• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.434-444
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• 1994

Physical and acoustic properties of sediment core samples recovered from the Kwangyang Bay, the Yeosu Sound, and the inner shelf of central South Sea, Korea were investigated. Compressional wave velocity, density, porosity, and shear strength were measured at 10cm interval's along the core depth. Sediment texture(grain size, sand, silt, and clay contents) were also measured and correlated with the physical properties(density, porosity, and shear strength). The physical and acoustic properties of the sediment changed gradually from the Kwangyang Bay to the shelf area in accordance with the distance from the input source of the terrigenous sediment. The Yeosu Sound acted as a route of sediment transport from the estuary(the Seomjin River) to the shelf and vice versa. The physical and acoustic properties of the Yeosu Sound sediment conformed to an intermediate stage between river mouth and shelf areas. These results can be utilized to trace the influence of the Seomjin River on the so-called mud belt of Korea.

• International Commerce and Information Review
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• v.15 no.2
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• pp.3-23
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• 2013

In 1997, 180 countries signed the Kyoto Protocol in Kyoto, Japan. The Kyoto Protocol came into force in February 2005. The agreement calls for industrialized nations to cut greenhouse gas emissions by 5 percent from 1990 levels by 2008 to 2012. One of those polices is a modal shift that change from road freight to sea, inland waterway and railroad transportation that is eco-friendly. The increase of road freight brings road congestion, accidents, logistic costs, air pollution and greenhouse gases. Railroads are superior than the other modes of transportation in mass transportability, high speed, timeliness, safety and environmental-friendliness, but the railway industry has been pushed behind in competition. Korean railroads were used by passengers and freight transport popularly until the middle of 20th century, however, by the sudden change of logistics environments, a shaving time efficiency being most important, railroad logistic lost its competitive power against the transportation by truck. From the research which sees consequently investigated a various policy, a system and a law about Chinese logistics industry and present condition of the Chinese goods enterprise and instance analysis of the large Chinese corporation that branch out to undeveloped markets led and a Chinese logistics industry and problem point escape hereafter the heightening of competitiveness plan which is rational under prsenting boil.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.1
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• pp.39-51
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• 2011

Acute toxicity test and behavioral change analysis of seawater acclimated Japanese medaka were conducted to identify the brine effects on fish by seawater desalination. 7 day acute toxicity test of brine revealed linear concentration-response relationship from 40.0~80.0 psu treatment groups. There was no significant brine effect for 30-40 psu groups and mass mortality was observed from >50 psu exposure (7-day $LC_{50}$=51.4 psu). Images from the real time camera system were analyzed to observe the changes in behavioral patterns of medaka exposed to various salinity. 40.0 and 50.0 psu exposed groups were stabilized in behavioral patterns after 3.1 and 4.6 hours, respectively and 60.0 psu group showed sharp increase in activity during first 12 hours and 50% mortality thereafter. Similar patterns were observed to 70 and 80 psu groups and both experimental groups showed 100% mortality within 12 hours. Acute toxicity test and behavioral patterns showed very similar toxicity results which revealed the increases in mortality and behavioral activities from 50.0 psu. This critical salinity for fish impacts must be implemented to brine discharge strategy by seawater desalination into the coastal area. Also, we recommend that real time camera monitoring system must be a useful tool for early warning of fish toxicity for other applications. This research was funded by Ministry of Land, Transport and Maritime Affairs, Korea.

• Ocean and Polar Research
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• v.37 no.2
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• pp.127-140
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• 2015

A continuous series of 60 snow samples was collected at a 2.5-cm interval from a 1.5-m snow pit at a site on the Styx Glacier Plateau in Victoria Land, Antarctica, during the 2011/2012 austral summer season. Various chemical components (${\delta}D$, ${\delta}^{18}O$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $SO_4{^2-}$, $NO_3{^-}$, $F^-$, $CH_3SO_3{^-}$, $CH_3CO_2{^-}$ and $HCO_2{^-}$) were determined to understand the highly resolved seasonal variations of these species in the coastal atmosphere near the Antarctic Jang Bogo station. Based on vertical profiles of ${\delta}^{18}O$, $NO_3{^-}$and MSA, which showed prominent seasonal changes in concentrations, the snow samples were dated to cover the time period from 2009 austral winter to 2012 austral summer with a mean accumulation rate of $226kgH_2Om^{-2}yr^{-1}$. Our snow profiles show pronounced seasonal variations for all the measured chemical species with a different pattern between different species. The distinctive feature of the occurrence patterns of the seasonal variations is clearly linked to changes in the relative strength of contributions from various natural sources (sea salt spray, volcanoes, crust-derived dust, and marine biogenic activities) during different short-term periods. The results allow us to understand the transport pathways and input mechanisms for each species and provide valuable information that will be useful for investigating long-term (decades to century scale periods) climate and environmental changes that can be deduced from an ice core to be retrieved from the Styx Glacier Plateau in the near future.

• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.246-258
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• 2012

Particulate matter deposited on leaf surfaces may cause erosion/abrasion of epicuticular wax and the malfunction of stomata. However, the deposition processes of particulate matter, such as elemental carbon (EC), has not been studied sufficiently in Asian forest ecosystems. Deposition processes for particulate ${SO_4}^{2-}$ and EC were studied in a Japanese cedar forest in Kajikawa, Niigata Prefecture, Japan, and in a dry evergreen forest and a dry deciduous forest in Sakaerat, Nakhon Ratchasima province, Thailand. The ${SO_4}^{2-}$ fluxes attributed to rainfall outside the forest canopy (RF), throughfall (TF), and stemflow (SF) showed distinct seasonalities at both sites, increasing from November to February at the Kajikawa site and in March/April at the Sakaerat site. Seasonal west/northwest winds in winter may transport sulfur compounds across the Sea of Japan to the Kajikawa site. At the Sakaerat site, pollutants suspended in the air or dry deposits from the dry season might have been washed away by the first precipitations of the wet season. The EC fluxes from RF and TF showed similar variations by season at the Kajikawa site, while the flux from TF was frequently lower than that from RF at the Sakaerat site. Particulate matter strongly adsorbed onto leaf surfaces is not washed away by rainfall and contributes to the EC flux. At the Kajikawa site, Japanese cedar leaf surfaces accumulated the highest levels of particulate matter and could not be neglected when calculating the total flux. When such leaf-surface particles were considered, the contribution of dry deposition to the total EC flux was estimated to be 67%, 77%, and 82% at the Kajikawa site, and at the evergreen and deciduous forests of the Sakaerat site, respectively. Leaf-surface particles must be included when evaluating the dry and total fluxes of particulate matter, in particular for water-insoluble constituents such as EC.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.5
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• pp.344-351
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• 2010

Uncertainty analysis on the net flow discharge (NFD) influencing the long-term material transport and the simulation results of the salinity and COD concentration distribution using the MIKE21 diffusion model in Gyeonggi bay and Han-River estuary is carried out. The NFD flowing the Gyodongdo - Seokmodo channel via the North channel of Ganghwado is estimated about 97% of the total NFD and the NFD of the Yeomha channel is estimated as only $2.5{\sim}3.0%$. On the other hand, the uncertainty defined as the difference by the different time-scale data input is analysed by the comparison of the model simulation result of the salinity and COD concentration distribution. One is computed based on the daily river flow data, and the other is computed based on the monthlymean river flow data. The results show that the salinity and COD concentration differences are about -10~20 psu and ${\pm}1.0\;mg/L$ during the summer season having a high flow discharge in Yeomha channel, respectively. The difference is clearly negligible in the open sea area.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.1-8
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• 2004

In this study, the change of the current in the coastal zone before and after the construction of Jeju new harbor was predicted by using the numerical model, which uses Hardy-Cross method. The numerical model was carried out for the present state, before the construction, and the state after the construction, and for the wave direction the NNW direction for winter and NE direction for summer were tested so that the seasonal change may be considered. The computation result shows that a large amount of the wave induced current was occurred when there were high waves coming in from NNW direction before and after the construction. Also, before the construction a longshore current occurred moving from the west to the east at the new harbor construction site so that it formed a rip current in the Hwabuk-dong front sea. And also, after the construction, the tip current produced changed into nearshore circulating current and a small circulating current appeared at the harbor entrance. On the other hand, at Samyang 4each, which is 3.0km away from the new harbor in the NE direction, shows that there was a longshore current occurred from the west to the east, which is in the opposite direction the new harbor, and the effect on the new harbor by sediment transport at Samyang beach is thought to be very small.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.1
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• pp.1-9
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• 2000

Vertical temperature distributions in muddy intertidal sediments near the Jebu Island on the west coast of Korea were obtained during the period of ebb tide which occurred in day time. The observations of mud temperature were made with thermistor embedded probe at 2cm interval for 18cm-layer of sediment for five different months of the year. Temporal changes in the vertical profile of the sediment temperature are strongly depend on the air temperature, the previous time of flood tide and the time of ebb tide. Heat exchanges in the surface layer (0-2 cm) in terms of magnitude and direction are greater than and opposite to those in the deeper sediment layer (8-12 cm), respectively and do not show any significant seasonal variations. In general, the surface layer gains heat while the deeper layer loses the heat. By using the 1-D diffusion equation temporal vertical profiles of the sediment temperature were obtained and were compared with the observed ones. The results show that in the sediment layer below 4 cm-depth the heat transport is predominantly by molecular diffusion. The average magnitude of heat flux into the sediment layer (0-18 cm) during the ebb tide when the mudflats were exposed in the middle of the day were between 4.1 and $28.9\;W/m^2$.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.37-49
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• 1996

The objectives of this study are to investigate the groundwater and surface water contamination, to interpret the attenuation mechanism of contaminant transport, and to find the appropriate contamination indicator. at the two big landfill sites : Nanjido Landfill and Hwasung Landfill. Leachate from the Nanjido, th, Hwasung and the Kimpo waste disposal sites is characterized by high temperature (31.7-40.1$^{\circ}C$), high electric conductivity (14,650-32,800 ${\mu}$S/cm), somewhat higher pH(7.58-8.45) and low Eh (-119.4-20.4 mV), and is enriched in both major (Na$^{＋}$, K$^{＋}$, Ca$^{2＋}$, Mg$^{2＋}$, HC $O_3$$^{－}$, Cl$^{－}$) and minor (Mn, Sr$^{2＋}$, Ba$^{2＋}$, Li$^{＋}$, F$^{－}$, Br$^{－}$) ions. Municipal solid waste leachate and industrial waste leachate are effectively discriminated by the content of S $O_4$$^{2－}$, Fe, and heavy metals. The attenuation mechanism of each component was assessed using the chemical analysis. Cl-normalizing process, WATEQ4F simulation, and preceding flownet analysis. Based on the calculation of Contamination Factor, K, Na, Ca, Mg, B, Zn, HC $O_3$, Cl, F, Br and TOC are effective contamination indicators in the Nanjido landfill site, and K, Na, Ca, Mg, B, S $O_4$, HC $O_3$, Cl, F, Br and TOC in the Habsburg landfill site Particularly, TOC is the best contamination indicator in landfill sites influenced by sea water.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.113-122
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• 2016

In this study, the dispersion process of pollutant substances in a port under wave and current environments was evaluated by a hydraulic experiment. Once the contaminants washed ashore into the port of Wolseong nuclear power plant, transport processes of pollutants were investigated by tracking the tracer according to the variations of experimental condition through a hydraulic experiment. Several hydraulic experiments were performed to analyze the pollutant discharge rate of the surface coming from the different coastal environments. From the hydraulic experiment results, the tracer concentration decreased exponentially. These results suggested that, after the tracer was transported to the open sea, a different gradient was shown under different conditions. For the case of a diluted condition, the half-life of flow rate was 2.70, 10.40, and 26.39 days for 30, 20 and 10 rpm in the left-side, respectively. The decrease of the tracer concentration under conditions of 30 rpm was much faster than that under conditions of 10 rpm. For the wave condition, the half-life of flow rate was 4.59 and 15.35 days for the right and left side of the port in a hydraulic scale prototype, respectively.