• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.553-558
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• 2004

Periodic profiling by level is a conventional method for monitoring topographic changes in a specific part of tidal zone. Periodic aerial photographs are used for monitoring topographic change of broad tidal zone area. In this study, spot heights at interval of 50m on 5 profiling lines were leveled periodically for precise monitoring topographic change of tidal zone. For monitoring broad topographic change of tidal zone, aerial photographs were also taken by film camera loaded on pilotless helicopter periodically Periodic profiling shows the change of heights on the lines well. On the other hand, aerial photographs taken by film camera loaded on pilotless helicopter have some problems to detect topographic change of tidal zone precise. Because the scale and incline of the photographs were not same, it is hard to compare them. Therefore, for more precise monitoring of topographic changes in tidal zone, it is need to take aerial pictures with same scale and same incline.

• Ocean and Polar Research
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• v.33 no.3
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• pp.309-319
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• 2011

This is a preliminary study of the feasibility of obtaining reliable tidal current harmonic constants, using one month of current observations, to verify the accuracy of a tidal model. An inference method is commonly used to separate out the tidal harmonic constituents when the available data spans less than a synodic period. In contrast to tidal constituents, studies of the separation of tidal-current harmonics are rare, basically due to a dearth of the long-term observation data needed for such experiments. We conducted concurrent and monthly harmonic analyses for tidal current velocities and heights, using 2 years (2006 and 2007) of current and sea-level records obtained from the Tidal Current Signal Station located in the narrow waterway in front of Incheon Lock, Korea. Firstly, the l-year harmonic analyses showed that, with the exception of $M_2$ and $S_2$ semidiurnal constituents, the major constituents were different for the tidal currents and heights. $K_1$, for instance, was found to be the 4th major tidal constituent but not an important tidal current constituent. Secondly, we examined monthly variation in the amplitudes and phase-lags of the $S_2$ and $K_1$ current-velocity and tide constituents over a 23-month period. The resultant patterns of variation in the amplitudes and phase-lags of the $S_2$ tidal currents and tides were similar, exhibiting a sine curve form with a 6-month period. Similarly, variation in the $K_1$ tidal constant and tidal current-velocity phase lags showed a sine curve pattern with a 6-month period. However, that of the $K_1$ tidal current-velocity amplitude showed a somewhat irregular sine curve pattern. Lastly, we investigated and tested the inference methods available for separating the $K_2$ and $S_2$ current-velocity constituents via monthly harmonic analysis. We compared the effects of reduction in monthly variability in tidal harmonic constants of the $S_2$ current-velocity constituent using three different inference methods and that of Schureman (1976). Specifically, to separate out the two constituents ($S_2$ and $K_2$), we used three different inference parameter (i.e. amplitude ratio and phase-lag diggerence) values derived from the 1-year harmonic analyses of current-velocities and tidal heights at (near) the short-term observation station and from tidal potential (TP), together with Schureman's (1976) inference (SI). Results from these four different methods reveal that TP and SI are satisfactorily applicable where results of long-term harmonic analysis are not available. We also discussed how to further reduce the monthly variability in $S_2$ tidal current-velocity constants.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.33-38
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• 2006

In marine salvage, extreme tide heights and tidal currents are necessary to anchor an accidental ship. In order to meet this requirement, a simple scheme was developed which yields the spatial informations on the extreme tide from the distribution of approximate highest astronomical tide heights using a relationship between extreme and highest astronomical tides at the standard port. This method is the inference method based on horizontally homogeneity of tide. This scheme was applied to estimate extreme tide heights and tidal currents in the Namhae (southern sea of Korea). The highest astronomical tide heights are computed by amplitude of four major constituents (M2, S2, K1, O1 tide). The estimated extreme tide heights are ranged from 70 to 260 cm for return period 50 years and from 80 to 270cm for return period 100 years, respectively. For return period 100 years, extreme tidal currents show value of 1.55 times as strong as those of normal state.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.2
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• pp.87-95
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• 2000

Spectral wave models are applied to the area of Kyung-gi bay with two different combinations. One combination assumes a constant tidal elevation over the whole region when applying the wave model to the area. In this case no tidal currents exist in any place. The other combination employs tide model as well as wave model so that tidal condition is defined at every computation time when wave modelling is carried out. Significant wave heights and wave directions are shown for these two cases. With these two different constraints of tidal variation, the results are checked and compared with each other. Both results are found significantly different from each other.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.514-517
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• 2008

An hydraulic experiment was carried out in an open channel flume in order to investigate the water discharge capability of the sluice caisson for tidal power generation, which greatly affects the economical efficiency of the construction of a tidal power plant. To predict the influence of change in the major design parameters relating to the sluice shape on the water discharge capability of the sluice, the experiment was carried out very precisely. The experiment was carried out for the six different sluice models of different widths and bottom heights of the sluice throat section. The experimental data showed that the water discharge generally increased by increasing the width of the throat section if the side shape of the sluice was the same. In addition, the coefficient of discharge was larger when the bottom height of the throat section was higher for the two bottom heights that were tested.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.381-389
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• 2012

An EST-based method which is applicable for estimating extreme sea levels from short sea-level records in a tide dominated coastal zone was developed. Via the method, annual maximum tidal level is chosen from the simulated 1-yr tidal data which are constituted by the independent daily high water levels, short term and long term surge heights and typhoon-induced surge heights. The high water levels are generated considering not only spring/neap tides and annual tide but also 18.6-year lunar nodal cycle. Typhoon-induced surges are selected from the training set which is constructed by observed or simulated surge heights. This yearly simulation is repeated many hundred years to yield the extreme tidal levels, and the whole process is carried out many hundred times repeatedly to get robust statistics of the levels. In addition, validation of the method is also shown by comparing the result with other researches with the tidal data of Mokpo Harbor.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.376-381
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• 2003

The reliability analysis of overtopping probability is proposed. In order to estimate the expected overtopping probability of the rubble mound breakwater, the experimental results of individual wave runup height is applied for the analysis of irregular wave system. The joint distribution of wave heights and periods is used for the input data of runup calculation because the runup height depends on the wave height and period. The runup heights during the one event that the design wave attacks the rubble mound breakwater extend to the one life cycle of 60 years. Utilizing the Monte-Carlo method, the one life cycle is tried more about 60 times for obtaining the expected value of overtopping probability. It is found that the inclusion of the variability of wave tidal and wave steepness has great influence on the computation of the expected overtopping probability of rubble mound breakwater. The previous design disregarding the tidal fluctuation largely overestimates or underestimates the expected overtopping probability depending on tidal range and wave steepness.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.4
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• pp.317-322
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• 2003

This paper have calculated a relative heights of an each station using the data which were observed by GPS permanent stations(Chejudo, Homigoj, Jumunjin, Marado, Palmido, Ulengdo, Youndo) established in Korea. We performed spectrum analysis with a calculated relative heights by CLEAN algorithm. Through these process, we estimated vertical displacement of earth surface by semi-dinural ocean tidal loading components, and compared them with the results which were calculated by improving ocean tide model(NA099jb) for adjacent seas around Japan and Korea. As the result of this study, we determined the ocean tidal loading components with loading effects of $M_2$ and $N_2$, and we noted that the amplitude and the phase lags of ocean tidal loading components from observed GPS data were almost equal to values calculated from ocean tide models. However, the loading components about semi-diurnal tide $S_2$, $K_2$ couldn't estimate because of periods. Also, the diurnal ocean tide loading components were not considered, because the noise level have increased during the diurnal frequency.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.361-373
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• 2010

Analysis has been made on the tide/storm surges characteristics near the Korean marginal seas in the 2008 and 2009 years using operational ocean prediction model of the Korea Meteorological Administration(KMA). In order to evaluate its performance, its results were compared with the observed data by tidal stations around Korean Peninsula. The model used in this study predicts very well the characteristics of tide/storm surges near the Korean Peninsula. Simulated storm surges show the evident effects of Typhoons in summer season. The averaged root mean square error(RMSE) of 48 hr forecasting between the modeled and observed storm surges are 0.272 and 0.420 m in 2008 and 2009, respectively. Due to strong sea winds, the highest storm surges heights was found in summer season of 2008, however, in 2009, the high storm surges heights was also found in other seasons. When Typhoon Kalmaegi(2008) and Morokot(2009) approached to Korean Peninsular, the accuracy of model predictions is almost same as annual mean value but the precision accuracy for Typhoon Morakot is lower than of Typhoon Kalmaegi similar to annual results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.5
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• pp.343-353
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• 2018

Ocean tides in Antarctica are not well constrained mostly due to the lack of tidal observations. Especially, tides underneath and around ice shelves are uncertain. InSAR (Interferometric Synthetic Aperture Radar) data has been used to observe ice shelf movements primarily caused by ocean tides. Here, we demonstrate that it is possible to estimate tidal constituents underneath the Sulzberger ice shelf, West Antarctica, solely using ERS-1/2 tandem mission DInSAR (differential InSAR) observations. In addition, the tidal constituents can be estimated in a high-resolution (~200 m) grid which is beyond any tidal model resolution. We assume that InSAR observed ocean tidal heights can be derived after correcting the InSAR data for the effect of atmospheric loading using the inverse barometric effect, solid earth tides, and ocean tide loading. The ERS (European Remote Sensing) tandem orbit configuration of a 1-day separation between SAR data takes diminishes the sensitivity to major tidal constituents including $K_1$ and $S_2$. Here, the dominant tidal constituent $O_1$ is estimated using 8 differential interferograms underneath the Sulzberger ice shelf. The resulting tidal constituent is compared with a contemporary regional tide model (CATS2008a) and a global tide model (TPXO7.1). The InSAR estimated tidal amplitude agrees well with both models with RMS (root-mean-square) differences of < 2.2 cm and the phase estimate corroborating both tide models to within $8^{\circ}$. We conclude that fine spatial scale (~200 m) Antarctic ice shelf ocean tide determination is feasible for dominant constituents using C-band ERS-1/2 tandem mission InSAR.