• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1053-1057
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• 2005

The occurrence probability (OP) distributions of tide levels using harmonic constants of six tidal gauging stations in Korean coastal zone were estimated and analysed in detail. OP analysis using harmonic constants data of Incheon(Youldo), Mokpo, Yeosu, Pusan, Pohang and Sokcho was carried out and compared with the OP using hourly tidal elevation data which were served through the Internet Homepage by the National Ocean Research Institute. The tidal elevation data were divided by the AHHW (ALLW) value referenced to MSL in order to compare the OP patterns in a relative scale. The OP of the tidal elevation calculated using 38 harmonic tidal constituents relatively well agreed with those of hourly observed tidal elevation data. However, the OP results using four harmonic tidal constituents overestimate the occurrence probability at the peak points and underestimate at the tail-regions of the OP. Especially, the OP patterns of the Sokcho and Pohang tidal gauging stations on the East Sea show totally different patterns and the estimation method using four harmonic constants should be modified and application should be strictly limited on the East Sea areas. The OP patterns are considerably well generated in case of the OP generation using the additional two or three dominant tidal constituents,

• 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 Korean Society of Coastal and Ocean Engineers
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• v.24 no.5
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• pp.319-325
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• 2012

A new formulae for the estimation of the exposure duration in the inter-tidal zone are developed. The exposure duration is one of the most important factors influencing the habitat distribution of the benthic organisms. The formulae can estimate the exposure duration only using the four major tidal harmonic constants available in almost coastal areas. It is easier than the existing method using the frequency analysis of the hourly tidal elevation data. The estimation results by using the formulae suggested in this study are compared with the value by using the observed tidal elevation data analysis in the west coast, Korea. The mean RMS (root-mean squared) errors ranged form 0.8 to 1.4%. It can be used to simply estimate the accurate exposure duration in the region not having the longterm hourly tidal elevation data.

• Journal of Environmental Science International
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• v.23 no.4
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• pp.661-672
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• 2014

Due to tidal force, it is very difficult to estimate the hydraulic parameters of high permeable aquifer near coastal area in Jeju Island. Therefore, to eliminate the impact of tidal force from groundwater level and estimate the hydraulic properties, tidal response technique has been mainly studied. In this study we have extracted 38 tidal constituents from groundwater level and harmonic constants including frequency, amplitude, and phase of each constituent using T_TIDE subroutine which is used to estimate oceanic tidal constituents, and then we have estimated hydraulic diffusivity associated with amplitude attenuation factor(that is the ratio of groundwater level amplitude to sea level amplitude for each tidal constituent) and phase lag(that is phase difference between groundwater level and sea level for each constituent). Also using harmonic constants for each constituent, we made the sinusoidal wave and then we constructed the synthesized wave which linearly combined sinusoidal wave. Finally, we could get residuals(net groundwater level) which was excluded most of tidal influences by eliminating synthesized wave from raw groundwater level. As a result of comparing statistics for synthesized level and net groundwater level, we found that the statistics for net groundwater level was more insignificant than those of synthesized wave. Moreover, in case of coastal aquifer which the impact of tidal force is even more than those of other environmental factors such as rainfall and groundwater yield, it is possible to predict groundwater level using synthesized wave and regression analysis of residuals.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.81-91
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• 2016

Harmonic analysis of tide data observed on the western coasts has been conducted. The changing trends of harmonic constants were reviewed. Overall, amplitudes of semidiurnal tide are not changed and present phases are faster than in the past. In Mokpo located in a semi-enclosed bay, the amplitudes have been greatly increased and the phases have become earlier due to construction of sea-dike and seawalls. Harmonic constants of diurnal tide have not been changed except Mokpo. In Mokpo the phases of diurnal tide have been earlier. Tidal ranges in spring tide and neap tide have not been significantly changed except Mokpo. In Mokpo tidal ranges have been increased and tidal flats widened. Approximate higher high water has been overall rising. Therefore, Korean western coasts can be easily inundated than before.

• Journal of the Korean Institute of Navigation
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• v.7 no.2
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• pp.47-63
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• 1983

In this paper, we have investigated the tidal characteristics of the Nakdongpo estuary. We have carried out the analysis of harmonic constant with the use of the recorded data on tidal level at the Gadeong Do tide station and analyzed the flow velocity data obtained by ourselves at two points in the Nakdongpo estuary. In addition, we have analyzed the variation of the mean-sea level. Typical items of the characteristics we have found are; (1) The principal harmonic constants and non-harmonic constants are shown in table 2. (2) Tide in this area shows the semidiurnal inequality. (3) The mean-sea level is shown to be depressed at the rate of about 1cm to the rise of 1 mbar of the atmospheric pressure. (4) (i) At $K_2$ point, The E-W component of the velocty reveals the nature of progressive waves. The N-S component reveals the nature of stationary waves. (ii) At $K_3$ point, The E-W component shows the characteristics of progressive waves to some degree. The N-S component shows a weak hint of stationary waves. (5) At $K_2$ point, S-component is predominant due to the flow of river. At $K_3$ point, E-component is predominant due to the Tsushima current.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.4
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• pp.355-367
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• 1995

Tidal prediction at a given location has been conventionally made by harmonic method. Another means of tidal prediction is through numerical modeling of tides. Present research focussed on whether prediction of tides and tidal currents can be made everywhere in the Inchon Bay using the numerical model directly or by harmonic constants of tides and tidal currents of the whole Bay derived from the extended model run.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.255-265
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• 2013

In the coastal region of Korea, historical tide harmonic constants were collected. Long-term tides and short-term tides observed by the KHOA were analyzed by a tide harmonic analysis method. Based on the harmonic constants, tidal characteristics such as tide asymmetry in Korean coastal waters were investigated. The harmonic constants obtained from the long-term tide data in the western coast have been used to show the relation between tide variation and reclamation project. $M_2$ amplitudes in the western coast have been decreased and $M_2$ phases were faster. $M_4$ amplitudes also were reduced and $M_4$ phases were faster in overall. In Mokpo and Kunsan tidal nonlinearity is relatively conspicuous. Overall, non-linearity of tidal currents is higher in the tidal channels flowing fast. The tidal non-linearity has increased by the development projects including large reclamation. The flood dominant characteristic in the northern and central part of Korean western coastal waters and the ebb dominant characteristic in the southern part have been intensified. The construction of Saemangeum sea dike has significantly changed the tidal characteristic in Korean western coastal waters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.1
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• pp.31-40
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• 1998

Through the combination of existing tidal prediction model and numerical tidal model, the efficient tidal prediction system was formulated and applied to the neighboring area of Pusan port. Because all tidal constituents for tidal prediction (69 tidal constituents are normally used) couldn't be considered due to the physical limits on computing process, some errors between the observed and predicted values were inevitably occurred. But it was confirmed that the computed values with maximum 10% of relative errors can be obtained if four major tidal constituents(M2, S2, K1, O1) are used. Thus, if other constituents than four major tidal constituents are additionally used, more accurate values will be obtained. Furthermore, if the database for harmonic constants in coastal waters is made in advance, using the numerical tidal model, prompt tidal prediction can be achieved at any time when it is required.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1997.10a
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• pp.111-124
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• 1997

With the combination of existing tidal predictio model and numerical tidal model, the efficient tidal prediction system was formulated and applied to the neighboring area of Pusan port. Because all tidal constituents for prediction (normally 69 constituents are used) can't be considered due to difficulties on computing efforts, some errors between the observed and predicted values were inevitably occurred. But it was confirmed that the practical results with about 10% of relative errors were obtained if four major tidal constituents(M$_2$, S$_2$. $K_1$, $O_1$) are used at least. Thus, if other constituents than four major tidal constituents are additornaly used, more accurate results will be obtained . Furthermore, if the databases of harmonic constants in coastal waters is made in advance using the numberical tidal model, prompt tidal prediction could be achieved whenever required.