Offshore wave climate, Perth (Western Australia), 1994 - 96

1999 ◽  
Vol 50 (2) ◽  
pp. 95 ◽  
Author(s):  
A. J. Lemm ◽  
B. J. Hegge ◽  
G. Masselink
Keyword(s):  
Western Australia ◽  
Annual Variation ◽  
Wave Climate ◽  
Sea Breezes ◽  
Wave Data ◽  
Mean Wave Period ◽  
The Mean ◽  
Wave Conditions ◽  
Offshore Wave ◽  
Low Amplitude

The offshore wave climate of Perth (Western Australia) was analysed by using 2.5 years of non-directional 20-min wave data collected from March 1994 to August 1996. The mean wave conditions are characterized by a significant wave height (Hs) of 2.0 m and a spectral mean wave period (Tm) of 8.8 s. However, considerable annual variation in the wave conditions is experienced because of a distinct seasonality in the regional wind regime. During summer, daily sea breezes generate moderate seas (ambient Hs 1 to 2 m; Tm <8 s). During winter, frequent storms associated with mid-latitude depressions generate heavy seas and swell (ambient Hs 1.5 to 2.5 m; Tm >8 s). A low-amplitude background swell (Hs ~0.5 m), generated distantly in the Indian and Southern Oceans, is present all year round. Analysis of extreme wave conditions (Hs >4 m) indicates that, on average, 30 storms are experienced annually, and the storms are most frequent and intense during July. Estimates of extreme Hs, based on all available offshore wave data (12 years, 1975–96), for 1- and 100-year return periods, are 6.7 m and 9.8 m, respectively.

Nearshore Wave Modelling in a Norwegian Fjord

2020 ◽  
Author(s):  
Christos N. Stefanakos ◽  
Birgitte R. Furevik ◽  
Øyvind Knutsen ◽  
Konstantinos Christakos
Keyword(s):  
Wave Model ◽  
Wave Climate ◽  
Wave Modelling ◽  
Good Accordance ◽  
Norwegian Fjord ◽  
Wave Conditions ◽  
Wave Models ◽  
Model Setup ◽  
Offshore Wave

Abstract Phase averaged wave models is a good supplement of in situ measurements for the study of wave climate in a specific location. In spite of having been tested in smoothly varying coastal areas, they haven’t previously been systematically validated in complex topography (coastline and bathymetry) such as Norwegian fjords, due to lack of measurements. However, in planning for large fjord crossings, the Norwegian Public Roads Administration have launched a number of buoys which allow for validation of model setup. In the present work, nearshore wave conditions in the area of Sulafjord, central Norway, are investigated as derived from numerical modelling with several different setups, and are compared against in situ buoy measurements with good accordance. The analysis is carried out by transferring offshore wave conditions to the nearshore area by successive applications of the well-known third-generation wave model SWAN. As input has been used a very detailed bathymetry of the area, and time series of wind and wave parameters derived from ERA5 and NORA10 datasets. Various scenarios reconstructing the wave input spectra have been considered.

WORLDWAVES: High Quality Coastal and Offshore Wave Data Within Minutes for Any Global Site

2003 ◽  
Author(s):  
Stephen F. Barstow ◽  
Gunnar Mo̸rk ◽  
Lasse Lo̸nseth ◽  
Peter Schjo̸lberg ◽  
Ulla Machado ◽  
...  
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Fish Farming ◽  
Series Data ◽  
High Quality ◽  
Wave Statistics ◽  
Wave Data ◽  
Wave Conditions ◽  
Offshore Wave

There has been a growing demand for reliable information on the wave conditions, in particular at coastal sites, as a result of increased utilisation of the coastal zone to a multitude of activities including various shoreline developments related to transportation, tourism, fish farming and recently wind and wave energy industries. This trend is likely to continue. Reliable data is also needed with respect to the management and protection of these often fragile environments. Many of those concerned with these wave-impacted environments still use antiquated data sources, usually from offshore waters as, in the absence of long term wave data collected at the site of interest, the calculation of reliable wave statistics at a coastal site is a complicated, time consuming and expensive business, requiring various data sets to be assembled. WORLDWAVES simplifies and speeds up the modelling of wave conditions in coastal waters by integrating the following under a single Matlab toolbox: High quality long-term wave data offshore all global coasts; worldwide bathymetric and coastline data; SWAN and backward raytracing wave models; sophisticated offshore and nearshore wave statistics toolboxes with tabular and graphical presentations, including a facility to export ASCII time series data at offshore or inshore locations; a geographic module with easy zooming to any area worldwide; tools to set up model grids and display and edit bathymetry and coastline; a facility for the import of user offshore data and export of inshore time series data. In this paper we describe the design and implementation of WorldWaves including the fusion of satellite, model and buoy wave and wind data in the global offshore database and the new raytracing model.

Transferring Wave Conditions From Offshore to Nearshore: The Case of Nordfold

2014 ◽  
Author(s):  
Christos N. Stefanakos ◽  
Grim Eidnes
Keyword(s):  
Wave Model ◽  
Wave Climate ◽  
Third Generation ◽  
Satellite Altimeter ◽  
Northern Norway ◽  
Area Of Interest ◽  
Wave Parameters ◽  
Long Time ◽  
Wave Conditions ◽  
Offshore Wave

In the present work, an analysis of the wave climate in Nord-fold area in the northern Norway has been performed. The analysis was carried out by transferring offshore wave conditions to the nearshore area of interest by successive applications of the well-known third-generation wave model SWAN. The area presents a particular interest, since it has a very deep and complex bathymetry near the coast and a very complicated coastline. Analysis has been carried out using a very detailed bathymetry of the area provided by the Norwegian Mapping Authority. Moreover, as input, five year long time series of directional spectra of offshore wave parameters have been used, after being calibrated using the best available satellite altimeter dataset.

SOME FEATURES OF THE EQUILIBRIUM COASTAL PROFILE FOR DIFFERENT INITIAL BED SLOPES BASED ON MODELLING STUDY

2017 ◽  
Author(s):  
Dmitry Korzinin ◽  
Dmitry Korzinin ◽  
Igor Leontiev ◽  
Igor Leontiev
Keyword(s):  
Time Scales ◽  
Wave Impact ◽  
Grain Sizes ◽  
Equilibrium Profiles ◽  
Equilibrium Profile ◽  
The Mean ◽  
Wave Conditions ◽  
Bed Slope ◽  
Coastal Profile ◽  
Modelling Study

Modelling study of the equilibrium profiles formed on sandy coasts of different bed slopes and grain sizes under the various wave conditions was realized by using the CROSS-P and Xbeach morphodynamic models. A special criterion taking into account a total volume of bed deformations per one hour was suggested to determine the conditions of profile stabilization. For both models the time scales of equilibrium profile formation were found to be the same. However, the deformation magnitudes differed significantly. Bed deformations were computed on the whole profile length over the 200-hours duration of wave impact. It was concluded that both models predict a trend of the bed slope toward a stable value. CROSS-P model shows the widening of accumulative terrace during the profile evolution. The mean slope of the equilibrium profile was found to depend on the initial bed slope.

scholarly journals Future Changes in Wave Conditions at the German Baltic Sea Coast Based on a Hybrid Approach Using an Ensemble of Regional Climate Change Projections

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 167
Author(s):  
Norman Dreier ◽  
Edgar Nehlsen ◽  
Peter Fröhle ◽  
Diana Rechid ◽  
Laurens M. Bouwer ◽  
...  
Keyword(s):  
21St Century ◽  
Wind Wave ◽  
Regional Climate ◽  
Hybrid Approach ◽  
Wave Modelling ◽  
Long Term Changes ◽  
Mean Wave Period ◽  
Wave Conditions ◽  
Sea Coast

In this study, the projected future long-term changes of the local wave conditions at the German Baltic Sea coast over the course of the 21st century are analyzed and assessed with special focus on model agreement, statistical significance and ranges/spread of the results. An ensemble of new regional climate model (RCM) simulations with the RCM REMO for three RCP forcing scenarios was used as input data. The outstanding feature of the simulations is that the data are available with a high horizontal resolution and at hourly timesteps which is a high temporal resolution and beneficial for the wind–wave modelling. A new data interface between RCM output data and wind–wave modelling has been developed. Suitable spatial aggregation methods of the RCM wind data have been tested and used to generate input for the calculation of waves at quasi deep-water conditions and at a mean water level with a hybrid approach that enables the fast compilation of future long-term time series of significant wave height, mean wave period and direction for an ensemble of RCM data. Changes of the average wind and wave conditions have been found, with a majority of the changes occurring for the RCP8.5 forcing scenario and at the end of the 21st century. At westerly wind-exposed locations mainly increasing values of the wind speed, significant wave height and mean wave period have been noted. In contrast, at easterly wind-exposed locations, decreasing values are predominant. Regarding the changes of the mean wind and wave directions, westerly directions becoming more frequent. Additional research is needed regarding the long-term changes of extreme wave events, e.g., the choice of a best-fit extreme value distribution function and the spatial aggregation method of the wind data.

scholarly journals Future behavior of wind wave extremes due to climate change

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hector Lobeto ◽  
Melisa Menendez ◽  
Iñigo J. Losada
Keyword(s):  
Climate Change ◽  
Wave Climate ◽  
Climate Change Scenarios ◽  
Return Periods ◽  
Extreme Wave ◽  
Future Behavior ◽  
Climate Simulations ◽  
Wave Conditions ◽  
Ne Pacific ◽  
Change In Mean

AbstractExtreme waves will undergo changes in the future when exposed to different climate change scenarios. These changes are evaluated through the analysis of significant wave height (Hs) return values and are also compared with annual mean Hs projections. Hourly time series are analyzed through a seven-member ensemble of wave climate simulations and changes are estimated in Hs for return periods from 5 to 100 years by the end of the century under RCP4.5 and RCP8.5 scenarios. Despite the underlying uncertainty that characterizes extremes, we obtain robust changes in extreme Hs over more than approximately 25% of the ocean surface. The results obtained conclude that increases cover wider areas and are larger in magnitude than decreases for higher return periods. The Southern Ocean is the region where the most robust increase in extreme Hs is projected, showing local increases of over 2 m regardless the analyzed return period under RCP8.5 scenario. On the contrary, the tropical north Pacific shows the most robust decrease in extreme Hs, with local decreases of over 1.5 m. Relevant divergences are found in several ocean regions between the projected behavior of mean and extreme wave conditions. For example, an increase in Hs return values and a decrease in annual mean Hs is found in the SE Indian, NW Atlantic and NE Pacific. Therefore, an extrapolation of the expected change in mean wave conditions to extremes in regions presenting such divergences should be adopted with caution, since it may lead to misinterpretation when used for the design of marine structures or in the evaluation of coastal flooding and erosion.

scholarly journals Regional Downscaling of Copernicus ERA5 Wave Data for Coastal Engineering Activities and Operational Coastal Services

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 859
Author(s):  
Giorgio Bellotti ◽  
Leopoldo Franco ◽  
Claudia Cecioni
Keyword(s):  
Time Series ◽  
National Level ◽  
Wave Model ◽  
Wave Climate ◽  
Tyrrhenian Sea ◽  
Computational Domain ◽  
Multiple Wave ◽  
Space Resolution ◽  
Wave Data ◽  
Fundamental Information

Hindcasted wind and wave data, available on a coarse resolution global grid (Copernicus ERA5 dataset), are downscaled by means of the numerical model SWAN (simulating waves in the nearshore) to produce time series of wave conditions at a high resolution along the Italian coasts in the central Tyrrhenian Sea. In order to achieve the proper spatial resolution along the coast, the finite element version of the model is used. Wave data time series at the ERA5 grid are used to specify boundary conditions for the wave model at the offshore sides of the computational domain. The wind field is fed to the model to account for local wave generation. The modeled sea states are compared against the multiple wave records available in the area, in order to calibrate and validate the model. The model results are in quite good agreement with direct measurements, both in terms of wave climate and wave extremes. The results show that using the present modeling chain, it is possible to build a reliable nearshore wave parameters database with high space resolution. Such a database, once prepared for coastal areas, possibly at the national level, can be of high value for many engineering activities related to coastal area management, and can be useful to provide fundamental information for the development of operational coastal services.

scholarly journals Characteristics and treatment of geriatric patients in an osteopathic neuromusculoskeletal medicine (ONMM) clinic

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alicia A. King ◽  
Jayme Cox ◽  
Shalini Bhatia ◽  
Karen T. Snider
Keyword(s):  
Treatment Response ◽  
Geriatric Patients ◽  
Private Insurance ◽  
Epidemiological Data ◽  
Health Impact ◽  
Adjunctive Treatment ◽  
Clinical Encounters ◽  
Thoracolumbar Region ◽  
The Mean ◽  
Low Amplitude

Abstract Context Osteopathic manipulative medicine (OMM) is an adjunctive treatment approach available to geriatric patients, but few studies provide details about presenting conditions, treatments, and response to osteopathic manipulative treatment (OMT) in that patient population. Objectives To provide descriptive data on the presentation and management of geriatric patients receiving OMT at an outpatient osteopathic neuromusculoskeletal medicine (ONMM) clinic. Methods Data were retrospectively collected from electronic health records (EHR) at a single outpatient clinic for clinical encounters with patients over 60 years of age who were treated with OMT between July 1, 2016, and June 30, 2019. Records were reviewed for demographic information, insurance type, presenting concerns, assessments, regions treated, OMT techniques used, and treatment response. Results There were 9,155 total clinical encounters with 1,238 unique patients found during the study period. More women than men were represented for overall encounters (6,910 [75.4%] vs. 2,254 [24.6%]) and unique patients (850 [68.7%] vs. 388 [31.3%]; both p<0.001). The mean (standard deviation, SD) number of encounters per patient per year was 4.5 (4.0) and increased with increasing age by decade (p<0.001). Medicare was the most common primary insurance (7,246 [79.2%]), with private insurance the most common secondary insurance (8,440 [92.2%]). The total number of presenting concerns was 12,020, and back concerns were most common (6,406 [53.3%]). The total number of assessments was 18,290; most were neuromusculoskeletal (17,271 [94.5%]) and in the thoracolumbar region (7,109 [38.9%]). The mean (SD) number of somatic dysfunction assessments per encounter was 5 (1.7); the thoracic region was the most documented and treated (7,263 [15.8%]). With up to 19 technique types per encounter, the total number of OMT techniques documented across all encounters was 43,862, and muscle energy (7,203 [16.4%]) was the most documented. The use of high-velocity, low-amplitude (HVLA) declined as age increased (p<0.001). The overall treatment response was documented in 7,316 (79.9%) encounters, and most indicated improvement (7,290 [99.6%]). Conclusions Our results showed that geriatric patients receiving OMT at our clinic were predominately presenting for neuromusculoskeletal concerns associated with back, neck, and extremity conditions, consistent with national epidemiological data for this population. The most common OMT techniques were also consistent with those used nationally by osteopathic medical students and practicing physicians. Future longitudinal studies are needed to determine the length of time improvement persists and the overall health impact experienced by geriatric patients receiving OMT.

scholarly journals Optimizing the Power Take Off of a Wave Energy Converter With Regard to the Wave Climate

2005 ◽  
Vol 128 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Gaelle Duclos ◽  
Aurelien Babarit ◽  
Alain H. Clément
Keyword(s):  
Wave Energy ◽  
Simple Wave ◽  
Wave Climate ◽  
Wave Energy Converter ◽  
Optimal Parameters ◽  
Energy Converter ◽  
Wave Energy Converters ◽  
Classical Wave ◽  
Project Site ◽  
Wave Conditions

Considered as a source of renewable energy, wave is a resource featuring high variability at all time scales. Furthermore wave climate also changes significantly from place to place. Wave energy converters are very often tuned to suit the more frequent significant wave period at the project site. In this paper we show that optimizing the device necessitates accounting for all possible wave conditions weighted by their annual occurrence frequency, as generally given by the classical wave climate scatter diagrams. A generic and very simple wave energy converter is considered here. It is shown how the optimal parameters can be different considering whether all wave conditions are accounted for or not, whether the device is controlled or not, whether the productive motion is limited or not. We also show how they depend on the area where the device is to be deployed, by applying the same method to three sites with very different wave climate.

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