• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.730-737
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• 2014

In this study, chloride content of marine concrete bridge at the south coast in 5~34years was calculated based on the measured data and the validity of the proposed value was evaluated. Also, correlation of existence of salt injury prevention coating, chloride content, carbonation depth and the compressive strength of marine concrete bridges were derived and relationship of the four was evaluated. According to the research results, surface chloride content value in the tidal zone proposed form KCI 2009 and value in the splash zone and atmospheric zone proposed form Cheong et al.(2005) was the most valid. Also, salt injury prevention coating of marine concrete bridges had the outstanding effect of preventing chloride content penetration, carbonation depth and reduction in the compressive strength. Compressive strength of concrete was reduced by the increase of carbonation depth and chloride content.

• Journal of Korean Society on Water Environment
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• v.35 no.3
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• pp.234-247
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• 2019

In a deep lake and reservoir, thermal stratification is of great importance for characteristics of hydrodynamic mixing of the waterbody, and thereby influencesvertical distribution of dissolved oxygen, substances, nutrients, and the phytoplankton community. The purpose of this study, was to project the effect of a future climate change scenario on water temperature, stratification strength, and thermal stability in the Soyanggang Reservoir in the Han River basin of South Korea, using a suite of mathematical models; SWAT, HEC-ResSim, and CE-QUAL-W2(W2). W2 was calibrated with historical data observed 2005-2015. Using climate data generated by HadGEM2-AO with the RCP 4.5 scenario, SWAT predicted daily reservoir inflow 2016-2070, and HEC-ResSim simulated changes in reservoir discharge and water level, based on inflow and reservoir operation rules. Then, W2 was applied, to predict long-term continuous changes of water temperature, in the reservoir. As a result, the upper layer (5 m below water surface) and lower layer (5 m above bottom) water temperatures, were projected to rise $0.0191^{\circ}C/year$(p<0.05) and $0.008^{\circ}C/year$(p<0.05), respectively, in response to projected atmospheric temperature rise rate of $0.0279^{\circ}C/year$(p<0.05). Additionally, with increase of future temperature, stratification strength of the reservoir is projected to be stronger, and the number of the days when temperature difference of the upper layer and the lower layer becomes greater than $5^{\circ}C$, also increase. Increase of water temperature on the surface of the reservoir, affected seasonal growth rate of the algae community. In particular, the growth rate of cyanobacteria increased in spring, and early summer.

• Analytical Science and Technology
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• v.25 no.6
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• pp.441-446
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• 2012

In this study, mercury, methylmercury and heavy metals in sediment from the lake Andong were analyzed, along with the estimation of mercury flux between sediments and water in the lake Andong. Average mercury concentrations in sediments sampled in 2009~2011 were $155.0{\pm}71.9$ ng/g, $211{\pm}62$ ng/g and $198{\pm}6.88$ ng/g, respectively. The average methylmercury concentration were $1.85{\pm}1.09$ ng/g (2009) and $3.49{\pm}1.79$ ng/g (2011), and %methylmercury, the fraction of methylmercury in total mercury were $1.17{\pm}0.39%$ and $1.77{\pm}0.94%$, respectively. Heavy metal (Zn, Cd, Pb, Cu) concentrations of the sediments exceeded ERL (Effect Range Low) level of US NOAA (National Oceanic and Atmospheric Administration)'s sediment quality criteria. Estimated mercury sedimentation flux was found to be 83.7 $ng/cm^2{\cdot}yr$ and mercury diffusion flux was estimated as 1.24 $ng/cm^2{\cdot}yr$.

• Journal of Environmental Science International
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• v.20 no.7
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• pp.819-828
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• 2011

This research was done to clarify the cooling effect of water particles generated from a fountain. This effect is a one way to control the heat island effect of big cities. The result of this research was drawn by setting the jets of water in a certain height, and then studying the diffusion of water particles, which is affected by the size of the particles and the wind speed, and the cooling effect caused by the diffusion. 1) When a diameter of a water drop was 500 ${\mu}m$ and the wind speed was 2.0 to 6.0 m/sec, the water drop diffused 75 to 190m, and the water vapor spread over 175 to 440 m. As a result, there was more than $0.5^{\circ}C$ of cooling effect on the temperature in the atmosphere 130 to 330m around the water fountain. 2) When a diameter of a water drop was 750 ${\mu}m$ and the wind speed was 2.0 to 6.0 m/sec, the water drop diffused 65 to 150 m, and the water vapor spread over 160 to 405 m. Moreover, there was more than $0.5^{\circ}C$ of cooling effect on the temperature in the atmosphere 110 to 275 m around the water fountain. 3) After studying on the relationship between the diameter of water drop and the wind speed, and the diffusion of water particles and the range of the atmosphere that was cooled, a result could be drawn from the research that the smaller the diameter of the water vapor gets and the faster the wind speed becomes, the wider the water particles diffuse and the cooler the atmosphere around the fountain becomes. 4) This research further extrapolates that when the ordinary water(tap water, water from river and stream) is used in a fountain, the cooling effect of the air near the fountain can be approached similarly. If the seawater is used in a fountain, there is to be more to concern not only on cooling effect on the air, but also on other effects on surrounding environment generated by the salt in seawater.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.73-80
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• 2009

Recently in order to mange better life quality much effort was spent for environmental-friendly urban development project and environmental restoration project. During these projects, there should be deep understanding about atmospheric environment change analysis and long term monitoring so that it would be helpful for better environment promotion such as heat island mitigation effect and wind way construction. In this study, the surface temperature environment change between before and after Cheonggye Stream Restoration Project was mapped and analyzed by using ASTER(Advanced Spaceborne Thermal Emission Reflection Radiometer) TIR(Thermal Infrared) satellite imagery and finally the fact, that the heat island effect was mitigated, was clarified. For this study, the correlation analysis was conducted through comparing the difference between atmosphere temperature of AWS(Automatic Weather System) and surface temperature of ASTER. Furthermore, this study will be the infrastructure of urban meteorology model development by understanding surface temperature pattern change and executing quantitative analysis of heat island.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.522-534
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• 2017

The purpose of this study is to verify urban flow and thermal environment by using the simulated Computational Fluid Dynamics (CFD) model in the area of Gangnam Seonjeongneung, and then to compare the CFD model simulation results with that of Seonjeongneung-monitoring networks observation data. The CFD model is developed through the collaborative research project between National Institute of Meteorological Sciences and Seoul National University (CFD_NIMR_SNU). The CFD_NIMR_SNU model is simulated using Korea Meteorological Administration (KMA) Local Data Assimilation Prediction System (LDAPS) wind and potential temperature as initial and boundary conditions from August 4-6, 2015, and that is improved to consider vegetation effect and surface temperature. It is noticed that the Root Mean Square Error (RMSE) of wind speed decreases from 1.06 to $0.62m\;s^{-1}$ by vegetation effect over the Seonjeongneung area. Although the wind speed is overestimated, RMSE of wind speed decreased in the CFD_NIMR_SNU than LDAPS. The temperature forecast tends to underestimate in the LDAPS, while it is improved by CFD_NIMR_SNU. This study shows that the CFD model can provide detailed and accurate thermal and urban area flow information over the complex urban region. It will contribute to analyze urban environment and planning.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.104-110
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• 2006

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Accordingly, release of contaminants from non-point sources, released with surface runoff of rainwater, is influenced by atmospheric phenomena, geology, and topography. This makes the control of non-point source difficult. Therefore, this study intends to reveal the characteristics of runoff and particle size distribution to observe the fundamental characteristics of runoff. Experiments were carried out at inner road of research center. Average concentration of runoff ranged from 26.8 to 126.4 mg/L for SS and $COD_{Cr}\;15.3{\sim}117.7mg/L,\;TN\;0.07{\sim}5.16mg/L,\;TP\;0.06{\sim}0.49mg/L$ and heavy metals $0.00{\sim}0.29mg/L$. First flush, indicated wash off of pollutant at first rain, was observed for all types of pollutants. Most pollutants revealed a very close correlation with SS ($R^2=0.93{\sim}0.99$). After analyzing characteristics of particle, particle was finer than that from previously examined data.

• Particle and aerosol research
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• v.17 no.4
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• pp.125-132
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• 2021

Fresh PM_2.5 smokes emitted from combustion of four biomass materials (pellet, palm fruit fiber (PFF), PKS, and sawdust) in a laboratory-controlled environment were characterized using an attenuated total reflectance-fourier transform infrared (ATR-FTIR) technique. In smoke samples emitted from combustion of pellets, PFF and PKS, which is being used as boiler fuels for greenhouses in rural areas, the organic carbon/elemental carbon (OC/EC) ratios in PM_2.5 were very high (14.0-35.5), whereas in sawdust smoke samples they were significantly low (<4.0) due to the combustion method close to flaming combustion. ATR-FTIR analysis showed that OH(3400-3250 cm^-1), CH₃(2958-2840 cm^-1), CH₂(2910 cm^-1 and 2850 cm^-1), ketone(1726-1697 cm^-1), C=C(1607-1606 cm^-1 and 1515-1514 cm^-1), lignin (1463-1462 cm^-1 and 1430-1428 cm^-1) and -NO₂(1360-1370 cm^-1) peaks were identified in all biomass burning (BB) smoke samples. However, additional peaks appeared depending on the type of biomass. Among the four types of biomass materials, an additional peak of the methylene group CH₃(2872-2870 cm^-1) appeared only in PFF and PKS smoke samples, and a peak of C=O(1685 cm^-1) was also confirmed. And in the case of PKS smoke samples, a peak of aromatic C=C(1593 cm^-1 and 1476 cm^-1) that did not appear in other BB samples was also observed. This indicates that the molecular structure of organic compounds emitted during BB differs depending on the type of biomass materials. The results of this study are expected to provide valuable information to more specifically reveal the effect of BB on PM_2.5 collected in the atmospheric environment.

• Journal of ILASS-Korea
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• v.20 no.1
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• pp.28-34
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• 2015

Recently, some researchers have been carried out risk assessment of vehicles exhaust on human health. Especially, some of VOCs which is non-controlled, was classified to hazardous pollutant, such as 1,3-Butadiene and BTEX(Benzene, Toluene, Ethylbenzene and Xylene). Therefore, the profile on non-controlled pollutant may be needed in the future, because it would be critical data or information to control them. Additionally, with increasing amount of motorcycle, the source profiling is essential for estimating emission factor and amount on motorcycle exhaust. For these, in this study, imported motorcycles (8 vehicles) were selected as a test model while considering the increasing ratio on sales volume between 2013 and 2014; it was also compared with domestic motorcycles on those. The experiment was conducted by driving mode, UDC and ECE+EUDC that made from EURO III. In addition, it was performed at cold start driving mode without effect by displacement, for evaluating only correlation of BTEX with HC. In order to apply the ratio (m,p-Xylene/o-Xylene) as a marker, the ratio was compared with those of tunnel, road side and residential area. As a result, it showed best correlation ($R^2=0.98$) among those. In the future, it has to be considered as a marker for effect evaluation to atmospheric environment by exhaust emission.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.43-50
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• 2007

In order to calculate the strength and to. see the variation af the stratification in the Southern Waters af Korea, the stratification parameter defined as potential energy anomaly (PEA, $V(J/m^3)$) introduced by Simpson and Hunter (1974) was used The data used in this paper were observed in August 1999 and February 2000 by National Fisheries Research and Development Institute (NFRDI). Also to know the effects af the temperature and the salinity an the stratification respectively, averaged temperature and salinity were used in the process af calculation the parameter. V is generally high in the offshore. However, in February, V in the onshore is higher than that of the offshore due to the vertical temperature gradient caused by the expansion of South Korean Coastal Waters (SKCW). In the summer, the increase af the atmospheric heating, the temperature inversion phenomenon act an the stratification as the buoyancy forcing. In most cases, the effects of the temperature on the stratification is stronger than that of the salinity. The temperature effect is predominantly due to the extent af the intrusion of Tsushima Warm Current into the study area. However, at stations where V is high the effect af the salinity is also significant. In the winter, V is very low due to the decrease of the buoyancy forcing, but same stations show the relatively high V due to the expansion of SKCW and Tsushima Warm Current.