM, H.; Ryu, J. E.; Yoo, S.; Ryoo, H.

2014-12-01

Recently, natural hazards has been more unpredictable with increasing frequency and strength due to climate change. Especially, coastal areas would be more vulnerable in the future because of sea-level rise (SLR). In case of Korea, it is surrounded by oceans and has many big cities at coastal area, thus a hazard prevention plan in coastal area is absolutely necessary. However, prior to making the plan, finding areas at risk would be the first step. In order to find the vulnerable area, local characteristics of coastal areas should also be considered along with SLR. Therefore, the objective of the research is to find vulnerable areas, which could be damaged by coastal hazards considering local environment and SLR of coastal areas. Spatial scope of the research was set up as 1km from the coastline according to the 'coastal management law' in Korea. The assessment was done up to the year of 2050, and the highest sea level rise scenario was used. For risk analysis, biophysical and socioeconomic characteristics were considered as to represent local characteristics of coastal area. Risk analysis was carried out through the combination of 'possibility of hazard' and the 'level of damages', and both of them reflect the above-mentioned regional characteristics. Since the range of inundation was narrowed down to the inundation from typhoon in this research, the possibility of inundation caused by typhoon was estimated by using numerical model, which calculated the height of storm surge considering wave, tide, sea-level pressure and SLR. Also the level of damage was estimated by categorizing the socioeconomic character into four factors; human, infrastructure, ecology and socioeconomic. Variables that represent each factor were selected and used in damage estimation with their classification and weighting value. The result shows that the urban coastal areas are more vulnerable and hazardous than other areas because of socioeconomic factors. The east and the south coast are

Rock armour for birds and their prey: ecological enhancement of coastal engineering

OpenAIRE

Naylor, Larissa A.; MacArthur, Mairi; Hampshire, Stephanie; Bostock, Kieran; Coombes, Martin A.; Hansom, Jim; Byrne, Rowan; Folland, Tristan

2017-01-01

The authors present key design, construction and ecological enhancement criteria for sustainable coastal defence structures at Hartlepool, UK, a high-energy wave climate. Such ‘ecologically favourable’ coastal defences fulfil the habitats directive and key engineering and cost criteria. Bird, rocky intertidal ecological and biogeomorphological data underpin recommendations for ‘passive’ enhancement mitigation to maximise ecological potential involving rock armour material choice (partially en...

Seasonal electrical resistivity surveys of a coastal bluff, Barter Island, North Slope Alaska

Science.gov (United States)

Swarzenski, Peter W.; Johnson, Cordell; Lorenson, Thomas; Conaway, Christopher H.; Gibbs, Ann E.; Erikson, Li; Richmond, Bruce M.; Waldrop, Mark P.

2016-01-01

Select coastal regions of the North Slope of Alaska are experiencing high erosion rates that can be attributed in part to recent warming trends and associated increased storm intensity and frequency. The upper sediment column of the coastal North Slope of Alaska can be described as continuous permafrost underlying a thin (typically less than 1–2 m) active layer that responds variably to seasonal thaw cycles. Assessing the temporal and spatial variability of the active layer and underlying permafrost is essential to better constrain how heightened erosion may impact material fluxes to the atmosphere and the coastal ocean, and how enhanced thaw cycles may impact the stability of the coastal bluffs. In this study, multi-channel electrical resistivity tomography (ERT) was used to image shallow subsurface features of a coastal bluff west of Kaktovik, on Barter Island, northeast Alaska. A comparison of a suite of paired resistivity surveys conducted in early and late summer 2014 provided detailed information on how the active layer and permafrost are impacted during the short Arctic summer. Such results are useful in the development of coastal resilience models that tie together fluvial, terrestrial, climatic, geologic, and oceanographic forcings on shoreline stability.

Global climate change implications for coastal and offshore oil and gas development

International Nuclear Information System (INIS)

Burkett, Virginia

2011-01-01

The discussion and debate about climate change and oil and gas resource development has generally focused on how fossil fuel use affects the Earth's climate. This paper explores how the changing climate is likely to affect oil and gas operations in low-lying coastal areas and the outer continental shelf. Oil and gas production in these regions comprises a large sector of the economies of many energy producing nations. Six key climate change drivers in coastal and marine regions are characterized with respect to oil and gas development: changes in carbon dioxide levels and ocean acidity, air and water temperature, precipitation patterns, the rate of sea level rise, storm intensity, and wave regime. These key drivers have the potential to independently and cumulatively affect coastal and offshore oil and gas exploration, production, and transportation, and several impacts of climate change have already been observed in North America. - Highlights: ► Climate change effects on coastal and offshore energy development have been observed in some regions. ► Key drivers include changes in temperature, precipitation, sea level rise, storm intensity and wave regime. ► These can independently and cumulatively affect coastal and offshore exploration, production, and transportation. ► A methodical vulnerability and impact assessment is needed to support adaptation in this sector of the global economy.

Spatial variability of coastal wetland resilience to sea-level rise using Bayesian inference

Science.gov (United States)

Hardy, T.; Wu, W.

2017-12-01

The coastal wetlands in the Northern Gulf of Mexico (NGOM) account for 40% of coastal wetland area in the United States and provide various ecosystem services to the region and broader areas. Increasing rates of relative sea-level rise (RSLR), and reduced sediment input have increased coastal wetland loss in the NGOM, accounting for 80% of coastal wetland loss in the nation. Traditional models for predicting the impact of RSLR on coastal wetlands in the NGOM have focused on coastal erosion driven by geophysical variables only, and/or at small spatial extents. Here we developed a model in Bayesian inference to make probabilistic prediction of wetland loss in the entire NGOM as a function of vegetation productivity and geophysical attributes. We also studied how restoration efforts help maintain the area of coastal wetlands. Vegetation productivity contributes organic matter to wetland sedimentation and was approximated using the remotely sensed normalized difference moisture index (NDMI). The geophysical variables include RSLR, tidal range, river discharge, coastal slope, and wave height. We found a significantly positive relation between wetland loss and RSLR, which varied significantly at different river discharge regimes. There also existed a significantly negative relation between wetland loss and NDMI, indicating that in-situ vegetation productivity contributed to wetland resilience to RSLR. This relation did not vary significantly between river discharge regimes. The spatial relation revealed three areas of high RSLR but relatively low wetland loss; these areas were associated with wetland restoration projects in coastal Louisiana. Two projects were breakwater projects, where hard materials were placed off-shore to reduce wave action and promote sedimentation. And one project was a vegetation planting project used to promote sedimentation and wetland stabilization. We further developed an interactive web tool that allows stakeholders to develop similar wetland

Processes of coastal bluff erosion in weakly lithified sands, Pacifica, California, USA

Science.gov (United States)

Collins, B.D.; Sitar, N.

2008-01-01

Coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern California. In this study, we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of San Francisco, California. Using the results of a five year observational study consisting of site visits, terrestrial lidar scanning, and development of empirical failure indices, we identify the lithologic and process controls that determine the failure mechanism and mode for coastal bluff retreat in this region and present concise descriptions of each process. Bluffs composed of weakly cemented sands (unconfined compressive strength - UCS between 5 and 30??kPa) fail principally due to oversteepening by wave action with maximum slope inclinations on the order of 65 at incipient failure. Periods of significant wave action were identified on the basis of an empirical wave run-up equation, predicting failure when wave run-up exceeds the seasonal average value and the bluff toe elevation. The empirical relationship was verified through recorded observations of failures. Bluffs composed of moderately cemented sands (UCS up to 400??kPa) fail due to precipitation-induced groundwater seepage, which leads to tensile strength reduction and fracture. An empirical rainfall threshold was also developed to predict failure on the basis of a 48-hour cumulative precipitation index but was found to be dependent on a time delay in groundwater seepage in some cases.

Secondary Flows and Sediment Transport due to Wave - Current Interaction

Science.gov (United States)

Ismail, Nabil; Wiegel, Robert

2015-04-01

Objectives: The main purpose of this study is to determine the modifications of coastal processes driven by wave-current interaction and thus to confirm hydrodynamic mechanisms associated with the interaction at river mouths and tidal inlets where anthropogenic impacts were introduced. Further, the aim of the work has been to characterize the effect of the relative strength of momentum action of waves to the opposing current on the nearshore circulation where river flow was previously effective to entrain sediments along the shoreline. Such analytical information are useful to provide guidelines for sustainable design of coastal defense structures. Methodology and Analysis: Use is made of an earlier study reported by the authors (1983) on the interaction of horizontal momentum jets and opposing shallow water waves at shorelines, and of an unpublished laboratory study (1980). The turbulent horizontal discharge was shore-normal, directed offshore, and the incident wave direction was shore-normal, travelling toward shore. Flow visualization at the smooth bottom and the water surface, velocity and water surface elevation measurements were made. Results were obtained for wave , current modifications as well as the flow pattern in the jet and the induced circulation on both sides of the jet, for a range of wave and jet characteristics. The experimental data, obtained from measurement in the 3-D laboratory basin, showed several distinct flow pattern regimes on the bottom and the water surface. The observed flow circulation regimes were found to depend on the ratio of the wave momentum action on the jet to the jet initial momentum. Based on the time and length scales of wave and current parameters and using the time average of the depth integrated conservation equations, it is found that the relative strength of the wave action on the jet could be represented by a dimensionless expression; Rsm ( ) 12ρSa20g-L0h-Cg- 2 Rsm ≈ (C0 - U) /ρ0U w (1) In the above dimensionless

Variability in benthic exchange rate, depth, and residence time beneath a shallow coastal estuary

Science.gov (United States)

Russoniello, C. J.; Michael, H. A.; Heiss, J.

2017-12-01

Hydrodynamically-driven exchange of water between the water column and shallow seabed aquifer, benthic exchange, is a significant and dynamic component of coastal and estuarine fluid budgets, but wave-induced benthic exchange has not been measured in the field. Mixing between surface water and groundwater solutes promotes ecologically important chemical reactions, so quantifying benthic exchange rates, depths, and residence times, constrains estimates of coastal chemical cycling. In this study, we present the first field-based direct measurements of wave-induced exchange and compare it to exchange induced by the other primary drivers of exchange - tides, and currents. We deployed instruments in a shallow estuary to measure benthic exchange and temporal variability over an 11-day period. Differential pressure sensors recorded pressure gradients across the seabed, and up-and down-looking ADCPs recorded currents and pressures from which wave parameters, surface-water currents, and water depth were determined. Wave-induced exchange was calculated directly from 1) differential pressure measurements, and indirectly with an analytical solution based on wave parameters from 2) ADCP and 3) weather station data. Groundwater flow models were used to assess the effects of aquifer properties on benthic exchange depth and residence time. Benthic exchange driven by tidal pumping or current-bedform interaction was calculated from tidal stage variation and from ADCP-measured currents at the bed, respectively. Waves were the primary benthic exchange driver (average = 20.0 cm/d, maximum = 92.3 cm/d) during the measurement period. Benthic exchange due to tides (average = 3.7 cm/d) and current-bedform interaction (average = 6.5x10-2 cm/d) was much lower. Wave-induced exchange calculated from pressure measurements and ADCP-measured wave parameters matched well, but wind-based rates underestimated wave energy and exchange. Groundwater models showed that residence time and depth increased

Integration of wave energy and other marine renewable energy sources with the needs of coastal societies

Directory of Open Access Journals (Sweden)

Richard Manasseh

2017-04-01

Full Text Available Marine renewable energy has the potential to solve both the energy-security and coastal-protection problems affecting coastal societies. In this article, the potential benefits arising from the combination of marine renewable energy technologies with infrastructural needs for coastal protection and other local needs are analysed. Classifications of technologies are developed to inform future coastal planning. Explanations of the resources and technologies are presented in layperson’s term. The threat of coastal inundation under climate-change scenarios is a major global issue. The investment in new infrastructure demanded by cities, ports and communities at risk of inundation could very substantially reduce the levelised cost of electricity from renewable sources, provided the infrastructure is designed with the dual purpose of power generation and coastal protection. Correspondingly, the sale of electricity from such infrastructure could defray the long-term cost of installing coastal protection. Furthermore, many marine renewable energy technologies provide a platform on which other forms of renewable energy generation could be mounted. It is noted that the complex geophysical and engineering issues arising from this opportunity must be assessed considering socio-economic factors.

Connecting large-scale coastal behaviour with coastal management of the Rhône delta

Science.gov (United States)

Sabatier, François; Samat, Olivier; Ullmann, Albin; Suanez, Serge

2009-06-01

The aim of this paper is to connect the Large Scale Coastal Behaviour (LSCB) of the Rhône delta (shoreface sediment budget, river sediment input to the beaches, climatic change) with the impact and efficiency of hard engineering coastal structures. The analysis of the 1895 to 1974 bathymetric maps as well as 2D modelling of the effect of wave blocking on longshore transport allows us to draw up a conceptual model of the LSCB of the Rhône delta. The river sand input, settled in the mouth area (prodeltaic lobe), favours the advance of adjacent beaches. There is however a very weak alongshore sand feeding of the non-adjacent beaches farther off the mouth. After a mouth shift, the prodelta is eroded by aggressive waves and the sand is moved alongshore to build spits. This conceptual model suggests that there is a "timeshift" between the input of river sediments to the sea and the build up of a beach (nonadjacent to the mouth). Nowadays, as the river channels are controlled by dykes and human interventions, a river shift is not possible. It thus appears unlikely that the river sediments can supply the beaches of the Rhône delta coast. Under these conditions, we must expect that the problems of erosion will continue at Saintes-Maries-de-la-Mer and on the Faraman shore, in areas with chronic erosion where the shoreline retreat has been partially stopped by hard engineering practices in the 1980s. Therefore, these artificially stabilised sectors remain potentially under threat because of profile steepening and downdrift erosion evidenced in this paper by bathymetric profile measurements. In the long-term (1905 to 2003), the temporal analysis of the storm surges and the sea level show very weak but reliable increasing trends. Thus, these climatic agents will be more aggressive on the beaches and on the coastal structures calling their efficiency into question. We also evidence that the hard engineering structures were built in a favourable climatic context during the

Coastal processes of the Elwha River delta: Chapter 5 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

Science.gov (United States)

Warrick, Jonathan A.; Stevens, Andrew W.; Miller, Ian M.; Gelfenbaum, Guy; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

To understand the effects of increased sediment supply from dam removal on marine habitats around the Elwha River delta, a basic understanding of the region’s coastal processes is necessary. This chapter provides a summary of the physical setting of the coast near the Elwha River delta, for the purpose of synthesizing the processes that move and disperse sediment discharged by the river. One fundamental property of this coastal setting is the difference between currents in the surfzone with those in the coastal waters offshore of the surfzone. Surfzone currents are largely dictated by the direction and size of waves, and the waves that attack the Elwha River delta predominantly come from Pacific Ocean swell from the west. This establishes surfzone currents and littoral sediment transport that are eastward along much of the delta. Offshore of the surfzone the currents are largely influenced by tidal circulation and the physical constraint to flow provided by the delta’s headland. During both ebbing and flooding tides, the flow separates from the coast at the tip of the delta’s headland, and this produces eddies on the downstream side of the headland. Immediately offshore of the Elwha River mouth, this creates a situation in which the coastal currents are directed toward the east much more frequently than toward the west. This suggests that Elwha River sediment will be more likely to move toward the east in the coastal system.

High-resolution reconstruction of a coastal barrier system

DEFF Research Database (Denmark)

Fruergaard, Mikkel; Andersen, Thorbjørn Joest; Nielsen, Lars Henrik

2015-01-01

This study presents a detailed reconstruction of the sedimentary effects of Holocene sea-level rise on a modern coastal barrier system (CBS). Increasing concern over the evolution of CBSs due to future accelerated rates of sea-level rise calls for a better understanding of coastal barriers response...... from retreat of the barrier island and probably also due to formation of a tidal inlet close to the study area. Continued transgression and shoreface retreat created a distinct hiatus and wave ravinement surface in the seaward part of the CBS before the barrier shoreline stabilised between 5.0 and 4...

Development of a Shipboard Remote Control and Telemetry Experimental System for Large-Scale Model's Motions and Loads Measurement in Realistic Sea Waves.

Science.gov (United States)

Jiao, Jialong; Ren, Huilong; Adenya, Christiaan Adika; Chen, Chaohe

2017-10-29

Wave-induced motion and load responses are important criteria for ship performance evaluation. Physical experiments have long been an indispensable tool in the predictions of ship's navigation state, speed, motions, accelerations, sectional loads and wave impact pressure. Currently, majority of the experiments are conducted in laboratory tank environment, where the wave environments are different from the realistic sea waves. In this paper, a laboratory tank testing system for ship motions and loads measurement is reviewed and reported first. Then, a novel large-scale model measurement technique is developed based on the laboratory testing foundations to obtain accurate motion and load responses of ships in realistic sea conditions. For this purpose, a suite of advanced remote control and telemetry experimental system was developed in-house to allow for the implementation of large-scale model seakeeping measurement at sea. The experimental system includes a series of technique sensors, e.g., the Global Position System/Inertial Navigation System (GPS/INS) module, course top, optical fiber sensors, strain gauges, pressure sensors and accelerometers. The developed measurement system was tested by field experiments in coastal seas, which indicates that the proposed large-scale model testing scheme is capable and feasible. Meaningful data including ocean environment parameters, ship navigation state, motions and loads were obtained through the sea trial campaign.

Smal-Scale Spatial Differences in Supply-Side Ecology of Barnacle Larvae Involves a Complex Suite of Factors (Including Surface Tide, Internal Tides And Surface Winds) in Baja California

Science.gov (United States)

Valencia, A.; Ladah, L. B.

2016-02-01

The objective of this study was to quantify and compare the daily settlement rate of barnacle larvae of Chthamalus spp. at small spatial scales ( 1 km) at three sites with unique geomorphology. Simultaneously, water-column temperature, currents, and coastal winds were measured to detect potential physical transport mechanisms responsible for supply of planktonic larvae to the coast. Autocorrelation artifacts in the environmental and settlement time series were removed with the Autoregressive Integrated Moving Average (ARIMA) and their residuals were used to perform a Principal Component Analysis (PCA). This analysis was carried out to determine the independent modes of variability in the environmental forcing mechanisms that may explain the settlement patterns. We found synchronous settlement pulses occurring throughout the study. Settlement at the wave exposed site was only associated to the wind-forcing mode and not to internal waves, which had not been detected previously and was surprising, considering the strong semidiurnal internal tide at this site. Settlement at both the reef-bounded site and the inside-bay site associated to vertical isotherm displacements, thereby suggesting the importance of internal waves for supply-side ecology at these more southern sites. Our results suggest that a complex suite of factors may interact to result in larval supply at the same site, and that larval supply at nearby sites may be forced by different factors due to differences in geomorphology and/or bathymetry, explaining spatial heterogeneity often detected in larval supply and settlement.

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Mayer, D.W.; Argo, R.S.

1982-02-01

A hydrodynamic model, CAFE-I, a wave refraction model, LO3D, and a sediment and contaminant transport model, FETRA, were selected as tools for evaluating exposure levels of radionuclides, heavy metals, and other toxic chemicals in coastal waters. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interactions (e.g., adsorption and desorption), and the mechanisms governing the transport, deposition, and resuspension of contaminated sediments

High-order finite difference solution for 3D nonlinear wave-structure interaction

DEFF Research Database (Denmark)

Ducrozet, Guillaume; Bingham, Harry B.; Engsig-Karup, Allan Peter

2010-01-01

This contribution presents our recent progress on developing an efficient fully-nonlinear potential flow model for simulating 3D wave-wave and wave-structure interaction over arbitrary depths (i.e. in coastal and offshore environment). The model is based on a high-order finite difference scheme O...

KwaZulu-Natal coastal erosion events of 2006/2007 and 2011: A predictive tool?

OpenAIRE

Alan Smith; Lisa A. Guastella; Andrew A. Mather; Simon C. Bundy; Ivan D. Haigh

2013-01-01

Severe coastal erosion occurred along the KwaZulu-Natal coastline between mid-May and November 2011. Analysis of this erosion event and comparison with previous coastal erosion events in 2006/2007 offered the opportunity to extend the understanding of the time and place of coastal erosion strikes. The swells that drove the erosion hotspots of the 2011 erosion season were relatively low (significant wave heights were between 2 m and 4.5 m) but of long duration. Although swell height was import...

The Arctic Coastal Erosion Problem

Energy Technology Data Exchange (ETDEWEB)

Frederick, Jennifer M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thomas, Matthew Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Craig A. [Integral Consulting Inc., San Francisco, CA (United States); Roberts, Jesse D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-09-01

evolving wave dynamics, thermodynamics, and sediment dynamics must be developed. The objective of this document is to present the state-of-the-science and outline the key steps for creation of a framework that will allow for improved prediction of Arctic coastal erosion rates. This is the first step towards the quantification of coastal hazards that will allow for sustainable planning and development of Arctic infrastructure.

Coastal Vulnerability and risk assessment of infrastructures, natural and cultural heritage sites in Greece.

Science.gov (United States)

Alexandrakis, George; Kampanis, Nikolaos

2016-04-01

The majority of human activities are concentrated around coastal areas, making coastline retreat, a significant threat to coastal infrastructure, thus increasing protection cost and investment revenue losses. In this study the management of coastal areas in terms of protecting coastal infrastructures, cultural and environmental heritage sites, through risk assessment analysis is been made. The scope is to provide data for spatial planning for future developments in the coastal zone and the protection of existing ones. Also to determine the impact of coastal changes related to the loss of natural resources, agricultural land and beaches. The analysis is based on a multidisciplinary approach, combining environmental, spatial and economic data. This can be implemented by integrating the assessment of vulnerability of coasts, the spatial distribution and structural elements of coastal infrastructure (transport, tourism, and energy) and financial data by region, in a spatial database. The approach is based on coastal vulnerability estimations, considering sea level rise, land loss, extreme events, safety, adaptability and resilience of infrastructure and natural sites. It is based on coupling of environmental indicators and econometric models to determine the socio-economic impact in coastal infrastructure, cultural and environmental heritage sites. The indicators include variables like the coastal geomorphology; coastal slope; relative sea-level rise rate; shoreline erosion/accretion rate; mean tidal range and mean wave height. The anthropogenic factors include variables like settlements, sites of cultural heritage, transport networks, land uses, significance of infrastructure (e.g. military, power plans) and economic activities. The analysis in performed by a GIS application. The forcing variables are determined with the use of sub-indices related to coastal geomorphology, climate and wave variables and the socioeconomics of the coastal zone. The Greek coastline in

Solitary waves in fluids

CERN Document Server

Grimshaw, RHJ

2007-01-01

After the initial observation by John Scott Russell of a solitary wave in a canal, his insightful laboratory experiments and the subsequent theoretical work of Boussinesq, Rayleigh and Korteweg and de Vries, interest in solitary waves in fluids lapsed until the mid 1960's with the seminal paper of Zabusky and Kruskal describing the discovery of the soliton. This was followed by the rapid development of the theory of solitons and integrable systems. At the same time came the realization that solitary waves occur naturally in many physical systems, and play a fundamental role in many circumstances. The aim of this text is to describe the role that soliton theory plays in fluids in several contexts. After an historical introduction, the book is divided five chapters covering the basic theory of the Korteweg-de Vries equation, and the subsequent application to free-surface solitary waves in water to internal solitary waves in the coastal ocean and the atmospheric boundary layer, solitary waves in rotating flows, ...

75 FR 59707 - Coastal Hydropower, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

Science.gov (United States)

2010-09-28

... Hydropower, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments... on July 16, 2010, Coastal Hydropower, LLC filed an application for a preliminary permit, pursuant to... Hydropower, LLC, Key Centre, 601 108th Avenue, NE., Suite 1900, Bellevue, WA 98004; phone: (425) 943-7690...

Upgrade and Design of Coastal Structures Exposed to Climate Changes

DEFF Research Database (Denmark)

Nørgaard, Jørgen Quvang Harck

This thesis “Upgrade and Design of Coastal Structures Exposed to Climate Changes” evaluates the performance of existing types of structures when exposed to climate changes. This includes also the potential of using cost‐sharing multipurpose structures for protection against the effects of future...... climate changes. The thesis consists of three parts. The first part evaluates the performance of existing design formulae for estimation of wave actions on structures, especially in shallow water since these structures are most vulnerable to the rising sea water levels caused by climate changes. Existing...... of coastal protection structures, which are extended to a wider range of wave conditions, and which can be used to more accurately estimate the influence from climate changes. In the second part of the thesis, the extended and modified formulae are used in case studies to evaluate the influence from climate...

Upgrade and Design of Coastal Structures Exposed to Climate Changes

DEFF Research Database (Denmark)

Nørgaard, Jørgen Quvang Harck

This thesis "Upgrade and Design of Coastal Structures Exposed to Climate Changes" evaluates the performance of existing types of structures when exposed to climate changes. This includes also the potential of using cost‐sharing multipurpose structures for protection against the effects of future...... climate changes. The thesis consists of three parts. The first part evaluates the performance of existing design formulae for estimation of wave actions on structures, especially in shallow water since these structures are most vulnerable to the rising sea water levels caused by climate changes. Existing...... of coastal protection structures, which are extended to a wider range of wave conditions, and which can be used to more accurately estimate the influence from climate changes. In the second part of the thesis, the extended and modified formulae are used in case studies to evaluate the influence from climate...

A depth semi-averaged model for coastal dynamics

Science.gov (United States)

Antuono, M.; Colicchio, G.; Lugni, C.; Greco, M.; Brocchini, M.

2017-05-01

The present work extends the semi-integrated method proposed by Antuono and Brocchini ["Beyond Boussinesq-type equations: Semi-integrated models for coastal dynamics," Phys. Fluids 25(1), 016603 (2013)], which comprises a subset of depth-averaged equations (similar to Boussinesq-like models) and a Poisson equation that accounts for vertical dynamics. Here, the subset of depth-averaged equations has been reshaped in a conservative-like form and both the Poisson equation formulations proposed by Antuono and Brocchini ["Beyond Boussinesq-type equations: Semi-integrated models for coastal dynamics," Phys. Fluids 25(1), 016603 (2013)] are investigated: the former uses the vertical velocity component (formulation A) and the latter a specific depth semi-averaged variable, ϒ (formulation B). Our analyses reveal that formulation A is prone to instabilities as wave nonlinearity increases. On the contrary, formulation B allows an accurate, robust numerical implementation. Test cases derived from the scientific literature on Boussinesq-type models—i.e., solitary and Stokes wave analytical solutions for linear dispersion and nonlinear evolution and experimental data for shoaling properties—are used to assess the proposed solution strategy. It is found that the present method gives reliable predictions of wave propagation in shallow to intermediate waters, in terms of both semi-averaged variables and conservation properties.

Instant Spring Tool Suite

CERN Document Server

Chiang, Geoff

2013-01-01

Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. A tutorial guide that walks you through how to use the features of Spring Tool Suite using well defined sections for the different parts of Spring.Instant Spring Tool Suite is for novice to intermediate Java developers looking to get a head-start in enterprise application development using Spring Tool Suite and the Spring framework. If you are looking for a guide for effective application development using Spring Tool Suite, then this book is for you.

Assessing wave energy effects on biodiversity: the wave hub experience.

Science.gov (United States)

Witt, M J; Sheehan, E V; Bearhop, S; Broderick, A C; Conley, D C; Cotterell, S P; Crow, E; Grecian, W J; Halsband, C; Hodgson, D J; Hosegood, P; Inger, R; Miller, P I; Sims, D W; Thompson, R C; Vanstaen, K; Votier, S C; Attrill, M J; Godley, B J

2012-01-28

Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative.

Transport of microplastics in coastal seas

Science.gov (United States)

Zhang, Hua

2017-12-01

Microplastic pollution of the marine environment has received increasing attention from scientists, the public, and policy makers over the last few years. Marine microplastics predominantly originate near the coast and can remain in the nearshore zone for some time. However, at present, there is little understanding of the fate and transport of microplastics in coastal regions. This paper provides a comprehensive overview of the physical processes involved in the movement of microplastics from estuaries to the continental shelf. The trajectory and speed of microplastics are controlled by their physical characteristics (density, size, and shape) and ocean dynamic conditions (wind, waves, tides, thermohaline gradients, and the influence of benthic sediments). Microplastic particles can be subjected to beaching, surface drifting, vertical mixing, and biofouling, as well as bed-load and suspended load transport processes, until reaching terminal deposition on beaches, in coastal marshes, in benthic sediments or until they are carried by ocean currents to subtropical convergence zones. The dynamic interaction of released microplastics with the shoreline is regulated by onshore/offshore transport, which is impacted by the source location as well as the geometry, vegetation, tidal regime, and wave direction. Wind and wave conditions dominate surface drifting of buoyant particles through Ekman drift, windage, and Stokes drift mechanisms. Neustic microplastic particles travel in the subsurface because of vertical mixing through wind-driven Langmuir circulation and heat cycling. Increasing accumulation of microplastics in benthic sediments needs to be quantitatively explored in terms of biofouling, deposition, entrainment, and transport dynamics. Further studies are required to understand the following: 1) the primary parameters (e.g., windage, terminal velocity, diffusivity, critical shear stress) that determine microplastic transport in different pathways; 2) dynamic

Space suit bioenergetics: framework and analysis of unsuited and suited activity.

Science.gov (United States)

Carr, Christopher E; Newman, Dava J

2007-11-01

Metabolic costs limit the duration and intensity of extravehicular activity (EVA), an essential component of future human missions to the Moon and Mars. Energetics Framework: We present a framework for comparison of energetics data across and between studies. This framework, applied to locomotion, differentiates between muscle efficiency and energy recovery, two concepts often confused in the literature. The human run-walk transition in Earth gravity occurs at the point for which energy recovery is approximately the same for walking and running, suggesting a possible role for recovery in gait transitions. Muscular Energetics: Muscle physiology limits the overall efficiency by which chemical energy is converted through metabolism to useful work. Unsuited Locomotion: Walking and running use different methods of energy storage and release. These differences contribute to the relative changes in the metabolic cost of walking and running as gravity is varied, with the metabolic cost of locomoting at a given velocity changing in proportion to gravity for running and less than in proportion for walking. Space Suits: Major factors affecting the energetic cost of suited movement include suit pressurization, gravity, velocity, surface slope, and space suit configuration. Apollo lunar surface EVA traverse metabolic rates, while unexpectedly low, were higher than other activity categories. The Lunar Roving Vehicle facilitated even lower metabolic rates, thus longer duration EVAs. Muscles and tendons act like springs during running; similarly, longitudinal pressure forces in gas pressure space suits allow spring-like storage and release of energy when suits are self-supporting.

Coastal risk forecast system

Science.gov (United States)

Sabino, André; Poseiro, Pedro; Rodrigues, Armanda; Reis, Maria Teresa; Fortes, Conceição J.; Reis, Rui; Araújo, João

2018-04-01

The run-up and overtopping by sea waves are two of the main processes that threaten coastal structures, leading to flooding, destruction of both property and the environment, and harm to people. To build early warning systems, the consequences and associated risks in the affected areas must be evaluated. It is also important to understand how these two types of spatial information integrate with sensor data sources and the risk assessment methodology. This paper describes the relationship between consequences and risk maps, their role in risk management and how the HIDRALERTA system integrates both aspects in its risk methodology. It describes a case study for Praia da Vitória Port, Terceira Island, Azores, Portugal, showing that the main innovations in this system are twofold: it represents the overtopping flow and consequent flooding, which are critical for coastal and port areas protected by maritime structures, and it works also as a risk assessment tool, extremely important for long-term planning and decision-making. Moreover, the implementation of the system considers possible known variability issues, enabling changes in its behaviour as needs arise. This system has the potential to become a useful tool for the management of coastal and port areas, due to its capacity to effectively issue warnings and assess risks.

Coastal risk forecast system

Science.gov (United States)

Sabino, André; Poseiro, Pedro; Rodrigues, Armanda; Reis, Maria Teresa; Fortes, Conceição J.; Reis, Rui; Araújo, João

2018-03-01

The run-up and overtopping by sea waves are two of the main processes that threaten coastal structures, leading to flooding, destruction of both property and the environment, and harm to people. To build early warning systems, the consequences and associated risks in the affected areas must be evaluated. It is also important to understand how these two types of spatial information integrate with sensor data sources and the risk assessment methodology. This paper describes the relationship between consequences and risk maps, their role in risk management and how the HIDRALERTA system integrates both aspects in its risk methodology. It describes a case study for Praia da Vitória Port, Terceira Island, Azores, Portugal, showing that the main innovations in this system are twofold: it represents the overtopping flow and consequent flooding, which are critical for coastal and port areas protected by maritime structures, and it works also as a risk assessment tool, extremely important for long-term planning and decision-making. Moreover, the implementation of the system considers possible known variability issues, enabling changes in its behaviour as needs arise. This system has the potential to become a useful tool for the management of coastal and port areas, due to its capacity to effectively issue warnings and assess risks.

Modeling Waves and Coastal Flooding along the Connecticut Coast

Science.gov (United States)

Cifuentes-Lorenzen, A.; Howard-Strobel, M. M.; Fake, T.; McCardell, G.; O'Donnell, J.; Asthita, M.

2015-12-01

We have used a hydrodynamic- wave coupled numerical model (FVCOM-SWAVE) to simulate flooding at the Connecticut coastline during severe storms. The model employed a one-way nesting scheme and an unstructured grid. The parent domain spanned most of the southern New England shelf and the fine resolution grid covered Long Island Sound (LIS) and extended across the Connecticut coast to the 10m elevation contour. The model results for sea level, current and wave statistics from the parent grid have been tested with data from several field campaigns at different locations spanning the western, central and eastern portions of LIS. Waves are fetch limited and improvements to the model-data comparison required modifications to spectral coefficients in the wave model. Finally, the nested results were validated with two field campaigns in shallow water environments (i.e. New Haven and Old Saybrook). To assess the spatial variability of storm wave characteristics the domain was forced with the hindcast winds obtained from meteorological models (NAM and WRF) for 13 severe weather events that affected LIS in the past 15 years. We have also forced the system with a simulation of Superstorm Sandy in a warmer climate to assess the impact a climate change on the character of flooding. The nested grid is currently being used to map flooding risks under severe weather events including the effects of precipitation on river flow and discharge.

Innovative Seawalls and Rubble Mound Breakwater Design for Wave Energy Conversion

DEFF Research Database (Denmark)

Vicinanza, Diego; Contestabile, P.; Ferrante, V.

2012-01-01

The development of contemporary coastal infrastructure is nowadays dictated by the need for economical and environmental sustainability, which can however be provided by the combination of breakwaters and Wave Energy Converters (WEC). The latter convert wave energy to electricity, whilst previous...

Airborne Mission Concept for Coastal Ocean Color and Ecosystems Research

Science.gov (United States)

Guild, Liane S.; Hooker, Stanford B.; Morrow, John H.; Kudela, Raphael M.; Palacios, Sherry L.; Torres Perez, Juan L.; Hayashi, Kendra; Dunagan, Stephen E.

2016-01-01

NASA airborne missions in 2011 and 2013 over Monterey Bay, CA, demonstrated novel above- and in-water calibration and validation measurements supporting a combined airborne sensor approach (imaging spectrometer, microradiometers, and a sun photometer). The resultant airborne data characterize contemporaneous coastal atmospheric and aquatic properties plus sea-truth observations from state-of-the-art instrument systems spanning a next-generation spectral domain (320-875 nm). This airborne instrument suite for calibration, validation, and research flew at the lowest safe altitude (ca. 100 ft or 30 m) as well as higher altitudes (e.g., 6,000 ft or 1,800 m) above the sea surface covering a larger area in a single synoptic sortie than ship-based measurements at a few stations during the same sampling period. Data collection of coincident atmospheric and aquatic properties near the sea surface and at altitude allows the input of relevant variables into atmospheric correction schemes to improve the output of corrected imaging spectrometer data. Specific channels support legacy and next-generation satellite capabilities, and flights are planned to within 30 min of satellite overpass. This concept supports calibration and validation activities of ocean color phenomena (e.g., river plumes, algal blooms) and studies of water quality and coastal ecosystems. The 2011 COAST mission flew at 100 and 6,000 ft on a Twin Otter platform with flight plans accommodating the competing requirements of the sensor suite, which included the Coastal-Airborne In-situ Radiometers (C-AIR) for the first time. C-AIR (Biospherical Instruments Inc.) also flew in the 2013 OCEANIA mission at 100 and 1,000 ft on the Twin Otter below the California airborne simulation of the proposed NASA HyspIRI satellite system comprised of an imaging spectrometer and thermal infrared multispectral imager on the ER-2 at 65,000 ft (20,000 m). For both missions, the Compact-Optical Profiling System (Biospherical

Multidsciplinary Approaches to Coastal Adaptation - Aplying Machine Learning Techniques to assess coastal risk in Latin America and The Caribbean

Science.gov (United States)

Calil, J.

2016-12-01

The global population, currently at 7.3 billion, is increasing by nearly 230,000 people every day. As the world's population grows to an estimated 11.2 billion by 2100, the number of people living in low elevation areas, exposed to coastal hazards, is continuing to increase. In 2013, 22 million people were displaced by extreme weather events, with 37 events displacing at least 100,000 people each. Losses from natural disasters and disaster risk are determined by a complex interaction between physical hazards and the vulnerability of a society or social-ecological system, and its exposure to such hazards. Impacts from coastal hazards depend on the number of people, value of assets, and presence of critical resources in harm's way. Moreover, coastal risks are amplified by challenging socioeconomic dynamics, including ill-advised urban development, income inequality, and poverty level. Our results demonstrate that in Latin America and the Caribbean (LAC), more than half a million people live in areas where coastal hazards, exposure (of people, assets and ecosystems), and poverty converge, creating the ideal conditions for a perfect storm. In order to identify the population at greatest risk to coastal hazards in LAC, and in response to a growing demand for multidisciplinary coastal adaptation approaches, this study employs a combination of machine learning clustering techniques (K-Means and Self Organizing Maps), and a spatial index, to assess coastal risks on a comparative scale. Data for more than 13,000 coastal locations in LAC were collected and allocated into three categories: (1) Coastal Hazards (including storm surge, wave energy and El Niño); (2) Geographic Exposure (including population, agriculture, and ecosystems); and (3) Vulnerability (including income inequality, infant mortality rate and malnutrition). This study identified hotspots of coastal vulnerability, the key drivers of coastal risk at each geographic location. Our results provide important

Investigations of coastal zones using a modular amphibious vehicle

Science.gov (United States)

Zeziulin, Denis; Makarov, Vladimir; Filatov, Valery; Beresnev, Pavel; Belyakov, Vladimir; Kurkin, Andrey

2017-04-01

The project aims to develop a means of verification of data on sea excitement derived from Autonomous mobile robotic system (AMRS) for coastal monitoring and forecasting marine natural disasters [Kurkin A., Pelinovsky E., Tyugin D., Giniyatullin A., Kurkina O., Belyakov V., Makarov V., Zeziulin D., Kuznetsov K. Autonomous Robotic System for Coastal Monitoring // Proceedings of the 12th International Conference on the Mediterranean Coastal Environment MEDCOAST. 2015. V. 2. P. 933-944]. The chassis of the developed remote-controlled modular amphibious vehicle (MAV) will be equipped with a video camera and a hydrostatic wave-plotting device with strings sensors mounted on the stationary body's supports. To track the position of the MAV there will be installed the navigation system in order to correct the measurement data. The peculiarity of the tricycle MAV is the ability to change its geometric parameters that will increase its stability to actions of destructive waves and mobility. In May-June 2016 authors took part in conducting field tests of the AMRS on the Gulf of Mordvinov (Sea of Okhotsk, Sakhalin Island). Participation in this expedition contributed to obtaining experimental data on the topography and the physical and mechanical properties of the surf zone of the most promising field of using the MAV as a road for its moving. Within the project there was developed a mathematical model of the MAV motion in coastal conditions taking into account the new analytical dependences describing the physical and mechanical characteristics of the ground surfaces and the landscape, as well as hydrodynamic effects of surf zones. The reasonable selection of rational parameters of the MAV and developing the methodology of creating effective vehicles for investigations of specific coastal areas of the Okhotsk Sea will be made by using the mathematical model.

Evaluation of Dynamic Coastal Response to Sea-level Rise Modifies Inundation Likelihood

Science.gov (United States)

Lentz, Erika E.; Thieler, E. Robert; Plant, Nathaniel G.; Stippa, Sawyer R.; Horton, Radley M.; Gesch, Dean B.

2016-01-01

Sea-level rise (SLR) poses a range of threats to natural and built environments, making assessments of SLR-induced hazards essential for informed decision making. We develop a probabilistic model that evaluates the likelihood that an area will inundate (flood) or dynamically respond (adapt) to SLR. The broad-area applicability of the approach is demonstrated by producing 30x30m resolution predictions for more than 38,000 sq km of diverse coastal landscape in the northeastern United States. Probabilistic SLR projections, coastal elevation and vertical land movement are used to estimate likely future inundation levels. Then, conditioned on future inundation levels and the current land-cover type, we evaluate the likelihood of dynamic response versus inundation. We find that nearly 70% of this coastal landscape has some capacity to respond dynamically to SLR, and we show that inundation models over-predict land likely to submerge. This approach is well suited to guiding coastal resource management decisions that weigh future SLR impacts and uncertainty against ecological targets and economic constraints.

Lecture Notes for the Course in Water Wave Mechanics

DEFF Research Database (Denmark)

Andersen, Thomas Lykke; Frigaard, Peter; Burcharth, Hans F.

knowledge. The course is at the same time an introduction to the course in coastal hydraulics on the 8th semester. The notes cover the first four lectures of the course: • Definitions. Governing equations and boundary conditions. • Derivation of velocity potential for linear waves. Dispersion relationship...... Particle velocities and accelerations. • Particle paths, pressure variation, deep and shallow water waves, wave energy and group velocity. • Shoaling, refraction, diffraction and wave breaking. The last part of the course is on analysis of irregular waves and was included in the first two editions...

Coral reefs for coastal protection: A new methodological approach and engineering case study in Grenada.

Science.gov (United States)

Reguero, Borja G; Beck, Michael W; Agostini, Vera N; Kramer, Philip; Hancock, Boze

2018-03-15

Coastal communities in tropical environments are at increasing risk from both environmental degradation and climate change and require urgent local adaptation action. Evidences show coral reefs play a critical role in wave attenuation but relatively little direct connection has been drawn between these effects and impacts on shorelines. Reefs are rarely assessed for their coastal protection service and thus not managed for their infrastructure benefits, while widespread damage and degradation continues. This paper presents a systematic approach to assess the protective role of coral reefs and to examine solutions based on the reef's influence on wave propagation patterns. Portions of the shoreline of Grenville Bay, Grenada, have seen acute shoreline erosion and coastal flooding. This paper (i) analyzes the historical changes in the shoreline and the local marine, (ii) assess the role of coral reefs in shoreline positioning through a shoreline equilibrium model first applied to coral reef environments, and (iii) design and begin implementation of a reef-based solution to reduce erosion and flooding. Coastline changes in the bay over the past 6 decades are analyzed from bathymetry and benthic surveys, historical imagery, historical wave and sea level data and modeling of wave dynamics. The analysis shows that, at present, the healthy and well-developed coral reefs system in the southern bay keeps the shoreline in equilibrium and stable, whereas reef degradation in the northern bay is linked with severe coastal erosion. A comparison of wave energy modeling for past bathymetry indicates that degradation of the coral reefs better explains erosion than changes in climate and historical sea level rise. Using this knowledge on how reefs affect the hydrodynamics, a reef restoration solution is designed and studied to ameliorate the coastal erosion and flooding. A characteristic design provides a modular design that can meet specific engineering, ecological and

STS-93 Pilot Ashby suits up before launch

Science.gov (United States)

1999-01-01

In the Operations and Checkout Building during final launch preparations for the second time, STS-93 Pilot Jeffrey S. Ashby waves after donning his launch and entry suit while a suit tech adjusts his boot. After Space Shuttle Columbia's July 20 launch attempt was scrubbed at the T-7 second mark in the countdown, the launch was rescheduled for Thursday, July 22, at 12:28 a.m. EDT. The target landing date is July 26, 1999, at 11:24 p.m. EDT. STS- 93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected unlock the secrets of supernovae, quasars and black holes. The STS-93 crew numbers five: Commander Eileen M. Collins, Ashby, and Mission Specialists Stephen A. Hawley (Ph.D.), Catherine G. Coleman (Ph.D.) and Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES). Collins is the first woman to serve as commander of a shuttle mission.

High-Resolution Wave Energy Assessment in Shallow Water Accounting for Tides

Directory of Open Access Journals (Sweden)

Dina Silva

2016-09-01

Full Text Available The wave energy in a shallow water location is evaluated considering the influence of the local tide and wind on the wave propagation. The target is the coastal area just north of the Portuguese city of Peniche, where a wave energy converter operates on the sea bottom. A wave modelling system based on SWAN has been implemented and focused on this coastal environment in a multilevel computational scheme. The first three SWAN computational belonging to this wave prediction system were defined using the spherical coordinates. In the highest resolution computational domain, Cartesian coordinates have been considered, with a resolution of 25 m in both directions. An in-depth analysis of the main characteristics of the environmental matrix has been performed. This is based on the results of eight-year model system simulations (2005–2012. New simulations have been carried out in the last two computational domains with the most relevant wave and wind patterns, considering also the tide effect. The results show that the tide level, together with the wind intensity and direction, may influence to a significant degree the wave characteristics. This especially concerns the wave power in the location where the wave converter operates.

Sea state indices for a coastal strait

Science.gov (United States)

Gemmrich, Johannes; Dewey, Richard

2017-04-01

The Strait of Georgia at the west coast of Canada is an enclosed coastal strait, about 250km long and 25 to 50 km wide, with great socio-economic importance. Regular freighter traffic, ferry services, commercial and sport fisheries, and recreational boating, makes the area one of the busiest marine areas in the world. Waves in SoG are generally small, with the median value of the significant wave height Hs=0.3m. However, strong outflows off the mountainous terrain can generate significant wave heights Hs > 2.5m, with high spatial and temporal variability. In addition, strong tidal currents and the Fraser River outflow generate localized regions of steep and breaking waves that are of particular concern. We have implemented the Wavewatch III model at 500m-resolution, forced by Environment Canada's high resolution atmospheric model winds and currents from the UBC NEMO implementation of the Salish Sea. The final output combines GIS layers of the predicted wave field (Hs, dominant wave length and direction), the modeled wind field and currents, observed currents from a set of CODAR systems, and a sea state index that highlights regions of potentially steep and dangerous waves.

Multi-Decadal Coastal Behavioural States From A Fusion Of Geohistorical Conceptual Modelling With 2-D Morphodynamic Modelling

Science.gov (United States)

Goodwin, I. D.; Mortlock, T.

2016-02-01

Geohistorical archives of shoreline and foredune planform geometry provides a unique evidence-based record of the time integral response to coupled directional wave climate and sediment supply variability on annual to multi-decadal time scales. We develop conceptual shoreline modelling from the geohistorical shoreline archive using a novel combination of methods, including: LIDAR DEM and field mapping of coastal geology; a decadal-scale climate reconstruction of sea-level pressure, marine windfields, and paleo-storm synoptic type and frequency, and historical bathymetry. The conceptual modelling allows for the discrimination of directional wave climate shifts and the relative contributions of cross-shore and along-shore sand supply rates at multi-decadal resolution. We present regional examples from south-eastern Australia over a large latitudinal gradient from subtropical Queensland (S 25°) to mid-latitude Bass Strait (S 40°) that illustrate the morphodynamic evolution and reorganization to wave climate change. We then use the conceptual modeling to inform a two-dimensional coupled spectral wave-hydrodynamic-morphodynamic model to investigate the shoreface response to paleo-directional wind and wave climates. Unlike one-line shoreline modelling, this fully dynamical approach allows for the investigation of cumulative and spatial bathymetric change due to wave-induced currents, as well as proxy-shoreline change. The fusion of the two modeling approaches allows for: (i) the identification of the natural range of coastal planform geometries in response to wave climate shifts; and, (ii) the decomposition of the multidecadal coastal change into the cross-shore and along-shore sand supply drivers, according to the best-matching planforms.

A Systems Approach Framework for Coastal Zones

Directory of Open Access Journals (Sweden)

Tom S. Hopkins

2011-12-01

Full Text Available This Special Feature Volume examines the potential value of the Systems Approach Framework (SAF as a methodological framework for the transition to sustainable development in coastal zones. This article provides insight on the Systems Approach, the theory behind it, and how its practical application to coastal zone systems (CZSs was developed. The SAF is about information for management through a focus on how to generate a higher, dynamic level of information about complex CZSs and how to render this information more useful to end users through a participatory suite of communication methods. The SAF is an open research methodology that investigates the function of systems in order to simulate specific issues or questions concerning their function. The research articles that are included in this Volume demonstrate examples of coupled multidisciplinary methods integrated into SAF simulations appropriate to a selected policy issue and to the social-environmental conditions of each Study Site Application. Their findings are not the result of funded research projects; instead, they are by-products of pilot applications conducted to develop and improve the SAF methodology. The final article of this Volume synthesizes these results in the context of the SAF as a higher level instrument for integrated coastal zone management.

Sand waves on an epicontinental shelf: Northern Bering Sea

Science.gov (United States)

Field, M.E.; Nelson, C.H.; Cacchione, D.A.; Drake, D.E.

1981-01-01

Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km ?? 5 km ?? 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of Bering Strait, is exposed to the strong continuous flow of coastal water northward toward Bering Strait. A hierarchy of three sizes of superimposed bedforms, all facing northward, was observed in successive cruises in 1976 and 1977. Large sand waves (height 2 m; spacing 200 m) have smaller sand waves (height 1 m; spacing 20 m) lying at a small oblique angle on their stoss slopes. The smaller sand waves in turn have linguoid ripples on their stoss slopes. Repeated studies of the sand wave fields were made both years with high-resolution seismic-reflection profiles, side-scan sonographs, underwater photographs, current-meter stations, vibracores, and suspended-sediment samplers. Comparison of seismic and side-scan data collected along profile lines run both years showed changes in sand wave shape that indicate significant bedload transport within the year. Gouge marks made in sediment by keels of floating ice also showed significantly different patterns each year, further documenting modification to the bottom by sediment transport. During calm sea conditions in 1977, underwater video and camera observations showed formation and active migration of linguoid and straight-crested current ripples. Current speeds 1 m above the bottom were between 20 and 30 cm/s. Maximum current velocities and sand wave migration apparently occur when strong southwesterly winds enhance the steady northerly flow of coastal water. Many cross-stratified sand bodies in the geologic record are interpreted as having formed in a tidal- or storm-dominated setting. This study provides an example of formation and migration of large bedforms by the interaction of storms with strong uniform coastal currents in an open-marine setting. ?? 1981.

The Damage To The Armour Layer Due To Extreme Waves

Science.gov (United States)

Oztunali Ozbahceci, Berguzar; Ergin, Aysen; Takayama, Tomotsuka

2010-05-01

The sea waves are not regular but random and chaotic. In order to understand this randomness, it is common to make individual wave analysis in time domain or spectral analysis in frequency domain. Characteristic wave heights like Hmax, H%2,H1-10, H1-3, Hmean are obtained through individual wave analysis in time domain. These characteristic wave heights are important because they are used in the design of different type of coastal structures. It is common to use significant wave height, H1-3,for the design of rubble mound structures. Therefore, only spectrally derived or zero-crossing significant wave height is usually reported for the rubble mound breakwaters without any information on larger waves. However, even the values of H1-3are similar; some train of irregular waves may exhibit a large fluctuation of instantaneous wave energy, while another train may not show such a fluctuation (Goda, 1998). Moreover, freak or rogue wave, simply defined as the wave exceeding at least twice the significant wave height may also occur. Those larger waves were called as extreme waves in this study and the effect of extreme waves on the damage to the armour layer of rubble mound breakwaters was investigated by means of hydraulic model experiment. Rock armored rubble mound breakwater model with 1:1.5 slope was constructed in the wave channel of Hydraulics Laboratory of the Disaster Prevention Research Institute of Kyoto University, Japan. The model was consisted of a permeable core layer, a filter and armour layer with two stones thicknesses. Size of stones were same for both of the slopes as Dn50(armour)=0.034m, Dn50(filter)=0.021m and Dn50(core)=0.0148m for armour, filter and core layers, respectively. Time series which are approximately equal to 1000 waves, with similar significant wave height but different extreme wave height cases were generated. In order to generate necessary time series in the wave channel, they were firstly computed by numerically. For the numerical

Temperature Calculations in the Coastal Modeling System

Science.gov (United States)

2017-04-01

ERDC/CHL CHETN-IV-110 April 2017 Approved for public release; distribution is unlimited . Temperature Calculations in the Coastal Modeling...tide) and river discharge at model boundaries, wave radiation stress, and wind forcing over a model computational domain. Physical processes calculated...calculated in the CMS using the following meteorological parameters: solar radiation, cloud cover, air temperature, wind speed, and surface water temperature

RAJA Performance Suite

Energy Technology Data Exchange (ETDEWEB)

2017-09-01

The RAJA Performance Suite is designed to evaluate performance of the RAJA performance portability library on a wide variety of important high performance computing (HPC) algorithmic lulmels. These kernels assess compiler optimizations and various parallel programming model backends accessible through RAJA, such as OpenMP, CUDA, etc. The Initial version of the suite contains 25 computational kernels, each of which appears in 6 variants: Baseline SequcntiaJ, RAJA SequentiaJ, Baseline OpenMP, RAJA OpenMP, Baseline CUDA, RAJA CUDA. All variants of each kernel perform essentially the same mathematical operations and the loop body code for each kernel is identical across all variants. There are a few kernels, such as those that contain reduction operations, that require CUDA-specific coding for their CUDA variants. ActuaJ computer instructions executed and how they run in parallel differs depending on the parallel programming model backend used and which optimizations are perfonned by the compiler used to build the Perfonnance Suite executable. The Suite will be used primarily by RAJA developers to perform regular assessments of RAJA performance across a range of hardware platforms and compilers as RAJA features are being developed. It will also be used by LLNL hardware and software vendor panners for new defining requirements for future computing platform procurements and acceptance testing. In particular, the RAJA Performance Suite will be used for compiler acceptance testing of the upcoming CORAUSierra machine {initial LLNL delivery expected in late-2017/early 2018) and the CORAL-2 procurement. The Suite will aJso be used to generate concise source code reproducers of compiler and runtime issues we uncover so that we may provide them to relevant vendors to be fixed.

Southern California Coastal Processes Annotated Bibliography.

Science.gov (United States)

1985-12-01

05/01/71 TITLE : Avalon Transportation Wharf CITATION : Journal of Waterways, Harbors and Coastal Engineering Division, ASCE, N. Y., Vol. 97, No. WW2 ...105, No. WW2 ; ASCE, N. Y., pp. 131-147 DESCRIPTION s Effect of various offshore structures as significant barriers to normal wave progress...California, 33 pp. DESCRIPTION Infrared satellite images are shown for each of two areas near +- the California coast, Cape Mendocino and Point

Intra-annual wave resource characterization for energy exploitation: A new decision-aid tool

International Nuclear Information System (INIS)

Carballo, R.; Sánchez, M.; Ramos, V.; Fraguela, J.A.; Iglesias, G.

2015-01-01

Highlights: • A decision-aid tool is developed for computing the monthly performance of WECs. • It allows the generation of high-resolution monthly characterization matrices. • The decision-aid tool is implemented to the Death Coast (N Spain). • The monthly matrices can be obtained at any coastal location within the Death Coast. • The tool is applied to a coastal location of a proposed wave farm. - Abstract: The wave energy resource is usually characterized by a significant variability throughout the year. In estimating the power performance of a Wave Energy Converter (WEC) it is fundamental to take into account this variability; indeed, an estimate based on mean annual values may well result in a wrong decision making. In this work, a novel decision-aid tool, iWEDGE (intra-annual Wave Energy Diagram GEnerator) is developed and implemented to a coastal region of interest, the Death Coast (Spain), one of the regions in Europe with the largest wave resource. Following a comprehensive procedure, and based on deep water wave data and high-resolution numerical modelling, this tool provides the monthly high-resolution characterization matrices (or energy diagrams) for any location of interest. In other words, the information required for the accurate computation of the intra-annual performance of any WEC at any location within the region covered is made available. Finally, an application of iWEDGE to the site of a proposed wave farm is presented. The results obtained highlight the importance of the decision-aid tool herein provided for wave energy exploitation

Sea Level Change and Coastal Climate Services: The Way Forward

NARCIS (Netherlands)

le Cozannet, G.; Nicholls, R.J.; Hinkel, J.; Sweet, W.V.; McInnes, K.L.; Van de Wal, R.S.E.; Slangen, A.B.A.; Lowe, J.A.; White, K.D.

2017-01-01

For many climate change impacts such as drought and heat waves, global and nationalframeworks for climate services are providing ever more critical support to adaptation activities.Coastal zones are especially in need of climate services for adaptation, as they are increasinglythreatened by sea

Experimental and numerical analysis of coastal protection provided by natural ecosystems

Science.gov (United States)

Maza, M.; Lara, J. L.; Losada, I. J.; Nepf, H. M.

2016-12-01

The risk of flooding and erosion is increasing for many coastal areas owing to global and regional changes in climate conditions together with increasing exposure and vulnerability. After hurricane Katrina (2005) and Sandy (2012) and the tsunami in Indonesia (2004), coastal managers have become interested in low environmental impact alternatives, or nature-based solutions, to protect the coast. Although capacity for coastal ecosystems to damp flow energy has been widely recognized, they have not been firmly considered in the portfolio of coastal protection options. This is mainly due to the complexity of flow-vegetation interaction and of quantifying the value of coastal protection provided by these ecosystems. This complex problem involves different temporal and spatial scales and disciplines, such as engineering, ecology and economics. This work aims to make a step forward in better understanding the physics involved in flow-vegetation interaction leading to new formulations and parameterizations to address some unsolved questions in literature: the representation of plants and field properties; the influence of wave parameters on the relevant processes; the role of the combined effect of waves and currents and the effect of extreme events on vegetation elements. The three main coastal vegetated ecosystems (seagrasses, saltmarshes and mangroves) are studied with an experimental and numerical approach. Experimental analysis is carried out using mimics and real vegetation, considering different flow and vegetation parameters and characterizing flow energy attenuation for the different scenarios. Numerical simulations are performed using 2-D and 3-D Navier-Stokes models in which the effect of vegetation is implemented and validated. These models are used to extend experimental results by simulating different vegetation distributions and analyzing variables such as high-spatial-resolution free surface and velocity data and forces exerted on vegetation elements.

Fragmented coastal boundary layer induced by gap winds

Science.gov (United States)

Caldeira, Rui M. A.; Iglesias, Isabel; Sala, Iria; Vieira, Rui R.; Bastos, Luísa

2015-04-01

The oceanic impact of offshore-localized winds in the NW Iberian Peninsula was studied. Satellite and in situ observations showed the formation of plumes protruding offshore from the coast. To study the dynamics of such episodes tee Coupled-Ocean-Atmosphere-Wave- Sediment Transport Modeling System (COAWST) was used to reproduce the coastal conditions of the nortwestern Iberian Peninsula, allowing the concurrent representation of local winds, waves, currents, and rivers runoff. The use of coupled models is of outmost importance in order to accurately study the impact of the local winds on the coastal currents. The NW Iberian Peninsula has prominent capes, promontories and submarine canyons, which produce persistent hydrodynamic features. Thus far, the scientific literature shows that the western Iberian rivers produce a recurrent combined plume often denominated as the Western Iberian Buoyant Plume (WIBP) which increases the stratification of the water column and produces a vertical retention mechanism that keeps the biological material inshore. The WIBP extends northward along the coast (over the inner-shelf), and forms a front with the warmer and more saline surface (offshore) waters. However during episodes of strong offshore winds this coastal boundary layer is broken interrupting the WIBP. Coastal orography allows the formation of down-valley winds that produce coastal jets, promoting the offshore transport of pollutants, larvae and sediments. Acknowledgments: Acknowledgments: Numerical model solutions were calculated at CIIMARs HPC unit, acquired and maintained by FCT pluriannual funds (PesTC/Mar/LA0015/2013), and RAIA (0313-RAIA-1-E) and RAIA.co (0520-RAIACO-1-E) projects. The NICC (POCTI/CTA/49563/2002) project provided databases for this work. Rui Caldeira was supported by funds from the ECORISK project (NORTE-07-0124-FEDER-000054), co-financed by the North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference

Projection of wave conditions in response to climate change: A community approach to global and regional wave downscaling

Science.gov (United States)

Erikson, Li H.; Hemer, M.; Lionello, Piero; Mendez, Fernando J.; Mori, Nobuhito; Semedo, Alvaro; Wang, Xiaolan; Wolf, Judith

2015-01-01

Future changes in wind-wave climate have broad implications for coastal geomorphology and management. General circulation models (GCM) are now routinely used for assessing climatological parameters, but generally do not provide parameterizations of ocean wind-waves. To fill this information gap, a growing number of studies use GCM outputs to independently downscale wave conditions to global and regional levels. To consolidate these efforts and provide a robust picture of projected changes, we present strategies from the community-derived multi-model ensemble of wave climate projections (COWCLIP) and an overview of regional contributions. Results and strategies from one contributing regional study concerning changes along the eastern North Pacific coast are presented.

Wave farm impact on the beach profile: A case study

OpenAIRE

Abanades, J; Greaves, D; Iglesias, G

2014-01-01

If wave energy is to become a fully-fledged renewable, its environmental impacts must be fully understood. The objective of the present work is to examine the impact of a wave farm on the beach profile through a case study. The methodology is based on two coupled numerical models: a nearshore wave propagation model and a morphodynamic model, which are run in two scenarios, both with and without the wave farm. Wave data from a nearby coastal buoy are used to prescribe the boundary conditions. ...

a Numerical Study of Basic Coastal Upwelling Processes.

Science.gov (United States)

Li, Zhihong

Available from UMI in association with The British Library. Two-dimensional (2-D) and three-dimensional (3 -D) numerical models with a second order turbulence closure are developed for the study of coastal upwelling processes. A logarithmic coordinate system is introduced to obtain increased resolution in the regions near the surface and bottom where high velocity shear occurs and in the upwelling zone where its width is confined to the coast. In the experiments performed in the 2-D model an ocean initially at rest is driven by a spatially uniform alongshore wind-stress. There is a development of an offshore flow in the surface layer and an onshore flow below the surface layer. In the wind-stress direction there is a development of a coastal surface jet. The neglect of the alongshore pressure gradient leads to the intensification of the jet, and the concentration of the onshore flow in an over-developed Ekman layer yielding an unrealistic deepening of a bottom mixed layer. When bathymetric variations are introduced, some modifications in the dynamics of upwelling are observed. On the shelf region there is another upwelling zone and isotherms are interested with the bottom topography. When an alongshore pressure gradient is added externally into the model, the strength of the coastal jet decreases and a coastal undercurrent exists at greater depth. In addition the return onshore flow is largely independent of depth and the deepening of the bottom mixed layer disappears. In the experiments performed in the 3-D model a wind-stress with limited domain is used. Coastally trapped waves are generated and propagate along the coastline leading to a development of an alongshore pressure gradient, which has a significant effect on upwelling. The evolution of the alongshore flow, vertical velocity and the temperature is determined by both remote and local wind due to the propagation of waves. As the integration proceeds, the flow pattern becomes remarkably 3-dimensional

Use of modular amphibious vehicles for conducting research in coastal zone

Science.gov (United States)

Zeziulin, Denis; Makarov, Vladimir; Belyaev, Alexander; Beresnev, Pavel; Kurkin, Andrey

2016-04-01

The project aims to create workable running systems of research complexes, moving along the bottom of coastal areas (in shallow waters) for investigation of waves, currents, sediment transport; investigation of ecosystems and biodiversity assessment of organisms; inspection and monitoring environmental conditions and anthropogenic load on nature; bathymetric studies. With all the variety of functional capabilities of modern robotic systems, possibilities of their application in the context of the study of coastal zones are extremely limited. Conducting research using aerial vehicles is limited to safety conditions of flight. Use of floating robotic systems in environmental monitoring and ecosystem research is only possible in conditions of relatively «soft» wave climate of the coastal zone. For these purposes, there are special amphibians such as remote-controlled vehicle Surf Rover [Daily, William R., Mark A. Johnson, and Daniel A. Oslecki. «Initial Development of an Amphibious ROV for Use in Big Surf.» Marine Technology Society 28.1 (1994): 3-10. Print.], mobile system MARC-1 [«The SPROV'er.» Florida Institute of Technology: Department of Marine and. Environmental Systems. Web. 05 May 2010.]. The paper describes methodological approaches to the selection of the design parameters of a new system.

Apparatus for storing protective suits

International Nuclear Information System (INIS)

Englemann, H.J.; Koller, J.; Schrader, H.R.; Schade, G.; Pedrerol, J.

1975-01-01

Arrangements are described for storing one or more protective suits when contaminated on the outside. In order to permit a person wearing a contaminated suit to leave a contaminated area safely, and without contaminating the environment, it has hitherto been the practice for the suit to be passed through a 'lock' and cleansed under decontaminating showers whilst still being worn. This procedure is time wasting and not always completely effective, and it may be necessary to provide a second suit for use whilst the first suit is being decontaminated. Repeated decontamination may also result in undue wear and tear. The arrangements described provide a 'lock' chamber in which a contaminated suit may be stowed away without its interior becoming contaminated, thus allowing repeated use by persons donning and shedding it. (U.K.)

Policies for Reducing Coastal Risk on the East and Gulf Coasts

Science.gov (United States)

Glickson, D.; Johnson, S.

2014-12-01

Hurricane- and coastal storm-related economic losses have increased substantially over the past century, largely due to expanding population and development in susceptible coastal areas. Concurrent with this growth, the federal government has assumed an increasing proportion of the financial responsibility associated with U.S. coastal storms, which may discourage state and local governments from taking appropriate actions to reduce risk and enhance resilience. Strategies to manage coastal storm risks fall into two categories: reducing the probability of flooding or wave impact (such as seawalls, storm surge barriers, beach nourishment, dune building, restoration/expansion of oyster reefs, salt marshes, and mangroves) and reducing the number or vulnerability of people or structures (such as relocation, land-use planning, and elevating or floodproofing buildings). Over the past century, most coastal risk management programs have emphasized coastal armoring, while doing little to decrease development in harm's way. This National Research Council report calls for the development of a national vision for managing coastal risks that includes a long-term view, regional solutions, and recognition of all benefits. A national coastal risk assessment is needed to identify high priority areas. Benefit-cost analysis provides a reasonable framework to evaluate national investments in coastal risk reduction, if constrained by other important environmental, social, and life-safety factors. Extensive collaboration and additional policy changes will be necessary to move from a nation that is primarily reactive to coastal disasters to one that invests wisely in coastal risk reduction and builds resilience among coastal communities.

Multiple stressors, nonlinear effects and the implications of climate change impacts on marine coastal ecosystems.

Science.gov (United States)

Hewitt, Judi E; Ellis, Joanne I; Thrush, Simon F

2016-08-01

Global climate change will undoubtedly be a pressure on coastal marine ecosystems, affecting not only species distributions and physiology but also ecosystem functioning. In the coastal zone, the environmental variables that may drive ecological responses to climate change include temperature, wave energy, upwelling events and freshwater inputs, and all act and interact at a variety of spatial and temporal scales. To date, we have a poor understanding of how climate-related environmental changes may affect coastal marine ecosystems or which environmental variables are likely to produce priority effects. Here we use time series data (17 years) of coastal benthic macrofauna to investigate responses to a range of climate-influenced variables including sea-surface temperature, southern oscillation indices (SOI, Z4), wind-wave exposure, freshwater inputs and rainfall. We investigate responses from the abundances of individual species to abundances of functional traits and test whether species that are near the edge of their tolerance to another stressor (in this case sedimentation) may exhibit stronger responses. The responses we observed were all nonlinear and some exhibited thresholds. While temperature was most frequently an important predictor, wave exposure and ENSO-related variables were also frequently important and most ecological variables responded to interactions between environmental variables. There were also indications that species sensitive to another stressor responded more strongly to weaker climate-related environmental change at the stressed site than the unstressed site. The observed interactions between climate variables, effects on key species or functional traits, and synergistic effects of additional anthropogenic stressors have important implications for understanding and predicting the ecological consequences of climate change to coastal ecosystems. © 2015 John Wiley & Sons Ltd.

Pharmacy settles suit.

Science.gov (United States)

1998-10-02

A suit was filed by an HIV-positive man against a pharmacy that inadvertently disclosed his HIV status to his ex-wife and children. His ex-wife tried to use the information in a custody battle for their two children. The suit against the pharmacy was settled, but the terms of the settlement remain confidential.

Infragravity-wave dynamics in a barred coastal region, a numerical study

NARCIS (Netherlands)

Rijnsdorp, Dirk P.; Ruessink, Gerben; Zijlema, Marcel

2015-01-01

This paper presents a comprehensive numerical study into the infragravity-wave dynamics at a field site, characterized by a gently sloping barred beach. The nonhydrostatic wave-flow model SWASH was used to simulate the local wavefield for a range of wave conditions (including mild and storm

Sea level change and coastal climate services : The way forward

NARCIS (Netherlands)

Le Cozannet, Gonéri; Nicholls, Robert J.; Hinkel, Jochen; Sweet, William V.; McInnes, Kathleen L.; Van de Wal, Roderik S.W.; Slangen, Aimée B.A.; Lowe, Jason A.; White, Kathleen D.

2017-01-01

For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones are especially in need of climate services for adaptation, as they are increasingly threatened by sea

Low-canopy seagrass beds still provide important coastal protection services

NARCIS (Netherlands)

Christianen, M.J.A.; van Belzen, J.; Herman, P.M.J.; van Katwijk, M.M.; Lamers, L.P.M.; Bouma, T.J.

2013-01-01

One of the most frequently quoted ecosystem services of seagrass meadows is their value for coastal protection. Many studies emphasize the role of above-ground shoots in attenuating waves, enhancing sedimentation and preventing erosion. This raises the question if short-leaved, low density (grazed)

Regional Wave Climates along Eastern Boundary Currents

Science.gov (United States)

Semedo, Alvaro; Soares, Pedro

2016-04-01

Two types of wind-generated gravity waves coexist at the ocean surface: wind sea and swell. Wind sea waves are waves under growing process. These young growing waves receive energy from the overlaying wind and are strongly coupled to the local wind field. Waves that propagate away from their generation area and no longer receive energy input from the local wind are called swell. Swell waves can travel long distances across entire ocean basins. A qualitative study of the ocean waves from a locally vs. remotely generation perspective is important, since the air sea interaction processes is strongly modulated by waves and vary accordingly to the prevalence of wind sea or swell waves in the area. A detailed climatology of wind sea and swell waves along eastern boundary currents (EBC; California Current, Canary Current, in the Northern Hemisphere, and Humboldt Current, Benguela Current, and Western Australia Current, in the Southern Hemisphere), based on the ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis will be presented. The wind regime along EBC varies significantly from winter to summer. The high summer wind speeds along EBC generate higher locally generated wind sea waves, whereas lower winter wind speeds in these areas, along with stronger winter extratropical storms far away, lead to a predominance of swell waves there. In summer, the coast parallel winds also interact with coastal headlands, increasing the wind speed through a process called "expansion fan", which leads to an increase in the height of locally generated waves downwind of capes and points. Hence the spatial patterns of the wind sea or swell regional wave fields are shown to be different from the open ocean along EBC, due to coastal geometry and fetch dimensions. Swell waves will be shown to be considerably more prevalent and to carry more energy in winter along EBC, while in summer locally generated wind sea waves are either more comparable to swell waves or

Porous models for wave-seabed interactions

Energy Technology Data Exchange (ETDEWEB)

Jeng, Dong-Sheng [Shanghai Jiaotong Univ., SH (China)

2013-02-01

Detailed discussion about the phenomenon of wave-seabed interactions. Novel models for wave-induced seabed response. Intensive theoretical derivations for wave-seabed interactions. Practical examples for engineering applications. ''Porous Models for Wave-seabed Interactions'' discusses the Phenomenon of wave-seabed interactions, which is a vital issue for coastal and geotechnical engineers involved in the design of foundations for marine structures such as pipelines, breakwaters, platforms, etc. The most important sections of this book will be the fully detailed theoretical models of wave-seabed interaction problem, which are particularly useful for postgraduate students and junior researchers entering the discipline of marine geotechnics and offshore engineering. This book also converts the research outcomes of theoretical studies to engineering applications that will provide front-line engineers with practical and effective tools in the assessment of seabed instability in engineering design.

Coastal sea-ice processes in Alaska and their relevance for sediment dynamics and coastal retreat (Invited)

Science.gov (United States)

Eicken, H.; Kapsch, M.; Johnson, M. A.; Weyapuk, W. U., Jr.

2009-12-01

Sea ice plays an important, complicated role in Arctic coastal sediment dynamics. It helps protect the shoreline from wave action and constrains coastal permafrost thaw; at the same time, sea ice is a highly effective sediment erosion and transport agent. For the coastline of (sub-)Arctic Alaska we have examined key processes that govern the role of sea ice as a geologic agent. Based on passive microwave satellite data for the time period 1979 to 2008 and augmented by field measurements and observations conducted by local sea-ice experts in coastal communities from 2006 onwards, we determined the onset of coastal ice spring break-up and fall freeze-up. These two events define the start and end of the open-water season during which the coast is rendered most vulnerable to thermal and dynamic processes promoting erosion. Satellite data show significant trends toward later fall freeze-up in many locations and moreover provide a picture of the statistical significance and variability of such trends in great spatio-temporal detail. Coastal ice observations suggest that important sea-ice processes (such as formation of ice berms) that precede freeze-up as detected by passive microwave data need to be taken into consideration in evaluating the vulnerability of the coastline and the specific threat of individual storms. Field observations, satellite data and local knowledge also highlight the substantial change in winter sea-ice regimes over the past two decades, with a much more mobile ice cover enhancing winter sediment transport. Ultimately, the shorter sea-ice season and the greater mobility and the lack of stability of winter coastal sea ice work in concert to increase the vulnerability of the coastline to erosion and flooding. At the same time, these changes provide a mechanism for effective redistribution and cross-shelf transport of sediments that prepares the stage for further erosive action in subsequent seasons.

CTD, current meter, pressure gauge, and wave spectra data from fixed platforms and other platforms from the Coastal Waters of California as part of the Santa Barbara Channel project from 1983-04-27 to 1985-01-04 (NODC Accession 8500177)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — CTD, current meter, pressure gauge, and wave spectra data were collected from fixed platforms and other platforms from the Coastal Waters of California from 27 April...

Evaluation of Hydraulic Response of the Wave Dragon

DEFF Research Database (Denmark)

Frigaard, Peter; Kofoed, Jens Peter

The present study investigates the hydraulic response of the wave energy converter Wave Dragon. This is done by peforming model tests in a wave tank in the Hydraulics & Coastal Engineering Laboratory at Aalborg University. In the model tests a floating scale model (length scale 1:50) of the Wave...... Dragon is subjected to irregular, long crested irregular and short crested sea conditions corresponding to typical situations under which the Wave Dragon will produce power. Furthermore two situations corresponding to extreme storm conditions are tested. The objective of the study is to determine...... the wave induced forces in the moorings and in the junction between the reflectors and the reservoir part, and motions of the Wave Dragon situated in different sea conditions....

Our evolving conceptual model of the coastal eutrophication problem

Science.gov (United States)

Cloern, James E.

2001-01-01

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5

Open-Ocean and Coastal Properties of Recent Major Tsunamis

Science.gov (United States)

Rabinovich, A.; Thomson, R.; Zaytsev, O.

2017-12-01

The properties of six major tsunamis during the period 2009-2015 (2009 Samoa; 2010 Chile; 2011 Tohoku; 2012 Haida Gwaii; 2014 and 2015 Chile) were thoroughly examined using coastal data from British Columbia, the U.S. West Coast and Mexico, and offshore open-ocean DART and NEPTUNE stations. Based on joint spectral analyses of the tsunamis and background noise, we have developed a method to suppress the influence of local topography and to use coastal observations to determine the underlying spectra of tsunami waves in the deep ocean. The "reconstructed" open-ocean tsunami spectra were found to be in close agreement with the actual tsunami spectra evaluated from the analysis of directly measured open-ocean tsunami records. We have further used the spectral estimates to parameterize tsunamis based on their integral open-ocean spectral characteristics. Three key parameters are introduced to describe individual tsunami events: (1) Integral open-ocean energy; (2) Amplification factor (increase of the mean coastal tsunami variance relative to the open-ocean variance); and (3) Tsunami colour, the frequency composition of the open-ocean tsunami waves. In particular, we found that the strongest tsunamis, associated with large source areas (the 2010 Chile and 2011 Tohoku) are "reddish" (indicating the dominance of low-frequency motions), while small-source events (the 2009 Samoa and 2012 Haida Gwaii) are "bluish" (indicating strong prevalence of high-frequency motions).

Study on the influence of the distance to shore for a wave energy farm operating in the central part of the Portuguese nearshore

International Nuclear Information System (INIS)

Rusu, Eugen; Onea, Florin

2016-01-01

Graphical abstract: Nearshore impact of the wave farm (significant wave height fields and wave vectors). Conditions for a wave farm operating at 7 km from the shore, where: (a) average conditions for total time; (b) average conditions for winter time; (c) high energy non storm conditions. (MA) – Moderate absoption, (HA) – High absorption. - Highlights: • The coastal influence of a generic wave farm is assessed. • The target area is located in the central part of Portugal. • The wave decay down wave the farm is evaluated. • The impact on the coastal circulation is also assessed. - Abstract: The objective of the present work is to assess the coastal impact induced by a generic wave farm operating in the central part of the Portuguese continental coastal environment, south of Lisbon. In order to identify better the most relevant wave patterns in the target area, two data sets were processed and analyzed. The first is represented by the ‘in situ’ measurements provided by the Sines buoy, which operates in the immediate vicinity south of the target area, and the second consists in the wave data coming from the European Centre for Medium-Range Weather Forecasts, in a point located offshore close to the target area. Three scenarios were considered for the numerical simulations that were carried out with a computational framework combining a wave and a circulation model. A generic wave farm was defined in the computational domain considering various distances from the shore: 1 km, 4 km and 7 km, respectively. In the first part of the work, the down-wave effect of the farm was evaluated taking into account the local wave characteristics in the target area and analyzing various wave parameters, as for example the wave power, wave height and mean wave direction. In the second part of the work, the influence of the farm on the nearshore circulation was also assessed. Based on the results of the present work it can be concluded that the nearshore impact of such a

Surfzone wave characteristics during flood tide on the central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

JayaKumar, S.; Jishad, M.; Yadhunath, E.M.; Rajasekaran, C.; Gowthaman, R.; Pednekar, P.S.; Luis, R.; Mehra, P.

, D.A., Bird, P.A.D., O’Hare, T.J. and Bullock, G.N., 2000. Breakpoint generated surf beat induced by bichromatic wave groups. Coastal Engineering, 39: 213-242. Basco, D.R., 1983. Surfzone currents. Coastal Engineering, 7(4): 331-355. Bird, E... and mass transport in gravity waves, with application to 'surf beats'. Journal of Fluid Mechanics, 13(4): 481-504. Madsen, P.A., Sørensen, O.R. and Schäffer, H.A., 1997. Surf zone dynamics simulated by a boussinesq type model. Part i. Model description...

Coastal Morphology and Coastal Protection

NARCIS (Netherlands)

Van de Graaff, J.

2009-01-01

Lecture notes ct5309. Tides, currents and water; coastal problems; sediment transport processes; coastal transport modes; longshore transport; cross-shore transport; fundamentals of mud; channels and trenches; coastal protection; application of structures; application of nourishments.

Ocean surface waves in Hurricane Ike (2008) and Superstorm Sandy (2012): Coupled model predictions and observations

Science.gov (United States)

Chen, Shuyi S.; Curcic, Milan

2016-07-01

Forecasting hurricane impacts of extreme winds and flooding requires accurate prediction of hurricane structure and storm-induced ocean surface waves days in advance. The waves are complex, especially near landfall when the hurricane winds and water depth varies significantly and the surface waves refract, shoal and dissipate. In this study, we examine the spatial structure, magnitude, and directional spectrum of hurricane-induced ocean waves using a high resolution, fully coupled atmosphere-wave-ocean model and observations. The coupled model predictions of ocean surface waves in Hurricane Ike (2008) over the Gulf of Mexico and Superstorm Sandy (2012) in the northeastern Atlantic and coastal region are evaluated with the NDBC buoy and satellite altimeter observations. Although there are characteristics that are general to ocean waves in both hurricanes as documented in previous studies, wave fields in Ike and Sandy possess unique properties due mostly to the distinct wind fields and coastal bathymetry in the two storms. Several processes are found to significantly modulate hurricane surface waves near landfall. First, the phase speed and group velocities decrease as the waves become shorter and steeper in shallow water, effectively increasing surface roughness and wind stress. Second, the bottom-induced refraction acts to turn the waves toward the coast, increasing the misalignment between the wind and waves. Third, as the hurricane translates over land, the left side of the storm center is characterized by offshore winds over very short fetch, which opposes incoming swell. Landfalling hurricanes produce broader wave spectra overall than that of the open ocean. The front-left quadrant is most complex, where the combination of windsea, swell propagating against the wind, increasing wind-wave stress, and interaction with the coastal topography requires a fully coupled model to meet these challenges in hurricane wave and surge prediction.

Extreme Wave Analysis by Integrating Model and Wave Buoy Data

Directory of Open Access Journals (Sweden)

Fabio Dentale

2018-03-01

Full Text Available Estimating the extreme values of significant wave height (HS, generally described by the HS return period TR function HS(TR and by its confidence intervals, is a necessity in many branches of coastal science and engineering. The availability of indirect wave data generated by global and regional wind and wave model chains have brought radical changes to the estimation procedures of such probability distribution—weather and wave modeling systems are routinely run all over the world, and HS time series for each grid point are produced and published after assimilation (analysis of the ground truth. However, while the sources of such indirect data are numerous, and generally of good quality, many aspects of their procedures are hidden to the users, who cannot evaluate the reliability and the limits of the HS(TR deriving from such data. In order to provide a simple engineering tool to evaluate the probability of extreme sea-states as well as the quality of such estimates, we propose here a procedure based on integrating HS time series generated by model chains with those recorded by wave buoys in the same area.

Estimation of Tsunami Bore Forces on a Coastal Bridge Using an Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Iman Mazinani

2016-04-01

Full Text Available This paper proposes a procedure to estimate tsunami wave forces on coastal bridges through a novel method based on Extreme Learning Machine (ELM and laboratory experiments. This research included three water depths, ten wave heights, and four bridge models with a variety of girders providing a total of 120 cases. The research was designed and adapted to estimate tsunami bore forces including horizontal force, vertical uplift and overturning moment on a coastal bridge. The experiments were carried out on 1:40 scaled concrete bridge models in a wave flume with dimensions of 24 m × 1.5 m × 2 m. Two six-axis load cells and four pressure sensors were installed to the base plate to measure forces. In the numerical procedure, estimation and prediction results of the ELM model were compared with Genetic Programming (GP and Artificial Neural Networks (ANNs models. The experimental results showed an improvement in predictive accuracy, and capability of generalization could be achieved by the ELM approach in comparison with GP and ANN. Moreover, results indicated that the ELM models developed could be used with confidence for further work on formulating novel model predictive strategy for tsunami bore forces on a coastal bridge. The experimental results indicated that the new algorithm could produce good generalization performance in most cases and could learn thousands of times faster than conventional popular learning algorithms. Therefore, it can be conclusively obtained that utilization of ELM is certainly developing as an alternative approach to estimate the tsunami bore forces on a coastal bridge.

Socializing the coast: Engaging the social science of tropical coastal research

Science.gov (United States)

Spalding, Ana K.; Biedenweg, Kelly

2017-03-01

The broad scale and rapid rate of change in the global environment is causing some of the world's most challenging problems, such as habitat degradation, loss of biodiversity, and food insecurity. These problems are especially pressing in coastal environments in the tropics, resulting in significant impacts on human wellbeing and ecological systems across the globe. The underlying causes of marine and coastal environmental change are both anthropogenic and natural; and, while it is difficult to parse out causal linkages as either exclusively human or naturally occurring, feedbacks between drivers only exacerbate the issues. Increasingly, scholars are turning to integrated research efforts, whereby multiple disciplines are used to answer pressing questions about and find solutions for the sustainability of human life and natural ecosystems across the coastal tropics. This article leverages the recent wave of interdisciplinary research to explore the various ways in which the social sciences have successfully contributed to a more complete understanding of coastal systems across the tropics. It also identifies opportunities for research that move beyond single disciplinary approaches to coastal science. The concluding discussion suggests social science knowledge areas that are underutilized in coastal research and provides suggestions for increasing the incorporation of social science in coastal research programs.

Simple estimate of entrainment rate of pollutants from a coastal discharge into the surf zone.

Science.gov (United States)

Wong, Simon H C; Monismith, Stephen G; Boehm, Alexandria B

2013-10-15

Microbial pollutants from coastal discharges can increase illness risks for swimmers and cause beach advisories. There is presently no predictive model for estimating the entrainment of pollution from coastal discharges into the surf zone. We present a novel, quantitative framework for estimating surf zone entrainment of pollution at a wave-dominant open beach. Using physical arguments, we identify a dimensionless parameter equal to the quotient of the surf zone width l(sz) and the cross-flow length scale of the discharge la = M(j) (1/2)/U(sz), where M(j) is the discharge's momentum flux and U(sz) is a representative alongshore velocity in the surf zone. We conducted numerical modeling of a nonbuoyant discharge at an alongshore uniform beach with constant slope using a wave-resolving hydrodynamic model. Using results from 144 numerical experiments we develop an empirical relationship between the surf zone entrainment rate α and l(sz)/(la). The empirical relationship can reasonably explain seven measurements of surf zone entrainment at three diverse coastal discharges. This predictive relationship can be a useful tool in coastal water quality management and can be used to develop predictive beach water quality models.

A statistical methodology for the estimation of extreme wave conditions for offshore renewable applications

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Kalogeri, Christina; Galanis, George

2015-01-01

and post-process outputs from a high resolution numerical wave modeling system for extreme wave estimation based on the significant wave height. This approach is demonstrated through the data analysis at a relatively deep water site, FINO 1, as well as a relatively shallow water area, coastal site Horns...... as a characteristic index of extreme wave conditions. The results from the proposed methodology seem to be in a good agreement with the measurements at both the relatively deep, open water and the shallow, coastal water sites, providing a potentially useful tool for offshore renewable energy applications. © 2015...... Rev, which is located in the North Sea, west of Denmark. The post-processing targets at correcting the modeled time series of the significant wave height, in order to match the statistics of the corresponding measurements, including not only the conventional parameters such as the mean and standard...

Two centuries of coastal change at Caesarea, Israel: natural processes vs. human intervention

Science.gov (United States)

Shtienberg, Gilad; Zviely, Dov; Sivan, Dorit; Lazar, Michael

2014-08-01

The coast at Caesarea, Israel, has been inhabited almost continuously for the last 2,400 years, and the archeological sites are today a major international tourist attraction. Because the sites straddle the shoreline, they are subject to constant damage by wave action, and must therefore be frequently restored. In this paper, local shoreline migrations over the last 200 years are investigated with the aim of distinguishing between natural and man-made coastal changes. In order to assess these changes accurately, geomorphological and sedimentological data were examined based on detailed beach profile measurements, bathymetric surveys, and grain-size analyses. In addition, series of old aerial photographs, as well as historical topographic maps and nautical charts were consulted. The results show that shoreline changes can be grouped into two main time periods. During the first period from 1862 to 1949 before the expansion of modern settlements, the position of the shoreline changed irregularly by up to 30 m. In the second period from 1949 onward, numerous coastal structures have been erected, and various coastal modifications have been carried out. The evaluation of the data suggests that human interventions have had relatively little effect on the overall position of the shoreline, as displacements ranged only from 5 to 18 m. Thus, coastal changes at Caesarea are predominantly due to natural wave action reflected in the heterogeneous geomorphological and sedimentological characteristics of the shore. This contradicts the common assumption that human activities are always mainly responsible for large-scale shoreline modifications in the region. It is concluded that, in order to implement meaningful mitigating countermeasures, coastal archeological sites need to be individually assessed with respect to the dominant factors causing local coastal change.

Sea Level Change and Coastal Climate Services: The Way Forward

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Gonéri Le Cozannet

2017-10-01

Full Text Available For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones are especially in need of climate services for adaptation, as they are increasingly threatened by sea level rise and its impacts, such as submergence, flooding, shoreline erosion, salinization and wetland change. In this paper, we examine how annual to multi-decadal sea level projections can be used within coastal climate services (CCS. To this end, we review the current state-of-the art of coastal climate services in the US, Australia and France, and identify lessons learned. More broadly, we also review current barriers in the development of CCS, and identify research and development efforts for overcoming barriers and facilitating their continued growth. The latter includes: (1 research in the field of sea level, coastal and adaptation science and (2 cross-cutting research in the area of user interactions, decision making, propagation of uncertainties and overall service architecture design. We suggest that standard approaches are required to translate relative sea level information into the forms required to inform the wide range of relevant decisions across coastal management, including coastal adaptation.

Geomorphometry in coastal morphodynamics

Science.gov (United States)

Guisado-Pintado, Emilia; Jackson, Derek

2017-04-01

Geomorphometry is a cross-cutting discipline that has interwoven itself into multiple research themes due to its ability to encompass topographic quantification on many fronts. Its operational focus is largely defined as the extraction of land-surface parameters and earth surface characterisation. In particular, the coastal sciences have been enriched by the use of digital terrain production techniques both on land and in the nearshore/marine area. Numerous examples exist in which the utilisation of field instrumentation (e.g. LIDAR, GPS, Terrestrial Laser Scanning, multi-beam echo-sounders) are used for surface sampling and development of Digital Terrain Models, monitoring topographic change and creation of nearshore bathymetry, and have become central elements in modern investigations of coastal morphodynamics. The coastal zone is a highly dynamic system that embraces variable and at times, inter-related environments (sand dunes, sandy beaches, shoreline and nearshore) all of which require accurate and integrated monitoring. Although coastal studies can be widely diverse (with interconnected links to other related disciplines such as geology or biology), the characterisation of the landforms (coastal geomorphology) and associated processes (morphodynamics, hydrodynamics, aeolian processes) is perhaps where geomorphometry (topo-bathymetry quantification) is best highlighted. In this respect, many tools have been developed (or improved upon) for the acquisition of topographic data that now commands a high degree of accuracy, simplicity, and ultimately acquisition cost reduction. We present a series of field data acquisitions examples that have produced land surface characterisation using a range of techniques including traditional GPS surveys to more recent Terrestrial Laser Scanning and airborne LIDAR. These have been conducted within beach and dune environments and have helped describe erosion and depositional processes driven by wind and wave energy (high

Quantifying the effectiveness of shoreline armoring removal on coastal biota of Puget Sound.

Science.gov (United States)

Lee, Timothy S; Toft, Jason D; Cordell, Jeffery R; Dethier, Megan N; Adams, Jeffrey W; Kelly, Ryan P

2018-01-01

Shoreline armoring is prevalent around the world with unprecedented human population growth and urbanization along coastal habitats. Armoring structures, such as riprap and bulkheads, that are built to prevent beach erosion and protect coastal infrastructure from storms and flooding can cause deterioration of habitats for migratory fish species, disrupt aquatic-terrestrial connectivity, and reduce overall coastal ecosystem health. Relative to armored shorelines, natural shorelines retain valuable habitats for macroinvertebrates and other coastal biota. One question is whether the impacts of armoring are reversible, allowing restoration via armoring removal and related actions of sediment nourishment and replanting of native riparian vegetation. Armoring removal is targeted as a viable option for restoring some habitat functions, but few assessments of coastal biota response exist. Here, we use opportunistic sampling of pre- and post-restoration data for five biotic measures (wrack % cover, saltmarsh % cover, number of logs, and macroinvertebrate abundance and richness) from a set of six restored sites in Puget Sound, WA, USA. This broad suite of ecosystem metrics responded strongly and positively to armor removal, and these results were evident after less than one year. Restoration responses remained positive and statistically significant across different shoreline elevations and temporal trajectories. This analysis shows that removing shoreline armoring is effective for restoration projects aimed at improving the health and productivity of coastal ecosystems, and these results may be widely applicable.

Quantifying the effectiveness of shoreline armoring removal on coastal biota of Puget Sound

Directory of Open Access Journals (Sweden)

Timothy S. Lee

2018-02-01

Full Text Available Shoreline armoring is prevalent around the world with unprecedented human population growth and urbanization along coastal habitats. Armoring structures, such as riprap and bulkheads, that are built to prevent beach erosion and protect coastal infrastructure from storms and flooding can cause deterioration of habitats for migratory fish species, disrupt aquatic–terrestrial connectivity, and reduce overall coastal ecosystem health. Relative to armored shorelines, natural shorelines retain valuable habitats for macroinvertebrates and other coastal biota. One question is whether the impacts of armoring are reversible, allowing restoration via armoring removal and related actions of sediment nourishment and replanting of native riparian vegetation. Armoring removal is targeted as a viable option for restoring some habitat functions, but few assessments of coastal biota response exist. Here, we use opportunistic sampling of pre- and post-restoration data for five biotic measures (wrack % cover, saltmarsh % cover, number of logs, and macroinvertebrate abundance and richness from a set of six restored sites in Puget Sound, WA, USA. This broad suite of ecosystem metrics responded strongly and positively to armor removal, and these results were evident after less than one year. Restoration responses remained positive and statistically significant across different shoreline elevations and temporal trajectories. This analysis shows that removing shoreline armoring is effective for restoration projects aimed at improving the health and productivity of coastal ecosystems, and these results may be widely applicable.

A Coupled Atmospheric and Wave Modeling System for Storm Simulations

DEFF Research Database (Denmark)

Du, Jianting; Larsén, Xiaoli Guo; Bolanos, R.

2015-01-01

to parametrize z0. The results are validated through QuikScat data and point measurements from an open ocean site Ekosk and a coastal, relatively shallow water site Horns Rev. It is found that the modeling system captures in general better strong wind and strong wave characteristics for open ocean condition than......This study aims at improving the simulation of wind and waves during storms in connection with wind turbine design and operations in coastal areas. For this particular purpose, we investigated the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System which couples the Weather...... resolution ranging from 25km to 2km. Meanwhile, the atmospheric forcing data of dierent spatial resolution, with one about 100km (FNL) and the other about 38km (CFSR) are both used. In addition, bathymatry data of diferent resolutions (1arc-minute and 30arc-seconds) are used. We used three approaches...

Analysis and Synthesis of WAVCIS Data for Characteristics of Waves and Currents on Louisiana Coast

Science.gov (United States)

Li, C.; Gibson, B.; Huang, W.; Luo, Y.; Milan, B.

2017-12-01

Texas-Louisiana coastal currents have been studied before, with a generally well-known pattern that is quasi steady except during the summer when it may weaken or reverse briefly. In the past decade, lot more efforts have been made and there is a large quantity of current velocity data accumulated. Among these data are those from the long-term mooring observations from the Wave Current-Surge Information System (WAVCIS), with a focus on the Louisiana coastal waters. More specifically, velocity and wave time series from current meters and pressure sensors or directional wave sensors at several locations on Louisiana coast provided unique opportunity to analyze and synthesize the characteristics of waves and currents on both east and west side of the Birdfoot Delta. In this study, we assembled all available WAVCIS data for a thorough analysis and synthesis of the characteristics of waves and coastal current in the area as a function of weather during different seasons. Year-to-year variabilities and seasonal variations are discussed. Spectrum, harmonic, and EOF analyses allowed a description and comparison of circulation patterns, wave and flow energy regimes, vertical shear of horizontal flows, tidal characteristics, synoptic weather effect, and severe weather impact. We provide basic statistics, as well as classifications of type of flows/circulations, and the major mechanisms that contribute to the variability.

Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

Directory of Open Access Journals (Sweden)

Park Sang Kil

2014-12-01

Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

Directory of Open Access Journals (Sweden)

Sang Kil Park

2014-12-01

Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (γν = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

A Study on Coastal Flooding and Risk Assessment under Climate Change in the Mid-Western Coast of Taiwan

Directory of Open Access Journals (Sweden)

Tai-Wen Hsu

2017-06-01

Full Text Available This study integrated coastal watershed models and combined them with a risk assessment method to develop a methodology to investigate the impact resulting from coastal disasters under climate change. The mid-western coast of Taiwan suffering from land subsidence was selected as the demonstrative area for the vulnerability analysis based on the prediction of sea level rise (SLR, wave run-up, overtopping, and coastal flooding under the scenarios of the years from 2020 to 2039. Databases from tidal gauges and satellite images were used to analyze SLR using Ensemble Empirical Mode Decomposition (EEMD. Extreme wave condition and storm surge were estimated by numerical simulation using the Wind Wave Model (WWM and the Princeton Ocean Model (POM. Coastal inundation was then simulated via the WASH123D watershed model. The risk map of study areas based on the analyses of vulnerability and disaster were established using the Analytic Hierarchy Process (AHP technique. Predictions of sea level rise, the maximum wave condition, and storm surge under the scenarios of 2020 to 2039 are presented. The results indicate that the sea level at the mid-western coast of Taiwan will rise by an average of 5.8 cm, equivalent to a rising velocity of 2.8 mm/year. The analysis indicates that the Wuqi, Lukang, Mailiao, and Taixi townships are susceptive, low resistant and low resilient and reach the high-risk level. This assessment provides important information for creating an adaption policy for the mid-western coast of Taiwan.

Development of a Shipboard Remote Control and Telemetry Experimental System for Large-Scale Model’s Motions and Loads Measurement in Realistic Sea Waves

Directory of Open Access Journals (Sweden)

Jialong Jiao

2017-10-01

Full Text Available Wave-induced motion and load responses are important criteria for ship performance evaluation. Physical experiments have long been an indispensable tool in the predictions of ship’s navigation state, speed, motions, accelerations, sectional loads and wave impact pressure. Currently, majority of the experiments are conducted in laboratory tank environment, where the wave environments are different from the realistic sea waves. In this paper, a laboratory tank testing system for ship motions and loads measurement is reviewed and reported first. Then, a novel large-scale model measurement technique is developed based on the laboratory testing foundations to obtain accurate motion and load responses of ships in realistic sea conditions. For this purpose, a suite of advanced remote control and telemetry experimental system was developed in-house to allow for the implementation of large-scale model seakeeping measurement at sea. The experimental system includes a series of technique sensors, e.g., the Global Position System/Inertial Navigation System (GPS/INS module, course top, optical fiber sensors, strain gauges, pressure sensors and accelerometers. The developed measurement system was tested by field experiments in coastal seas, which indicates that the proposed large-scale model testing scheme is capable and feasible. Meaningful data including ocean environment parameters, ship navigation state, motions and loads were obtained through the sea trial campaign.

A global classification of coastal flood hazard climates associated with large-scale oceanographic forcing.

Science.gov (United States)

Rueda, Ana; Vitousek, Sean; Camus, Paula; Tomás, Antonio; Espejo, Antonio; Losada, Inigo J; Barnard, Patrick L; Erikson, Li H; Ruggiero, Peter; Reguero, Borja G; Mendez, Fernando J

2017-07-11

Coastal communities throughout the world are exposed to numerous and increasing threats, such as coastal flooding and erosion, saltwater intrusion and wetland degradation. Here, we present the first global-scale analysis of the main drivers of coastal flooding due to large-scale oceanographic factors. Given the large dimensionality of the problem (e.g. spatiotemporal variability in flood magnitude and the relative influence of waves, tides and surge levels), we have performed a computer-based classification to identify geographical areas with homogeneous climates. Results show that 75% of coastal regions around the globe have the potential for very large flooding events with low probabilities (unbounded tails), 82% are tide-dominated, and almost 49% are highly susceptible to increases in flooding frequency due to sea-level rise.

Physical and economic impacts of sea-level rise and low probability flooding events on coastal communities.

Directory of Open Access Journals (Sweden)

Thomas Prime

Full Text Available Conventionally flood mapping typically includes only a static water level (e.g. peak of a storm tide in coastal flood inundation events. Additional factors become increasingly important when increased water-level thresholds are met during the combination of a storm tide and increased mean sea level. This research incorporates factors such as wave overtopping and river flow in a range of flood inundation scenarios of future sea-level projections for a UK case study of Fleetwood, northwest England. With increasing mean sea level it is shown that wave overtopping and river forcing have an important bearing on the cost of coastal flood events. The method presented converts inundation maps into monetary cost. This research demonstrates that under scenarios of joint extreme surge-wave-river events the cost of flooding can be increased by up to a factor of 8 compared with an increase in extent of up to a factor of 3 relative to "surge alone" event. This is due to different areas being exposed to different flood hazards and areas with common hazard where flood waters combine non-linearly. This shows that relying simply on flood extent and volume can under-predict the actual economic impact felt by a coastal community. Additionally, the scenario inundation depths have been presented as "brick course" maps, which represent a new way of interpreting flood maps. This is primarily aimed at stakeholders to increase levels of engagement within the coastal community.

Physical and economic impacts of sea-level rise and low probability flooding events on coastal communities.

Science.gov (United States)

Prime, Thomas; Brown, Jennifer M; Plater, Andrew J

2015-01-01

Conventionally flood mapping typically includes only a static water level (e.g. peak of a storm tide) in coastal flood inundation events. Additional factors become increasingly important when increased water-level thresholds are met during the combination of a storm tide and increased mean sea level. This research incorporates factors such as wave overtopping and river flow in a range of flood inundation scenarios of future sea-level projections for a UK case study of Fleetwood, northwest England. With increasing mean sea level it is shown that wave overtopping and river forcing have an important bearing on the cost of coastal flood events. The method presented converts inundation maps into monetary cost. This research demonstrates that under scenarios of joint extreme surge-wave-river events the cost of flooding can be increased by up to a factor of 8 compared with an increase in extent of up to a factor of 3 relative to "surge alone" event. This is due to different areas being exposed to different flood hazards and areas with common hazard where flood waters combine non-linearly. This shows that relying simply on flood extent and volume can under-predict the actual economic impact felt by a coastal community. Additionally, the scenario inundation depths have been presented as "brick course" maps, which represent a new way of interpreting flood maps. This is primarily aimed at stakeholders to increase levels of engagement within the coastal community.

Estimation of Wave Disturbance in Harbours

DEFF Research Database (Denmark)

Helm-Petersen, Jacob

. Information on how the sponge layers perform with respect to reflection of short-crested waves are presented mainly in terms of overall reflection coefficients and main directions as functions of incident main direction relative to the structure. The influence of a irregular structure front has also been......The motivation for the present study has been to improve the reliability in using numerical wave propagation models as a tool for estimating wave disturbance in harbours. Attention has been directed towards the importance of the modelling of reflection in the applied mild-slope model. Methods have...... been presented for the analysis of reflected wave fields in 2D and 3D. The Bayesian Directional Wave Spectrum Estimation Method has been applied throughout the study. Reflection characteristics have been investigated by use of physical models for three types of coastal structures with vertical fronts...

Coastal observing and forecasting system for the German Bight – estimates of hydrophysical states

Directory of Open Access Journals (Sweden)

W. Petersen

2011-09-01

Full Text Available A coastal observing system for Northern and Arctic Seas (COSYNA aims at construction of a long-term observatory for the German part of the North Sea, elements of which will be deployed as prototype modules in Arctic coastal waters. At present a coastal prediction system deployed in the area of the German Bight integrates near real-time measurements with numerical models in a pre-operational way and provides continuously state estimates and forecasts of coastal ocean state. The measurement suite contributing to the pre-operational set up includes in situ time series from stationary stations, a High-Frequency (HF radar system measuring surface currents, a FerryBox system and remote sensing data from satellites. The forecasting suite includes nested 3-D hydrodynamic models running in a data-assimilation mode, which are forced with up-to-date meteorological forecast data. This paper reviews the present status of the system and its recent upgrades focusing on developments in the field of coastal data assimilation. Model supported data analysis and state estimates are illustrated using HF radar and FerryBox observations as examples. A new method combining radial surface current measurements from a single HF radar with a priori information from a hydrodynamic model is presented, which optimally relates tidal ellipses parameters of the 2-D current field and the M2 phase and magnitude of the radials. The method presents a robust and helpful first step towards the implementation of a more sophisticated assimilation system and demonstrates that even using only radials from one station can substantially benefit state estimates for surface currents. Assimilation of FerryBox data based on an optimal interpolation approach using a Kalman filter with a stationary background covariance matrix derived from a preliminary model run which was validated against remote sensing and in situ data demonstrated the capabilities of the pre-operational system. Data

Trapped waves of the 27 November 1945 Makran tsunami: observations and numerical modeling

Digital Repository Service at National Institute of Oceanography (India)

Neetu, S.; Suresh, I.; Shankar, R.; Nagarajan, B.; Sharma, R.; Shenoi, S.S.C.; Unnikrishnan, A.S.; Sundar, D.

the Makran coast and at Karachi were the result of trapping of the tsunami-wave energy on the continental shelf off the Makran coast and that these coastally-trapped edge waves were trapped in the alongshore direction within a approx 300-km stretch...

Durable Suit Bladder with Improved Water Permeability for Pressure and Environment Suits

Science.gov (United States)

Bue, Grant C.; Kuznetz, Larry; Orndoff, Evelyne; Tang, Henry; Aitchison, Lindsay; Ross, Amy

2009-01-01

Water vapor permeability is shown to be useful in rejecting heat and managing moisture accumulation in launch-and-entry pressure suits. Currently this is accomplished through a porous Gortex layer in the Advanced Crew and Escape Suit (ACES) and in the baseline design of the Constellation Suit System Element (CSSE) Suit 1. Non-porous dense monolithic membranes (DMM) that are available offer potential improvements for water vapor permeability with reduced gas leak. Accordingly, three different pressure bladder materials were investigated for water vapor permeability and oxygen leak: ElasthaneTM 80A (thermoplastic polyether urethane) provided from stock polymer material and two custom thermoplastic polyether urethanes. Water vapor, carbon dioxide and oxygen permeability of the DMM's was measured in a 0.13 mm thick stand-alone layer, a 0.08 mm and 0.05 mm thick layer each bonded to two different nylon and polyester woven reinforcing materials. Additional water vapor permeability and mechanical compression measurements were made with the reinforced 0.05 mm thick layers, further bonded with a polyester wicking and overlaid with moistened polyester fleece thermal underwear .This simulated the pressure from a supine crew person. The 0.05 mm thick nylon reinforced sample with polyester wicking layer was further mechanically tested for wear and abrasion. Concepts for incorporating these materials in launch/entry and Extravehicular Activity pressure suits are presented.

Satellite observation of bio-optical indicators related to North-Western Black Sea coastal zone changes

Science.gov (United States)

Zoran, Maria

Satellite remote sensing provides a means for locating, identifying and mapping certain coastal zone features and assessing of spatio-temporal changes.The Romanian coastal zone of the Black Sea is a mosaic of complex, interacting ecosystems, exposed to dramatic changes due to natural and anthropogenic causes (increase in the nutrient and pollutant load of rivers input, industrial and municipal wastewater pollution along the coast, and dumping on the open sea). This study focuses on the assessment of coastal zone land cover changes based on the fusion of satellite remote sensing data.The evaluation of coastal zone landscapes is based upon different sub-functions which refer to landscape features such as water, soil, land-use, buildings, groundwater, biotope types. Mixed pixels result when the sensor's instantaneous field-of-view includes more than one land cover class on the ground. Based on different satellite data (Landsat TM, ETM, SAR ERS, IKONOS, Quickbird, and MODIS) was performed object recognition for North-Western Black Sea coastal zone. Preliminary results show significant coastline position changes of North Western Black Sea during the period of 1987-2007 and urban growth of Constantza town. Also the change in the position of the coastline is examined and linked to the urban expansion in order to determine if the changes are natural or anthropogenic. A distinction is made between landfill/sedimentation processes on the one hand and dredging/erosion processes on the other. Waves play an important role for shoreline configuration. Wave pattern could induce erosion and sedimentation. A quasi-linear model was used to model the rate of shoreline change. The vectors of shoreline were used to compare with wave spectra model in order to examine the accuracy of the coastal erosion model. The shoreline rate modeled from vectors data of SAR ERS-1 has a good correlation with a quasi-linear model. Wave refraction patterns are a good index for shoreline erosion. A coast

Coastal erosion and accretion rates in Greece

Science.gov (United States)

Foteinis, Spyros; Papadopoulos, Costas; Koutsogiannaki, Irini; Synolakis, Costas

2010-05-01

Erosion threatens many coastal regions of Greece. Anthropogenic changes of landforms such as coastal roads built on even narrow beaches, sand mining for construction, poor design of coastal structures that interfere with sediment, and dams without sediment bypasses have significantly reduced beach widths. We present erosion rates for different beaches, some of which are in sensitive ecosystems, otherwise "protected" by local and EU ordinances. By comparing inferences of beach widths in varying intervals from 1933 to 2006, we infer that the construction of dams in Acheloos river in western Greece, built in a faraonic attempt to partially divert its flows to eastern Greece, this is responsible for up to 20m/year erosion rates observed in certain locales in the Acheloos delta. More characteristic erosion rates in the region are ~ 2m/year. By contrast, there appears rapid accretion of up to 4m/year in the beaches around the Nestos delta in northern Greece (Papadopoulos, 2009). In beaches that are not near large river deltas, erosion rates range from 0.5m/year to 1m/year. While we have not done comprehensive comparisons among coastlines with different levels of coastal development, it does appear that rapid coastal development correlates well with erosion rates. The underlying problem is the complete lack of any semblance of coastal zone management in Greece and substandard design of coastal structures, which are often sited without any measurements of waves and currents offshore (Synolakis et al, 2008). Beach maintenance remains an exotic concept for most local authorities, who invariably prefer to build hard coastal structures to "protect" versus nourish, siting lack of experience with nourishment and "environmental" concerns. In certain cases, choices are dictated by costs, the larger the cost the easier the project gets approved by regulatory authorities, hence the preference for concrete or rubble structures. We conclude that, unless urgent salvage measures are

A methodology to analize the safety of a coastal nuclear power plant against the Typhoon external flooding risks

International Nuclear Information System (INIS)

Chen Tian; He Mi; Chen Guofei; Joly, Antoine; Pan Rong; Ji Ping

2015-01-01

For the protection of coastal Nuclear Power Plant (NPP) against the external flooding hazard, the risks caused by natural events have to be taken into account. In this article, a methodology is proposed to analyze the risk of the typical natural event in China (Typhoon). It includes the simulation of the storm surge and the strong waves due to its passage in Chinese coastal zones and the quantification of the sequential overtopping flow rate. The simulation is carried out by coupling 2 modules of the hydraulic modeling system TELEMAC-MASCARET from EDF, TELEMAC2D (Shallow water module) and TOMAWAC (spectral wave module). As an open-source modeling system, this methodology could still be enriched by other phenomena in the near future to ameliorate its performance in safety analysis of the coastal NPPs in China. (author)

Sea-Level Rise Implications for Coastal Protection from Southern Mediterranean to the U.S.A. Atlantic Coast

Science.gov (United States)

Ismail, Nabil; Williams, Jeffress

2013-04-01

demonstrated in autumn 2010 when the storm Becky reached the Santander Bay, Spain. As reported by THESEUS, the FP-7 EU project (2009-2013), the peak of nearshore significant wave height was about 8 m, the storm surge reached 0.6 m, with tidal level of 90% of the tidal range. The latest storm in December 2010, which hit the Nile Delta and which was the severest in the last decades showed that generated surges, up to 1.0 m as well as a maximum of 7.5 m wave height in the offshore of Alexandria presented a major natural hazard in coastal zones in terms of wave run up and overtopping. Along the US Atlantic Coast, where Hurricane Sandy this autumn and Hurricane Irene in 2011 left chaos in their wakes, a perfect storm of rising sea levels and dense coastal development at high risk . Super storm Sandy sent a storm surge of 4-5 m onto New Jersey's and New York's fragile barrier island and urban shorelines, causing an estimated 70 billion (USD) in damages and widespread misery for coastal inhabitants. Sea Level Rise and Impact on Upgrade of Coastal Structures: Williams (2013) highlights in his recent paper that adaptation planning on national scales in the USA for projected sea-level rise of 0.5-2 m by A.D. 2100 is advisable. Further he points out that sea-level rise, as a major driving force of change for coastal regions, is becoming increasingly important as a hazard to humans and urban areas in the coastal zone worldwide as global climate change takes effect. During the 20th century, sea level began rising at a global average rate of 1.7 mm/yr (). The current average rise rate is 3.1 mm/yr, a 50% increase over the past two decades. Many regions are experiencing even greater rise rates due to local geophysical (e.g., Louisiana, Chesapeake Bay) and oceanographic (mid-Atlantic coast) forces. Further the Mississippi River Delta plain region of Louisiana has much higher than average rates of LRSL rise due to geologic factors such as subsidence and man-made alterations to the delta plain

The kelp highway hypothesis: marine ecology, the coastal migration theory, and the peopling of the Americas

Science.gov (United States)

Erlandson, Jon M.; Graham, Michael H.; Bourque, Bruce J.; Corbett, Debra; Estes, James A.; Steneck, Robert S.

2007-01-01

In this article, a collaborative effort between archaeologists and marine ecologists, we discuss the role kelp forest ecosystems may have played in facilitating the movement of maritime peoples from Asia to the Americas near the end of the Pleistocene. Growing in cool nearshore waters along rocky coastlines, kelp forests offer some of the most productive habitats on earth, with high primary productivity, magnified secondary productivity, and three-dimensional habitat supporting a diverse array of marine organisms. Today, extensive kelp forests are found around the North Pacific from Japan to Baja California. After a break in the tropicswhere nearshore mangrove forests and coral reefs are highly productivekelp forests are also found along the Andean Coast of South America. These Pacific Rim kelp forests support or shelter a wealth of shellfish, fish, marine mammals, seabirds, and seaweeds, resources heavily used historically by coastal peoples. By about 16,000 years ago, the North Pacific Coast offered a linear migration route, essentially unobstructed and entirely at sea level, from northeast Asia into the Americas. Recent reconstructions suggest that rising sea levels early in the postglacial created a highly convoluted and island-rich coast along Beringia's southern shore, conditions highly favorable to maritime hunter-gatherers. Along with the terrestrial resources available in adjacent landscapes, kelp forests and other nearshore habitats sheltered similar suites of food resources that required minimal adaptive adjustments for migrating coastal peoples. With reduced wave energy, holdfasts for boats, and productive fishing, these linear kelp forest ecosystems may have provided a kind of kelp highway for early maritime peoples colonizing the New World.

Deriving nearshore wave climate along South African coast

CSIR Research Space (South Africa)

Rossouw, M

2015-04-01

Full Text Available The present study addressed aspects of the highly interrelated study area of coastal safety and vulnerability, climate change and setback lines for South African coast. A medium resolution numerical wave analysis was undertaken, in the form...

Marine and Coastal Morphology: medium term and long-term area modelling

DEFF Research Database (Denmark)

Kristensen, Sten Esbjørn

This thesis documents development and application of a modelling concept developed in collaboration between DTU and DHI. The modelling concept is used in morphological modelling in coastal areas where the governing sediment transport processes are due to wave action. The modelling concept...... is defined: Hybrid morphological modelling and it is based on coupling calculated sediment transport fields from a traditional process based coastal area model with a parametrised morphological evolution model. The focus of this study is to explore possible parametric formulations of the morphological...... solution has a two dimensional nature. 1.5D shoreline model A so-called “1.5D” implementation which introduces redistribution of sediment within a coastal profile in response to horizontal 2D currents makes it possible to simulate the morphological development in areas where 2D evolution occurs...

Coastal Geographic Structures in Coastal-Marine Environmental Management

Science.gov (United States)

Baklanov, P. Ya.; Ganzei, K. S.; Ermoshin, V. V.

2018-01-01

It has been proposed to distinguish the coastal geographic structures consisting of a spatial combination of three interconnected and mutually conditioned parts (coastal-territorial, coastal, coastal-marine), which are interlinked with each other by the cumulative effect of real-energy flows. Distinguishing specific resource features of the coastal structures, by which they play a connecting role in the complex coastalmarine management, has been considered. The main integral resource feature of the coastal structures is their connecting functions, which form transitional parts mutually connecting the coastal-territorial and coastalmarine environmental management.

The record of iceberg roll generated waves from sediments and seismics

Science.gov (United States)

Rosser, N. J.; Szczucinski, W.; Strzelecki, M.; Long, A. J.; Norman, E. C.; Dunning, S.; Drewniak, M.

2013-12-01

Iceberg-roll tsunamis in coastal settings have been observed to generate significant local waves, that hold potential to be recorded in coastal depositional records. Capturing the past magnitude and frequency of such events remains challenging, hindered by a lack of a good understanding of the nature, recurrence and scale of iceberg rolls, and more specifically those rolls that generate waves. Here we consider the sedimentary evidence for iceberg rolls in West Central Greenland, based upon survey of depositional environments in a range of open and confined coastal environments. We examine both an open 80 km fjord setting, and a series of confined ice-marginal beaches. We combine a detailed interpretation of sediment deposits from shore-normal transects with wider-scale high-resolution terrestrial laser scanning of sediments. Our sites - Vaigat, which separates Disko Island from the Nussuaq Peninsular, and the northern shore of Icefjord - both have a recent history of tsunamis, triggered variously by large rock avalanches, landslides and iceberg rolls. Icebergs in Vaigat and Icefjord are observed to undergo frequent failure and roll, generating - where circumstances permit - nearshore waves of meter-scale. To obtain a more detailed understanding of the likely recurrence of such iceberg roll waves and to consider their influence upon the preserved sedimentary record, we undertook an intensive 2-month monitoring campaign during sea-ice free conditions in summer 2013 to determine the patterns in the location, magnitude, frequency and timing of iceberg roll waves. Innovatively, using microseismic monitoring combined with time-lapse photography and weather monitoring, we derive a first-order model of the occurrence of iceberg roll waves. We then use this to inform our interpretation of deposits in these two environments, and consider the presence and absence of records of iceberg roll deposits in such settings. The study was funded by Polish National Science Centre grant

Risk Analysis of Coastal Disaster of Semarang City, Indonesia

Science.gov (United States)

Sunaryo; Ambariyanto; Sugianto, Denny Nugroho; Helmi, Muhammad; Kaimuddin, Awaluddin Halirin; Indarjo, Agus

2018-02-01

Coastal areas are highly vulnerable to disasters, as they are affected by events occurring both on land and at sea. In the development of cities in these areas, information on vulnerability levels is needed as a consideration in determining policy. This study aims to identify potential vulnerability of Semarang city, and to investigate the potential of hazard and disaster risk levels of the city. The study was conducted in 17 villages in the northern coastal area of Semarang. The assessment approach used was score analysis to some variables, i.e geomorphology, erosion, coastal slope, waves and socio-economic aspects. The research showed that the highest level of coastal vulnerability in the Semarang city were at three villages i.e.Terboyo Kulon, Terboyo Wetan and Trimulyo with value of 4.5; while the lowest level were at the Maron beach, Marina beach and Tanah Mas with value of 2.8. The highest potential coastal hazard in the Semarang city were at two villages i.e. Tanjung Mas and Tambak Lorok with value of 4.5; and the lowest value were in the village of Randugarut, Karanganyar, Tugurejo, Marina beach and Tanah Mas with value of 1.25.The highest level of coastal risk in the Semarang city were in the Trimulyo village with value of 3.13; and the lowest level were in the Marina beach and Tanah mas with value of 1.32.

Human Stressors Are Driving Coastal Benthic Long-Lived Sessile Fan Mussel Pinna nobilis Population Structure More than Environmental Stressors.

Science.gov (United States)

Deudero, Salud; Vázquez-Luis, Maite; Álvarez, Elvira

2015-01-01

Coastal degradation and habitat disruption are severely compromising sessile marine species. The fan shell Pinna nobilis is an endemic, vulnerable species and the largest bivalve in the Mediterranean basin. In spite of species legal protection, fan shell populations are declining. Models analyzed the contributions of environmental (mean depth, wave height, maximum wave height, period of waves with high energy and mean direction of wave source) versus human-derived stressors (anchoring, protection status, sewage effluents, fishing activity and diving) as explanatory variables depicting Pinna nobilis populations at a mesoscale level. Human stressors were explaining most of the variability in density spatial distribution of fan shell, significantly disturbing benthic communities. Habitat protection affected P. nobilis structure and physical aggression by anchoring reveals a high impact on densities. Environmental variables instead played a secondary role, indicating that global change processes are not so relevant in coastal benthic communities as human-derived impacts.

Analysis of Multi Temporal Satellite Imagery for Total Suspended Sediments in a Wave-Active Coastal Area-Gaza Strip Coastal Water, Palestine

Directory of Open Access Journals (Sweden)

Midyan D.I. Aldabash

2016-03-01

Full Text Available Sediment load materials is one of the key factors that determine the surface water quality, both of oceanic and river water, and it specifies water optical properties. Thus it provides a background for a plenty of applications and projects in the water and oceanography community. Landsat detects and classifies reflected solar energy from bodies on the earth's surface. Suspended sediments existing in water column have an optical influences. So that, Landsat images could detect suspended sediments concentration in such a water surface. In this study we have three main objectives to be achieved as; TSS Concentration maps generation in the Gaza Strip coastal zone, achieving analysis processes on TSS trend itself and TSS related coastal phenomenon, and investigation of the ability of Landsat images to detect TSS comprehensively in a wavy coastal zone. For this purpose two landsat TM5 images acquired in 1999 and 2010, one Landsat TM7 images acquired in 2003, and 2 Landsat Oli 8 images acquired in 2014 and 2015 were used for TSS mapping. In addition, 64 TSS in-situ tested samples were also to calculate a correlation equation between Digital Numbers - DN in each image pixels and TSS values in the ground data. All image analysis and remote sensing steps have been done in this study using Integrated Land and Water Information System - ILWIS software version ILWIS academic 3.3. Green and Red bands in all used Landsat images contained the highest linear correlation factors -R- for the images acquired in 1999, 2003, 2010, 2014, and 2015. Resulted correlation factors were higher by reducing time difference between acquisition time and sampling time. Generated maps showed that circulation in Gaza coastal area are counterclockwise, and it brings the sediments from Nile River Delta toward Gaza Strip.

Research and absence of bats across habitat scales in the upper coastal plain of South Carolina

Science.gov (United States)

W. Mark Ford; Jennifer M. Menzel; Michael A. Menzel; John W. Edwards; John C. Kilgo

2006-01-01

During 2001, we used active acoustical sampling (Anabat 11) to survey foraging habitat relationships of bats on the Savannah River Site (SRS) in the upper Coastal Plain of South Carolina. Using an a priori information-theoretic approach, we conducted logistic regression analysis to examine presence of individual bat species relative to a suite of microhabitat, stand,...

Edge waves excited by underwater landslides : scenarios in the sea of Marmara

Science.gov (United States)

Sinan Özeren, Mehmet; Postacioglu, Nazmi; Canlı, Umut; Gasperini, Luca

2014-05-01

In this work we quantify the travel distance of edge waves created by submarine landslide over slopes of finite length. Edge waves, if generated, can constitute severe coastal hazard because they can travel long distances along the shores. In the Sea of Marmara there are several submarine masses susceptible to slide in case of a big earthquake on the Main Marmara Fault and some damage scenarios might involve edge waves. The edge waves generated by landslide Tsunamis over slopes of infinite lenghts are recently studied by Sammarco and Renzi (Landslide tsunamis propagating along a plane beach, 2008, Journal of Fluid Mech.). However the infinite slope length assumption causes a perfect confinement of the waves over the coastal slope, thereby overestimating the edge wave damage. Because of this, in their work there is no alongshore length scale over which these waves can lose their energy. In the real worls, the off-shore limiting depth will be finite and the off-shore direction wave vector will not be completely complex, pointing to radiation damping of these edge waves. In this work we analytically quantify the amount of this damping and we estimate the travel distance of the edge waves along the shoreline as a function of the limiting depth. We examine some some scenarios in the north coast of the Sea of Marmara and the northern shelf to quantify the edge waves. Since the method does not require high-resolution numerical computing, it can be used to calculate the edge-wave related risk factor anywhere with submarine landslide risk.

Numerical modelling of extreme waves by Smoothed Particle Hydrodynamics

Directory of Open Access Journals (Sweden)

M. H. Dao

2011-02-01

Full Text Available The impact of extreme/rogue waves can lead to serious damage of vessels as well as marine and coastal structures. Such extreme waves in deep water are characterized by steep wave fronts and an energetic wave crest. The process of wave breaking is highly complex and, apart from the general knowledge that impact loadings are highly impulsive, the dynamics of the breaking and impact are still poorly understood. Using an advanced numerical method, the Smoothed Particle Hydrodynamics enhanced with parallel computing is able to reproduce well the extreme waves and their breaking process. Once the waves and their breaking process are modelled successfully, the dynamics of the breaking and the characteristics of their impact on offshore structures could be studied. The computational methodology and numerical results are presented in this paper.

Extraction of coastal ocean wave characteristics using remote sensing and computer vision technologies

CSIR Research Space (South Africa)

Johnson, M

2017-05-01

Full Text Available optical imagery from the RapidEye satellite can be used to extract ocean wave characteristics such as wave direction, wavelength, wave period and wave velocity. If successful, the advantage of the proposed remote sensing-based approach would...

Assessing the Wave Energy Potential of Jamaica, a Greater Antilles Island, through Dynamic Modelling

Science.gov (United States)

Daley, A. P., Jr.; Dorville, J. F. M.; Taylor, M. A.

2017-12-01

Globally wave energy has been on the rise as a result of the impacts of climate change and continuous fluctuation in oil prices. The water's inertia provides waves with greater stability than that of other renewable energy sources such as solar and wind. Jamaica is part of the Greater Antilles Arc and has over 1000 km of coast line with an abundance of shallow water approximately 80% within a 50km band. This configuration provides a wealth of sites for wave exploitation even in minimal wave energy conditions. Aside from harnessing the oceans waves converters can be viewed as a tool for protection of coastal areas against natural marine occurrences. Jamica has done extensive studies where solar, hydro and wind resouces are concerned. However, there has been no studies done to date on the country's wave energy resources.The aim of this study is to bridge this gap by characterizing Jamaica's wave energy resources generating in a half-closed Caribbean Sea using data available from: buoys, altimetric satellite, and numerical model. Available data has been used to assess the available resource on the coastal area for the last 12 years. Statistical analysis of the available energy is determined using the sea state (Hs, Tp and Dir) and the atmospheric forcing (10m-wind, atmospheric pressure, sea-air temperature) relating to the season.The chain of dynamical model is presented (WW3-SWAN-SWASH), allowing for the tracking of the propagation of the wave energy from an offshore region to nearshore zone along with their interaction with areas of shallow depth. This will provide a better assessment of the energy and the quality of the waves closer to the electrical grid.Climate prediction is used to estimate the sea state and wave energy exploitable up to 2100. An analysis of the possible usage of the available coastal resource up to 2100. The main results present small but exploitable resources with seasonal variability in the energy available but not wave direction.

Innovative Design for Sea Dikes and Breakwaters for Wave Energy Conversion

DEFF Research Database (Denmark)

Vicinanza, Diego; Stagonas, Dimitris; Müller, Gerald

2012-01-01

This paper intends contributing to an economically and environmentally sustainable development of coastal infrastructures by investigating the possibility of combining together breakwaters and Wave Energy Converters (WEC). The latter change the wave energy to electricity, which may serve both the...... the rubble mound breakwaters and seawall related activity and the energy demand of small human communities....

Development of Power Assisting Suit

Science.gov (United States)

Yamamoto, Keijiro; Ishii, Mineo; Hyodo, Kazuhito; Yoshimitsu, Toshihiro; Matsuo, Takashi

In order to realize a wearable power assisting suit for assisting a nurse to carry a patient in her arms, the power supply and control systems of the suit have to be miniaturized, and it has to be wireless and pipeline-less. The new wearable suit consists of shoulders, arms, back, waist and legs units to be fitted on the nurse's body. The arms, waist and legs have new pneumatic rotary actuators driven directly by micro air pumps supplied by portable Ni-Cd batteries. The muscle forces are sensed by a new muscle hardness sensor utilizing a sensing tip mounted on a force sensing film device. An embedded microcomputer is used for the calculations of control signals. The new wearable suit was applied practically to a human body and a series of movement experiments that weights in the arms were held and taken up and down was performed. Each unit of the suit could transmit assisting torque directly to each joint verifying its practicability.

A mm-wave planar microcavity structure for electron linear accelerator system

International Nuclear Information System (INIS)

Kang, Y.W.; Kustom, R.; Mills, F.; Mavrogenes, G.; Henke, H.

1993-01-01

The muffin-tin cavity structure is planar and well suited for mm-wave accelerator with silicon etching techniques. A constant impedance traveling-wave structure is considered for design simplicity. The RF parameters are calculated and the shunt impedance is compared with the shunt impedance of a disk loaded cylindrical structure

Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

Science.gov (United States)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2017-12-01

Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in

Space Suit Joint Torque Testing

Science.gov (United States)

Valish, Dana J.

2011-01-01

In 2009 and early 2010, a test was performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design meets the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future space suits. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis and a variance in torque values for some of the tested joints was apparent. Potential variables that could have affected the data were identified and re-testing was conducted in an attempt to eliminate these variables. The results of the retest will be used to determine if further testing and modification is necessary before the method can be validated.

Extreme winds and waves for offshore turbines: Coupling atmosphere and wave modeling for design and operation in coastal zones

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Bolanos, Rodolfo; Du, Jianting

modeling for oshore wind farms. This modeling system consists of the atmospheric Weather Research and Forecasting (WRF) model, the wave model SWAN and an interface the Wave Boundary Layer Model WBLM, within the framework of coupled-ocean-atmosphere-wave-sediment transport modeling system COAWST...... (Hereinafter the WRF-WBLM-SWAN model). WBLM is implemented in SWAN, and it calculates stress and kinetic energy budgets in the lowest atmospheric layer where the wave-induced stress is introduced to the atmospheric modeling. WBLM ensures consistent calculation of stress for both the atmospheric and wave......, which can aect the choice of the off-shore wind turbine type. X-WiWa examined various methodologies for wave modeling. The offline coupling system using atmospheric data such as WRF or global reanalysis wind field to the MIKE 21 SW model has been improved with considerations of stability, air density...

Reflection of equatorial Kelvin waves at eastern ocean boundaries Part I: hypothetical boundaries

Directory of Open Access Journals (Sweden)

J. Soares

1999-06-01

Full Text Available A baroclinic shallow-water model is developed to investigate the effect of the orientation of the eastern ocean boundary on the behavior of equatorial Kelvin waves. The model is formulated in a spherical polar coordinate system and includes dissipation and non-linear terms, effects which have not been previously included in analytical approaches to the problem. Both equatorial and middle latitude response are considered given the large latitudinal extent used in the model. Baroclinic equatorial Kelvin waves of intraseasonal, seasonal and annual periods are introduced into the domain as pulses of finite width. Their subsequent reflection, transmission and dissipation are investigated. It is found that dissipation is very important for the transmission of wave energy along the boundary and for reflections from the boundary. The dissipation was found to be dependent not only on the presence of the coastal Kelvin waves in the domain, but also on the period of these coastal waves. In particular the dissipation increases with wave period. It is also shown that the equatorial β-plane approximation can allow an anomalous generation of Rossby waves at higher latitudes. Nonlinearities generally have a small effect on the solutions, within the confines of this model.Key words. Oceanography: general (equatorial oceanography; numerical modeling · Oceanography: physical (eastern boundary currents

Directional wave and temperature data from five wave-rider buoys at locations along the California coast, 2003-01 to 2003-12 (NODC Accession 0001306)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Data Information Program (CDIP) is an extensive network for monitoring waves along the coastlines of the United States, with a strong emphasis on our...

Directional wave and temperature data from eight wave-rider buoys at locations along the California coast, 2002-06 to 2003-12 (NODC Accession 0001298)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Data Information Program (CDIP) is an extensive network for monitoring waves along the coastlines of the United States, with a strong emphasis on our...

Linking source region and ocean wave parameters with the observed primary microseismic noise

Science.gov (United States)

Juretzek, C.; Hadziioannou, C.

2017-12-01

In previous studies, the contribution of Love waves to the primary microseismic noise field was found to be comparable to those of Rayleigh waves. However, so far only few studies analysed both wave types present in this microseismic noise band, which is known to be generated in shallow water and the theoretical understanding has mainly evolved for Rayleigh waves only. Here, we study the relevance of different source region parameters on the observed primary microseismic noise levels of Love and Rayleigh waves simultaneously. By means of beamforming and correlation of seismic noise amplitudes with ocean wave heights in the period band between 12 and 15 s, we analysed how source areas of both wave types compare with each other around Europe. The generation effectivity in different source regions was compared to ocean wave heights, peak ocean gravity wave propagation direction and bathymetry. Observed Love wave noise amplitudes correlate comparably well with near coastal ocean wave parameters as Rayleigh waves. Some coastal regions serve as especially effective sources for one or the other wave type. These coincide not only with locations of high wave heights but also with complex bathymetry. Further, Rayleigh and Love wave noise amplitudes seem to depend equally on the local ocean wave heights, which is an indication for a coupled variation with swell height during the generation of both wave types. However, the wave-type ratio varies directionally. This observation likely hints towards a spatially varying importance of different source mechanisms or structural influences. Further, the wave-type ratio is modulated depending on peak ocean wave propagation directions which could indicate a variation of different source mechanism strengths but also hints towards an imprint of an effective source radiation pattern. This emphasizes that the inclusion of both wave types may provide more constraints for the understanding of acting generation mechanisms.

Refined Source Terms in WAVEWATCH III with Wave Breaking and Sea Spray Forecasts

Science.gov (United States)

2015-09-30

dissipation and breaking, nonlinear wave-wave interaction, bottom friction, wave-mud interaction, wave-current interaction as well as sea spray flux. These...shallow water outside the surf zone. After careful testing within a comprehensive suite of test bed cases, these refined source terms will be...aim to refine the parameterization of air-sea and upper ocean fluxes, including wind input and sea spray as well as dissipation, and hence improve

Assessment of Damage and Adaptation Strategies for Structures and Infrastructure from Storm Surge and Sea Level Rise for a Coastal Community in Rhode Island, United States

Directory of Open Access Journals (Sweden)

Christopher Small

2016-10-01

Full Text Available This paper presents an evaluation of inundation, erosion, and wave damage for a coastal community in Rhode Island, USA. A methodology called the Coastal Environmental Risk Index (CERI was used that incorporates levels of inundation including sea level rise, wave heights using STWAVE, and detailed information about individual structures from an E911 database. This information was input into damage functions developed by the U.S. Army Corps of Engineers following Hurricane Sandy. Damage from erosion was evaluated separately from local published erosion rates. Using CERI, two different adaptation strategies were evaluated that included a combination of dune restoration, protective berms, and a tide gate. A total of 151 out of 708 structures were estimated to be protected from inundation and wave action by the combined measures. More importantly, the use of CERI allowed for the assessment of the impact of different adaptation strategies on both individual structures and an entire community in a Geographical Information Systems (GIS environment. This tool shows promise for use by coastal managers to assess damage and mitigate risk to coastal communities.

Human Stressors Are Driving Coastal Benthic Long-Lived Sessile Fan Mussel Pinna nobilis Population Structure More than Environmental Stressors.

Directory of Open Access Journals (Sweden)

Salud Deudero

Full Text Available Coastal degradation and habitat disruption are severely compromising sessile marine species. The fan shell Pinna nobilis is an endemic, vulnerable species and the largest bivalve in the Mediterranean basin. In spite of species legal protection, fan shell populations are declining. Models analyzed the contributions of environmental (mean depth, wave height, maximum wave height, period of waves with high energy and mean direction of wave source versus human-derived stressors (anchoring, protection status, sewage effluents, fishing activity and diving as explanatory variables depicting Pinna nobilis populations at a mesoscale level. Human stressors were explaining most of the variability in density spatial distribution of fan shell, significantly disturbing benthic communities. Habitat protection affected P. nobilis structure and physical aggression by anchoring reveals a high impact on densities. Environmental variables instead played a secondary role, indicating that global change processes are not so relevant in coastal benthic communities as human-derived impacts.

Evaluating Suit Fit Using Performance Degradation

Science.gov (United States)

Margerum, Sarah E.; Cowley, Matthew; Harvill, Lauren; Benson, Elizabeth; Rajulu, Sudhakar

2011-01-01

The Mark III suit has multiple sizes of suit components (arm, leg, and gloves) as well as sizing inserts to tailor the fit of the suit to an individual. This study sought to determine a way to identify the point an ideal suit fit transforms into a bad fit and how to quantify this breakdown using mobility-based physical performance data. This study examined the changes in human physical performance via degradation of the elbow and wrist range of motion of the planetary suit prototype (Mark III) with respect to changes in sizing and as well as how to apply that knowledge to suit sizing options and improvements in suit fit. The methods implemented in this study focused on changes in elbow and wrist mobility due to incremental suit sizing modifications. This incremental sizing was within a range that included both optimum and poor fit. Suited range of motion data was collected using a motion analysis system for nine isolated and functional tasks encompassing the elbow and wrist joints. A total of four subjects were tested with motions involving both arms simultaneously as well as the right arm only. The results were then compared across sizing configurations. The results of this study indicate that range of motion may be used as a viable parameter to quantify at what stage suit sizing causes a detriment in performance; however the human performance decrement appeared to be based on the interaction of multiple joints along a limb, not a single joint angle. The study was able to identify a preliminary method to quantify the impact of size on performance and to develop a means to gauge tolerances around optimal size. More work is needed to improve the assessment of optimal fit and to compensate for multiple joint interactions.

Modelling the coastal processes at the mouths of the Danube River in the Black Sea

Science.gov (United States)

Rusu, Eugen; Zanopol, Andrei

2014-05-01

The mouths of the Danube River in the Black Sea represent the main southern entrance in the seventh Pan European transportation corridor that links the Black and the Northern seas and is the most important inland navigable waterway in Europe. For this reason the coastal area close to the Danube Delta is subjected to high navigation traffic, which is crucially affected by the strong processes mainly induced by the interactions between the waves and the currents generated by the Danube River outflow. From this perspective, the objective of the present work is to develop a computational framework based on numerical models able to evaluate properly the effects of these interactions and to provide reliable predictions concerning the wave and current conditions corresponding to various environmental patterns. Following this target, a wave modelling system, SWAN based, was implemented in the entire basin of the Black Sea and focused on the coastal sector at the entrance of the Danube Delta. As a next step of the modelling process, SWAN simulations were performed at two different computational levels, considering in parallel the situations without and with the current fields for the main environmental conditions characteristic to the target area. The first level covers the entire coastal area at the mouths of the Danube River and has a resolution in the geographical space of 500m. The second is a computational domain with the resolution of 50m that is focused on the Sulina channel, which is the main navigation gate at the mouths of the Danube River. The results show that the presence of the currents induces relevant enhancements in terms of significant wave heights. Additionally, the Benjamin Feir index (BFI) was also evaluated. This is a spectral shape parameter that is related to the kurtosis of the distribution and indicates the risk of the freak wave occurrence. The enhanced values for BFI in the case when the current fields are considered in the modelling process

Creating a Coastal National Elevation Database (CoNED) for science and conservation applications

Science.gov (United States)

Thatcher, Cindy A.; Brock, John C.; Danielson, Jeffrey J.; Poppenga, Sandra K.; Gesch, Dean B.; Palaseanu-Lovejoy, Monica; Barras, John; Evans, Gayla A.; Gibbs, Ann

2016-01-01

The U.S. Geological Survey is creating the Coastal National Elevation Database, an expanding set of topobathymetric elevation models that extend seamlessly across coastal regions of high societal or ecological significance in the United States that are undergoing rapid change or are threatened by inundation hazards. Topobathymetric elevation models are raster datasets useful for inundation prediction and other earth science applications, such as the development of sediment-transport and storm surge models. These topobathymetric elevation models are being constructed by the broad regional assimilation of numerous topographic and bathymetric datasets, and are intended to fulfill the pressing needs of decision makers establishing policies for hazard mitigation and emergency preparedness, coastal managers tasked with coastal planning compatible with predictions of inundation due to sea-level rise, and scientists investigating processes of coastal geomorphic change. A key priority of this coastal elevation mapping effort is to foster collaborative lidar acquisitions that meet the standards of the USGS National Geospatial Program's 3D Elevation Program, a nationwide initiative to systematically collect high-quality elevation data. The focus regions are located in highly dynamic environments, for example in areas subject to shoreline change, rapid wetland loss, hurricane impacts such as overwash and wave scouring, and/or human-induced changes to coastal topography.

Investigating extreme event loading on coastal bridges using wireless sensor technology

Science.gov (United States)

Gelineau, Douglas A.; Davis, Justin R.; Rice, Jennifer A.

2017-04-01

Coastal infrastructure, such as bridges, are susceptible to many forms of coastal hazards: particularly hurricane surge and wave loading. These two forms of loading can cause catastrophic damage to aging highway infrastructure. It is estimated that storm damage costs the United States about $50 Billion per year. In light of this, it is crucial that we understand the damaging forces placed on infrastructure during storm events so that we can develop safer and more resilient coastal structures. This paper presents the ongoing research to enable the efficient collection of extreme event loads acting on both the substructure and superstructure of low clearance, simple span, reinforced concrete bridges. Bridges of this type were commonly constructed during the 1950's and 60's and are particularly susceptible to deck unseating caused by hurricane surge and wave loading. The sensing technology used to capture this data must be ruggedized to survive in an extremely challenging environment, be designed to allow for redundancy in the event of sensors or other network components being lost in the storm, and be relatively low cost to allow for more bridges to be instrumented per storm event. The prototype system described in this paper includes wireless technology, rapid data transmission, and, for the sensors, self-contained power. While this specific application focuses on hurricane hazards, the framework can be extended to include other natural hazards.

The Evolution and Revival Structure of Localized Quantum Wave Packets

OpenAIRE

Bluhm, Robert; Kostelecky, Alan; Porter, James

1995-01-01

Localized quantum wave packets can be produced in a variety of physical systems and are the subject of much current research in atomic, molecular, chemical, and condensed-matter physics. They are particularly well suited for studying the classical limit of a quantum-mechanical system. The motion of a localized quantum wave packet initially follows the corresponding classical motion. However, in most cases the quantum wave packet spreads and undergoes a series of collapses and revivals. We pre...

Αutomated 2D shoreline detection from coastal video imagery: an example from the island of Crete

Science.gov (United States)

Velegrakis, A. F.; Trygonis, V.; Vousdoukas, M. I.; Ghionis, G.; Chatzipavlis, A.; Andreadis, O.; Psarros, F.; Hasiotis, Th.

2015-06-01

Beaches are both sensitive and critical coastal system components as they: (i) are vulnerable to coastal erosion (due to e.g. wave regime changes and the short- and long-term sea level rise) and (ii) form valuable ecosystems and economic resources. In order to identify/understand the current and future beach morphodynamics, effective monitoring of the beach spatial characteristics (e.g. the shoreline position) at adequate spatio-temporal resolutions is required. In this contribution we present the results of a new, fully-automated detection method of the (2-D) shoreline positions using high resolution video imaging from a Greek island beach (Ammoudara, Crete). A fully-automated feature detection method was developed/used to monitor the shoreline position in geo-rectified coastal imagery obtained through a video system set to collect 10 min videos every daylight hour with a sampling rate of 5 Hz, from which snapshot, time-averaged (TIMEX) and variance images (SIGMA) were generated. The developed coastal feature detector is based on a very fast algorithm using a localised kernel that progressively grows along the SIGMA or TIMEX digital image, following the maximum backscatter intensity along the feature of interest; the detector results were found to compare very well with those obtained from a semi-automated `manual' shoreline detection procedure. The automated procedure was tested on video imagery obtained from the eastern part of Ammoudara beach in two 5-day periods, a low wave energy period (6-10 April 2014) and a high wave energy period (1 -5 November 2014). The results showed that, during the high wave energy event, there have been much higher levels of shoreline variance which, however, appeared to be similarly unevenly distributed along the shoreline as that related to the low wave energy event, Shoreline variance `hot spots' were found to be related to the presence/architecture of an offshore submerged shallow beachrock reef, found at a distance of 50-80 m

Implementation of boundary conditions for locked waves

NARCIS (Netherlands)

Petit, H.A.H.; Battjes, J.A.

2001-01-01

This report refers to the work done at the Fluid Mechanics Section within the framework of the Netherlands Centre for Coastal Research (NCK). As shown by Reniers et al. (2000) there are strong indications that wave-group related phenomena are important in the development of rip channels. It is to be

Quantity, distribution, and impacts of coastal driftwood triggered by a typhoon.

Science.gov (United States)

Doong, Dong-Jiing; Chuang, Hui-Chieh; Shieh, Chjeng-Lun; Hu, Jian-Hwa

2011-07-01

Typhoon Morakot pounded Taiwan in 2009 with record-breaking rainfall, washing an unprecedented amount of driftwood into the sea that was partially deposited at the coastal areas. According to the satellite imagery analysis, more than three million trees fell and were washed away to occupy 83.2% of the Taiwanese coastline, including 52 fishing harbors. The amount cleaned-up was only 1/7 of the total coastal driftwood. It was found that the amount of coastal driftwood is not only related to the amount of precipitation but is also related to the distance from the location of the landslide to the river mouth and to the landslide area. The amount of accumulated coastal driftwood demonstrated log-profile declines with increasing distance to the river mouth. Nearshore current and wave motion are the critical factors for driftwood deposition. Much of the driftwood washed into the sea harmed the tourism and fishing industries, endangered navigation and oceanic activities, and impacted the marine environment and ecosystem. Copyright © 2011 Elsevier Ltd. All rights reserved.

The influence of coral reefs and climate change on wave-driven flooding of tropical coastlines

Science.gov (United States)

Quataert, Ellen; Storlazzi, Curt; van Rooijen, Arnold; van Dongeren, Ap; Cheriton, Olivia

2015-01-01

A numerical model, XBeach, calibrated and validated on field data collected at Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands, was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave-driven flooding and how these effects may be altered by projected climate change. The results presented herein suggest that coasts fronted by relatively narrow reefs with steep fore reef slopes (~1:10 and steeper) and deeper, smoother reef flats are expected to experience the highest wave runup. Wave runup increases for higher water levels (sea level rise), higher waves, and lower bed roughness (coral degradation), which are all expected effects of climate change. Rising sea levels and climate change will therefore have a significant negative impact on the ability of coral reefs to mitigate the effects of coastal hazards in the future.

The influence of coral reefs and climate change on wave-driven flooding of tropical coastlines

Science.gov (United States)

Quataert, Ellen; Storlazzi, Curt; Rooijen, Arnold; Cheriton, Olivia; Dongeren, Ap

2015-08-01

A numerical model, XBeach, calibrated and validated on field data collected at Roi-Namur Island on Kwajalein Atoll in the Republic of Marshall Islands, was used to examine the effects of different coral reef characteristics on potential coastal hazards caused by wave-driven flooding and how these effects may be altered by projected climate change. The results presented herein suggest that coasts fronted by relatively narrow reefs with steep fore reef slopes (~1:10 and steeper) and deeper, smoother reef flats are expected to experience the highest wave runup. Wave runup increases for higher water levels (sea level rise), higher waves, and lower bed roughness (coral degradation), which are all expected effects of climate change. Rising sea levels and climate change will therefore have a significant negative impact on the ability of coral reefs to mitigate the effects of coastal hazards in the future.

Challenges of Tsunami Disaster and Extreme climate Events Along Coastal Region in Asia-Pacific

Science.gov (United States)

Chaudhari, S.

2017-12-01

South Asia is more vulnerable to Geo disasters and impacts of climate changes in recent years. On 26 December 2004 massive waves triggered by an earthquake surged into coastal communities in Asia and East Africa with devastating force. Hitting Indonesia, Sri Lanka , Thailand and India hardest, the deadly waves swept more than 200 000 people to their deaths. Also in an another extreme climate change phenomenon during 2005 - 2006,causing heavy rains and flooding situation in the South Asia - Europe and Pacific region ,more than 100 million population in these regions are witnessing the social- economical and ecological risks and impacts due to climate changes and Geohazards. For mitigating geo-disasters, marine hazards and rehabilitation during post tsunami period, scientific knowledge is needed, requiring experienced research communities who can train the local population during tsunami rehabilitation. Several civil society institutions jointly started the initiatives on the problem identifications in management of risks in geo-disasters, tsunami rehabilitation ,Vulnerability and risk assessments for Geohazards etc., to investigate problems related to social-economic and ecological risks and management issues resulting from the December tsunami and Geo- disaster, to aid mitigation planning in affected areas and to educate scientists and local populations to form a basis for sustainable and economic solutions. The poster aims to assess the potential risk and hazard , technical issues, problems and damage arising from Tsunami in the Asia-pacific region in coastal geology, coastal ecosystems and coastal environmental systems . This poster deals with the status and issues of interactions between Human and Ocean Systems, Geo-risks, marine risks along coastal region of Asia- Pacific and also human influence on the earth system . The poster presentation focuses on capacity building of the local population, scientists and researchers for integration of human and ocean

Using an autonomous Wave Glider to detect seawater anomalies related to submarine groundwater discharge - engineering challenge

Science.gov (United States)

Leibold, P.; Brueckmann, W.; Schmidt, M.; Balushi, H. A.; Abri, O. A.

2017-12-01

Coastal aquifer systems are amongst the most precious and vulnerable water resources worldwide. While differing in lateral and vertical extent they commonly show a complex interaction with the marine realm. Excessive groundwater extraction can cause saltwater intrusion from the sea into the aquifers, having a strongly negative impact on the groundwater quality. While the reverse pathway, the discharge of groundwater into the sea is well understood in principle, it's mechanisms and quantities not well constrained. We will present a project that combines onshore monitoring and modeling of groundwater in the coastal plain of Salalah, Oman with an offshore autonomous robotic monitoring system, the Liquid Robotics Wave Glider. Eventually, fluxes detected by the Wave Glider system and the onshore monitoring of groundwater will be combined into a 3-D flow model of the coastal and deeper aquifers. The main tool for offshore SGD investigation project is a Wave Glider, an autonomous vehicle based on a new propulsion technology. The Wave Glider is a low-cost satellite-connected marine craft, consisting of a combination of a sea-surface and an underwater component which is propelled by the conversion of ocean wave energy into forward thrust. While the wave energy propulsion system is purely mechanical, electrical energy for onboard computers, communication and sensors is provided by photovoltaic cells. For the project the SGD Wave Glider is being equipped with dedicated sensors to measure temperature, conductivity, Radon isotope (222Rn, 220Rn) activity concentration as well as other tracers of groundwater discharge. Dedicated software using this data input will eventually allow the Wave Glider to autonomously collect information and actively adapt its search pattern to hunt for spatial and temporal anomalies. Our presentation will focus on the engineering and operational challenges ofdetecting submarine groundwater discharges with the Wave Glider system in the Bay of Salalah

Coastal hazards and groundwater salinization on low coral islands.

Science.gov (United States)

Terry, James P.; Chui, T. F. May

2016-04-01

Remote oceanic communities living on low-lying coral islands (atolls) without surface water rely for their survival on the continuing viability of fragile groundwater resources. These exist in the form of fresh groundwater lenses (FGLs) that develop naturally within the porous coral sand and gravel substrate. Coastal hazards such as inundation by high-energy waves driven by storms and continuing sea-level rise (SLR) are among many possible threats to viable FGL size and quality on atolls. Yet, not much is known about the combined effects of wave washover during powerful storms and SLR on different sizes of coral island, nor conversely how island size influences lens resilience against damage. This study investigates FGL damage by salinization (and resilience) caused by such coastal hazards using a modelling approach. Numerical modelling is carried out to generate steady-state FGL configurations at three chosen island sizes (400, 600 and 800 m widths). Steady-state solutions reveal how FGL dimensions are related in a non-linear manner to coral island size, such that smaller islands develop much more restricted lenses than larger islands. A 40 cm SLR scenario is then imposed. This is followed by transient simulations to examine storm-induced wave washover and subsequent FGL responses to saline damage over a 1 year period. Smaller FGLs display greater potential for disturbance by SLR, while larger and more robust FGLs tend to show more resilience. Further results produce a somewhat counterintuitive finding: in the post-SLR condition, FGL vulnerability to washover salinization may actually be reduced, owing to the thinner layer of unsaturated substrate lying above the water table into which saline water can infiltrate during a storm event. Nonetheless, combined washover and SLR impacts imply overall that advancing groundwater salinization may lead to some coral islands becoming uninhabitable long before they are completely submerged by sea-level rise, thereby calling

Trend analysis of the wave storminess: the wave direction

Science.gov (United States)

Casas Prat, M.; Sierra, J. P.; Mösso, C.; Sánchez-Arcilla, A.

2009-09-01

Climate change has an important role in the current scientific research because of its possible future negative consequences. Concerning the climate change in the coastal engineering field, the apparent sea level rise is one of the key parameters as well as the wave height and the wave direction temporal variations. According to the IPCC (2007), during the last century the sea level has been increasing with a mean rate of 1.7 ± 0.5 mm/yr. However, at local/regional scale the tendency significantly differs from the global trend since the local pressure and wind field variations become more relevant. This appears to be particularly significant in semi-enclosed areas in the Mediterranean Sea (Cushman-Roisin et al., 2001). Even though the existing unsolved questions related to the sea level rise, the uncertainty concerning the wave height is even larger, in which stormy conditions are especially important because they are closely related to processes such as coastal erosion, flooding, etc. Therefore, it is necessary to identify possible existing tendencies of storm related parameters. In many studies, only the maximum wave height and storm duration are analysed, remaining the wave direction in a second term. Note that a possible rotation of the mean wave direction may involve severe consequences since most beach and harbour defence structures have been designed assuming a constant predominant wave incidence. Liste et al. (2004) illustrated this fact with an example in which a rotation of only 2 degrees of the mean energy flux vector could produce a beach retreat of 20 m. Another possible consequence would be a decrease of the harbour operability: increased frequency of storms in the same direction as the harbour entrance orientation would influence the navigability. The present study, which focuses in the Catalan coast (NW Mediterranean Sea), aims to improve the present knowledge of the wave storminess variations at regional scale, specially focusing on the wave

Prediction of the Low Frequency Wave Field on Open Coastal Beaches

National Research Council Canada - National Science Library

Ozkan-Haller, H. T

2005-01-01

... (both abrupt and gradual) affect the resulting low frequency wave climate. 3. The assessment of the importance of interactions between different modes of time-varying motions in the nearshore region, as well as interactions between these modes and the incident wave field. 4. To arrive at a predictive understanding of low frequency motions.

Holocene evolution of a wave-dominated fan-delta: Godavari delta, India

Science.gov (United States)

Saito, Y.; Nageswara Rao, K.; Nagakumar, K.; Demudu, G.; Rajawat, A.; Kubo, S.; Li, Z.

2013-12-01

The Godavari delta is one of the world's largest wave-dominated deltas. The Godavari River arises in the Western Ghats near the west coast of India and drains an area of about 3.1x10^5 km^2, flowing about 1465 km southeast across the Indian peninsula to the Bay of Bengal. The Godavari delta consists of a gentle seaward slope from its apex (12 m elevation) at Rajahmundry and a coastal beach-ridge plain over a distance of about 75 km and covers ~5200 km^2 as a delta plain. The river splits into two major distributary channels, the Gautami and the Vasishta, at a barrage constructed in the mid-1800s. The coastal environment of the deltaic coast is microtidal (~1 m mean tidal range) and wave-dominated (~1.5 m mean wave height in the June-September SW monsoon season, ~0.8 m in the NE monsoon season). Models of the Holocene evolution of the Godavari delta have changed from a zonal progradation model (e.g. Nageswara Rao & Sadakata, 1993) to a truncated cuspate delta model (Nageswara Rao et al., 2005, 2012). Twelve borehole cores (340 m total length), taken in the coastal delta plain during 2010-2013, yielded more than 100 C-14 dates. Sediment facies and C-14 dates from these and previous cores and remote-sensing data support a new delta evolution model. The Holocene coastal delta plain is divided into two parts by a set of linear beach ridges 12-14 km landward from the present shoreline in the central part of the delta. The location of the main depocenter (lobe) has shifted during the Holocene from 1) the center to 2) the west, 3) east, 4) center, 5) west, and 6) east. The linear beach ridges separate the first three from the last three stages. These lobe shifts are controlled by river channel shifts near the apex. Just as the current linear shoreline of the central part of the delta and the concave-up nearshore topography are the result of coastal erosion of a cuspate delta, the linear beach ridges indicate a former eroded shoreline. An unconformity within the deltaic

Projected 21st century coastal flooding in the Southern California Bight. Part 2: Tools for assessing climate change-driven coastal hazards and socio-economic impacts

Science.gov (United States)

Erikson, Li; Barnard, Patrick; O'Neill, Andrea; Wood, Nathan J.; Jones, Jeanne M.; Finzi Hart, Juliette; Vitousek, Sean; Limber, Patrick; Hayden, Maya; Fitzgibbon, Michael; Lovering, Jessica; Foxgrover, Amy C.

2018-01-01

This paper is the second of two that describes the Coastal Storm Modeling System (CoSMoS) approach for quantifying physical hazards and socio-economic hazard exposure in coastal zones affected by sea-level rise and changing coastal storms. The modelling approach, presented in Part 1, downscales atmospheric global-scale projections to local scale coastal flood impacts by deterministically computing the combined hazards of sea-level rise, waves, storm surges, astronomic tides, fluvial discharges, and changes in shoreline positions. The method is demonstrated through an application to Southern California, United States, where the shoreline is a mix of bluffs, beaches, highly managed coastal communities, and infrastructure of high economic value. Results show that inclusion of 100-year projected coastal storms will increase flooding by 9–350% (an additional average 53.0 ± 16.0 km2) in addition to a 25–500 cm sea-level rise. The greater flooding extents translate to a 55–110% increase in residential impact and a 40–90% increase in building replacement costs. To communicate hazards and ranges in socio-economic exposures to these hazards, a set of tools were collaboratively designed and tested with stakeholders and policy makers; these tools consist of two web-based mapping and analytic applications as well as virtual reality visualizations. To reach a larger audience and enhance usability of the data, outreach and engagement included workshop-style trainings for targeted end-users and innovative applications of the virtual reality visualizations.

STS-93 Commander Collins suits up for launch

Science.gov (United States)

1999-01-01

During the third launch preparations in the Operations and Checkout Building, STS-93 Commander Eileen M. Collins waves while having her launch and entry suit checked. After Space Shuttle Columbia's July 20 and 22 launch attempts were scrubbed, the launch was again rescheduled for Friday, July 23, at 12:24 a.m. EDT. STS-93 is a five-day mission primarily to release the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The STS-93 crew numbers five: Commander Collins, Pilot Jeffrey S. Ashby, and Mission Specialists Stephen A. Hawley (Ph.D.), Catherine G. Coleman (Ph.D.) and Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES). Collins is the first woman to serve as commander of a shuttle mission.

Measuring changes in ambient noise levels from the installation and operation of a surge wave energy converter in the coastal ocean

Energy Technology Data Exchange (ETDEWEB)

Haxel, Joe H [Oregon State Univ., Newport, OR (United States); Henkel, Sarah K [Oregon State Univ., Newport, OR (United States)

2017-10-18

Ecosystem impacts resulting from elevated underwater noise levels generated by anthropogenic activities in the coastal ocean are poorly understood and remain difficult to address as a result of a significant gap in knowledge for existing nearshore sound levels. Ambient noise is an important habitat component for marine mammals and fish that use sound for essential functions such as communication, navigation, and foraging. Questions surrounding the amplitudes, frequency distributions, and durations of noise emissions from renewable wave energy conversion (WEC) projects during their construction and operation present concerns for long-term consequences in marine habitats. Oregon’s dynamic nearshore environment presents significant challenges for passive acoustic monitoring that include flow noise contamination from wave orbital motions, turbulence from breaking surf, equipment burial, and fishing pressure from sport and commercial crabbers. This project included 2 techniques for passive acoustic data collection: 1) campaign style deployments of fixed hydrophone lander stations to capture temporal variations in noise levels and 2) a drifting hydrophone system to record spatial variations within the project site. The hydrophone lander deployments were effective and economically feasible for enabling robust temporal measurements of ambient noise levels in a variety of sea state conditions. Limiting factors for the fixed stations included 1) a flow shield mitigation strategy failure in the first deployment resulting in significant wideband data contamination and 2) flow noise contamination of the unshielded sensors restricting valuable analysis to frequencies above 500 Hz for subsequent deployments. Drifting hydrophone measurements were also effective and economically feasible (although logistically challenging in the beginning of the project due to vessel time constraints) providing a spatial distribution of sound levels, comparisons of noise levels in varying levels

Wave Energy, Lever Operated Pivoting Float LOPF Study

DEFF Research Database (Denmark)

Margheritini, Lucia

The fully instrumented Resen Waves Lever Operated Pivoting Float LOPF wave energy buoy model has gone through the first stage of testing in regular waves in scale 1:25 of the North Sea wave conditions, in the 3D deep wave basin at the Hydraulic and Coastal Engineering Laboratory of Aalborg...... University in Denmark. The model size was 60cm W x 90cm L x 21cm H. The 60 cm width pointed towards the wave front. The LOPF buoy is characterized by a simple mechanical design with few moving parts and direct electrical output and it is taut moored to the sea bed, so all forces are referenced to the seabed...... for maximum energy output in regular as well as irregular waves. During storms the buoy pivots and streamlines itself to minimize loads on the mooring line. A conservative estimate shows that a full scale system for North Sea conditions has a float size width of 15 m that will, with 60% generator efficiency...

Assessment of tsunami hazard for coastal areas of Shandong Province, China

Science.gov (United States)

Feng, Xingru; Yin, Baoshu

2017-04-01

Shandong province is located on the east coast of China and has a coastline of about 3100 km. There are only a few tsunami events recorded in the history of Shandong Province, but the tsunami hazard assessment is still necessary as the rapid economic development and increasing population of this area. The objective of this study was to evaluate the potential danger posed by tsunamis for Shandong Province. The numerical simulation method was adopted to assess the tsunami hazard for coastal areas of Shandong Province. The Cornell multi-grid coupled tsunami numerical model (COMCOT) was used and its efficacy was verified by comparison with three historical tsunami events. The simulated maximum tsunami wave height agreed well with the observational data. Based on previous studies and statistical analyses, multiple earthquake scenarios in eight seismic zones were designed, the magnitudes of which were set as the potential maximum values. Then, the tsunamis they induced were simulated using the COMCOT model to investigate their impact on the coastal areas of Shandong Province. The numerical results showed that the maximum tsunami wave height, which was caused by the earthquake scenario located in the sea area of the Mariana Islands, could reach up to 1.39 m off the eastern coast of Weihai city. The tsunamis from the seismic zones of the Bohai Sea, Okinawa Trough, and Manila Trench could also reach heights of >1 m in some areas, meaning that earthquakes in these zones should not be ignored. The inundation hazard was distributed primarily in some northern coastal areas near Yantai and southeastern coastal areas of Shandong Peninsula. When considering both the magnitude and arrival time of tsunamis, it is suggested that greater attention be paid to earthquakes that occur in the Bohai Sea. In conclusion, the tsunami hazard facing the coastal area of Shandong Province is not very serious; however, disasters could occur if such events coincided with spring tides or other

Wave Height and Water Level Variability on Lakes Michigan and St Clair

Science.gov (United States)

2012-10-01

Observations: http://www.ssec.wisc.edu/sose/glwx_activity.html 4. NASA Atlas of Extratropical Storm Tracks: http://data.giss.nasa.gov/stormtracks...term meteorological, ice, wave, and water level measurements. 15. SUBJECT TERMS Base flood elevation Coastal flood Extratropical storms Great...Box 1027 Detroit, MI 48231-1027 ERDC/CHL TR-12-23 ii Abstract The Great Lakes are subject to coastal flooding as a result of severe storms

Flooding Risk for Coastal Infrastructure: a Stakeholder-Oriented Approach

Science.gov (United States)

Plater, A. J.; Prime, T.; Brown, J. M.; Knight, P. J.; Morrissey, K.

2015-12-01

A flood risk assessment for coastal energy infrastructure in the UK with respect to long-term sea-level rise and extreme water levels has been conducted using a combination of numerical modelling approaches (LISFLOOD-FP, SWAB, XBeach-G, POLCOMS). Model outputs have been incorporated into a decision-support tool that enables users from a wide spectrum of coastal stakeholders (e.g. nuclear energy, utility providers, local government, environmental regulators, communities) to explore the potential impacts of flooding on both operational (events to 10 years) and strategic (10 to 50 years) timescales. Examples illustrate the physical and economic impacts of flooding from combined extreme water levels, wave overtopping and high river flow for Fleetwood, NW England; changes in the extent of likely flooding arising from an extreme event due to sea-level rise for Oldbury, SW England; and the relative vulnerability to overtopping and breaching of sea defences for Dungeness, SE England. The impacts of a potential large-scale beach recharge scheme to mitigate coastal erosion and flood risk along the southern shoreline of Dungeness are also examined using a combination of coastal evolution and particle-tracking modelling. The research goal is to provide an evidence base for resource allocation, investment in interventions, and communication and dialogue in relation to sea-level rise to 2500 AD.

Projected inundations on the South African coast by tsunami waves

African Journals Online (AJOL)

Hayley.Cawthra

wind waves and swells, and because of its relatively short period, .... Inundation modelling attempts to recreate the tsunami generation in deep or ... The preservation of tsunami deposits in the coastal geological record is a function of the.

Stability of Cubipod Armoured Roundheads in Short Crested Waves

DEFF Research Database (Denmark)

Burcharth, Hans F.; Andersen, Thomas Lykke; Medina, Josep R.

2011-01-01

The paper presents a comparison of the stability of concrete cube armour and Cubipod armour in a breakwater roundhead with slope 1:1.5, exposed to both 2-D (long-crested) and 3-D (short-crested) waves. The model tests were performed at the Hydraulics and Coastal Engineering Laboratory at Aalborg...... University, Denmark. The model tests showed that Cubipod armour is more stable than cube armour when exposed to longer waves (steepness approx. 0.025) and has equal stability to cubes in shorter waves. The Cubipod armour layer contained due to its high porosity approximately 6-17% less concrete than the cube...

Extreme Wave Runup over the Steep Rocky Cliffs of Banneg Island, France

Science.gov (United States)

Ardhuin, F.; Dodet, G.; Leckler, F.; Suanez, S.; Filipot, J. F.

2016-12-01

Ocean waves are constantly shaping coastal morphology. When storm waves are combined with high water levels, the wave runup can reach unexpected elevations and become a threat for coastal populations, through dike overtopping, dune breaching or accelerated coastline erosion. Therefore, the wave runup has been largely investigated over the last decades for its key importance in coastal engineering and risk management. Although the strongly nonlinear nature of swash flows prevented theoreticians and modellers from accurately predicting its kinematics, numerous laboratory and field studies provided a means for establishing wave runup empirical formula, which are now commonly used in engineering practice. However, most of the field studies only concerned gently sloping sand beaches, and run-up formula have barely been validated against field observations in steep rocky environments, where data are still very sparse. This study presents water elevation data acquired with pressure sensors solidly fixed to the bedrock of Banneg Island, France, during winter 2013/14. Offshore wave parameters and water levels were also measured during this winter and recorded storm events with Hm0 up to 9 m in spring tide conditions, which caused flooding and boulder transports across the island. A methodology to infer R2% from the local pressure measurements was implemented. The 4-month time-series of run-up measurements at the top and at the bottom of subvertical cliff profiles (with slopes ranging from 20% to 30%) were compared with offshore wave parameters and revealed a strong dependence of R2% to the Hunt parameter (ξ.Hm0). Several period parameters based on the spectral moments were also tested to compute ξ and the best correlations were obtained with T(m0,-1). Finally, the exceptional run-up values (up to 8 m) measured at the cliff top during the major storms allowed to test the validity of existing run-up formula for a range of conditions that exceeds any other observations, to

Past and future changes in extreme sea levels and waves

Digital Repository Service at National Institute of Oceanography (India)

Lawe, J.A.; Woodworth, P.L.; Knutson, T.; McDonald, R.E.; Mclnnes, K.L.; Woth, K.; Von Storch, H.; Wolf, J.; Swail, V.; Bernier, N.B.; Gulev, S.; Horsburgh, K.J.; Unnikrishnan, A.S.; Hunter, J.R.; Weisse, R.

of Extreme Sea Level 11.3.1 An Introduction to Storms Both mid-latitude and tropical storms are associated with extremes of sea level. Storm surges are generated by low atmospheric pressure and intense winds over the ocean. The latter also cause high wave... timescales, extremes and mean-sea-level change are both major factors in determining coastal evolution including the development of coastal ecosystems. It will be seen below that, although it is difficult to determine how mean sea level has changed...

Adobe Creative Suite 4 Bible

CERN Document Server

Padova, Ted

2009-01-01

As one of the few books to cover integration and workflow issues between Photoshop, Illustrator, InDesign, GoLive, Acrobat, and Version Cue, this comprehensive reference is the one book that Creative Suite users need; Two well-known and respected authors cover topics such as developing consistent color-managed workflows, moving files among the Creative Suite applications, preparing files for print or the Web, repurposing documents, and using the Creative Suite with Microsoft Office documents; More than 1,200 pages are packed with valuable advice and techniques for tackling common everyday issu

The Role of Porosity in the Formation of Coastal Boulder Deposits - Hurricane Versus Tsunami

Science.gov (United States)

Spiske, M.; Boeroecz, Z.; Bahlburg, H.

2007-12-01

Coastal boulder deposits are a consequence of high-energy wave impacts, such as storms, hurricanes or tsunami. Distinguishing parameters between storm, hurricane and tsunami origin are distance of a deposit from the coast, boulder weight and inferred wave height. Formulas to calculate minimum wave heights of both storm and tsunami waves depend on accurate determination of boulder dimensions and lithology from the respective deposits. At present however, boulder porosity appears to be commonly neglected, leading to significant errors in determined bulk density, especially when boulders consist of reef or coral limestone. This limits precise calculations of wave heights and hampers a clear distinction between storm, hurricane and tsunami origin. Our study uses Archimedean and optical 3D-profilometry measurements for the determination of porosities and bulk densities of reef and coral limestone boulders from the islands of Aruba, Bonaire and Curaçao (ABC Islands, Netherlands Antilles). Due to the high porosities (up to 68 %) of the enclosed coral species, the weights of the reef rock boulders are as low as 20 % of previously calculated values. Hence minimum calculated heights both for tsunami and hurricane waves are smaller than previously proposed. We show that hurricane action appears to be the likely depositional mechanism for boulders on the ABC Islands, since 1) our calculations result in tsunami wave heights which do not permit the overtopping of coastal platforms on the ABC Islands, 2) boulder fields lie on the windward (eastern) sides of the islands, 3) recent hurricanes transported boulders up to 35 m3 and 4) the scarcity of tsunami events affecting the coasts of the ABC Islands compared to frequent impacts of tropical storms and hurricanes.

Boulder accumulations related to extreme wave events on the eastern coast of Malta

Science.gov (United States)

Biolchi, Sara; Furlani, Stefano; Antonioli, Fabrizio; Baldassini, Niccoló; Causon Deguara, Joanna; Devoto, Stefano; Di Stefano, Agata; Evans, Julian; Gambin, Timothy; Gauci, Ritienne; Mastronuzzi, Giuseppe; Monaco, Carmelo; Scicchitano, Giovanni

2016-03-01

The accumulation of large boulders related to waves generated by either tsunamis or extreme storm events have been observed in different areas of the Mediterranean Sea. Along the eastern low-lying rocky coasts of Malta, five sites with large boulder deposits have been investigated, measured and mapped. These boulders have been detached and moved from the nearshore and the lowest parts of the coast by sea wave action. In the Sicily-Malta channel, heavy storms are common and originate from the NE and NW winds. Conversely, few tsunamis have been recorded in historical documents to have reached the Maltese archipelago. We present a multi-disciplinary study, which aims to define the characteristics of these boulder accumulations, in order to assess the coastal geo-hazard implications triggered by the sheer ability of extreme waves to detach and move large rocky blocks inland. The wave heights required to transport 77 coastal boulders were calculated using various hydrodynamic equations. Particular attention was given to the quantification of the input parameters required in the workings of these equations, such as size, density and distance from the coast. In addition, accelerator mass spectrometry (AMS) 14C ages were determined from selected samples of marine organisms encrusted on some of the coastal boulders. The combination of the results obtained both by the hydrodynamic equations, which provided values comparable with those observed and measured during the storms, and radiocarbon dating suggests that the majority of the boulders have been detached and moved by intense storm waves. These boulders testify to the existence of a real hazard for the coasts of Malta, i.e. that of very high storm waves, which, during exceptional storms, are able to detach large blocks of volumes exceeding 10 m3 from the coastal edge and the nearshore bottom, and also to transport them inland. Nevertheless, the occurrence of one or more tsunami events cannot be ruled out, since

Experimental and Numerical Studies on Wave Breaking Characteristics over a Fringing Reef under Monochromatic Wave Conditions

Directory of Open Access Journals (Sweden)

Jong-In Lee

2014-01-01

Full Text Available Fringing reefs play an important role in protecting the coastal area by inducing wave breaking and wave energy dissipation. However, modeling of wave transformation and energy dissipation on this topography is still difficult due to the unique structure. In the present study, two-dimensional laboratory experiments were conducted to investigate the cross-shore variations of wave transformation, setup, and breaking phenomena over an idealized fringing reef with the 1/40 reef slope and to verify the Boussinesq model under monochromatic wave conditions. One-layer and two-layer model configurations of the Boussinesq model were used to figure out the model capability. Both models predicted well (r2>0.8 the cross-shore variation of the wave heights, crests, troughs, and setups when the nonlinearity is not too high (A0/h0<0.07 in this study. However, as the wave nonlinearity and steepness increase, the one-layer model showed problems in prediction and stability due to the error on the vertical profile of fluid velocity. The results in this study revealed that one-layer model is not suitable in the highly nonlinear wave condition over a fringing reef bathymetry. This data set can contribute to the numerical model verification.

Seasonal Variability of Wind Sea and Swell Waves Climate along the Canary Current: The Local Wind Effect

Directory of Open Access Journals (Sweden)

Alvaro Semedo

2018-03-01

Full Text Available A climatology of wind sea and swell waves along the Canary eastern boundary current area, from west Iberia to Mauritania, is presented. The study is based on the European Centre for Medium-Range Weather Forecasts (ECMWF reanalysis ERA-Interim. The wind regime along the Canary Current, along west Iberia and north-west Africa, varies significantly from winter to summer. High summer wind speeds generate high wind sea waves, particularly along the coasts of Morocco and Western Sahara. Lower winter wind speeds, along with stronger extratropical storms crossing the North Atlantic sub-basin up north lead to a predominance of swell waves in the area during from December to February. In summer, the coast parallel wind interacts with the coastal headlands, increasing the wind speed and the locally generated waves. The spatial patterns of the wind sea or swell regional wave fields are shown to be different from the open ocean, due to coastal geometry, fetch dimensions, and island sheltering.

Abnormal storm waves in the winter East/Japan Sea: generation process and hindcasting using an atmosphere-wind wave modelling system

Directory of Open Access Journals (Sweden)

H. S. Lee

2010-04-01

Full Text Available Abnormal storm waves cause coastal disasters along the coasts of Korean Peninsula and Japan in the East/Japan Sea (EJS in winter, arising due to developed low pressures during the East Asia winter monsoon. The generation of these abnormal storm waves during rough sea states were studied and hindcast using an atmosphere-wave coupled modelling system. Wind waves and swell due to developed low pressures were found to be the main components of abnormal storm waves. The meteorological conditions that generate these waves are classified into three patterns based on past literature that describes historical events as well as on numerical modelling. In hindcasting the abnormal storm waves, a bogussing scheme originally designed to simulate a tropical storm in a mesoscale meteorological model was introduced into the modelling system to enhance the resolution of developed low pressures. The modelling results with a bogussing scheme showed improvements in terms of resolved low pressure, surface wind field, and wave characteristics obtained with the wind field as an input.

Improved airline-type supplied-air plastic suit

International Nuclear Information System (INIS)

Jolley, L. Jr.; Zippler, D.B.; Cofer, C.H.; Harper, J.A.

1978-06-01

Two piece supplied-air plastic suits are used extensively at the Savannah River Plant for personnel protection against inhalation of airborne plutonium and tritium. Worker comfort and noise level problems gave impetus to development of an improved suit and aid distribution system. The resulting plastic suit and development work are discussed. The plastic suit unit cost is less than $20, the hearing zone noise level is less than 75 dBA, protection factors exceed 10,000, and user comfort is approved. This suit is expected to meet performance requirements for unrestricted use

Coastal circulation and sediment dynamics in Maunalua Bay, Oahu, Hawaii, measurements of waves, currents, temperature, salinity, and turbidity; November 2008-February 2009

Science.gov (United States)

Storlazzi, Curt D.; Presto, M. Katherine; Logan, Joshua B.; Field, Michael E.

2010-01-01

High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Maunalua Bay, southern Oahu, Hawaii, during the 2008-2009 winter to better understand coastal circulation, water-column properties, and sediment dynamics during a range of conditions (trade winds, kona storms, relaxation of trade winds, and south swells). A series of bottom-mounted instrument packages were deployed in water depths of 20 m or less to collect long-term, high-resolution measurements of waves, currents, water levels, temperature, salinity, and turbidity. These data were supplemented with a series of profiles through the water column to characterize the vertical and spatial variability in water-column properties within the bay. These measurements support the ongoing process studies being done as part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program's Pacific Coral Reef Project; the ultimate goal of these studies is to better understand the transport mechanisms of sediment, larvae, pollutants, and other particles in coral reef settings. Project Objectives The objective of this study was to understand the temporal variations in currents, waves, tides, temperature, salinity and turbidity within a coral-lined embayment that receives periodic discharges of freshwater and sediment from multiple terrestrial sources in the Maunalua Bay. Instrument packages were deployed for a three-month period during the 2008-2009 winter and a series of vertical profiles were collected in November 2008, and again in February 2009, to characterize water-column properties within the bay. Measurements of flow and water-column properties in Maunalua Bay provided insight into the potential fate of terrestrial sediment, nutrient, or contaminant delivered to the marine environment and coral larval transport within the embayment. Such data are useful for providing baseline information for future watershed decisions and for establishing guidelines for

An assessment of two decades of contaminant monitoring in the Nation’s Coastal Zone.

OpenAIRE

Kimbrough, K. L.; Lauenstein, G. G.; Christensen, J. D.; Apeti, D. A.

2008-01-01

Executive Summary: Information found in this report covers the years 1986 through 2005. Mussel Watch began monitoring a suite of trace metals and organic contaminants such as DDT, PCBs and PAHs. Through time additional chemicals were added, and today approximately 140 analytes are monitored. The Mussel Watch Program is the longest running estuarine and coastal pollutant monitoring effort conducted in the United States that is national in scope each year. Hundreds of scientific journal art...

Atlantic Coast Hindcast, Shallow-Water, Significant Wave Information.

Science.gov (United States)

1983-01-01

AULICS LAB N E JENSEN JAN 83 UNCLASSIFIED W SRF 21NL mEEohhohhhmhEE EhhhEmmhhmhEEEE 1111 .0= 128 llI Ir111-1 11111.6 MICROCOPY RESOLUTION TEST CHART...six data products: 1. Geographical variation in the wave climate :, 2. Twenty-year percent occurrence tables: (Continued) DD EUnclassified SECUmTY...PAOCleWff DO& MIew0O I]1 Preface In late 1976, a study to produce a wave climate for U. S. coastal waters was initiated at the U. S. Army Engineer

Z-1 Prototype Space Suit Testing Summary

Science.gov (United States)

Ross, Amy

2013-01-01

The Advanced Space Suit team of the NASA-Johnson Space Center performed a series of test with the Z-1 prototype space suit in 2012. This paper discusses, at a summary level, the tests performed and results from those tests. The purpose of the tests were two-fold: 1) characterize the suit performance so that the data could be used in the downselection of components for the Z-2 Space Suit and 2) develop interfaces with the suitport and exploration vehicles through pressurized suit evaluations. Tests performed included isolated and functional range of motion data capture, Z-1 waist and hip testing, joint torque testing, CO2 washout testing, fit checks and subject familiarizations, an exploration vehicle aft deck and suitport controls interface evaluation, delta pressure suitport tests including pressurized suit don and doff, and gross mobility and suitport ingress and egress demonstrations in reduced gravity. Lessons learned specific to the Z-1 prototype and to suit testing techniques will be presented.

Hybrid Enhanced Epidermal SpaceSuit Design Approaches

Science.gov (United States)

Jessup, Joseph M.

A Space suit that does not rely on gas pressurization is a multi-faceted problem that requires major stability controls to be incorporated during design and construction. The concept of Hybrid Epidermal Enhancement space suit integrates evolved human anthropomorphic and physiological adaptations into its functionality, using commercially available bio-medical technologies to address shortcomings of conventional gas pressure suits, and the impracticalities of MCP suits. The prototype HEE Space Suit explored integumentary homeostasis, thermal control and mobility using advanced bio-medical materials technology and construction concepts. The goal was a space suit that functions as an enhanced, multi-functional bio-mimic of the human epidermal layer that works in attunement with the wearer rather than as a separate system. In addressing human physiological requirements for design and construction of the HEE suit, testing regimes were devised and integrated into the prototype which was then subject to a series of detailed tests using both anatomical reproduction methods and human subject.

Synoptic conditions and hazards in coastal zone

Science.gov (United States)

Surkova, Galina; Arkhipkin, Victor; Kislov, Alexsandr

2013-04-01

This work is an approach to the methodology of prediction of hazards in the coastal zone. For the past 60 years, according to the observations and reanalysis, meteorological conditions are rough in connection with the storm waves and strong winds resulting in catastrophic damage in the coastal zone of the Black and Caspian Seas. Forecast of similar events is taken from CMIP3 modeled for the future climate 2046-2065 by general global atmosphere and ocean circulation model MPI-ECHAM5. The research was conducted for the three types of calendar data samples: 1) storm wave and surge from observations (1948-2012), 2) storm simulations with wave height of 4 m and more (1948-2010), and 3) prognostic climate scenarios for 2046-2065. In the first sample especially rare events were chosen, accompanied by a large damage in the coastal zone. Second sample of cases was derived from modeling of SWAN (Simulating WAves Nearshore). The third sample was derived from projections of cases from group 1 in the MPI-ECHAM5 climate forecasts for 2046-2065. For each sample the data of large-scale fields of surface pressure, height 500 hPa isobaric surfaces, 700gPa (Reanalysis NCEP / NCAR) was analyzed. On the basis of statistical techniques (decomposition of fields in the natural orthogonal functions (EOF) and cluster analysis) the synoptic situations associated with these events were classified. Centroids of pressure fields for dominated cases show that there are two basic types of synoptic situations in case of storm waves for the Black Sea. In the first case main role play the Mediterranean cyclones located in the east of the Mediterranean Sea, they are spread over the Black Sea, and often form a local center of low pressure. Their movement is blocked by the high pressure over the European Russia and Eastern Europe. If the center of the cyclone is over Asia and the southern part of the Black Sea, the weather is dominated by the north-eastern, eastern, south-easterly winds. In some cases

Experimental modelling of wave amplification over irregular bathymetry for investigations of boulder transport by extreme wave events.

Science.gov (United States)

O'Boyle, Louise; Whittaker, Trevor; Cox, Ronadh; Elsäßer, Björn

2017-04-01

During the winter of 2013-2014 the west coast of Ireland was exposed to 6 storms over a period of 8 weeks with wind speeds equating to hurricane categories 3 and 4. During this period, the largest significant wave height recorded at the Marine Institute M6 wave buoy, approximately 300km from the site, was 13.6m (on 26th January 2014). However, this may not be the largest sea state of that winter, because the buoy stopped logging on 30th January and therefore failed to capture the full winter period. During the February 12th 2014 "Darwin" storm, the Kinsale Energy Gas Platform off Ireland's south coast measured a wave height of 25 m, which remains the highest wave measured off Ireland's coasts[1]. Following these storms, significant dislocation and transportation of boulders and megagravel was observed on the Aran Islands, Co. Galway at elevations of up to 25m above the high water mark and distances up to 220 m inland including numerous clasts with masses >50t, and at least one megagravel block weighing >500t [2]. Clast movements of this magnitude would not have been predicted from the measured wave heights. This highlights a significant gap in our understanding of the relationships between storms and the coastal environment: how are storm waves amplified and modified by interactions with bathymetry? To gain further understanding of wave amplification, especially over steep and irregular bathymetry, we have designed Froude-scaled wave tank experiments using the 3D coastal wave basin facility at Queen's University Belfast. The basin is 18m long by 16m wide with wave generation by means of a 12m wide bank of 24 top hinged, force feedback, sector carrier wave paddles at one end. The basin is equipped with gravel beaches to dissipate wave energy on the remaining three sides, capable of absorbing up to 99% of the incident wave energy, to prevent unwanted reflections. Representative bathymetry for the Aran Islands is modelled in the basin based on a high resolution

Wind turbine clutter mitigation in coastal UHF radar.

Science.gov (United States)

Yang, Jing; Pan, Chao; Wang, Caijun; Jiang, Dapeng; Wen, Biyang

2014-01-01

Coastal UHF radar provides a unique capability to measure the sea surface dynamic parameters and detect small moving targets, by exploiting the low energy loss of electromagnetic waves propagating along the salty and good conducting ocean surface. It could compensate the blind zone of HF surface wave radar at close range and reach further distance than microwave radars. However, its performance is susceptible to wind turbines which are usually installed on the shore. The size of a wind turbine is much larger than the wavelength of radio waves at UHF band, which results in large radar cross section. Furthermore, the rotation of blades adds time-varying Doppler frequency to the clutter and makes the suppression difficult. This paper proposes a mitigation method which is based on the specific periodicity of wind turbine clutter and performed mainly in the time-frequency domain. Field experimental data of a newly developed UHF radar are used to verify this method, and the results prove its effectiveness.

Vertical propagation of baroclinic Kelvin waves along the west coast ...

Indian Academy of Sciences (India)

Second, baroclinic Kelvin waves generated in the Bay of Bengal at periods shorter than about 120 ... significant energy remains trapped to the Indian west coast. .... ary condition, enables us to isolate the response of the West India Coastal ...

Analysis of Tide and Offshore Storm-Induced Water Table Fluctuations for Structural Characterization of a Coastal Island Aquifer

Science.gov (United States)

Trglavcnik, Victoria; Morrow, Dean; Weber, Kela P.; Li, Ling; Robinson, Clare E.

2018-04-01

Analysis of water table fluctuations can provide important insight into the hydraulic properties and structure of a coastal aquifer system including the connectivity between the aquifer and ocean. This study presents an improved approach for characterizing a permeable heterogeneous coastal aquifer system through analysis of the propagation of the tidal signal, as well as offshore storm pulse signals through a coastal aquifer. Offshore storms produce high wave activity, but are not necessarily linked to significant onshore precipitation. In this study, we focused on offshore storm events during which no onshore precipitation occurred. Extensive groundwater level data collected on a sand barrier island (Sable Island, NS, Canada) show nonuniform discontinuous propagation of the tide and offshore storm pulse signals through the aquifer with isolated inland areas showing enhanced response to both oceanic forcing signals. Propagation analysis suggests that isolated inland water table fluctuations may be caused by localized leakage from a confined aquifer that is connected to the ocean offshore but within the wave setup zone. Two-dimensional groundwater flow simulations were conducted to test the leaky confined-unconfined aquifer conceptualization and to identify the effect of key parameters on tidal signal propagation in leaky confined-unconfined coastal aquifers. This study illustrates that analysis of offshore storm signal propagation, in addition to tidal signal propagation, provides a valuable and low resource approach for large-scale characterization of permeable heterogeneous coastal aquifers. Such an approach is needed for the effective management of coastal environments where water resources are threatened by human activities and the changing climate.