• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.1
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• pp.1-10
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• 2011

To understand characteristics of the water quality on the coastal boundary on tidal flat, field observations between 2008 and 2009 were undertaken twice a month at five coastal areas (Muan bay, Tando bay, Hampyeong bay, Shinan Jido and Yeongkwang coastal areas). Yearly water temperature difference was large with the range between $1.3^{\circ}C$ and $31.1^{\circ}C$. Salinity was about 32 but was the lower less than 20 for the heavy rainfall season. DO was high in winter and low in summer according to the variation of water temperature. pH represented the variation similar to DO. Suspended solid was averagely high over 100 mg/l in Yeongkwang coastal area, especially. COD did not revealed large variation with the value of about 1 mg/l. DIN and DIP concentration were high when freshwater was highly input in summer. DIN concentration was low for winter and early spring but DIP concentration did not show the seasonal variation with the continuous increase from July 2009 to December 2009. Chlorophyll a appeared high for spring with approximately $10\;{\mu}g/l$ and was higher for summer in Yeongkwang coastal area than other sites. The results of principal component analysis conducted to compare the characteristics of water quality observed in study areas showed the distinguishable features as follows. The freshwater input fluctuation appeared as the first factor in Muan and Tando bays, and the change of water temperature was the first factor in Shinan Jido and Yeongkwang coastal areas. The influence mixed with the variation of freshwater outflow and the change of water temperature in Hampyeong bay was to be the first factor.

• Ocean and Polar Research
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• v.28 no.4
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• pp.369-383
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• 2006

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum studied area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after $(2002{\sim}2005)$ the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted The partial completion of Saemangeum dike $(4^{th}\;dike)$ in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the $4^{th}$ dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community resl)ended to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.247-247
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• 2023

Coastal lagoons play a crucial role in water exchange, water quality, and biodiversity. It is essential to monitor and understand the dynamics of hydrogeochemistry in lagoon water and its groundwater to preserve and sustainably manage the groundwater-dependent ecosystems like coastal lagoons. This study investigated the spatial and temporal hydrogeochemical characteristics of coastal lagoon (Songjiho) and groundwater on the east coast of Korea. The concentrations of major ions, water isotopes, and nutrients (nitrogen and dissolved organic carbon) in lagoon water and groundwater were periodically monitored for one year. The study revealed that major ions and total dissolved solids (TDS) concentration were higher at deeper depths of aquifers and closer to the coastal area. The hydrogeochemical characteristics of coastal lagoon and groundwater chemistry were classified into two types, Ca-Mg-HCO₃ and Na-Cl, based on their spatial location from inland to coastal area. Moreover, the hydrogeochemical characteristics of coastal lagoons and groundwater varied significantly depending on the season. During the wet season, the increased precipitation and evaporation lead to changes in water chemistry. As a result, the total organic carbon (TOC) of coastal lagoons increases during this season, likely due to increased runoff by rainfall whereas the variation of chemical compositions in the lagoon and groundwater were not significant because there is reduced precipitation, resulting in stable water levels and during the dry season. The study emphasizes the impact of spatial distribution and seasonal changes in precipitation, evaporation, and river discharge on the hydrogeochemical characteristics of the coastal aquifer and lagoon system. Understanding these impacts is crucial for managing and protecting coastal lagoons and groundwater resources.

• Ocean and Polar Research
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• v.31 no.4
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• pp.361-368
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• 2009

An operational oceanographic system needs to be established for the preservation and management of marine environments and resources, and also to secure the safety and efficiency of marine operations in Korea. One of the major roles of operational oceanography is to deliver ocean science products which can meet the requirements of users such as marine industries, the general public, government agencies, and scientific research communities. Technical issues in relation to development of an effective operational oceanographic system in Korea are identified and discussed. Among others, cooperation among the agencies in ocean, meteorology, hydrology and environment, and also among those of neighboring countries is important for the development of an effective operational oceanographic system. The strategy for building a system that meets the demands of users, with consideration to potential problems, are explored.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.375-388
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• 2009

Numerical simulation is essential to indicate the flow of the atmosphere in the region with a complicated topography which consists of many mountains in the inland while it is neighboring the seashore. Such complicated topography produces land and sea breeze as the mesoscale phenomenon of meteorology which results from the effect of the sea and inland. In the mesoscale simulation examines, the change of the temperature in relation to the one of the sea surface for the boundary condition and, in the inland, the interaction between the atmosphere and land surface reflecting the characteristic of the land surface. This research developed and simulated PNULSM to reflect both the SST and vegetation effect as a bottom boundary for detailed meteorological numerical simulation in coastal urban area. The result from four experiments performed according to this protocol revealed the change of temperature field and wind field depending on each effect. Therefore, the lower level of establishment of bottom boundary suitable for the characteristic of the region is necessary to figure out the atmospheric flow more precisely, and if the characteristic of the surface is improved to more realistic conditions, it will facilitate the simulation of regional environment.

• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.564-572
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• 2019

Numerical simulation of the sediment by the Delft3d model was conducted to examine the changes in the sediment budget transport caused by long-term wave changes at the Maengbang beach. Representative waves were generated with input reduction tools using NOAA NCEP wave data for about 40 years, i.e., from January 1979 to May 2019. To determine the adequacy of the model, wave and depth changes were compared and verified using wave and depth data observed for about 23 months beginning in March 2017. As a result of the error analysis, the bias was 0.05 and the root mean square error was 0.23, which indicated that the numerical wave results were satisfactory. Also, the observed change in depth and numerical result were similar. In addition, to examine the effect due to long-term changes in the waves, the NOAA wave data classified into each of the representative wave grades, and then the annual trend of the representative wave was analyzed. After deciding the weight of each wave class considering the changed wave environment in 2100, the amounts of sedimentation, deposition, and the sediment transport budget were reviewed for the same period. The results indicated that the sedimentation pattern did not change significantly compared to the current state, and the amount of the local sediment budget shown in the present state was slightly less. And there has been a local increase in the number of sediment budget transport, but there is no significant difference in the net and amount of sediment movements.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.767-777
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• 1999

In the coastal region air flow changes due to the abrupt change of surface temperature between land and sea. So a numerical simulation for atmospheric flow fields must be considered the correct fields of sea surface temperature(SST). In this study, we used variables such as latent heat flux, sensible heat flux, short and long wave radiation of ocean and atmosphere which exchanged across the sea surface between atmosphere and ocean model. We found that this consideration simulated the more precise SST fields by comparing with those of the observated results. Simulated horizontal SST differences in season were 2.5~4$^{\circ}C$. Therefore we simulated the more precise atmospheric flow fields and the movement and dispersion of the pollutants with the Lagrangian particle dispersion model. In the daytime dispersion pattern of the pollutants emitted from ship sources moved toward inland, in the night time moved toward sea by land/sea breeze criculation. But air pollutants dispersion can be affected by inland topography, especially Yangsan and coastal area because of nocturnal wind speed decrease.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.1
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• pp.59-65
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• 2007

Rapid variation of coastal ecosystem in the East Sea of Korea, such as fishery resource variation and subtropical chang of bentic flora, accordong to the global warming are actually noticed. In this study we try to identify the characterics of water mass existing in this coastal area and to consider the variation of their physical and chemical properties using data of temperature, salinity and dissolved oxygen obtained by National Fisheries Research & Development Institute from 1960 to 2005. The temperature of all water mass rise during last 45 years; the rise of North Korea Cold Water temperature (about $2.33^{\circ}C$) is 1.5 times higher than that of Tsushima warm water (about $1.6^{\circ}C$), and the temperature rise of Tsushima Surface Water, directly affected by climate chang is $2.57^{\circ}C$, higher than the atmospheric temperature rise during same period, indicating that subtropical change makes progress more rapidly in the coastal marine ecosystem than in the land ecosystem. Otherwise, the salinity in the surface water decrease $0.29\%_{\circ}$ during last 45 years due to the rising trend of rainfall with atmospheric temperature. The dissolved oxygen concentration in the all water mass make a decreasing trend. Specially for the North Korea Cold Water, the dissolved oxygen concentration diminish 0.021 mg/l per year and the decrease in the East Sea Proper Water indicate a change of inner water circulation system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.4
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• pp.292-301
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• 2012

The rise in sea surface temperature (SST) as a global warming enhance overall typhoon activity. We assumed that there exist thermodynamic limits to intensity that apply in the absence of significant interaction between storms and their environment. The limit calculations depend on SST and atmospheric profiles of temperature and moisture. This approach do appear to provide resonable upper bounds on the intensities of observed storms and may even be useful for predicting the change in intensity over a long period time. The maximum storm intensities was estimated through the global warming scenarios from IPCC-AR4 report over the North-East Asia. The result shows stronger intensities according to scenarios for increase of carbon dioxide levels. And storm surge simulations was performed with the typhoons which were combined route of the typhoon Maemi (2003) and intensity as climate change scenarios. The maximum increase of storm surge heights was shown about 29~110 cm (36~65%) regionally. Especially at Masan, the result of simulated maximum surge height exceed the 200 years return period surge.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.268-277
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• 2019

Severe damages will result in human society, when several different critical natural phenomena coincide. One example relates to the resting cysts of Alexandrium species (dinoflagellates that cause paralytic shellfish poisoning), which are preserved in surface sediments throughout Osaka Bay, Japan. These cysts have been found to accumulate particularly densely in shallow areas in the inner parts of Osaka Bay, where a tsunami caused by an earthquake could occur any time. Damage by a tsunami could cause a change of the coastal ecosystems at Osaka Bay including the resuspension of surface sediments containing resting Alexandrium tamarense cysts and the subsequent redistribution of the cysts in newly deposited sediment. Under certain environmental conditions, these cysts could germinate and form dense blooms, leading to paralytic shellfish poisoning. Such a scenario could also affect other coastal areas, including the southern coast of the Korean Peninsula.