• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.17-17
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• 2020

일반적인 연안 해역에서 창조지속시간과 낙조지속시간은 거의 동일한 수준을 보여 조위곡선은 대칭적인 형태를 띠게 된다. 그러나 M4분조나 MS4분조와 같은 천해조가 발달된 해역에서는 그 모체가 되는 M2분조나 S2분조와의 상대적인 위상차에 따라 조위곡선이 비대칭적인 형상을 띠기도 한다. 창조지속시간이 길 경우 낙조시 최대조류속이 크게 되는 낙조우세가 형성되는 반면 낙조지속시간이 길 경우에는 반대로 창조우세가 형성된다. 소류사의 움직임은 유속의 6승에까지 비례하므로 이러한 최대조류속 차이에 따라 창조우세 또는 낙조우세 해역에서 소류사 이동량에는 큰 차이가 발생할 수 있다. 감조하천의 경우 상류로 갈수록 창조우세화하는 것이 일반적인 것으로 알려져 있으며 국내에서는 금강을 비롯한 군산해역이 대표적이다. 창조우세인 군산해역과 반대로 영산강하구 및 목포해역의 경우 낙조우세를 보이고 있는데, 그 근원은 황해에서의 순환특성과 함께 목포해역 인근의 드넓은 조간대에 기인하는 것으로 추정하고 있다. 특히 인접한 무안만에서는 낙조지속시간이 창조지속시간에 비해 2시간 이상 짧아 국내에서 가장 심한 수준의 낙조우세를 보이고 있으며, 영산강하구 낙조우세의 근원으로 평가되고 있다. 한편 조간대가 발달된 해역은 천해조 생성에 따라 낙조우세 경향이 있음과 관련하여 Kang and Moon(2001)은 조간대가 조석파의 전파와 천해조 발생에 미치는 영향성에 대하여 수치실험을 통해 연구한 결과 무안만의 낙조우세는 조간대의 발달에 기인함을 재확인한 바 있다. 따라서 낙조 우세를 수치모형을 통해 재현하기 위해서는 조간대 모의가 필수적임과 동시에 낙조우세를 재현하기 위해서는 천해조 개방경계 설정이 필요하다고 알려져 있다. 또한 이렇게 천해조가 발달된 하구에서 조석비대칭 현상은 퇴적물 이동에 직접적인 영향을 미치게 되는데 Kang et al.(2002)은 소류사 및 부유사 이동에서 이러한 영향성에 대한 연구를 수행한 바 있다. 그 결과 천해조가 발달된 이러한 해역에서 퇴적물 이동과 관련된 수치모의시 M2분조와 같은 천문조 경계조건에 부가하여 M4분조의 천해조까지 포함시킬 것을 제안한 바 있다. 이와 같이 하구역에서는 천해조 발달로 인해 조석비대칭이 두드러지게 발달되어 있는 경우가 많으며, 감조하천 상류로 갈수록 비대칭은 더욱 심화되는 경향이 있다. 따라서 감조하천 하류부에서 조석을 고려한 경계조건을 부여하여 하천의 흐름양상을 수치적으로 모의할 경우 천해조가 발달된 하구역에서는 천해조가 포함된 경계조건은 필수적이라 할 수 있다.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.915-928
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• 2012

Han River estuary (HRE) is located at the middle of the western coast of Korea, and tidal currents were measured at 4 stations in this estuary during the winter season, and previously observed tide data was analyzed. The results of amplitude ratio of $M_4/M_2$ showed that increasing upward to estuary in the HRE. Tide harmonic constants of relative phase $2M_2-M_4$ represent flood dominance, with under 180 degree. But this method has a limit of analysis that typically based on the non-linear distortion of the tidal current in tidal lagoon system where freshwater discharge is assumed to be relatively small. The results of statistically tidal current data indicated that ebb current velocity would be great unlike tide data. Ebb and flood duration time is calculated by slack time of tidal current showed that ebb duration time is longer than flood. The results of correlation of analysis show high value (0.9) between tidal current stations from Incheon harbor to north entrance of Yeomha channel. We reconstructed to find the reasons for the features of ebb dominance the results of harmonic analysis. As major component ($M_2$) in combination with shallow water component ($M_4$), the tidal curve was presented flood dominance that has a flood current is stronger. However, these curve were changed to ebb dominance add up the non-harmonic components that had ebb direction flow by calculated tidally averaged current. The characteristic of enhancement on ebb is showed around the Yeomha channel in the HRE, because averaged flow which acts seaward such as long-term tidal current components due to non-linear effect and freshwater which overcome the flood current.

• 한국해양학회지
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• v.9 no.2
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• pp.19-30
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• 1974

Current observations were carried out in Jinhae Bay area during the period of January to February 1974. The data were synthetically analyzed and the characteristics of the water movement in Jinhae Bay were studied. The water movement in Jinhae Bay area is a reversing tidal current type and the Semi- diurnal tidal current is predominant. The ebb current begins at about high water time and the strongest current occurs at about 3 hour after high water. The flood current begins at 0.2-1.0 hour before low water and the strongest current occurs at about 3-4 hour after low water. The main ebb current flows to SE direction with the maximum welocity, about 100cm/sec and the lood flows to NW with the maximum velocity, about 70cm/sec. Generally, the ebb current in Jinhae Bay is more predominat than the flood current except at the west and the north coast area of Gadeog-do where the flood current is more predominant.

• Korean Journal of Ichthyology
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• v.28 no.3
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• pp.192-199
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• 2016

The Seokmo and Yeomha channels are representative areas of high tidal energy in the Han River estuary. Surveys of environmental variables and abundance of Coilia spp. larvae, an anadromous fish, were carried out following the tidal cycle in August 2007 and August 2008. It was found that mean water temperature varied by <$1^{\circ}C$ across flood and ebb tides. A clear difference in salinity was observed between tides, with a high of 15.1 psu during flood tide, and a low of 0.8 psu during ebb tide. Coilia spp. larvae were significantly more abundant during the ebb tide than the flood tide (p<0.05). Since Coilia spp. larvae are anadromous fish, it seems that they use the ebb tide as a Selective tidal stream transport (STST) for horizontal movement in order to settle in the estuary (cultivation area), following hatching in the upper/middle courses of the Han River. A high percentage of larvae with improved swimming ability (measuring ${\geq}13.6mm$ in length) was observed during the ebb tide.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.32-41
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• 2001

We measured the fluxes of COD, TN and 55 in addition to composition and quality of sediment in Komso Bay, West Coast of Korea. The fluxes of TN, SS and COD were measured during flood tide and ebb tide in April and August, 2000. Denitrification rates in the sediments was also measured by direct produced $N_2$ gas technique on April and August from 1999 to 2000 in the same sea area. The composition of the sediments were 0.33~5.67 % of sand, 20.2~25.6 of gravel and 68.7~77.0 % of silt. Ignition loss of the sediments were 6.58~7.50 %. The concentration of hydrogen sulfide in the sediments were 0.028~0.326 mg/gㆍdry and oxidation reduction potential of the sediments were -28~-15 mV Diurnal fluxes of COD, total nitrogen, and suspended solids with tidal current and denitrification rate in the tidal flat have been determined in Komso Bay The diurnal net flux of COD was same in April. While 14.4 ton COD/hr of net influx into the tidal flat was recorded in August. The diurnal net influx of total nitrogen was 0.16 ton N/hr in April and 1.13 ton N/hr in August. The diurnal net influx of suspended solids was 0.05 ton SS/hr in April, and also net influx of suspended solids was 0.29 ton SS/hr in August. The overall purification ability of the tidal flat were estimated 0.00~5.69 g COD/$m^2/day$, 0.06~0.45 g N/m²/day and 0.02~0.12 g SS/$m^2/day$ for COD, TN and SS, respectively. Denitrification rate was 0.009~1.720 m mole ${N_2}/m^2/day$ (average 0.702 m mole ${N_2}/m^2/day$) in April and 0.033~0.133 m mole ${N_2}/m^2/day$ (average 0.077 m mole ${N_2}/m^2/day$) in August, 1999. 0.000~l.909 m mole ${N_2}/m^2/day$ (average 0.756 m mole ${N_2}/m^2/day$) in April, 0.000~1.691 m mole ${N_2}/m^2/day$ (average 0.392 m mole ${N_2}/m^2/day$) in August, 2000. Even with a wide range of denitrification rate depending on the sampling location and studied periods, the average denitrification rate was estimated 0.482 m mole ${N_2}/m^2/day$ in the tidal flat of Komso Bay.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.201-211
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• 2006

55 zooplankton taxa including 35 copepoda were observed in the Uldolmok waterway during the sampling period from August 2003 to April 2004. Neritic species showed the seasonal species fluctuation, and oceanic warm-water species occurred throughout the year. The number of taxa tended to increase at the flood tide from low tide to high tide, and to decrease at the ebb tide from high tide to low tide. Therefore, species composition of zooplankton in the Uldolmok waterway seemed to be affected by the inflow of oceanic waters with oceanic species all the year round. Total abundance of zooplankton ranged from 104 (February 2004) to 2,717 indiv. $m^{-3}$ (August 2003). According to the tidal cycle, the change of total abundance was more irregular and variable in November 2003 and February 2004 than August 2003 and April 2004. In August 2003 and April 2004, total abundance was low at the strong tide, and was high at low and high tide when tidal current was weak. Average abundances of dominant species such as Paracalanus indicus, Cirripedia nauplii and Acartia hongi were on the order of twice higher at ebb tide than flood tide. However, their abundances were also subject to wide fluctuation within flood tide and ebb tide. The changes of environmental parameters such as water temperature, salinity and chlorophyll-a concentration were negligible along the tidal periods in the Uldolmok waterway. Therefore, the advection, transfer and loss of zooplankton population derived from strong tidal current and eddy formed by the local difference of tidal velocity lead temporal variation of zooplankton community more complex and variable in the Uldolmok waterway.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.301-306
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• 2006

In order to estimate the characteristics of water movements around artificial upwelling structure, current measurements were carried out along lines E-W and S-N on May 4th(neap tide} and May 30th(spring tide), 2006. In the study area, southeastward flow was dominant during the field observations, and the pattern of water movement in the upper layer above 30m depth was different from that in the lower layer below 30m depth Vertical flow(w-component} around the artificial structure area and western area was shown to be upward flow, but downward flow occurred in the southern, northern and eastern parts at the neap tide. At the spring tide, the ebb current along E-W line showed upwelling flow in the eastern part and western area and showed upwelling flow near the artificial structure area and downwelling flow far away that one. At the spring tide, upward flow was dominant along S-N line during the flood current Volume transport by upward flow was higher than that by downward flow. Volume transport by upward flow during ebb of neap tide was greater than during flood current of neap tide, but was reverse at the spring tide.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.425-428
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• 2019

본 연구에서는 남해 주변해역의 조석과 조류의 구조특성을 해석하기 위해 현장관측결과와 수치실험결과를 이용하였다. 남해 주변해역의 해수유동은 2003년~2008년 사이 노량수로, 대방수로, 여수수로, 창선수로, 강진만, 앵강만에서 ADCP 및 RCM 9 유속계를 사용하여 각 정점에서 1개월 정도 연속측류를 하였다. 노량수로와 대방수로에서는 ADCP를 사용하여 표층에서 저층까지 3m 간격으로 측류하였고, 여수수로, 창선수로, 강진만과 앵강만에서는 RCM-9 유속계를 사용하여 표층에서 연속 측류하였다. 노량수로 상층에서 동-서 방향의 최대 유속은 약 165~175 cm/sec, 대방수로에서는 창 낙조류 최대유속은 약 200~270 cm/sec, 여수수로에서는 약 85~96 cm/sec 정도 나타났다. 강진만의 표층에서 최대유속의 크기는 창 낙조류 비슷하게 35~46 cm/sec, 앵강만 입구 부근에서 낙 창조류 최대유속은 20~22 cm/sec으로 발생하였다. 또한, 조류수치모형실험을 수행하여 남해 주변해역의 조류분포 특성을 전반적으로 해석하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.232-237
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• 2008

A method to generate electric power from small scale water tank. For this purpose, manufacturing tank is investigated, measuring water level change at any time, and finally comparing experimental and theoretical value, are performed. Inner and outer tank are made to simulate flood and ebb generation. Two sets of pipe are connected between tanks, and experiments are performed under varying flowrate. Coefficients of flowrate are calculated comparing water level change data and theoretical value. Measured and theoretical water levels are highly correlated, and this ascertains that analytical equation simulates real water level changes well. Flowrate change depending on the existence of propeller and valve, on flood and ebb generation, shows the necessity of experiments in the process of manufacturing electric power system. Moreover, total energy calculated from experimental data agrees well with that of theoretical equation. In spite of small tidal power output, this generating system with optimum water tank can be applied to any place where high water level change occurs, and can make a contribution to producing new and renewable energy consequently.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.893-901
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• 2017

In order to understand the fluctuation characteristics of water temperature in August, water temperature, tide level, air temperature and wind data were analyzed using a power spectrum and coherence analysis for a region off the southern coast of Korea. Spectrum analysis showed that the water temperature and tide level in Wando, Goheung, Yeosu, Tongyeong and Masan have peaks over a semi-diurnal period. Coherence showed that water temperature was affected by tide in Wando, Goheung, Yeosu and Tongyeong where tidal range is relatively high. In Masan and Busan, where tidal range is relatively low, however, the tide did not affect water temperature significantly. In particular, wind was the most important factor in relation to water temperature in Masan. Time lags were calculated from phase. In Wando, water temperature decreased 1.5 hrs after a flood tide began. Water temperature decreased 0.3 hrs after a flood tide began in Goheung and Tongyeong. In Masan, water temperature increased 3 hrs after a south wind began. Water temperature in Yeosu was affected by tide, but air temperature, tide and wind in Busan affected water temperature very little.