Estimation of Maximum Wave Height of Observation Data and its Application to Freak Wave Prediction

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.

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Non-Gaussian Extreme Waves in the Central North Sea

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.2829061 ◽

1997 ◽

Vol 119 (3) ◽

pp. 146-150 ◽

Cited By ~ 7

Author(s):

J. Skourup ◽

N.-E. O. Hansen ◽

K. K. Andreasen

Keyword(s):

Wave Height ◽

North Sea ◽

Upper Bound ◽

Wave Crest ◽

Extreme Waves ◽

Freak Waves ◽

Freak Wave ◽

Wave Trains ◽

Central North Sea ◽

Crest Height

The area of the Central North Sea is notorious for the occurrence of very high waves in certain wave trains. The short-term distribution of these wave trains includes waves which are far steeper than predicted by the Rayleigh distribution. Such waves are often termed “extreme waves” or “freak waves.” An analysis of the extreme statistical properties of these waves has been made. The analysis is based on more than 12 yr of wave records from the Mærsk Olie og Gas AS operated Gorm Field which is located in the Danish sector of the Central North Sea. From the wave recordings more than 400 freak wave candidates were found. The ratio between the extreme crest height and the significant wave height (20-min value) has been found to be about 1.8, and the ratio between extreme crest height and extreme wave height has been found to be 0.69. The latter ratio is clearly outside the range of Gaussian waves, and it is higher than the maximum value for steep nonlinear long-crested waves, thus indicating that freak waves are not of a permanent form, and probably of short-crested nature. The extreme statistical distribution is represented by a Weibull distribution with an upper bound, where the upper bound is the value for a depth-limited breaking wave. Based on the measured data, a procedure for determining the freak wave crest height with a given return period is proposed. A sensitivity analysis of the extreme value of the crest height is also made.

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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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REPRODUCTION ANALYSIS OF HUMAN DRIFTING BEHAVIOR DURING TSUNAMI USING NUMERICAL CALCULATION

Coastal Engineering Proceedings ◽

10.9753/icce.v36v.currents.34 ◽

2020 ◽

pp. 34

Author(s):

Riko Morita ◽

Taro Arikawa

Keyword(s):

Numerical Calculation ◽

Wave Height ◽

Prediction Method ◽

Great East Japan Earthquake ◽

Numerical Calculations ◽

Water Tank ◽

Maximum Wave Height ◽

Hydraulic Experiment ◽

Secondary Damage ◽

Simulation Results

Along with the 2011 Great East Japan Earthquake (Mw 9.0), a huge tsunami exceeding a maximum wave height of 15 m occurred. Many people and objects were destroyed and drifted by the tsunami. In addition, these debris were transported to various places that could not be predicted, resulting in significant secondary damage and increase in the number of missing. Therefore, in order to reduce the amount of damage, it is important to predict the behavior and landing points of person after set adrift in a tsunami. The best way to increase the rescue rate is to predict in advance the area that people will be drifted, and prioritize searching operations at that area. Although there has been considerable number of studies which handle the drifting behavior of containers and ships (e.g., Kaida et al., 2016), the prediction of drifting areas focusing on people has not been conducted. Moreover, a drifting area prediction method has not yet been established. The purpose of this study is to conduct a hydraulic experiment using a flat water tank, and observe the drifting area of the drifting object. Then, we conducted numerical calculations and compared simulation results with the experimental ones.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/1yhKuodhCbg

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Evaluating skill of BMKG wave model forecast (Wavewatch-3) with observation data in Indian Ocean (5 – 31 December 2017).

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/893/1/012058 ◽

2021 ◽

Vol 893 (1) ◽

pp. 012058

Author(s):

R Kurniawan ◽

H Harsa ◽

A Ramdhani ◽

W Fitria ◽

D Rahmawati ◽

...

Keyword(s):

Indian Ocean ◽

Wave Height ◽

Model Performance ◽

Forecast Accuracy ◽

Wave Model ◽

Ocean Waves ◽

Observation Data ◽

Operating Characteristics ◽

Wave Forecast ◽

Good For

Abstract Providing Maritime meteorological forecasts (including ocean wave information) is one of BMKG duties. Currently, BMKG employs Wavewatch-3 (WW3) model to forecast ocean waves in Indonesia. Evaluating the wave forecasts is very important to improve the forecasts skill. This paper presents the evaluation of 7-days ahead BMKG’s wave forecast. The evaluation was performed by comparing wave data observation and BMKG wave forecast. The observation data were obtained from RV Mirai 1708 cruise on December 5th to 31st 2017 at the Indian Ocean around 04°14'S and 101°31'E. Some statistical properties and Relative Operating Characteristics (ROC) curve were utilized to assess the model performance. The evaluation processes were carried out on model’s parameters: Significant Wave Height (Hs) and Wind surface for each 7-days forecast started from 00 UTC. The comparation results show that, in average, WW3 forecasts are over-estimate the wave height than that of the observation. The forecast skills determined from the correlation and ROC curves are good for the first- and second-day forecast, while the third until seventh day decrease to fair. This phenomenon is suspected to be caused by the wind data characteristics provided by the Global Forecasts System (GFS) as the input of the model. Nevertheless, although statistical correlation is good for up to 2 days forecast, the average value of Root Mean Square Error (RMSE), absolute bias, and relative error are high. In general, this verifies the overestimate results of the model output and should be taken into consideration to improve BMKG’s wave model performance and forecast accuracy.

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Effect of Uni- and Bi-Directional Coupling of Ocean-Met Interaction on Significant Wave Height and Local Wind

Volume 7B: Ocean Engineering ◽

10.1115/omae2017-61681 ◽

2017 ◽

Author(s):

Adil Rasheed ◽

Jakob Kristoffer Süld ◽

Mandar Tabib

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

Surface Wind ◽

Wave Model ◽

Ocean Surface ◽

Observation Data ◽

Local Wind ◽

Near Surface ◽

Significant Wave ◽

Bidirectional Coupling

Accurate prediction of near surface wind and wave height are important for many offshore activities like fishing, boating, surfing, installation and maintenance of marine structures. The current work investigates the use of different methodologies to make accurate predictions of significant wave height and local wind. The methodology consists of coupling an atmospheric code HARMONIE and a wave model WAM. Two different kinds of coupling methodologies: unidirectional and bidirectional coupling are tested. While in Unidirectional coupling only the effects of atmosphere on ocean surface are taken into account, in bidirectional coupling the effects of ocean surface on the atmosphere are also accounted for. The predicted values of wave height and local wind at 10m above the ocean surface using both the methodologies are compared against observation data. The results show that during windy conditions, a bidirectional coupling methodology has better prediction capability.

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Pemanfaatan Data Angin Untuk Karakteristik Gelombang Laut Di Perairan Natuna Berdasarkan Data Angin tahun 2009 - 2018

BULETIN OSEANOGRAFI MARINA ◽

10.14710/buloma.v8i1.25304 ◽

2019 ◽

Vol 8 (2) ◽

pp. 55

Author(s):

Ary Afriady ◽

Tasdik Mustika Alam ◽

Mochamad Furqon Mustika Azis Ismail

Keyword(s):

Wave Height ◽

Wave Period ◽

Wind Data ◽

Wave Direction ◽

The West ◽

Maximum Wave Height ◽

Transition Season ◽

Forecasting Analysis ◽

Environmental Prediction ◽

Wave Forecasting

Analisis data angin dilakukan untuk meramalkan dan menentukan karakteristik gelombang laut di perairan Pulau Natuna. Data angin yang digunakan dalam penelitian ini berasal dari National Centers for Environmental Prediction (NCEP) selama 10 tahun dari tahun 2009 sampai dengan tahun 2018. Metoda yang digunakan untuk estimasi tinggi, periode dan arah gelombang laut yang dibangkitkan oleh angin adalah metode Svedrup, Munk dan Bretschneider (SMB). Hasil perhitungan peramalan karakteristik gelombang diperoleh bahwa pembentukan gelombang didominasi oleh arah yang berasal dari timur laut dan terjadi pada musim barat dan musim peralihan 1. Adapun pada musim timur dan peralihan, arah dominan gelombang masing-masing berasal dari selatan dan barat daya. Tinggi gelombang maksimum 1,0-1,4 m sering terjadi pada musim musim timur, adapun tinggi gelombang minimum 0,2-0,6 m dominan terjadi pada musim musim peralihan. Periode gelombang dominan ditemukan pada kisaran 7-9 detik yang terjadi pada tiap musim. The analysis of wind data has been done to forecast and determine the characteristic of the ocean wave in Natuna Island waters. The wind data in this study came from the National Centers for Environmental Prediction (NCEP) for a period of 10 years from 2009 to 2018. The method to estimate wave height, wave period, and wave direction generated by wind is Sverdrup, Munk dan Bretschneider (SMB) system. The results of wave forecasting analysis show that the formation of the wave is mainly originated from the northeast which occurs during the west and first transition season. As for the east and second transition season, the origin of wave formation coming from the south and southwest, respectively. The maximum wave height of 1.0-1.4 m frequently occurs during the east monsoon, while the minimum wave height. The dominant wave period is found in the range of 7-9 seconds, which occurs in every season.

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Probabilistic distribution of the maximum wave height

China Ocean Engineering ◽

10.1007/s13344-014-0079-3 ◽

2014 ◽

Vol 28 (5) ◽

pp. 579-586 ◽

Cited By ~ 1

Author(s):

Dong Hyawn Kim ◽

Taerim Kim

Keyword(s):

Wave Height ◽

Maximum Wave Height ◽

Distribution Of The Maximum ◽

Probabilistic Distribution

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NEW WAVE PRESSURE FORMULAE FOR COMPOSITE BREAKWATERS

Coastal Engineering Proceedings ◽

10.9753/icce.v14.100 ◽

1974 ◽

Vol 1 (14) ◽

pp. 100 ◽

Cited By ~ 5

Author(s):

Yoshimi Goda

Keyword(s):

Wave Height ◽

Wave Action ◽

Smooth Transition ◽

New Wave ◽

Wave Pressure ◽

Maximum Wave Height ◽

Design Wave Height

A proposal is made for new wave pressure formulae, which can be applied for the whole ranges of wave action from nonbreaking to postbreaking waves with smooth transition between them. The design wave height is specified as the maximum wave height possible at the site of breakwater. The new formulae as well as the existing formulae of Hiroi, Sainflou, and Minikin have been calibrated with the cases of 21 slidings and 13 nonslidings of the upright sections of prototype breakwaters. The calibration establishes that the new formulae are the most accurate ones.

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Evolution of a Random Directional Wave and Freak Wave Occurrence

Journal of Physical Oceanography ◽

10.1175/2008jpo4031.1 ◽

2009 ◽

Vol 39 (3) ◽

pp. 621-639 ◽

Cited By ~ 72

Author(s):

Takuji Waseda ◽

Takeshi Kinoshita ◽

Hitoshi Tamura

Keyword(s):

Wave Height ◽

Wave Interaction ◽

Northwest Pacific ◽

Frequency Bandwidth ◽

Extreme Wave ◽

Spectral Parameters ◽

Freak Wave ◽

Resonant Wave ◽

Directional Wave ◽

Wind Sea

Abstract The evolution of a random directional wave in deep water was studied in a laboratory wave tank (50 m long, 10 m wide, 5 m deep) utilizing a directional wave generator. A number of experiments were conducted, changing the various spectral parameters (wave steepness 0.05 < ɛ < 0.11, with directional spreading up to 36° and frequency bandwidth 0.2 < δk/k < 0.6). The wave evolution was studied by an array of wave wires distributed down the tank. As the spectral parameters were altered, the wave height statistics change. Without any wave directionality, the occurrence of waves exceeding twice the significant wave height (the freak wave) increases as the frequency bandwidth narrows and steepness increases, due to quasi-resonant wave–wave interaction. However, the probability of an extreme wave rapidly reduces as the directional bandwidth broadens. The effective Benjamin–Feir index (BFIeff) is introduced, extending the BFI (the relative magnitude of nonlinearity and dispersion) to incorporate the effect of directionality, and successfully parameterizes the observed occurrence of freak waves in the tank. Analysis of the high-resolution hindcast wave field of the northwest Pacific reveals that such a directionally confined wind sea with high extreme wave probability is rare and corresponds mostly to a swell–wind sea mixed condition. Therefore, extreme wave occurrence in the sea as a result of quasi-resonant wave–wave interaction is a rare event that occurs only when the wind sea directionality is extremely narrow.

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