• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.47-55
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• 2004

In this paper, The statistical properties of ocean waves in the sea area of Hong-do, Korea are examined based on 1998-2002's wave data from a directional wave buoy. Wave data aquisition rate, mean wave heights, frequency of wave direction are summarized. Wave height and period scatter diagrams and n-year return period wave heights are estimated. Wave periods of maximum wave heights are also estimated. Large amplitude wave characteristics during the typhoon Prapiroon in 2000, Rusa in 2002 are also examined.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.219-225
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• 2004

Following a preceding study if Shin et al.(2004), wave fields for a month if September if 2003 are simulated based on the modified WAM cycle 4 model that enables the precise wave hindcasting with fine spatial meshes, and characteristics of extreme waves at the south roast if Koreo are analyzed The accuracy if applied wave model is verified by comparing computed wave parameters and corresponding ones measured at Ieodo ocean research station. The wave hindasting if typhoon 'Maemi' with an hour time interval reveals the extreme wave characteristics at 4 primary locations if south coast of Korea as follows: 1) At the front sea of Chaguido in the south of Jeju-do, the maximum significant wave height, moon wave period and mean wave direction appear to be 7.41m, 13.65s and $6.4^{\circ}$, respectively at 16:00 KST if Sep. 12, 2003. 2) At the entrance of Masan Bay, 12.50m, 13.65s and $1.2^{\circ}$ at 21:00 KST if Sep. 12. 3) At the front sea of Suyoung Bay, 13.85m, 13.81s and $0.2^{\circ}$ at 22;00 KST if Sep. 12. 4) At the front sea of Ulsan port, 11.00m, 13.25s and $28^{\circ}$ at 23:00 KST if Sep.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.745-751
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• 2004

Following a preceding study of Shin et al.(2004), wave fields for a month of September of 2003 are simulated based on the modified WAM cycle 4 model that enables the precise wave hindcasting with fine spatial meshes, and characteristics of extreme waves at the south coast of Korea are analyzed The accuracy of applied wave model is verified by comparing computed wave parameters and corresponding ones measured at Ieodo ocean research station. The wave hindcasting of typhoon 'Maemi' with an hour time interval reveals the extreme wave characteristics at 4 primary locations of south coast of Korea as follows: 1) At the front sea of Chaguido in the south of Jeju-do, the maximum significant wave height, mean wave period and mean wave direction appear to be 7.41m, 13.65s and $6.4^{\circ}$ respectively at 16:00 KST of Sep. 12, 2003. 2) At the entrance of Masan Bay, 12.50m, 13.65s and $1.2^{\circ}$ at 21:00 KST of Sep. 12. 3) At the front sea of Suyoung Bay, 13.85m, 13.81s and $0.2^{\circ}$ at 22;00 KST of Sep. 12. 4) At the front sea of Ulsan port, l1.00m, 13.25s and $2.8^{\circ}$ at 23:00 KST of Sep. 12.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.1-12
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• 2023

Oceanic wind waves have been recognized as one of the important indicators of global warming and climate change. It is necessary to study the spatial and temporal variability of significant wave height (SWH) and wave direction in the Yellow Sea and a part of the East China Sea, which is directly affected by the East Asian monsoon and climate change. In this study, the spatial and temporal variability including seasonal and interannual variability of SWH and wave direction in the Yellow Sea and East China Sea were analyzed using European Center for Medium-Range Weather Forecasts (ECMWF) Reanalysis 5 (ERA5) data. Prior to analyzing the variability of SWH and wave direction using the model reanalysis, the accuracy was verified through comparison with SWH and wave direction measurements from Ieodo Ocean Science Station (I-ORS). The mean SWH ranged from 0.3 to 1.6 m, and was higher in the south than in the north and higher in the center of the Yellow Sea than in the coast. The standard deviation of the SWH also showed a pattern similar to the mean. In the Yellow Sea, SWH and wave direction showed clear seasonal variability. SWH was generally highest in winter and lowest in late spring or early summer. Due to the influence of the monsoon, the wave direction propagated mainly to the south in winter and to the north in summer. The seasonal variability of SWH showed predominant interannual variability with strong variability of annual amplitudes due to the influence of typhoons in summer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.69-83
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• 2006

A Level 3 reliability analysis has been performed for wave run-up and overtopping on a sloping seawall. A Monte-Carlo simulation was performed considering the uncertainties of various variables affecting the wave overtopping event. The wave overtopping probability was evaluated from the individual wave run-up by using the wave-by-wave method, while the mean overtopping rate was calculated directly from the significant wave height. Using the calculated overtopping probability and mean overtopping rate, the maximum overtopping volume was also calculated on the assumption of two-parameter Weibull distribution of individual wave overtopping volume. In addition, by changing wave directions, depths, and structure slopes, their effects on wave overtopping were analyzed. It was found that, when the variability of wave directions is considered or the water depth decreases toward shore, wave height become smaller due to wave refraction, which yields smaller mean overtopping rate, overtopping probability and maximum overtopping volume. For the same mean overtopping rate, the expected overtopping probability increases and the expected maximum overtopping volume decreases as approaching toward shore inside surfzone.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.3
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• pp.137-145
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• 2004

Long-term wave distribution at Jeju sea is investigated by a numerical simulation based on the thirdgeneration wave model SWAN (Simulating WAves Nearshore). The Jeju sea which retains relatively high wave energy density among Korean coastal regions is considered to be a suitable site for wave power generation and the efficiency of wave power generation is closely related to local wave characteristics. The monthly mean of a large-scale long-term wave data from 1979 to 2002, which is provided by Korea Ocean Research & Development Institute. is used as the boundary condition of SWAN model simulation with 1km grid. An analysis of wave distribution concentrates on the seasonal variation and spatial distribution of significant wave heights, mean wave directions and mean wave periods. Significant wave heights are higher in winter and summer and the west sea of Jeju appears relatively higher than east's. The highest significant wave height occurs at the northeast sea in winter and the second highest significant wave height appears at the southeast sea in summer, while the significant wave heights in spring and autumn are relatively low but homogeneous. The distribution of wave directions reveals that except the rear region influenced by wave refraction, the northwest wave direction is dominant in summer and the southeast in winter. Wave periods are longer in summer and winter and the west sea of Jeju appears relatively longer than east's. The longest wave period occurs at the west sea in winter, and in summer it appears relatively homogeneous with a little longer period at the south sea.

• Journal of Korea Water Resources Association
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• v.46 no.2
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• pp.205-218
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• 2013

The likelihood of rip current at Haeundae beach according to wave parameters, such as wave height, period, direction, and tidal elevation, was estimated by using numerical simulations with a Boussinesq model, FUNWAVE. To examine the estimation, the rip current occurred on 12th June, 2011 at Haeundae beach was simulated based on observations. For the estimation, the following procedure was carried out. First, extensive numerical simulations of nearshore circulations are performed under various random sea conditions according to the wave parameters. Second, from the numerical results, cross shore components of two-wave-period averaged velocities over the nearshore area were computed, and their seawardly maximum was defined as rip current velocity of the area. Third, using time series of the rip current velocity, we computed the ratio of the simulation time and the time period in which the rip current velocity exceed a threshold velocity for rip-current accidents, and thus the ratio was quantified as the likelihood of rip current at Haeundae beach for the input wave parameters. From the resultant estimations, it was found that the rip current likelihood increases as wave height and period increase, and tidal elevation decreases.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.2
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• pp.65-71
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• 1991

Many investigations of wave deformation without currents have been carried out experimentally and theoretically but, studies treating the effect of longshore current on the wave deformation are few. It is thus necessary to evaluate the effect of longshore current on the wave deformation after breaking. In the paper the wave height attenuation. the wave direction and the variation of mean water level are calculated in which effects of longshore current are involved. To assess the effect of longshore current on the wave deformation, factors above with longshore current are compared with them without longshore current by using calculated results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.109-119
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• 2012

Long-term wave observation was carried out near Busan New Port and the major wave characteristics were analyzed. At Busan New Port, waves from south direction were predominant throughout the year, while waves from the west, developed at the north sea of Geoje island, appeared almost the same frequency in winter season, showing apparent seasonal variation. During the observation period, the significant wave height was mostly less than 1 m, but it reached its maximum of 8.0 m when typhoon Maemi passed on September 2003. Also, the seasonal variation was hardly observed except July. In contrast, seasonal variation was apparent for the significant wave period, whose peak ranges 4~5 s in summer whereas about 3 s in winter. The largest significant wave period was 15.56 s, observed on June 2003. Meanwhile, the annual variation was negligible for mean wave direction as well as significant wave height and period. Further analysis of the wave data acquired for 5 years at 4.5 km south, in the south sea of Daejuk island, confirmed high correlation between the two observation points in summer and vice versa in winter.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.2
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• pp.174-184
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• 1996

In the present study, for fully-open rectangular harbors, sensitivity analyses are made for the major parameters which are relevant to the practical application of a hybrid element model widely used fur the analysis of harbor oscillation. The results show that it is desirable to extend the finite element region to the area in which depth change is not large and that it is appropriate to take the depth of the outer region for analytic solution as the average along the boundary between the two regions. It is expected that the number of Fourier components of the analytic solution may not be important for a constant-depth simple-shaped harbor but its significance may increase for harbors of varying depth and complex geometry. It is found that the effect of incident wave direction is not significant for the first resonance mode but its effect becomes important as the bottom slope increases, especially for the higher resonance modes.