Exploring Distributional Properties of the Maximum Wave Height in a Sea State

2018 ◽  
Author(s):  
Germán Rodríguez ◽  
Carlos Guedes Soares ◽  
José Carlos Nieto Borge
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Population Distribution ◽  
Empirical Distribution ◽  
Theoretical Models ◽  
Statistical Parameters ◽  
Sea State ◽  
Maximum Wave Height ◽  
Long Duration ◽  
Individual Wave

Location, dispersion, and asymmetry variability of the probability distribution of the maximum wave height from a set of N individual wave heights are examined in terms of the spectral peakedness and the duration of the sea states through the use of robust statistical parameters. The capability of various empirical and theoretical models to reproduce the observed features is also explored. The study is based on the analysis of numerically simulated Gaussian wave records with given target spectra to fulfill the long duration and stationarity jointly required conditions, seldom found in nature. Results indicate a clear dependence of the probability distribution structure and location on the record length and the spectral narrowness. Furthermore, it is observed that theoretical models based on the statistical independence of individual waves in a sea state and the knowledge of its population distribution assumptions are not able to characterize the structure and variations induced by these factors on the empirical distribution. However, the observed features can be reproduced by a simple empirical model depending on the sample quartiles.

Maximum Wave Height Distribution in a Sea State: Effects of Record Length and Spectral Peakedness

2004 ◽  
Author(s):  
Germa´n Rodri´guez ◽  
Mercedes Pacheco ◽  
Carlos Guedes Soares
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Spectral Shape ◽  
Height Distribution ◽  
Sea State ◽  
Maximum Wave Height ◽  
Record Length ◽  
State Duration ◽  
Long Duration ◽  
Wave Height Distribution

The probability distribution of the maximum wave height in a sea state is examined in terms of the spectral peakedness and the sea state duration. The study is based on the analysis of numerically simulated gaussian wave records with given target spectra to fulfill the long duration and stationarity jointly required conditions, seldom found in nature. Results indicate a clear dependence of the probability distribution structure and location on the record length and the spectral shape.

Maximum Wave Height Distribution in a Sea State: Effects of Record Length and Spectral Peakedness

2005 ◽  
Vol 127 (4) ◽  
pp. 340-344 ◽  
Author(s):  
Germán Rodríguez ◽  
Mercedes Pacheco ◽  
C. Guedes Soares
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Spectral Shape ◽  
Height Distribution ◽  
Sea State ◽  
Maximum Wave Height ◽  
Record Length ◽  
State Duration ◽  
Long Duration ◽  
Wave Height Distribution

The probability distribution of the maximum wave height in a sea state is examined in terms of the spectral peakedness and the sea state duration. The study is based on the analysis of numerically simulated Gaussian wave records with given target spectra to fulfill the long duration and stationarity jointly required conditions, seldom found in nature. Results indicate a clear dependence of the probability distribution structure and location on the record length and the spectral shape.

scholarly journals STATISTICAL PROPERTIES OF THE MAXIMUM RUN OF IRREGULAR SEA WAVES

1988 ◽  
Vol 1 (21) ◽  
pp. 48 ◽  
Author(s):  
Akira Kimura
Keyword(s):  
Probability Distribution ◽  
Wave Height ◽  
Probability Distributions ◽  
Confidence Regions ◽  
Statistical Properties ◽  
Irregular Waves ◽  
Sea Waves ◽  
Sea State ◽  
Irregular Wave ◽  
Distribution Of The Maximum

The probability distribution of the maximum run of irregular wave height is introduced theoretically. Probability distributions for the 2nd maximum, 3rd maximum and further maximum runs are also introduced. Their statistical properties, including the means and their confidence regions, are applied to the verification of experiments with irregular waves in the realization of a "severe sea state" in the test.

Wave Distributions and Sampling Variability

2007 ◽  
Author(s):  
O̸istein Hagen
Keyword(s):  
Wave Height ◽  
Extreme Values ◽  
Height Distribution ◽  
Short Term ◽  
Sea State ◽  
Sampling Variability ◽  
Wave Statistics ◽  
Individual Wave ◽  
Wave Heights ◽  
Crest Height

The paper describes the effect of sampling variability on the predicted extreme individual wave height and the predicted extreme individual crests height for long return periods, such as for the 100-year maximum wave height and 100-year maximum crest height. We show that the effect of sampling variability is different for individual crest or wave height as compared to for significant wave height. The short term wave statistics is modeled by the Forristall crest height distribution and the Forristall wave height distribution [3,4]. Samples from the 3-hour Weibull distribution are simulated for 100.000 years period, and the 100-year extreme values for wave heights and crest heights determined for respectively 20 minute and 3 hour sea states. The simulations are compared to results obtained by probabilistic analysis. The paper shows that state of the art analysis approaches using the Forristall distributions give about unbiased estimates for extreme individual crest or wave height if implemented appropriately. Direct application of the Forristall distributions for 3-hour sea state parameters give long term extremes that are biased low, and it is shown how the short term distributions can be modified such that consistent results for 20 minute and 3 hour sea states are obtained. These modified distributions are expected applicable for predictions based on hindcast sea state statistics and for the environmental contour approach.

scholarly journals Propulsion Performance Analysis of Wave-powered Boats

2020 ◽  
Vol 10 (2) ◽  
pp. 121-129
Author(s):  
Zong-Yu Chang ◽  
Chao Deng ◽  
Jia-Kun Zhang ◽  
Zhan-Xia Feng ◽  
Zhong-Qiang Zheng
Keyword(s):  
Wave Height ◽  
State Level ◽  
Sea State ◽  
Torsion Spring ◽  
Propulsion Performance ◽  
Long Duration ◽  
Level 1 ◽  
Heave Motion ◽  
The Relationship ◽  
Restoring Stiffness

With the development of oceanographic research and marine environment protection, mobile marine platforms are applied for ocean observation for a long journey. Wave-powered boats are capable of applying wave motion to propel itself and make a long-duration survey. This paper presents the dynamics of the wave-powered boat under the excitation of the heave motion and pitch motion. Taking the wave-powered boat with double fins as an example, the heave and pitch motions of the boat are obtained by ANSYS-AQWA firstly. Then the relationship between propulsion performance and three factors, including  wave height, wave period, and restoring stiffness of torsion spring, was analyzed through multibody dynamics software ADAMS. With the increase of sea state from level 1 to level 4 the average propulsion speed increased from 0.4m/s to 1.4m/s. Under the same wave height and period, with the increase of restoring stiffness of torsion spring from 0.0125N·m/deg to 0.3N·m /deg, the propulsion speed of the wave-powered boat increases first and then decreases, and there exists an optimum stiffness. Through the calculation it is found that when the restoring stiffness of torsional spring is increased from 0.025N·m /deg to 0.2N·m /deg with the sea state level 1 to 4, the wave powered boat has better propulsion performance.

scholarly journals Waves off Gopalpur, northern Bay of Bengal during Cyclone Phailin

2014 ◽  
Vol 32 (9) ◽  
pp. 1073-1083 ◽  
Author(s):  
M. M. Amrutha ◽  
V. Sanil Kumar ◽  
T. R. Anoop ◽  
T. M. Balakrishnan Nair ◽  
A. Nherakkol ◽  
...  
Keyword(s):  
Wave Height ◽  
Bay Of Bengal ◽  
Significant Wave Height ◽  
Wave Spectrum ◽  
Statistical Parameters ◽  
Freak Wave ◽  
Maximum Wave Height ◽  
Significant Wave ◽  
Before And After ◽  
Northern Bay Of Bengal

Abstract. The wave statistical parameters during Cyclone Phailin which crossed the northern Bay of Bengal are described based on the Directional Waverider buoy-measured wave data from 8 to 13 October 2013. On 12 October 2013, the cyclone passed within 70 km of the Waverider buoy location with a wind speed of 59.2 m s−1 (115 knots), and during this period, a maximum significant wave height of 7.3 m and a maximum wave height of 13.5 m were measured at 50 m water depth. Eight freak wave events are observed during the study period. The ratio of the maximum wave height to significant wave height recorded is found to be higher than the theoretical value and the ratio of the crest height to wave height during the cyclone was 0.6 to 0.7. The characteristics of the wave spectra before and after the cyclone is studied and found that the high-frequency face of the wave spectrum is proportional to f−3 before the cyclone and is between f−4 and f−5 during the cyclone period.

Analysis of Short-Term and Long-Term Wave Statistics by Time Domain Simulations Statistics

2017 ◽  
Author(s):  
Øistein Hagen ◽  
Ida Håøy Grue ◽  
Jørn Birknes-Berg ◽  
Gunnar Lian ◽  
Kjersti Bruserud
Keyword(s):  
Wave Height ◽  
Time Domain ◽  
Statistical Distributions ◽  
Short Term ◽  
Sea State ◽  
Wave Statistics ◽  
Individual Wave ◽  
Wave Heights ◽  
Crest Height

In the design of new structures and assessment of existing structures, short- and long term statistical distributions of wave height, crest height and wave periods, as well as joint distributions, are important for structural integrity assessment. It is important to model the statistical distributions accurately to calculate wave design criteria and to assess fatigue life. A detailed study of the wave statistics for an offshore location at the Norwegian Continental Shelf field is carried out. Extensive time domain simulations for the complete scatter diagram of possible sea states are carried out by a second order wave model. Time series of the surface elevation are generated for JONSWAP and Torsethaugen wave spectra, and for several wave spreading models. Statistics for individual wave heights, crest heights and wave periods are established. The simulated results for the short-term statistics are compared with existing short term models that are commonly used, viz. the Forristal, Næss and Rayleigh wave height distributions, and the Forristall 2nd order crest height distribution. Also, parameterized distributions for wave height and for crest height are fitted to the simulated data. The long-term distributions F(H) and F(C) of all simulated individual wave heights H and crest heights C are determined by weighting the simulations with the long-term probability of occurrence of the sea state. Likewise, the long-term distributions F(Hmax) and F(Cmax) of the maximum simulated individual wave heights Hmax and crest heights Cmax in the sea states are determined. The design criteria for return periods R = 1, 10, 100 and 10 000 years are determined from the appropriate quantile levels. The effect of statistical uncertainty is investigated by comparing the confidence intervals for the estimated extreme values results as function of the number N of 3-hour time domain simulations per sea state for 10<N<500.

scholarly journals A DISCUSSION OF SOME MEASURED WAVE DATA

1972 ◽  
Vol 1 (13) ◽  
pp. 3 ◽  
Author(s):  
J.R. Wilson ◽  
W.F. Baird
Keyword(s):  
Spectral Analysis ◽  
Nova Scotia ◽  
Wave Height ◽  
Significant Wave Height ◽  
Peak Period ◽  
Maximum Wave Height ◽  
Significant Wave ◽  
Individual Wave ◽  
Wave Heights ◽  
Classical Parameters

The significant wave height and peak period as derived from the spectral analysis of 171 measured wave records taken in the ocean off Western Head, Nova Scotia are compared to the more classical parameters derived from individual wave heights and by the Tucker method. The highest surface elevation and the maximum wave height occurring in the records are compared to values predicted by Cartwright and Longuet-Higgins (1956), Goda (1970), and Longuet-Higgins (1952).

scholarly journals Estimation of Significant Wave Heights from ASCAT Scatterometer Data via Deep Learning Network

2021 ◽  
Vol 13 (2) ◽  
pp. 195
Author(s):  
He Wang ◽  
Jingsong Yang ◽  
Jianhua Zhu ◽  
Lin Ren ◽  
Yahao Liu ◽  
...  
Keyword(s):  
Deep Learning ◽  
Wave Height ◽  
Significant Wave Height ◽  
Incidence Angle ◽  
Ocean Waves ◽  
Global Scale ◽  
Learning Technology ◽  
Sea State ◽  
Significant Wave ◽  
Wave Heights

Sea state estimation from wide-swath and frequent-revisit scatterometers, which are providing ocean winds in the routine, is an attractive challenge. In this study, state-of-the-art deep learning technology is successfully adopted to develop an algorithm for deriving significant wave height from Advanced Scatterometer (ASCAT) aboard MetOp-A. By collocating three years (2016–2018) of ASCAT measurements and WaveWatch III sea state hindcasts at a global scale, huge amount data points (>8 million) were employed to train the multi-hidden-layer deep learning model, which has been established to map the inputs of thirteen sea state related ASCAT observables into the wave heights. The ASCAT significant wave height estimates were validated against hindcast dataset independent on training, showing good consistency in terms of root mean square error of 0.5 m under moderate sea condition (1.0–5.0 m). Additionally, reasonable agreement is also found between ASCAT derived wave heights and buoy observations from National Data Buoy Center for the proposed algorithm. Results are further discussed with respect to sea state maturity, radar incidence angle along with the limitations of the model. Our work demonstrates the capability of scatterometers for monitoring sea state, thus would advance the use of scatterometers, which were originally designed for winds, in studies of ocean waves.

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