• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.13-26
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• 2016

Sea water level variations are generally influenced by a variety of factors such as tides, meteorological forces, water temperature, salinity, wave, and topography, etc. Among non-tidal conditions, atmospheric pressure is one of the major factors causing water level changes. In the East Sea, due to small tidal range which is opposite to large tidal range of the Yellow Sea, it is difficult to predict water level changes using a numerical model, which consider tidal forcing only. This study focuses on the effects of atmospheric pressure variations on sea level predictions along the eastern coast of Korea. Telemac-2D model is simulated with the Inverted Barometer Effect(IBE), and then its results are analyzed. In comparison between observed data and predictions, the correlation of prediction with IBE and tide is better than that of tide-only case. Therefore, IBE is strongly suggested to be considered for the numerical simulations of sea level changes in the East Sea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.99-106
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• 2006

Due to both global warming and constructions of seadike/seawalls, continuously or abruptly rising tendencies of extreme high water levels have been detected at Kunsan and Mokpo harbors. This paper deals firstly with the separation of each effect, namely global warming effect and construction effect, on increases of water level quantitatively by a linear regression method. And then, it can be explained why and how the extreme high water levels had been risen just after constructions at both harbors. A numerical simulation of $M_2$ tidal constituent at Mokpo coastal zone shows that the tidal amplification by constructions is mainly due to the extinguishment of TCE at Mokpogu. The tidal flat effect makes the amplification more deepen at spring tide or extreme high tide, which results in the increase of inundation risk at Mokpo harbor. A frequency analysis method is applied, which is shown to be effective at such a site of having non-homogeneous tidal data due to constructions as Mokpo harbor.

• Environmental Analysis Health and Toxicology
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• v.16 no.2
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• pp.67-74
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• 2001

In a previous study by Kim et al. (2000), sodium hypochlorite (NaOCl) has been demonstrated to be effective against algae that cause red tides. To secure the environmental safely of the chemical in practical use, effect of NaOCl, at concentrations required for algicidal activity, on the histology of rockfish and little neck clam was examined. When the animals were exposed to NaOCl at concentrations of 0.5 or 2ppm for 1 hr, there was no exposure-associated histological change in either animal. As the experimental exposure condition was set in consideration of the use, our results provide safety information necessary for practical application to marine fields.

• The Journal of Fisheries Business Administration
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• v.46 no.1
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• pp.63-74
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• 2015

Due to red tide and abnormal currents that take place every year, the damage of inland fish farms that takes sea water is increasing frequently. Also, the households of inland fish farm due to the increase in the cost of fuel and electricity are struggling many hardships economically. In relation to underground seawater for it's farm analyzed economic effect based on the actual conditions for 1,700 inland fish farms, from this I have deduced policy implications for direction this project to be pursued from now on. The saving rate of costs of the fuel and electricity through the development of an underground seawater were approximately analyzed to decline about 3.4~9.7%, if utilizing only about 5% of the undeveloped farms, it was estimated effect of about 61 billion won, if 10%, it was estimated effect of about 122 billion won. Consideration in selecting the developer of underground seawater will be selected an character of farm method. It is expected this study will be helpful for business analysis related government in the fisheries.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.933-944
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• 2019

This study analyzes the tide deformation of land boundary regions on the east (Region A) and west (Region B) sides of the Ross Ice Shelf in Antarctica using Double-Differential Interferometric Synthetic Aperture Radar (DDInSAR). A total of seven Sentinel-1A SAR images acquired in 2015-2016 were used to estimate the accuracy of tide prediction model and Young's modulus of ice shelf. First, we compared the Ross Sea Height-based Tidal Inverse (Ross_Inv) model, which is a representative tide prediction model for the Antarctic Ross Sea, with the tide deformation of the ice shelf extracted from the DDInSAR image. The accuracy was analyzed as 3.86 cm in the east region of Ross Ice Shelf and it was confirmed that the inverse barometric pressure effect must be corrected in the tide model. However, in the east, it is confirmed that the tide model may be inaccurate because a large error occurs even after correction of the atmospheric effect. In addition, the Young's modulus of the ice was calculated on the basis of the one-dimensional elastic beam model showing the correlation between the width of the hinge zone where the tide strain occurs and the ice thickness. For this purpose, the grounding line is defined as the line where the displacement caused by the tide appears in the DDInSAR image, and the hinge line is defined as the line to have the local maximum/minimum deformation, and the hinge zone as the area between the two lines. According to the one-dimensional elastic beam model assuming a semi-infinite plane, the width of the hinge region is directly proportional to the 0.75 power of the ice thickness. The width of the hinge zone was measured in the area where the ground line and the hinge line were close to the straight line shown in DDInSAR. The linear regression analysis with the 0.75 power of BEDMAP2 ice thickness estimated the Young's modulus of 1.77±0.73 GPa in the east and west of the Ross Ice Shelf. In this way, more accurate Young's modulus can be estimated by accumulating Sentinel-1 images in the future.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.1
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• pp.26-37
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• 2017

The purpose of this study was to investigate secondary pre-service science teachers' misconceptions of tide and to develop a learning module that can change misconceptions into scientific concepts and to examine the effect of the learning module for conceptual change. In order to achieve the purpose of the study, the researcher developed the test tool of tidal phenomena and the learning module using cognitive conflict strategy. The subjects of this study were 40 first year students who majored science education at a college of education in G metropolitan city. The results of this study are as follows. First, secondary pre-service science teachers had various misconceptions about tidal phenomena. Second, the developed learning module was effective in changing misconceptions about tide of pre-service science teachers into scientific concepts. However, some students had misconceptions about tidal phenomena after learning the developed module. The typical misconception was that they could not distinguish the centrifugal force generated when the earth and the moon revolve about the center of common mass as the center of rotation and the centrifugal force generated by the earth's rotation. And they did not know that they should not consider the earth's rotation while the earth was revolving around the center of common mass.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.13 no.4
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• pp.309-318
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• 2001

A zero-dimensional simple model is presented to predict the currents in the opening channel of tide embankment and the sea-level response of the interior basin to ocean sea level. In general, a tidal embayment has wide tidal flats so that the effect of tidal flats has been taken into account by formulating the volute variation vs. depth. The model has been verified through the comparison with the 2-dimensional depth-integrated model which can resolve the small area by using the multigrid method. As the results applied to the storage of dredged material of Incheon North Harbour, the results indicate that both models adequately describe the sea-level and current fluctuations in the storage.

• Journal of the Korean earth science society
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• v.30 no.5
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• pp.671-681
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• 2009

In the equilibrium theory of tides by Newton, tide on the Earth is a phenomenon driven by differential gravity contributed both by the Sun and the Moon. Due to the direct link of the generic tidal effect to the oceanic tides, college students in the earth science education department are exposed to this theory through oceanography lectures as well as astronomy lectures. Common oceanography textbooks adopt a non-inertial reference frame fixed to the Earth in which the fictitious, centrifugal force appears. This has a potential risk to provide misconceptions among students in various aspects including the followings: 1) this is how Newton originally derived the equilibrium theory of tides, and 2) the tide is a phenomenon appearing only in rotating systems. We show that in astronomy, a much simpler description, which employs the inertial frame, is generally used to explain tides and thus causes less confusion. We argue that the description used in astronomy is preferable both in the viewpoints of simplicity and ease of interpretation. Moreover, on a historical basis, an inertial frame was adopted by Newton in Principia to explain tides. Thus, the description used in astronomy is consistent with Newton's original approach. We also present various astrophysical tides which do not comply with the concept of centrifugal force in general. We therefore argue that the description used in oceanography should be compensated by that in astronomy, due to its complexity, historical inconsistency and limited applicability.

• Journal of Environmental Science International
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• v.30 no.11
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• pp.925-936
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• 2021

The study was aimed to investigate the correlation between tidal effects and fog occurrence in Incheon and Mokpo, which are located in the middle and southern coasts of the West Sea of Korea, respectively. The investigation used meteorological data obtained from the automated synoptic observing systems and automatic weather stations and ocean data from tide stations from 2010 to 2019. Fog occurrence frequency was highest at high tide (Incheon, 41%; Mokpo, 45%). During fog event days at high tide, the dew-point depression was low (Incheon, 0.5℃; Mokpo, 0.4℃) and the relative humidity was high (Incheon, 97%; Mokpo, 98%). The wind speed was 2.4 m/s in Incheon and 2.0 m/s in Mokpo, and the main wind directions were west-southwesterly from Incheon and southwesterly from Mokpo. In the fog case study, tidal flats were covered with water before and after the fog started. During the fog period, both stations experienced negative air-sea temperature differences, low dew-point depression, and high relative humidity were maintained, with weak winds forming from the tidal flats to the shore.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.399-404
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• 2006

Kweon et al. (2004) proposed the calculation method of Expected Overtopping Probability (EOP) that considers the occurrence frequency distribution of real sea tide. The method was applied for the comparison of the EOP of Mukho and Busan sea. They showed that the tide occurrence frequency had a great effect on the EOP and the value becomes smaller as the standard deviation of the frequency comes bigger. The present study following Kweon et al.'s method estimates the EOP characteristic of the crest elevation located on East, South, and West sea. The study shows that the EOP becomes smaller following East, South, West sea in order.