Distribution of Wave Height Maxima in Storm Sea States

The effect of the coefficient of kurtosis, as a measure of third order nonlinearity, on the distribution of wave height maxima has been investigated. Measurements of the surface elevation during a storm at the North Alwyn platform in the North Sea have been used. The mean number of waves in the series is around 100. The maximum wave statistics have been compared with nonlinear theoretical distributions. It was found that the empirical probability densities of the maximum wave heights describe qualitatively the shift of the distribution modes toward higher values. The tendency for the peak of distribution to diminish with an increase in the coefficient of kurtosis up to 0.6 is also clearly seen. However, the empirical peak remains higher than the theoretically predicted one. The exceedance probability of the maximum wave heights was also estimated from the data and was compared with the theory. For the highest coefficients of kurtosis, estimated at nearly 0.6, the theoretical distribution approximates very well the empirical data. For lower coefficients of kurtosis, the theory tends to overestimate the exceedance probability of the maximum wave heights.

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Distribution of Wave Height Maxima in Storm Sea States

Volume 2: Structures, Safety and Reliability ◽

10.1115/omae2008-58038 ◽

2008 ◽

Cited By ~ 1

Author(s):

Zhivelina Cherneva ◽

C. Guedes Soares ◽

Petya Petrova

Keyword(s):

Wave Height ◽

Exceedance Probability ◽

Third Order ◽

Wave Statistics ◽

The North ◽

Probability Densities ◽

Distribution Mode ◽

Wave Heights ◽

The North Sea ◽

The Mean

The effect of the coefficient of kurtosis as a measure of the nonlinearity of third order on the distribution of the wave height maxima has been investigated. Measurements of the surface elevation during a storm at the North Alwyn platform in the North Sea have been used. The mean number of waves in the series is around 100. The maximum wave statistics have been compared with nonlinear theoretical distributions. It was found that the empirical probability densities of the maximum wave heights describe qualitatively the shift of the distribution mode towards higher values. The tendency for the peak of distribution to diminish with increase of the coefficient of kurtosis up to 0.6 is also clearly seen. However, the empirical peak remains higher than the theoretically predicted one. Exceedance probability of the maximum wave heights was also estimated from the data and was compared with the theory. For the highest coefficients of kurtosis nearly 0.6 the theoretical distribution approximates very well the empirical data. For lower coefficients of kurtosis the theory tends to overestimate the exceedance probability of the maximum wave heights.

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Influence of the Third Order Nonlinearity on the Distribution of Wave Height Maxima in an Offshore Basin

Volume 2: Structures, Safety and Reliability ◽

10.1115/omae2008-58049 ◽

2008 ◽

Cited By ~ 6

Author(s):

Petya G. Petrova ◽

C. Guedes Soares ◽

Zhivelina I. Cherneva

Keyword(s):

Wave Height ◽

Third Order ◽

Data Set ◽

Wave Statistics ◽

The Third ◽

Surface Displacements ◽

Wave Heights ◽

Wave Maker ◽

Third Order Nonlinearity ◽

Range Of Values

The effect of the coefficient of kurtosis, λ40, on the distribution of wave height maxima has been investigated. The data set used consists of water surface displacements in irregular deep water unidirectional wave fields generated in an offshore basin and defined by the JONSWAP spectrum. The full-scale records are of almost 3h17min duration. The measurements have been performed at ten equidistant gauges along the basin, which permits to follow the changes in wave statistics away from the wave-generator. Subsequently, the records have been split into series of different length, corresponding to N = 100, 200 and 300 waves, and the probability density functions and the exceedance probabilities of the maximum wave heights have been constructed conditional on λ40. They have been compared with the modified Edgeworth-Rayleigh model of Mori and Janssen [1] applied to the maximum wave heights. The theoretical expressions are formulated as a simple function of the coefficient of kurtosis and the number of waves in the sample. The coefficient of kurtosis, reflecting the third order nonlinearity, is found to increase with the distance from the wave-maker. The considered theoretical density curves describe only qualitatively the shift of the empirical mode towards higher values. The tendency of the peak of the distribution to diminish with increase of λ40 has been observed. However, the most probable wave height remains underestimated by the theory for all classes of λ40, regardless of the length of the time series. Finally, the probability that a certain normalized height level Hmax/Hs will be exceeded increases with the increase of λ40, as being theoretically predicted, although it is overestimated by the theory in the lower range of values of λ40 and underestimated over the higher range of values of λ40.

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Searching for Factors that Limit Observed Extreme Maximum Wave Height Distributions in the North Sea

Extreme Ocean Waves ◽

10.1007/978-1-4020-8314-3_7 ◽

2008 ◽

pp. 127-138 ◽

Cited By ~ 2

Author(s):

Gerrit Burgers ◽

Frits Koek ◽

Hans de Vries ◽

Martin Stam

Keyword(s):

Wave Height ◽

North Sea ◽

Maximum Wave Height ◽

The North ◽

The North Sea

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FUTURE CHANGES IN SPECTRAL WAVE CLIMATE AROUND JAPAN UNDER GLOBAL WARMING

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.waves.10 ◽

2020 ◽

pp. 10

Author(s):

Tomoya Shimura ◽

Nobuhito Mori

Keyword(s):

Global Warming ◽

Wave Height ◽

Climate Change Impacts ◽

Wave Climate ◽

Structure Design ◽

Future Projections ◽

Wave Statistics ◽

The Mean ◽

Ocean Wave Climate ◽

East Asia Region

Future projections of ocean wave climate related with global warming has been conducted for the assessment of climate change impacts on coastal disaster, beach morphology, and coastal structure design. In this study, we conduct the high-resolution future wave climate projection in the East Asia region and detail analysis on wave climate based on two-dimensional wave spectra in addition to conventional wave statistics (significant wave height). Future changes in wave height, period and direction can be discussed consistently owing to analysis on the mean wave spectra.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/FEYPZFRr5SQ

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Comparison of Bivariate Models of the Distribution of Significant Wave Height and Peak Wave Period

Volume 2: Structures, Safety and Reliability; Petroleum Technology Symposium ◽

10.1115/omae2007-29740 ◽

2007 ◽

Cited By ~ 4

Author(s):

Catarina S. Soares ◽

C. Guedes Soares

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Bivariate Normal Distribution ◽

Wave Period ◽

Peak Period ◽

Data Set ◽

Significant Wave ◽

The North ◽

Bivariate Models ◽

The North Sea

This paper presents the results of a comparison of the fit of three bivariate models to a set of 14 years of significant wave height and peak wave period data from the North Sea. One of the methods defines the joint distribution from a marginal distribution of significant wave height and a set of distributions of peak period conditional on significant wave height. Other method applies the Plackett model to the data and the third one applies the Box-Cox transformation to the data in order to make it approximately normal and then fits a bivariate normal distribution to the transformed data set. It is shown that all methods provide a good fit but each one have its own strengths and weaknesses, being the choice dependent on the data available and applications in mind.

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North Atlantic storm driving of extreme wave heights in the North Sea

Journal of Geophysical Research Oceans ◽

10.1002/2016jc012501 ◽

2017 ◽

Vol 122 (4) ◽

pp. 3253-3268 ◽

Cited By ~ 9

Author(s):

R. J. Bell ◽

S. L. Gray ◽

O. P. Jones

Keyword(s):

North Sea ◽

North Atlantic ◽

Extreme Wave ◽

The North ◽

Wave Heights ◽

The North Sea

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Quantitative Evaluation of Ship Operational Effect in Actually Encountered Sea States

Volume 3: Structures, Safety, and Reliability ◽

10.1115/omae2019-95121 ◽

2019 ◽

Author(s):

Rei Miratsu ◽

Tsutomu Fukui ◽

Toshiyuki Matsumoto ◽

Tingyao Zhu

Keyword(s):

Exceedance Probability ◽

Natural Phenomena ◽

Following Seas ◽

Significant Wave ◽

The North ◽

Hull Structure ◽

Wave Heights ◽

Design Loads ◽

Significant Wave Heights ◽

Oil Tankers

Abstract Since ships are being operated under consideration of the safety for lives and properties, economical reasons and so on, the sea states in natural phenomena and those actually encountered by ships are thought to be different, the latter has some effects of human operational factors (called as “ship operational effect”). Evaluating the ship operational effect in detail is important to consider rational wave design loads for hull structure strength. The purpose of this study is to evaluate the ship operational effect in actually encountered sea states quantitatively. As the first report, comparison was made between IACS Rec.34 (a kind of the observed sea states in natural phenomena) and forecasted sea states corresponding to AIS data of ships (a kind of the sea states data actually encountered by ships) on the North Atlantic. Comparisons among the encountered significant wave heights by merchant ships such as bulk carriers, oil tankers and container ships and those specified in IACS Rec. 34 were carried out. Furthermore, the wave headings regarding the encountered waves were investigated. Finally, the relationships between encountered significant wave heights and ship speeds were derived to confirm the ship operational effect. It was confirmed from the results that the actually encountered wave heights were smaller than those in IACS Rec. 34, through comparing the exceedance probability of the significant wave heights for each type of ships and IACS Rec. 34. The exceedance probability in the encountered beam seas is relatively lower compared with those in the encountered head and following seas. The results also show that ship speeds decrease when the encountered wave heights become larger.

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The North Sea Andrea storm and numerical simulations

Natural Hazards and Earth System Science ◽

10.5194/nhess-14-1407-2014 ◽

2014 ◽

Vol 14 (6) ◽

pp. 1407-1415 ◽

Cited By ~ 18

Author(s):

E. M. Bitner-Gregersen ◽

L. Fernandez ◽

J. M. Lefèvre ◽

J. Monbaliu ◽

A. Toffoli

Keyword(s):

Numerical Simulations ◽

North Sea ◽

Rogue Wave ◽

Grid Point ◽

Wave Model ◽

Wave Statistics ◽

The North ◽

Nonlinear Phase ◽

Spectral Wave Model ◽

The North Sea

Abstract. A coupling of a spectral wave model with a nonlinear phase-resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8–9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform 1 January 1995. Hindcast data of the storm at the nearest grid point to the Ekofisk field are here applied as input to calculate the evolution of random realizations of the sea surface and its statistical properties. Numerical simulations are carried out using the Euler equations with a higher-order spectral method (HOSM). Results are compared with some characteristics of the Andrea wave record measured by the down-looking lasers at Ekofisk.

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Towards a vulnerability assessment of the UK and northern European coasts: the role of regional climate variability

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2005.1571 ◽

2005 ◽

Vol 363 (1831) ◽

pp. 1329-1358 ◽

Cited By ~ 55

Author(s):

M.N Tsimplis ◽

D.K Woolf ◽

T.J Osborn ◽

S Wakelin ◽

J Wolf ◽

...

Keyword(s):

Sea Level ◽

Wave Height ◽

North Sea ◽

Positive Response ◽

Sea Level Change ◽

Empirical Relationships ◽

Level Change ◽

The North ◽

The North Sea ◽

The Uk

Within the framework of a Tyndall Centre research project, sea level and wave changes around the UK and in the North Sea have been analysed. This paper integrates the results of this project. Many aspects of the contribution of the North Atlantic Oscillation (NAO) to sea level and wave height have been resolved. The NAO is a major forcing parameter for sea-level variability. Strong positive response to increasing NAO was observed in the shallow parts of the North Sea, while slightly negative response was found in the southwest part of the UK. The cause of the strong positive response is mainly the increased westerly winds. The NAO increase during the last decades has affected both the mean sea level and the extreme sea levels in the North Sea. The derived spatial distribution of the NAO-related variability of sea level allows the development of scenarios for future sea level and wave height in the region. Because the response of sea level to the NAO is found to be variable in time across all frequency bands, there is some inherent uncertainty in the use of the empirical relationships to develop scenarios of future sea level. Nevertheless, as it remains uncertain whether the multi-decadal NAO variability is related to climate change, the use of the empirical relationships in developing scenarios is justified. The resulting scenarios demonstrate: (i) that the use of regional estimates of sea level increase the projected range of sea-level change by 50% and (ii) that the contribution of the NAO to winter sea-level variability increases the range of uncertainty by a further 10–20 cm. On the assumption that the general circulation models have some skill in simulating the future NAO change, then the NAO contribution to sea-level change around the UK is expected to be very small (<4 cm) by 2080. Wave heights are also sensitive to the NAO changes, especially in the western coasts of the UK. Under the same scenarios for future NAO changes, the projected significant wave-height changes in the northeast Atlantic will exceed 0.4 m. In addition, wave-direction changes of around 20° per unit NAO index have been documented for one location. Such changes raise the possibility of consequential alteration of coastal erosion.

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