• Title/Summary/Keyword: Tide level

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The Evaluation of the Annual Time Series Data for the Mean Sea Level of the West Coast by Regression Model (회귀모형에 의한 서해안 평균해면의 연시계열자료의 평가)

  • 조기태;박영기;이장춘
    • Journal of Environmental Science International
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    • v.9 no.1
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    • pp.19-25
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    • 2000
  • As the tideland reclamation is done on a large scale these days, construction work is active in the coastal areas. Facilities in the coastal areas must be built with the tide characteristics taken into consideration. Thus the tide characteristics affect the overall reclamation plan. The analysis of the tide data boils down to a harmonic analysis of the hourly changes of long-term tide data and extraction of unharmonic coefficients from the results. Since considerable amount of tide data of the West Coast are available, the existing data can be collected and can be used to obtain the temporal changes of the tide by being fitted into the tide prediction model. The goal of this thesis lies in assessing whether the mean sea level used in the field agrees with the analysis results from the long-term observation data obtained with their homogeneity guaranteed. To achieve this goal, the research was conducted as follows. First the present conditions of the observation stations, the land level standard, and the sea level standard were analyzed to set up a time series model formula for representing them. To secure the homogeneity of the time series, each component was separated. Lastly the mean sea level used in the field was assessed based on the results obtained form the analysis of the time series.

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A Study on Making of Chart Datum Database (해도수준면(Chart Datum) 데이터베이스 제작 연구)

  • KANG YONG Q.;LEE MOONJIN
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.11 no.1
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    • pp.31-36
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    • 2006
  • A study on estimation of the datum level is carried out by combining observed and simulated harmonic constants of 4 major tides ($M_2$tide, $S_2$tide, $K_2$tide, and $O_1$tide). In the coastal zone, the datum level can be estimated by using observed tide harmonic constants at tide station. The observed tide harmonic constants, however, cannot be used to calculate the datum level of the sea because of the lack of tide station. In order to estimate the datum level of the sea, it is necessary to adopt the simulated harmonic constants instead of the observed ones. In this study, the datum level is calculated by using the simulated harmonic constants which is modified by tuning coefficient based on relationship between observed and simulated harmonic constants at tide station. Tuning coefficient of sea is interpolated on TIN (Triangulated Irregular Network) which has node points at tide stations.

Analysis of Operating Characteristics in Tidal Power Generation According to Tide Level

  • Hong, Jeong-Jo;Oh, Young-sun
    • International Journal of Contents
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    • v.18 no.1
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    • pp.76-84
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    • 2022
  • Tidal power generation plays a critical role in reducing greenhouse gas emissions. It uses a tidal force generated by gravitational force between the moon, the earth, and the sun. The change of seawater height generates the tide-generating force, and the magnitude of the change is the tide level. The tide level change has the same period as the tide-generating force twice a day, every 29.5 days, every year, and every 18.6 years. Sihwa Lake Tidal Power Station is Korea's first tidal power plant that began commercial power generation in August 2011 and has been accumulating a large volume of data on electricity production, power generation sales, sluice displacement, and tide levels. The purpose of this paper was to analyze the impact of the inefficiency factors affecting production and the tidal level change on tidal power generation and their characteristics using Sihwa Lake Tidal Power's operational performance data. Throughout this paper we show that tidal power generating operation is accurately predicting the trends of magnitude of tidal force to be periodical for each day. determining the drop to initiate the water turbine generator factoring the constraints on the operation of Sihwa Lake, and reflecting the water discharge through the floodgate and water turbine during the standby mode in the power generation plan to be in the optimal condition until the initiation of the next power generation can maximize power generation.

Long-term Change in Sea Level along the Eastern Coastal Waters of Korea using Tide Gauge, Water Temperature and Salinity (조위 및 수온, 염분 데이터를 이용한 동해 연안의 해수면 변화)

  • Park, Se-Young;Lee, Chung-Il
    • Journal of Environmental Science International
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    • v.23 no.5
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    • pp.801-806
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    • 2014
  • Long-term change in sea level along the eastern coast of Korea was illustrated using four tide-gauge station (Pohang, Mukho, Sokcho, Ulleung) data, water temperature and salinity. Seasonal variation in the sea level change was dominant. The sea level change by steric height derived from water temperature and salinity was relatively lower than that measured from the tide-gauge stations. Sea level rising rate per year by steric height increased with latitude. The effect of salinity(water temperature) on the sea level change is greater in winter(in summer).

Monitoring Activities of Permanent GPS Stations at Tide Gauge in South Korea

  • Won, Ji-Hye;Park, Kwan-Dong;Kim, Sang-Ho
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.525-528
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    • 2006
  • South Korea has about 80 permanent GPS stations, being used for a variety of applications such as DGPS, RTK, survey and geodesy. Some of them are installed in or near the coastal area for the purpose of maritime navigation. But, until recently, none of them are used for tide gauge benchmark monitoring. In order to monitor the absolute sea level changes, it is necessary to monitor the land uplift or subsidence occurring at tide gauge sites. It is a common practice to use GPS stations installed at tide gauges to determine absolute sea level. This collaborative efforts coordinated by IGS are called TIGA Pilot Project. Many countries including U.S., Canada, European Union nations, Australia and Japan are participating in TIGA, but South Korea is not a member yet. Recently, we established continuously operating GPS stations at tide gauges located in Incheon and Jeju to monitor the movement of tide gauges sites. This paper will introduce goals and progress of the efforts.

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Red Tide Detection through Image Fusion of GOCI and Landsat OLI (GOCI와 Landsat OLI 영상 융합을 통한 적조 탐지)

  • Shin, Jisun;Kim, Keunyong;Min, Jee-Eun;Ryu, Joo-Hyung
    • Korean Journal of Remote Sensing
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    • v.34 no.2_2
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    • pp.377-391
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    • 2018
  • In order to efficiently monitor red tide over a wide range, the need for red tide detection using remote sensing is increasing. However, the previous studies focus on the development of red tide detection algorithm for ocean colour sensor. In this study, we propose the use of multi-sensor to improve the inaccuracy for red tide detection and remote sensing data in coastal areas with high turbidity, which are pointed out as limitations of satellite-based red tide monitoring. The study area were selected based on the red tide information provided by National Institute of Fisheries Science, and spatial fusion and spectral-based fusion were attempted using GOCI image as ocean colour sensor and Landsat OLI image as terrestrial sensor. Through spatial fusion of the two images, both the red tide of the coastal area and the outer sea areas, where the quality of Landsat OLI image was low, which were impossible to observe in GOCI images, showed improved detection results. As a result of spectral-based fusion performed by feature-level and rawdata-level, there was no significant difference in red tide distribution patterns derived from the two methods. However, in the feature-level method, the red tide area tends to overestimated as spatial resolution of the image low. As a result of pixel segmentation by linear spectral unmixing method, the difference in the red tide area was found to increase as the number of pixels with low red tide ratio increased. For rawdata-level, Gram-Schmidt sharpening method estimated a somewhat larger area than PC spectral sharpening method, but no significant difference was observed. In this study, it is shown that coastal red tide with high turbidity as well as outer sea areas can be detected through spatial fusion of ocean colour and terrestrial sensor. Also, by presenting various spectral-based fusion methods, more accurate red tide area estimation method is suggested. It is expected that this result will provide more precise detection of red tide around the Korean peninsula and accurate red tide area information needed to determine countermeasure to effectively control red tide.

Comparison of Topex/Poseidon sea levels data and Tide Gause sea levels data from the South Indian Ocean (남인도양에서의 해수면에 대한 위성자료(Topex/Poseidon 고도계)와 현장자료(Tide Gauge 해면계)간의 비교)

  • 윤홍주;김상우;이문옥;박일흠
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.10a
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    • pp.281-285
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    • 2001
  • According to standard procedures as defined in the users handbook for sea level data processes, I was compared to Topex/poseidon sea level data from the first 350days of mission and Tide Gauge sea level data from the Amsterdam- Crozet- Kerguelen region in the South Indian Ocean. The comparison improves significantly when many factors for the corrections were removed, then only the aliased oceanic tidal energy is removed by oceanic tide model in this period. Making the corrections and smoothing the sea level data over 60km along-track segments and the Tide Gauge sea level data for the time series results in the digital correlation and RMS difference between the two data of c=-0.12 and rms=11.4cm, c=0.55 and rms=5.38cm, and c=0.83 and rms=2.83cm for the Amsterdam, Crozet and Kerguelen plateau, respectively. It was also found that the Kerguelen plateau has a comparisons due to propagating signals(the baroclinic Rossby wave with velocity of -3.9~-4.2cm/sec, period of 167days and amplitude of 10cm) that introduce temporal lags($\tau$=10~30days) between the altimeter and tide gauge time series. The conclusion is that on timescales longer than about 10days the RMS sea level errors are less than or of the order of several centimeters and are mainly due to the effects of currents rather than the effects of sterics(water temperature, density) and winds.

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Sea Level Change due to Nonlinear Tides in Coastal Region (연안해역에서 비선형 조석으로 인한 해수면 변화)

  • Jung, Tae Sung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.29 no.5
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    • pp.228-238
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    • 2017
  • In coastal region, tidal harmonic constants of semi-diurnal tides and nonlinear tides were collected. The observed tide data of KHOA were analyzed by a tide harmonic analysis method. In the southwestern coasts and Han river estuary, nonlinear tides are clearly generated. The generation of tide non-linearity and tide asymmetry is closely related with tide form factor in Korean coastal zone. Tide non-linearity and asymmetry in Mokpo harbour have increased by a series of coastal development projects. The increase has caused rise of high water level and drop of low water level, and increase of tidal range. In Kunsan Outport, tidal range has been declined due to inter-annual change of nonlinear tides after completion of Samangeum sea-dyke.

Tidal variations of Nutrient Concentration in Hampyeong Bay, West coast of Korea (서해 함평만에서 조위변화에 따른 영양염 변동)

  • Kang, Mi-Ran;Lim, Dhong-Il;Jang, Pung-Guk;Kim, Gi-Beum;Kang, Young-Shil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.3
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    • pp.202-208
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    • 2009
  • In order to understand the circulation of nutrient between muddy tidal flat and the surrounding coastal area, tidal time-scale variations in nutrient concentrations were seasonally investigated at the entrance of Hampyeong Bay. The results show that the temperature was higher in ebb tide and lower in flood tide during the summer, but it was lower in ebb tide and higher in flood tide during the autumn/winter. The salinity was higher in flood tide and lower in ebb tide during the summer/winter because of the inflow of external sea water resulting from the increase in the tide level. By contrast, the salinity was lower in flood tide and higher in ebb tide during the autumn. Salinity difference was lower than 0.3 psu between flood tide and ebb tide during survey period. Meanwhile, all nutrient concentrations observed in Hampyeong Bay was lower in flood tide and higher in ebb tide during the summer, and by contrast, it was higher in flood tide and lower in ebb tide during the winter. Characteristically, no clear variation of concentrations was found depending on the tide level during the autumn. This tidal variations imply that the muddy tidal flat of Hampyeong Bay supplies nutrients to the seawater in summer and removes nutrient from the seawater in winter. During tidal cycle, seasonal variation of nutrient concentration in seawater is considered as the result of complex interactions between the mud flat and external sea water.

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A Study on Water Level Rising Travel Time due to Discharge of Paldang Dam and Tide of Yellow Sea in Downstream Part of Paldang Dam (팔당댐 방류량과 황해(서해) 조석영향에 따른 팔당댐 하류부 수위상승도달시간 예측)

  • Lee, Jong-Kyu;Lee, Jae-Hong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.111-122
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    • 2010
  • As the Jamsu-bridge and the floodplains of the Han River can be flooded during the rainy season, the exact prediction of the peak flood time is very important for mitigation of flood hazard. This study analyzes the effect of outflow of Paldang Dam and tide of Yellow Sea on the Han River. A target area is from the Paldang dam to Jeonryu gauging station. Water level of Jeonryu as a downstream boundary condition was estimated through multi linear regression analysis with outflow of Paldang dam and tide level of Incheon, because it was influenced by both a tide of Yellow Sea and outflow of Paldang dam. In this study, Water Level Rising Travel Time of the Jamsu-bridge and some floodplains in the Han River are estimated. Also, The second order polynomial expressions for relationships of outflow of Paldang Dam and Water Level Rising Travel Time were developed considering the outflow of Paldang dam and tide of Yellow Sea.