scholarly journals The Expected Shoreline Effect of a Marine Energy Farm Operating Close to Sardinia Island

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2303 ◽  
Author(s):  
Onea ◽  
Rusu
Keyword(s):  
Wave Model ◽  
Breaking Waves ◽  
General Tendency ◽  
Target Area ◽  
Significant Wave ◽  
Marine Energy ◽  
Waves And Currents ◽  
Wave Heights ◽  
Wave Farm ◽  
The Impact

Coastal areas are defined by numerous opportunities and threats. Among them we can mention emerging renewable projects and on the other hand coastal erosion. In the present work, the impact of a generic wind–wave farm on the nearshore waves and currents in the vicinity of the Porto Ferro inlet (northwest Sardinia) was assessed. Using a reanalysis wave dataset that covers a 40-year interval (1979–2018), the most relevant wave characteristics in the target area were identified. These can reach during winter a maximum value of 7.35 m for the significant wave height. As a next step, considering a modeling system that combines a wave model (simulating waves nearshore (SWAN)) and a surf model, the coastal impact of some generic marine energy farms defined by a transmission coefficient of 25% was assessed. According to the results corresponding to the reference sites and lines defined close to the shore, it becomes obvious that there is a clear attenuation in terms of significant wave heights, and as regards current velocities, although the general tendency for them to decrease, there are, however, some situations when the values of the nearshore current velocities can also decrease. Finally, we can mention that the presence of a marine energy farm seems to be beneficial for the beach stability in this particular coastal environment, and in some cases the transformation of the breaking waves from plunging to spilling is noticed.

Wave climate change in the Gulf of Bothnia

2021 ◽  
Author(s):  
Jan-Victor Björkqvist ◽  
Jani Särkkä ◽  
Hedi Kanarik ◽  
Laura Tuomi
Keyword(s):  
Climate Change ◽  
Wave Model ◽  
Wave Climate ◽  
Atmospheric Forcing ◽  
Simulation Data ◽  
Significant Wave ◽  
Gulf Of Bothnia ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Projected Changes

<p>Wave climate change in the Gulf of Bothnia in 2030–2059 was investigated using regional wave climate projections. For the simulations we used wave model WAM. As the atmospheric forcing for the wave model we had three global climate scenarios (HADGEM2-ES, MPI-ESM, EC-EARTH) downscaled with RCA4-NEMO regional model. The ice concentration for the wave model was obtained from NEMO ocean model simulations using the same atmospheric forcing. We used both RCP4.5 and RCP8.5 greenhouse gas scenarios. The spatial resolution of the simulation data was 1.8 km, enabling detailed analyses of the wave properties near the coast. From the simulation data we calculated statistics and return levels of significant wave heights using extreme value analysis, and assessed the projected changes in the wave climate in the Gulf of Bothnia. The projected increase in the significant wave heights is mainly due to the decreasing ice cover, especially in the Bothnian Bay. Projected changes in the most prevalent wind direction impacts the spatial pattern of the wave heights in the Bothnian Sea.</p>

Assessing Climate Change in the North Atlantic Wave Regimes

2020 ◽  
Author(s):  
M. Bernardino ◽  
M. Gonçalves ◽  
C. Guedes Soares
Keyword(s):  
System Integration ◽  
Wave Model ◽  
Offshore Structures ◽  
Future Climate ◽  
Wave Direction ◽  
Peak Period ◽  
Significant Wave ◽  
The North ◽  
Wave Heights ◽  
Mean Wave Period

Abstract An improved understanding of the present and future marine climatology is necessary for numerous activities, such as operation of offshore structures, optimization of ship routes and the evaluation of wave energy resources. To produce global wave information, the WW3 wave model was forced with wind and ice-cover data from an RCP8.5 EC-Earth system integration for two 30-year time slices. The first covering the periods from 1980 to 2009 represents the present climate and the second, covering the periods from 2070–2099, represents the climate in the end of the 21st century. Descriptive statistics of wind and wave parameters are obtained for different 30-year time slices. Regarding wind, magnitude and direction will be used. For wave, significant wave height (of total sea and swell), mean wave period, peak period, mean wave direction and energy will be investigated. Changes from present to future climate are evaluated, regarding both mean and extreme events. Maps of the theses statistics are presented. The long-term monthly joint distribution of significant wave heights and peak periods is generated. Changes from present to future climate are assessed, comparing the statistics between time slices.

Assessing the Impact of the Grid-Connected Pacific Marine Energy Center Wave Farm

2015 ◽  
Vol 3 (4) ◽  
pp. 1011-1020 ◽  
Author(s):  
Sara Armstrong ◽  
Eduardo Cotilla-Sanchez ◽  
Thibaut Kovaltchouk
Keyword(s):  
Marine Energy ◽  
Energy Center ◽  
Wave Farm ◽  
The Impact

Climatology, Variability and Extrema of Ocean Waves: The Web-Based KNMI/ERA-40 Wave Atlas

2006 ◽  
Author(s):  
Andreas Sterl ◽  
Sofia Caires
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Wave Model ◽  
Ocean Waves ◽  
Wave Period ◽  
Web Based ◽  
Significant Wave ◽  
Wave Parameters ◽  
Wave Heights ◽  
The Web

The European Centre for Medium Range Weather Forecasts (ECMWF) has recently finished ERA-40, a reanalysis covering the period September 1957 to August 2002. One of the products of ERA-40 consists of 6-hourly global fields of wave parameters like significant wave height and wave period. These data have been generated with the Centre’s WAM wave model. From these results the authors have derived climatologies of important wave parameters, including significant wave height, mean wave period, and extreme significant wave heights. Particular emphasis is on the variability of these parameters, both in space and time. Besides for scientists studying climate change, these results are also important for engineers who have to design maritime constructions. This paper describes the ERA-40 data and gives an overview of the results derived. The results are available on a global 1.5° × 1.5° grid. They are accessible from the web-based KNMI/ERA-40 Wave Atlas at http://www.knmi.nl/waveatlas.

Equivalent Storm Model for Long-Term Statistics of Sea Storms Off Norway

2018 ◽  
Author(s):  
Valentina Laface ◽  
Anne Karin Magnusson ◽  
Elzbieta M. Bitner-Gregersen ◽  
Magnar Reistad ◽  
Alessandra Romolo ◽  
...  
Keyword(s):  
Spectral Characteristics ◽  
Wave Model ◽  
Significant Wave ◽  
Storm Intensity ◽  
Statistical Equivalence ◽  
Wave Heights ◽  
Model Time Series ◽  
Two Parameters ◽  
Storm Model

The paper deals with long-term analysis of ocean storms off Norway. Sixty years of wave model time series are considered for the analysis. The input data provide spectral characteristics of both wind and swell seas. The availability of global and partitioned significant wave heights enables the possibility of investigating how swell seas influence the storm shape in terms of growing and decay stages and on how this aspect affects the long-term estimates. The analysis is conducted by means of equivalent storm approach which consists of substituting the sequence of actual storms at a given site with a sequence of equivalent storms whose shape is fixed (such as triangular, power or exponential) and then calculating return periods of storm with given characteristics via analytical solutions derived on the basis of storm shape assumed. This is possible due to statistical equivalence between actual and equivalent storms which in turn leads to the equality of wave risk between actual and equivalent storm sequences at a given site. The equivalent storm associated with an actual one is defined by means of two parameters, related to the storm intensity and duration. The equivalent storm intensity is given by the maximum significant wave height in the actual storm history, while the duration is determined via an iterative procedure. In this paper the exponential shape is considered which is referred as equivalent exponential (EES) storm model. Some aspects related with the storm shape and its influence on return values estimate via EES model are investigated. Further, a sensitivity analysis of EES model to the storm threshold is proposed.

scholarly journals Statistical trend analysis and extreme distribution of significant wave height from 1958 to 1999 – an application to the Italian Seas

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 525-538 ◽  
Author(s):  
G. Martucci ◽  
S. Carniel ◽  
J. Chiggiato ◽  
M. Sclavo ◽  
P. Lionello ◽  
...  
Keyword(s):  
Extreme Values ◽  
Wave Model ◽  
Northern Adriatic Sea ◽  
Sea State ◽  
Northern Adriatic ◽  
Significant Wave ◽  
Peak Over Threshold ◽  
Wave Heights ◽  
Italian Coasts ◽  
A Site

Abstract. The study is a statistical analysis of sea states timeseries derived using the wave model WAM forced by the ERA-40 dataset in selected areas near the Italian coasts. For the period 1 January 1958 to 31 December 1999 the analysis yields: (i) the existence of a negative trend in the annual- and winter-averaged sea state heights; (ii) the existence of a turning-point in late 80's in the annual-averaged trend of sea state heights at a site in the Northern Adriatic Sea; (iii) the overall absence of a significant trend in the annual-averaged mean durations of sea states over thresholds; (iv) the assessment of the extreme values on a time-scale of thousand years. The analysis uses two methods to obtain samples of extremes from the independent sea states: the r-largest annual maxima and the peak-over-threshold. The two methods show statistical differences in retrieving the return values and more generally in describing the significant wave field. The r-largest annual maxima method provides more reliable predictions of the extreme values especially for small return periods (<100 years). Finally, the study statistically proves the existence of decadal negative trends in the significant wave heights and by this it conveys useful information on the wave climatology of the Italian seas during the second half of the 20th century.

Evaluation of hydromorphological conditions of Grand Popo Beach using two unique video cameras

2021 ◽  
pp. 1-36
Author(s):  
KoueKam K. Arnaud ◽  
Frédéric Bonou ◽  
Zacharie Sohou ◽  
Donatus B. Angnuureng ◽  
Rafael Almar
Keyword(s):  
Video Camera ◽  
Spatial And Temporal Patterns ◽  
Peak Period ◽  
Video Cameras ◽  
Significant Wave ◽  
Wave Heights ◽  
Wave Energy Flux ◽  
Significant Wave Heights ◽  
Erosion And Accretion ◽  
The Impact

Beaches are characterized by complex spatial and temporal patterns of erosion and accretion subjected to significant wave and tide influence. The objective of this study is to estimate the evolution of hydromorphodynamic conditions on the shoreline of Grand Popo Beach observed from two adjacent video camera setups. We have analyzed the impact of the variability of hydrodynamic parameters on the beach evolution and evaluated the variabilities of the hydrodynamic and morphologic parameters from the two cameras. Despite the nonhomogeneity within the cameras’ intrinsic properties, the various results obtained from the two systems indicate that wave conditions (peak period and significant height) from the cameras have the same variations, whereas the shoreline variations of camera A are not the same as those of camera B. It is generally during the summer that the Grand Popo Beach is exposed to an agitated environment with strong observed values of significant wave heights and wave energy flux, undoubtedly resulting in significant sediment transport along the beach leading a shoreline retreat. The results indicate that in 3.5 years the shoreline of Grand Popo Beach has retreated by 10 m.

Does Wave Height Matter for Effective Surface Dispersant Application?

2014 ◽  
Vol 2014 (1) ◽  
pp. 747-761
Author(s):  
Charles Huber ◽  
Alexis Steen ◽  
Brian Parscal
Keyword(s):  
Crude Oil ◽  
Wave Height ◽  
Breaking Waves ◽  
Time Of Application ◽  
Tier Ii ◽  
Increased Risk ◽  
Wave Heights ◽  
Wave Conditions ◽  
In The Beginning ◽  
The Impact

ABSTRACT The Deepwater Horizon (DWH) crude oil release provided an occasion to test the delivery and effectiveness of dispersants on surface oil slicks to reduce the potential exposure of shoreline habitats and marine wildlife to spilled oil. In the beginning of the DWH response, there was concern that the calm sea conditions did not provide sufficient wave energy for dispersant action to occur. At one point a minimum 3-foot wave height requirement for dispersant application was set in an attempt to ensure sufficient mixing energy for dispersant activation was present at the time of application. Because of the ability of aerial dispersant application to rapidly treat large spatial areas and quantities of oil, there was a contrasting concern that a 3-foot (0.91 m) minimum wave height requirement was overly restricting dispersant operations; thereby, increasing environmental exposures. To evaluate the wave heights that effectively dispersed the Macondo crude oil, the SMART (Special Monitoring of Applied Response Technologies) Tier II/III monitoring data of dispersant applications performed in low wave conditions, i.e., &lt; 3 ft (0.91m) were analyzed. Of the 27 SMART Tier II/III monitoring operations conducted in significant wave heights (SWHs) of &lt; 3 feet (0.91 m), 21 were reported as “effective,” 4 were reported as “inconclusive,” and only 2 were reported as “no observed dispersion.” These results demonstrate dispersants were effective in low wave conditions and on weathered Macondo crude oil as a function of distance from the spill site. The paper then estimates the impact that setting wave height restrictions has on dispersant operations showing that a &gt; 3 feet requirement could reduce surface dispersant operational days by as much as 67%. With the dispersant assets available during the DWH response, this could have resulted in leaving up to 700,000 gallons of oil per day on the water,a thus exposing shoreline habitat and offshore wildlife to an increased risk of oiling. The paper concludes thatWave height should not be used as a criterion for approving or conducting surface dispersant application operations, becausewave heights as low as 0.5–1.0 feet were effective in immediately dispersing fresh and weathered Macondo crude oil, and may be sufficient to disperse other oils, andResearch on dispersant application in calm sea conditions has shown that oils would rapidly and almost totally disperse when exposed to breaking waves after being left on a calm water surface for prolonged periods. The paper recommends that government and response organizations should review and consider revising their guidance and operational procedures for dispersant application approval in light of the analysis presented in this paper.

scholarly journals Determination of Significant Wave Heights Using Damping Coefficients of Attenuated GNSS SNR Data from Static and Kinematic Observations

2019 ◽  
Vol 11 (4) ◽  
pp. 409 ◽  
Author(s):  
Ole Roggenbuck ◽  
Jörg Reinking ◽  
Tomke Lambertus
Keyword(s):  
Signal To Noise Ratio ◽  
Wave Model ◽  
Significant Wave ◽  
Sea Surface Roughness ◽  
Wave Heights ◽  
Gnss Reflectometry ◽  
Significant Wave Heights ◽  
Using Data ◽  
Ocean Remote Sensing

Currently, GNSS reflectometry based on the signal-to-noise ratio (SNR) has become an established tool in ocean remote sensing. Here, the distance between an antenna and the water surface is measured by analyzing the oscillation of the SNR observation. Due to the antenna gain pattern, this oscillation is more pronounced for satellite signals coming from low elevation angles. Additionally, the sea surface roughness is related to the attenuation of the SNR oscillation. Hence, the significant wave height (SWH) can be estimated by analyzing the SNR signal. In this work, a method is presented with which the SWH can be calculated from the attenuation’s damping coefficient of the SNR observations measured with surface-based receivers. The method’s usability is demonstrated using data from a static antenna operated in the German Bight and with data from a ship-based antenna. The estimated SWH values were validated against numerical wave model data. For both experiments, a high correlation was found.

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