• Journal of Environmental Science International
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• v.26 no.12
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• pp.1375-1387
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• 2017

In order to investigate the $PM_{10}$ concentration trend and its characteristics over five different sub area in Busan from 2013 to 2015, data analysis with considering air flow distribution according to its topography was carried out using statistical methodology. The annual mean concentrations of $PM_{10}$ in Busan tend to decrease from $49.6{\mu}g/m^3$ in 2013 to $46.9{\mu}g/m^3$ in 2015. The monthly mean concentrations value of $PM_{10}$ were high during spring season, from March to May, and low during summer and fall due to frequent rain events. The concentration of $PM_{10}$ was the highest in five different sub-area in Busan. High concentration episodes over 90 percentile of daily $PM_{10}$ concentration were strongly associated with mean daily wind speed, and often occurred when the westerly wind or southwesterly wind were dominant. Regardless of wind direction, the highest correlation of $PM_{10}$ concentrations was observed between eastern and southern regions, which were geographically close to each other, and the lowest in the western and eastern regions blocked by mountains. Wind flow along the complex terrain in Busan is also one of the predominant factors to understand the temporal variation of $PM_{10}$ concentrations.

• Journal of the Korean association of regional geographers
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• v.20 no.3
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• pp.334-343
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• 2014

The number of malaria cases has been undulating for the past 10 years in Korea since the reemergence of malaria in early 1990's. Considering the spatial variations of malaria incidence across the northmost border areas near the demilitarized zone (DMZ), the occurrence of the disease seems to be influenced by the natural and human environment in the region. Malaria is an infectious disease that is transmitted to humans by the bites of vector-mosquitoes that carry malaria parasites, and its incidence rate depends on specific climatic and sociodemographic factors. This study found that the spatial characteristics of malaria incidence have varied depending on relative proportions of mosquito habitats, distance between mosquito habitats and human residence, the physical and sociodemographic environments of the city by urbanization, and local topography.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3A
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• pp.209-216
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• 2009

The structural stability as well as economical efficiency of the wind sensitive structures are strongly dependant on accurate evaluation of the design wind speed. Present study demonstrates a useful wind data obtained at the wind monitoring tower in the Kwangyang Suspension Bridge site. Moreover the Measure-Correlate-Predict (MCP) method has been applied to estimate the long-term wind data at the bridge site based on the wind data at the local weather station. The measured data indicate that the turbulent intensities and roughness exponents are strongly affected by the wind direction and surrounding topography. The new design wind speed based on MCP method is 20m/s lower than that at the original estimation, and the resulting design wind load is only 36% of the old prediction. The field measurement of wind data is recommended to ensure the economical and secure design of the wind sensitive structures because the measured wind data reveal much different from the estimated one due to local topography.

• Ocean and Polar Research
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• v.28 no.4
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• pp.361-368
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• 2006

The Saemangeum tidal flat with an area of approxirnately $233km^2$ is one of the biggest estuarine tidal flats on the west coast of Korea. Because of its location in the estuary of Mangyeong and Dongjin Rivers, the tidal flat receives large amount of sediments. A 33-km long sea dyke, enclosing a coastal zone of $401km^2$, was constructed to reclaim tidal flat in the Saemangeum area. The dyke construction radically changes the local tidal current regime and estuarine circulation. These have an effect on sedimentary environments in the tidal flat. On the tidal flats of the study area net deposition occurred, but net erosion occurred near tidal channel in 2004. The comparison of topography and surface sediments in summer 2004 with those in summer 1988 before the dyke construction showed that elevation increased with maximum 80cm and mean grain sizes were fining at Gwanghwal tidal flats. Sedimentary facies of two cores from Gwanghwal tidal flat revealed homogeneous layers in the upper part suggesting rapid deposition after the dyke construction. The sedimentation rate in Gwanghwal tidal flat(GW 6) using $^{210}Pb$ analysis was about 5.4cm/yr which is well matched with the sedimentation pattern revealed by change in topography.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.101-112
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• 2013

Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) offers opportunities to make advances in many research areas including hydrology by providing near-global scale elevation measurements at a uniform resolution. Its wide coverage and complimentary online access especially benefits researchers requiring topographic information of hard-to-access areas. However, SRTM DEM also contains inherent errors, which are subject to propagation with its manipulation into analysis outputs. Sensitivity of hydrologic analysis to the errors has not been fully understood yet. This study investigated their impact on estimation of hydrologic derivatives such as slope, stream network, and watershed boundary using Monte Carlo simulation and spatial moving average techniques. Different amount of the errors and their spatial auto-correlation structure were considered in the study. Two sub-watersheds of Geum and Deadong River areas located in South and North Korea, respectively, were selected as the study areas. The results demonstrated that the spatial presentations of stream networks and watershed boundaries and their length and area estimations could be greatly affected by the SRTM DEM errors, in particular relatively flat areas. In the Deadong River area, artifacts of the SRTM DEM created sinks even after the filling process and then closed drainage basin and short stream lines, which are not the case in the reality. These findings provided an evidence that SRTM DEM alone may not enough to accurately figure out the hydrologic feature of a watershed, suggesting need of local knowledge and complementary data.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.310-317
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• 2016

This study aimed to evaluate the nutrient load balance from rice paddy fields with different topographies, alluvial plain and local valley. Continuous monitoring from May to September, 2013 was conducted for water quantification and qualification from alluvial plain in Yeoju region (32 ha) and local valley in Jincheon region (24 ha). The discharge rates of T-N from the alluvial plain were 57.2, 5.84, 22.7, and $5.20kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-N loads were 34.6, 4.73, 21.1, and $4.15kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In contrary, the T-P loads from the alluvial plain were 2.23, 2.22, 2.54, and $0.41kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-P loads were 1.44, 1.57, 1.82, and $0.34kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. The nutrient contents in drainage water were influenced by the amount of waters, rainfall, and surface drainage water. The Pearson correlation analysis showed that rainfall was significantly correlated with nutrient loads from July to August due to the amount of runoff in local valley paddy field, and irrigation was related with nutrient loads of drainage from July to August. This study showed that paddy rice farming in alluvial plain and local valley might be beneficial to water quality protection.

• KIEAE Journal
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• v.7 no.2
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• pp.17-23
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• 2007

While heat island has been recognized as an unique environmental nuisance in cities, the phenomenon tends to be regarded as an inevitable side effect on urbanization. Recently the nature of the heat island has been disclosed and efforts for the remedy have been discussed in many ways. Some pioneering actions have been taken to mitigate the strength of the heat island's intensity in several countries. After studies for the heat island and speculations on current pilot policies of 3 different countries has been done, mitigation policies for heat island has been suggested as followings. 1. Preservation of natural topography is essential because latent energy consumption(evapotranspiration) from the site is the single most important factor to mitigate the energy surplus caused by urban heat island. 2. Because current national zoning ordinance or building law can not effectively control the site specific local environment, heat island policy should be established or employed at local level. 3. Incentives for the mitigation should be adopted on the process of implementation because environment is public concern. 4. Wind can easily dissipate energy surplus which is the major driving force for heat island. Therefore local wind, the direction and intensity should be sustained and sometimes facilitated fully through policies.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.73-83
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• 2002

Gloss is very important optical property influencing the perceived quality of the paper surface as well as the surface after printing. Although the average gloss level of paper products or printed images is important to meet end use specifications, the occurrence of gloss mottle, or non-uniformity of gloss, is often of greater concern for meeting quality requirements, especially for the high gloss paper. Gloss variation originates from the irregularities of paper surface, especially surface roughness of paper. Roughness of paper can be divided into micro-roughness (under $1\mu m$ scale in variation) and macro-roughness (over $1\mu m$ scale in variation) depending on the scale of the irregularities. A clearer understanding of the gloss variation of paper can be achieved by separating the contributions of these two scales of roughness, and characterizing them independently. In order to do this, a novel gloss measuring method was introduced. This can detect local gloss with very high resolution. The effect of macro-roughness on gloss variation, which was identified by the measurable surface topography, was separated from the total gloss variation by using this method. The effect of micro-roughness was then estimated indirectly. The local gloss variations of various paper samples were then evaluated to demonstrate the utility of this approach.

• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.484-497
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• 2016

In order to understand the characteristics of the topography change in front of an impermeable breakwater, a coupled model for a two-way analysis of the existing LES-WASS-2D and newly developed morphodynamic model was suggested. A comparison to existing experimental results revealed that the results computed using the 2-D hydro-morphodynamic model were in good agreement with the experimental results for the wave form, pore water pressure in the seabed, and topographical change in front of a submerged breakwater. It was shown that the two-way model suggested in this study is applicable to a morphological change in the seabed around a submerged breakwater. Then, using the numerical results, the topographical changes in front of an impermeable submerged breakwater were examined in relation to partial standing waves. Moreover, the characteristics of the local scour depths in front of them are also discussed in relation to incident wave conditions, sediment qualities, and submerged breakwater shapes.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1133-1140
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• 2002

The growth and extent of the local pressure field at any point is of primary importance as it supplies the driving force for the local wind circulation which causes a medium-range transport of air pollutants. The local pressure field is produced by the variation of temperature in the lower layers of the atmosphere, and is called the thermal wave. The thermal wave is influenced by the difference in the diurnal variations between two regions with different surface condition, for example land and sea. This difference produces the land- and sea-breeze phenomenon, and brings corresponding variations in the form of the thermal wave. Daytime temperature over the inland area (Daegu) was higher than that of the coastal area (Busan). The temperature difference reached about 5~6$^{\circ}C$ in the late afternoon(30-31 May 1999). The low pressure system of Daegu was most fully developed at the time. In this study, we investigated the possibility of thermal low onset around Daegu in summer with an analytical model. The topography effect was neglected in the model. We could predict a thermal low-pressure of about 3.4hPa at Daegu with wide flat land surface, when the inland area is about 6K warmer than the coastal area temperature. The pressure decrease is somewhat less than the observed value(4~5 hPa).