The Experts below are selected from a list of 61749 Experts worldwide ranked by ideXlab platform
Philip Jonathan - One of the best experts on this subject based on the ideXlab platform.
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On the distribution of Wave Height in shallow water
Coastal Engineering, 2016Co-Authors: David Randell, Marios Christou, Kevin Ewans, Philip JonathanAbstract:Abstract The statistical distribution of the Height of sea Waves in deep water has been modelled using the Rayleigh (Longuet-Higgins, 1952) and Weibull distributions (Forristall, 1978). Depth-induced Wave breaking leading to restriction on the ratio of Wave Height to water depth requires new parameterisations of these or other distributional forms for shallow water. Glukhovskiy (1966) proposed a Weibull parameterisation accommodating depth-limited breaking, modified by van Vledder (1991). Battjes and Groenendijk (2000) suggested a two-part Weibull–Weibull distribution. Here we propose a two-part Weibull-generalised Pareto model for Wave Height in shallow water, parameterised empirically in terms of sea state parameters (significant Wave Height, H S , local Wave-number, k L , and water depth, d ), using data from both laboratory and field measurements from 4 offshore locations. We are particularly concerned that the model can be applied usefully in a straightforward manner; given three pre-specified universal parameters, the model further requires values for sea state significant Wave Height and Wave number, and water depth so that it can be applied. The model has continuous probability density, smooth cumulative distribution function, incorporates the Miche upper limit for Wave Heights (Miche, 1944) and adopts H S as the transition Wave Height from Weibull body to generalised Pareto tail forms. Accordingly, the model is effectively a new form for the breaking Wave Height distribution. The estimated model provides good predictive performance on laboratory and field data.
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Uncertainties in Extreme Wave Height Estimates for Hurricane-Dominated Regions
Journal of Offshore Mechanics and Arctic Engineering, 2007Co-Authors: Philip Jonathan, Kevin EwansAbstract:Inherent uncertainties in estimation of extreme Wave Heights in hurricane-dominated regions are explored using data from the GOMOS Gulf of Mexico hindcast for 1900-2005. In particular, the effect of combining correlated values from a neighborhood of 72 grid locations on extreme Wave Height estimation is quantified. We show that, based on small data samples, extreme Wave Heights are underestimated and site averaging usually improves estimates. We present a bootstrapping approach to evaluate uncertainty in extreme Wave Height estimates. We also argue in favor of modeling supplementary indicators for extreme Wave characteristics, such as a high percentile (95%) of the distribution of 100-year significant Wave Height, in addition to its most probable value, especially for environments where the distribution of 100-year significant Wave Height is strongly skewed.
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Uncertainties in Extreme Wave Height Estimates for Hurricane Dominated Regions
Volume 3: Safety and Reliability; Materials Technology; Douglas Faulkner Symposium on Reliability and Ultimate Strength of Marine Structures, 2006Co-Authors: Philip Jonathan, Kevin EwansAbstract:The inherent uncertainties in estimation of extreme Wave Heights in hurricane-dominated regions are explored using data from the GOMOS Gulf of Mexico hindcast for the period 1900–2005. In particular, the effect of combining correlated values from a neighbourhood of 72 grid locations on extreme Wave Height estimation is quantified. We show that, based on small data samples, extreme Wave Heights can be underestimated and that site averaging usually improves estimates. We present a bootstrapping approach to evaluate the uncertainty in extreme Wave Height estimates. We also argue in favour of modelling supplementary indicators for extreme Wave characteristics, such as a high percentile (95%) of the distribution of 100-year significant Wave Height, in addition to its most probable value, especially for environments where the distribution of 100-year significant Wave Height may be skewed.Copyright © 2006 by ASME
Kevin Ewans - One of the best experts on this subject based on the ideXlab platform.
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On the distribution of Wave Height in shallow water
Coastal Engineering, 2016Co-Authors: David Randell, Marios Christou, Kevin Ewans, Philip JonathanAbstract:Abstract The statistical distribution of the Height of sea Waves in deep water has been modelled using the Rayleigh (Longuet-Higgins, 1952) and Weibull distributions (Forristall, 1978). Depth-induced Wave breaking leading to restriction on the ratio of Wave Height to water depth requires new parameterisations of these or other distributional forms for shallow water. Glukhovskiy (1966) proposed a Weibull parameterisation accommodating depth-limited breaking, modified by van Vledder (1991). Battjes and Groenendijk (2000) suggested a two-part Weibull–Weibull distribution. Here we propose a two-part Weibull-generalised Pareto model for Wave Height in shallow water, parameterised empirically in terms of sea state parameters (significant Wave Height, H S , local Wave-number, k L , and water depth, d ), using data from both laboratory and field measurements from 4 offshore locations. We are particularly concerned that the model can be applied usefully in a straightforward manner; given three pre-specified universal parameters, the model further requires values for sea state significant Wave Height and Wave number, and water depth so that it can be applied. The model has continuous probability density, smooth cumulative distribution function, incorporates the Miche upper limit for Wave Heights (Miche, 1944) and adopts H S as the transition Wave Height from Weibull body to generalised Pareto tail forms. Accordingly, the model is effectively a new form for the breaking Wave Height distribution. The estimated model provides good predictive performance on laboratory and field data.
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Uncertainties in Extreme Wave Height Estimates for Hurricane-Dominated Regions
Journal of Offshore Mechanics and Arctic Engineering, 2007Co-Authors: Philip Jonathan, Kevin EwansAbstract:Inherent uncertainties in estimation of extreme Wave Heights in hurricane-dominated regions are explored using data from the GOMOS Gulf of Mexico hindcast for 1900-2005. In particular, the effect of combining correlated values from a neighborhood of 72 grid locations on extreme Wave Height estimation is quantified. We show that, based on small data samples, extreme Wave Heights are underestimated and site averaging usually improves estimates. We present a bootstrapping approach to evaluate uncertainty in extreme Wave Height estimates. We also argue in favor of modeling supplementary indicators for extreme Wave characteristics, such as a high percentile (95%) of the distribution of 100-year significant Wave Height, in addition to its most probable value, especially for environments where the distribution of 100-year significant Wave Height is strongly skewed.
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Uncertainties in Extreme Wave Height Estimates for Hurricane Dominated Regions
Volume 3: Safety and Reliability; Materials Technology; Douglas Faulkner Symposium on Reliability and Ultimate Strength of Marine Structures, 2006Co-Authors: Philip Jonathan, Kevin EwansAbstract:The inherent uncertainties in estimation of extreme Wave Heights in hurricane-dominated regions are explored using data from the GOMOS Gulf of Mexico hindcast for the period 1900–2005. In particular, the effect of combining correlated values from a neighbourhood of 72 grid locations on extreme Wave Height estimation is quantified. We show that, based on small data samples, extreme Wave Heights can be underestimated and that site averaging usually improves estimates. We present a bootstrapping approach to evaluate the uncertainty in extreme Wave Height estimates. We also argue in favour of modelling supplementary indicators for extreme Wave characteristics, such as a high percentile (95%) of the distribution of 100-year significant Wave Height, in addition to its most probable value, especially for environments where the distribution of 100-year significant Wave Height may be skewed.Copyright © 2006 by ASME
Inigo J. Losada - One of the best experts on this subject based on the ideXlab platform.
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global extreme Wave Height variability based on satellite data
Geophysical Research Letters, 2011Co-Authors: Cristina Izaguirre, Fernando J. Méndez, Melisa Menendez, Inigo J. LosadaAbstract:[1] The spatial and temporal variability of the extreme significant Wave Height (SWH) in the ocean is presented. The study has been performed using a highly reliable dataset from several satellite altimeter missions, which provide a good worldwide coverage for the period 1992 onwards. A non-stationary extreme value analysis, which models seasonality and interannual variations, has been applied to characterize the extreme SWH. The interannual variability is explained through variations in the atmosphere and ocean systems, represented by different climate indices, allowing a quantitative contribution of the climate-related patterns. Results demonstrate the strong relationship between the interannual variability of extreme SWH and different ocean and atmosphere variations. A contribution of the AO and NAO indices in the North Atlantic ocean (e.g., every positive unit of the AO explains up to 70 cm of extreme Wave Height south of Iceland), the NINO3 in the Pacific (every negative unit of NINO3 explains up to 60 cm of extreme Wave Height in the Drake Passage), the SAM in the Southern ocean and the DMI in the Indian ocean reveal these climate patterns as the most relevant in the interannual extreme Wave climate.
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Transformation model of Wave Height distribution on planar beaches
Coastal Engineering, 2004Co-Authors: Fernando J. Méndez, Inigo J. Losada, Raúl MedinaAbstract:A new probability density function (pdf) for the transformation of depth-limited Wave Height distributions is presented. Assuming the bore approach for modeling the energy dissipation in the inner surf zone to be valid, an analytical expression for the transformation of Wave Height distribution including shoaling and breaking on a planar beach is obtained. The resulting expression for the pdf is formulated with a single function and only one shape parameter, which is calibrated as a function of the local root-mean-square (rms) Wave Height-to-water depth ratio and the local Iribarren number. The transformed pdf is able to reproduce the shape of field and laboratory measured Wave Height histograms and the sharp change in the shape of the Wave Height distribution in depth-limited breaking conditions for low exceedance probability. Results show that the theory is appropriate to represent Wave Height distribution transformation over shallow foreshores or in the surf zone. Alternatively, a combination of the new model with existing state-of-the-art Wave energy propagation models allows the complete definition of the Wave Height distribution transformation on a planar beach.
Fernando J. Méndez - One of the best experts on this subject based on the ideXlab platform.
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global extreme Wave Height variability based on satellite data
Geophysical Research Letters, 2011Co-Authors: Cristina Izaguirre, Fernando J. Méndez, Melisa Menendez, Inigo J. LosadaAbstract:[1] The spatial and temporal variability of the extreme significant Wave Height (SWH) in the ocean is presented. The study has been performed using a highly reliable dataset from several satellite altimeter missions, which provide a good worldwide coverage for the period 1992 onwards. A non-stationary extreme value analysis, which models seasonality and interannual variations, has been applied to characterize the extreme SWH. The interannual variability is explained through variations in the atmosphere and ocean systems, represented by different climate indices, allowing a quantitative contribution of the climate-related patterns. Results demonstrate the strong relationship between the interannual variability of extreme SWH and different ocean and atmosphere variations. A contribution of the AO and NAO indices in the North Atlantic ocean (e.g., every positive unit of the AO explains up to 70 cm of extreme Wave Height south of Iceland), the NINO3 in the Pacific (every negative unit of NINO3 explains up to 60 cm of extreme Wave Height in the Drake Passage), the SAM in the Southern ocean and the DMI in the Indian ocean reveal these climate patterns as the most relevant in the interannual extreme Wave climate.
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Transformation model of Wave Height distribution on planar beaches
Coastal Engineering, 2004Co-Authors: Fernando J. Méndez, Inigo J. Losada, Raúl MedinaAbstract:A new probability density function (pdf) for the transformation of depth-limited Wave Height distributions is presented. Assuming the bore approach for modeling the energy dissipation in the inner surf zone to be valid, an analytical expression for the transformation of Wave Height distribution including shoaling and breaking on a planar beach is obtained. The resulting expression for the pdf is formulated with a single function and only one shape parameter, which is calibrated as a function of the local root-mean-square (rms) Wave Height-to-water depth ratio and the local Iribarren number. The transformed pdf is able to reproduce the shape of field and laboratory measured Wave Height histograms and the sharp change in the shape of the Wave Height distribution in depth-limited breaking conditions for low exceedance probability. Results show that the theory is appropriate to represent Wave Height distribution transformation over shallow foreshores or in the surf zone. Alternatively, a combination of the new model with existing state-of-the-art Wave energy propagation models allows the complete definition of the Wave Height distribution transformation on a planar beach.
Han Shu-zong - One of the best experts on this subject based on the ideXlab platform.
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Studies of Distribution and Variabilities of Wave Height Entropy in the Atlantic Ocean
Coastal Engineering, 2003Co-Authors: Han Shu-zongAbstract:The Topex/Poseidon satellite altimeter significant Wave Height (SWH) data from October 1992 to December 1998 were used to study the Wave Height entropy in the Atlantic Ocean, and the statistical analysis of spatial distributions and temporal variabilites of Wave Height entropy in the Atlantic Ocean was made. It is shown from the analysis results that the Wave Height entropy in the Atlantic Ocean shows a saddle distribution with low value in the equatorial area and high value in the northern and southern sea areas and obvious seasonal variabilities, and is consistent with the distributions and variabilities of mean SWH, wind speed and atmospheric activities in the Atlantic Ocean.
