• 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.

• The Korean Journal of Ecology
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• v.27 no.2
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• pp.73-77
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• 2004

Movement of shorebirds for roosting was studied to find their response to insufficient roosting area on Ganghwa Island. It was taken from two kinds of aspects of population fluctuation and direct observation of movement from March to October in 2002. Based on the data from their weekly fluctuation and flight observation, shorebirds on Ganghwa Island moved to roosts located far away. Shorebirds feeding at southern Ganghwa Island moved to Yeongjong Island for roosting during the spring tide period. High tide count showed that the number of shorebirds on Yeongjong Island increased strikingly, while the number of birds on Ganghwa Island decreased. As the tide level increased, the number of shorebirds on Ganghwa Island decreased in the fall migrating season (r$_{s}$= -0.81, p＜0.001), whereas that on Yeongjong Island was not correlated significantly. Direct observation showed that some of the birds on the upper tidal zone of Ganghwa Island moved directly to the northern mudflat of Yeongjong Island during the flowing tide or dropped by flat zone on Seondu-ri. Insufficient coastal wetlands on Ganghwa Island induced them to move away from the island for roosting place and to endure costly flight energy expenditure. The development of wetlands on the southern Yeongjong Island would make them have no place available to roosts. Therefore this study proposes that shorebird roosts on Ganghwa Island should be created to conserve their habitat.t.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1303-1304
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• 2005

The sea water and the soil of surface zone in lagoon have many physical relations between each other by both physical phenomena such as tidal motion and wave action, and activity of a creature which lives in soil zone. The soil zone has an activity of filtering the sea water at lowering tide and also the organic materials in sea water are supplied into the soil. And small creatures such as small crab eat organic materials. Usually the surface zone of lagoon becomes under the sea water in two times of a day and also is coming in two times under the sunshine and it becomes dries up conditions. Authors made the field observation at Sanbannse lagoon in Tokyo bay in several times between 2002 to 2004. The observation has been done in a half period of tide in October and November 2002 and also full tide observation is made in July 2, 2003 in summer and November 26, 2003 in autumn. In 2004, three times observations of full tide has been made in three times as June 22, July 20 and December 14. This report is the summary of results on these observations focusing on the soil surface zone and sea water at under ground and wave breaking zone.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1842-1853
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• 2015

The behavior characteristics of the saltwater intrusion in the Seomjin River Estuary by the inflow of fresh water were analysed by the field observation using CTD in the neap tide in January, June, and August 2013 as well as a numerical model, EFDC (Environmental Fluid Dynamics Code). As a result, Seomjin River Estuary is found that the saltwater intrusion is sensitive to the tide and tidal and freshwater flow. The results of field observation and numerical model were similar in the range of salt, but the results of salt wedge distribution were quite different. The observation of tide and tidal current as well as hydrographic surveying the Seomjin River Estuary will be jointly conducted for the accurate analysis.

• Journal of Environmental Science International
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• v.31 no.12
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• pp.1027-1038
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• 2022

The intertidal zone has both land and marine characteristics and shows complex weather environments. These characteristics are suited for studying climate change, energy balance and ecosystems, and may play an important role in coastal and marine weather prediction and analysis. This study was conducted at Odo Island, approximately 300m from the mainland in Yeosu. We built a weather observation system capable of real-time monitoring on the mud flat in the intertidal zone and measured actual weather and marine data. Weather observation was conducted from April to June 2022. The results showed changes in air temperature and water temperature with changes in the tide level during spring. Correlation analysis revealed characteristic changes in air temperature and water temperature during the day and night, and with inundation and exposure.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.233-239
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• 2003

Coastal wave and tide information is very important in various occasions for port and harbor engineers, in the stages such as port and harbor planning, maritime structure design, maritime construction management, and coastal disaster study This paper introduces recent improvement of Japanese coastal wave-tide observation and information system named as NOWPHAS (Nationwide Ocean Wave information network for Ports and HArbourS). Development and improvement of the NOWPHAS has been achieved during recent decade in the following points of view (Nagai,2002a,2002b). (omitted)

• Journal of Astronomy and Space Sciences
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• v.10 no.2
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• pp.189-196
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• 1993

Satellite laser ranging observation of LAGEOS II has been performed using the SLR System at Sheshan Laser Ranging Station, Shanghai Observatory. And we obtained 1,838 observational points. The observed range data is corrected by means of system delay correction using ground target observation, atmospheric refraction delay correction, offset correction, general relativistic correction and tide correction including solid tide, polar tide and ocean tide. As a result, the determined range delay mean value is 19.12m and the mean internal accuracy by means of polynomial fitting and least square method is $\pm$7cm. Corrected observational points are 1,340 and noise ratio to total observational points is 27.1%.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.137-142
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• 2003

Offshore observation of tsunami and storm surge before arriving to the coast is very important fur coastal disaster prevention. But up to ten years ago, coastal tide stations had been supposed to be the only means to observe tsunami and storm surge profile, fir difficulty of offshore observation (Goda.et.al., 2002). Recently seabed installed coastal wave gauges have been repeatedly reported to successfully observe various tsunami profiles by conducting continuous data acquisition (Goda.et.al., 2001 ： Nagai, 2002a; Nagai.et.al, 1996, 2000, 2002b). (omitted)

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.874-881
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• 2022

Until 2016, before discussions on the restoration of brackish water of the Nakdong River Estuary started in earnest, the downstream water level was predicted using the data of existing tide level observatories (Busan and Gadeokdo) several kilometers away from the estuary. However, it was not easy to carry out the prediction due to the dif erence in tide level and phase. Therefore, this study was conducted to estimate tide prediction more accurately through tidal harmonic analysis using the measured water level affected by the tides in the offshore waters adjacent to the Nakdong River Estuary. As a research method, the storage status of observation data according to the period and abnormal data were checked at 10-minute intervals in the offshore sea area near the Nakdong River Estuary bank, and the observed and predicted tides were measured using TASK2000 (Tidal Analysis Software Kit) Package, a tidal harmonic analysis program. Regression analysis based on one-to-one comparison showed that the correlation between the two components was high correlation coef icient 0.9334. In predicting the tides for the current year, if possible, more accurate data can be obtained by harmonically analyzing one-year tide observation data from the previous year and performing tide prediction using the obtained harmonic constant. Based on this method, the predicted tide for 2022 was generated and it is being used in the calculation of seawater inflow for the restoration of brackish water of the Nakdong River Estuary.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.654-655
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• 2003

Korea has experienced 10 a Cochlodinium polykrikoides red tide outbreaks during the last 10 years (1993-2002). The monitoring activities at National Fisheries Research and Development Institute (NFRDI) in Korea have been extended to all the coastal waters after the worst of fish killing by C. polykrikoides blooms in 1995. NFRDI is looking forward to finding out the feasibility of red tide detection around Korean waters using satellite remote sensing of NOAA/AVHRR, Orbview-2/SeaWiFS, IRS-P4/OCM and Terra/MODIS on real time base. In this study, we used several alternative methods including climatological analysis, spectral and optical methods which may offer a potential detection of the major species of red tide in Korean waters. The relationship between the distribution of SST and C. polykrikoides bloom areas was studied. In climatological analysis, NOAA, SeaWiFS, OCM satellite data in 20th and 26th August 2001 were chosen using the known C. polykrikoides red tide bloom area mapped by helicopter reconnaissance and ground observation. The 26th August, 2001 SeaWiFS chlorophyll a anomaly imageries against the imageries of non-occurring red tide for August 20, 2001 showed the areas C. polykrikoides occurred. The anomalies of chlorophyll a concentration from satellite data between before and after red tide outbreaks showed the similar distribution of C. polykrikoides red tide in 26th August, 2001. The distribution of the difference in SST between daytime and nighttime also showed the possibility of red tide detection. We used corrected vegetation index (CVI) to detect floating vegetation and submerged vegetation containing algal blooms. The simple result of optical absorption from C. polykrikoides showed that if we use the optical characteristics of each red tide we will be able to get the feasibility of the red tide detection.