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2021, Vol.30, No.3

  • 1.

    CFD Simulation of Changes in NOx Distribution according to an Urban Renewal Project

    KIM JIHYUN | Yeon-Uk Kim | HeonSeok DO and 1other persons | 2021, 30(3) | pp.141~154 | number of Cited : 0
    Abstract PDF
    In this study, the effect of the restoration of Yaksa stream and the construction of an apartment complex by the urban renewal project in the Yaksa district of Chuncheon on air quality in the surrounding area was evaluated using computational fluid dynamics (CFD) model simulations. In order to compare the impact of the project, wind and pollutant concentration fields were simulated using topographic data in 2011 and 2017, which stand for the periods before and after the urban renewal project, respectively. In the numerical experiments, the scenarios were set to analyze the effect of the construction of the apartment complex and the effect of stream restoration. Wind direction and wind speed data obtained from the Chuncheon Automated Synoptic Observing System (ASOS) were used as the inflow boundary conditions, and the simulation results were weighted according to the frequencies of the eight-directional inflow wind directions. The changes in wind speed and NOx concentration distribution according to the changes in building and terrain between scenarios were compared. As a result, the concentration of NOx emitted from the surrounding roads increased by the construction of the apartment complex, and the magnitude of the increase was reduced as the result of including the effect of stream restoration. The concentration of NOx decreased around the restored stream, while the concentration increased significantly around the constructed apartment complex. The increase in the concentration of NOx around the apartment complex was more pronounced in the place located in the rear of the wind direction to the apartment complex, and the effect remains up to the height of the building. In conclusion, it was confirmed that the relative arrangement of apartment complex construction and stream restoration in relation to the main wind direction of the target area was one of the major factors in determining the surrounding air quality.
  • 2.

    Comparison of Accuracy between Analysis Tree Detection in UAV Aerial Image Analysis and Quadrat Method for Estimating the Number of Trees to be Removed in the Environmental Impact Assessment

    Minkyu Park | 2021, 30(3) | pp.155~163 | number of Cited : 0
    Abstract PDF
    The number of trees to be removed trees (ART) in the environmental impact assessment is an environmental indicator used in various parts such as greenhouse gas emissions and waste of forest trees calculation. Until now, the ART has depended on the forest tree density of the vegetation survey, and the uncertainty of estimating the amount of removed trees has increased due to the sampling bias. A full-scale survey can be offered as an alternative to improve the accuracy of ART, but the reality is that it is impossible. As an alternative, there is an individual tree detection using aerial image (ITD), and in this study, we compared the ARTs estimated by full-scale survey, sample survey, and ITD. According to the research results, compared to the result of full-scale survey, the result of ITD was overestimated by 25. While 58 were overestimated by the sample survey (average). However, as the sample survey is an estimate based on random samples, ART will be overestimated or underestimated depending on the number and size of quadrats.
  • 3.

    Wintering Avifauna Change Long-term Monitoring in Major Watershed Tributaries in Han River: Fundamental and Phylogenetic Biodiversity Assessment and Comparison

    Seongho Yun | Hong Mi Jin | Choi Jin hwan and 2other persons | 2021, 30(3) | pp.164~174 | number of Cited : 0
    Abstract PDF
    Information on biodiversity plays an important role in conservation planning for ecosystem. As existing biodiversity indices are calculated and predicted only based on the number of individuals and species, it is difficult to explain aspects of genetic and ecological diversity. Phylogenetic diversity can indirectly evaluate ecological diversity as well as genetic diversity overlooked by existing biodiversity assessments. In this study, typical metrics of biodiversity (e.g., species diversity, species richness, etc.) and phylogenetic diversity were evaluated together using a long-term monitoring data of winter birds in Jungrang, Cheonggye and Anyang stream where are designated as Seoul migratory bird reserves. Then discussed the meaning of each assessmentresult. In Jungrang and Anyang stream, the number of individuals generally decreased overtime, whereas in Cheonggye stream, there was no significant change. In addition, species abundance increased over time slightly in Cheonggye stream, while there was no significant change in Jungrang and Anyang stream. Species diversity temporally increased in Jungrang and Cheonggye stream, excluding Anyang stream, but phylogenetic diversity showed a tendency to increase only in Cheonggye stream. These changes in the biodiversity assessment indices are thought to be due to anthropogenic disturbances such as construction that occurred within each site, and it was shown that species diversity and phylogenetic diversity do not always lead to the same assessment results. Therefore, this study suggests that biodiversity assessment needs to be considered from various contexts such as genetic and ecological perspectives.
  • 4.

    Relationship between the Spatial Allocation of Developed Area and the Heat Wave Phenomenon: The Case of Five Metropolitan Cities

    Sangjun Kang | 2021, 30(3) | pp.175~185 | number of Cited : 0
    Abstract PDF
    To better understand the heat wave phenomenon in the urban areas, it is desirable to explore the relationship between spatial allocation of land use and the heat wave. The purpose of this paper is to investigate the ranking correlation between heat wave days and developed types, specifically, core and islet developments. The methods employed are morphological spatial pattern, spatial autocorrelation, and spearman ranking correlation analyses by using the 30-year annual heat wave day records forthe five metropolitans. This research indicates that a fragmented development pattern including islets has mostly negative effects to the urban heat wave phenomenon. It means there is a relation between development pattern and heat wave