• 한국환경과학회지
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• 제26권4호
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• pp.493-507
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• 2017

Since the late 20th century, the urbanization in Korea has been rapidly increasing, especially in major cities like Seoul, as a result of industrialization. One of the aspects of urbanization is coating the surfaces with impervious concrete or asphalt that water cannot penetrate. In addition, various urban, such as urban heat islands, which also have a great impact on the urban environment, occur within the cities. Therefore, the urban environment is gradually becoming hot and dry, and the need for more urban parks to compensate for these negative impacts is growing. Thus, several numerical studies have been conducted to assess these problems using coupled Numerical Weather Prediction (NWP) and Computational Fluid Dynamics (CFD). In this study, an experiment was conducted to determine the accuracy of the area of the input field using Weather Research and Forecasting (WRF) model, and applying the more accurate input field to a numerical simulation using ENVI-met, in order to investigate the effect of urban parks on the thermal comfort. The results showed that an input field with a larger area is more accurate than that with a smaller area, because the surrounding terrain and cities are considered in details in the experiment with the larger area. Subsequently, the more accurate input field was used in ENVI-met, and the results of this simulation showed that the presence of the urban park increased the thermal comfort and improved the humidity conditions.

• 대기
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• 제21권3호
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• pp.257-271
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• 2011

The aim of this study is to examine weather modification by urbanization and human activities. The characteristics of the urban heat island (UHI) and precipitation in Seoul metropolitan area of Korea are investigated to demonstrate that cities can change or modify local and nearby weather and climate, and to confirm that cities can initiate convection, change the behavior of convective precipitation, and enhance downstream precipitation. The data used in this study are surface meteorological station data observed in Seoul and its nearby 5 cities for the period of 1960 to 2009, and 162 Automatic Weather System stations data observed in the Seoul metropolitan area from 1998 to 2009. Air temperature and precipitation amount tend to increase with time, and relative humidity decreases because of urbanization. Similar to previous studies for other cities, the average maximum UHI is weakest in summer and is strong in autumn and winter, and the maximum UHI intensity is more frequently observed in the nighttime than in the daytime, decreases with increasing wind speed, and is enhanced for clear skies. Relatively warm regions extend in the east-west direction and relatively cold regions are located near the northern and southern mountains inside Seoul. The satellite cities in the outskirts of Seoul have been rapidly built up in recent years, thus exhibiting increases in near-surface air temperature. The yearly precipitation amount during the last 50 years is increased with time but rainy days are decreased. The heavy rainfall events of more than $20mm\;hr^{-1}$ increases with time. The substantial changes observed in precipitation in Seoul seem to be linked with the accelerated increase in the urban sprawl in recent decades which in turn has induced an intensification of the UHI effect and enhanced downstream precipitation. We also found that the frequency of intense rain showers has increased in Seoul metropolitan area.

• KIEAE Journal
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• 제12권2호
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• pp.65-75
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• 2012

The rapid urbanization caused drastic temperature changes in Korea. Excessive urbanization and development result in unpredictable and abnormal climate change all over the world. These changes are reflected in Korean government policy and research about cities, such that various research endeavors have been undergone recently. There are lots of ways to improve the urban environment; the easiest way to solve the urban heat effect problem is to make green spaces within the city. Even though we can't enlarge green spaces over the city limitlessly, it is desperately need for a methodology to efficiently create green space in limited area. Based on awareness of issues as mentioned earlier, we would like to propose landscaping method that can increase thermal comfort in the same area. For this study, simulating the change of temperature, mean radiant temperature, PMV were done due to number of species planted in apartment complex. To increase the reliability of the simulation, first above all, field measurement for temperature change was performed in apartment complex, where residential building are arranged in the form of ㄷ. And based on this data, Envi-met simulation was performed varying 1-7 kinds of species divided by grass, shrubs, arbor (deciduous, conifers) planted in apartment complex. As a result, there was a change less than $1^{\circ}C$ with the increasing number of species in daytime, but the average radiation temperature about $6-7^{\circ}C$ was reduced. In addition, PMV index was improved by more than 0.5 point. Thermal comfort indicator improved significantly depending on the number of species during the day, on the other hand, there were no significant changes at night. As a consequence, this study has shown that not single-species planting but mixed planting varied the number of species would improve the thermal comfort in the same area of landscaping space at daytime.

• 한국물환경학회지
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• 제35권1호
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• pp.35-42
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• 2019

Urbanization has led to extreme changes in land use on urban watersheds. Most cities are becoming residential, commercial and industrial areas, making infiltration and storage of rainfall less favorable. The demand for LID (Low Impact Development) technology is increasing in order to mitigate this water cycle distortion and return to existing hydrological conditions. The LID technique is effective in reducing runoff by permeating the urban impervious area. However, considering the limit of the installation area and the financial requirement of the installation, there is not much research on the linkage of each LID component technology for optimum efficiency according to the appropriate scale. In this study, the effects of the LID facilities applied to the target site were simulated using the SWMM model, suggesting the optimal linkage method considering interconnectivity, and applying the effects as an existing installation of individual facilities. The water balance at the time of application of the LID technology, short-term and long-term rainfall event were compared. Also, the individual application and the linkage application were compared with each other. If each component technology has sufficient processing size, then linkage application is more effective than individual application.

• 한국방재학회 논문집
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• 제4권3호
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• pp.51-60
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• 2004

최근 도시지역의 수해요인은 내수침수불량에 기인하기 때문에 유수지 및 배수펌프장을 신설하여 유수지로 유입되는 유출량을 하천으로 강제배수하게 된다. 그러나 하수관거의 용량이 부족하여 유수지로 미처 유입되기 전에 하수관거의 역류로 침수피해가 자주 발생하고 있다. 따라서 본 연구에서는 도시 내배수 체계의 조사방법을 제시, 하수관거의 위험도를 평가하고 개선할 수 있는 방안을 제시하였다. 또한 배수펌프의 가동대수를 단순한 수위기준에서 변화시켜 실무에서 전문가가 아니더라도 사용할 수 있는 전산모형 8개를 개발하여 제시하였고, 지속기간, 설계빈도, 시간분포 등을 변화시켜 유수지 수위의 적정 조절여부를 검토하였다. 그리고 강제적인 배수에 의해 하류부의 수위영향이 예견되기 때문에 해당 유역의 수위를 안전하게 유지하면서도 하류부에 수위영향을 최소화할 수 있는 방안에 대해서도 검토하였다. 연구결과 Fuzzy 모형이 기존의 운영방법보다 더 효과적으로 유수지의 수위를 저하시킬 수 있었으며, 하류부 수위는 약 8cm 정도 감소시킬 수 있었다.

• 대기
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• 제31권2호
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• pp.143-156
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• 2021

This study investigates the impacts of land cover change due to urbanization on the Urban Heat Island Intensity (UHII) and the Heat Index (HI) over the Seoul metropolitan area using the Unified Model (UM) with the Met Office Reading Urban Surface Exchange Scheme (MORUSES) during the heat wave from 16, July to 5, August 2018. Two simulations are performed with the late 1980s land-use (EXP1980) and the late 2000s land-use (EXP2000). EXP2000 is verified using Automatic Weather Station (AWS) data from 85 points in the study area, and observation sites are classified into two categories according to the urban fraction change over 20 years; Category A is 0.2 or less increase, and Category B is 0.2 or more increase. The 1.5-m temperature and relative humidity in Category B increase by up to 1.1℃ and decreased by 7% at 1900 LST and 2000 LST, respectively. This means that the effect of the urban fraction changes is higher at night. UHII increases by up to 0.3℃ in Category A and 1.3℃ in Category B at 1900 LST. Analysis of the surface energy balance shows that the heat store for a short time during the daytime and release at nighttime with upward sensible heat flux. As a result of the HI, there is no significant difference between the two experiments during the daytime, but it increases 1.6℃ in category B during the nighttime (2200 LST). The results indicate that the urbanization increase both UHII, and HI, but the times of maximum difference between EXP1980 and EXP2000 are different.

• 대한토목학회논문집
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• 제28권6D호
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• pp.915-922
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• 2008

불투수층은 자연적인 침투를 허용하지 않는 인위적인 토지피복상태로, 도시화율을 추정하거나 도시의 환경변화 정도를 분석하기 위한 척도로 사용되어 왔다. 수문학적인 관점에서 불투수층은 단기 유출현상에 큰 영향을 끼치는 요소로 급속한 도시화로 인해 불투수층의 영향이 더욱 커짐에 따라 불투수층의 추정에 대한 필요성이 증가하고 있다. 따라서 본 연구에서는 불투수층을 추정하기 위해 중랑천 유역을 대상지역으로 선정하고, $30m{\times}30m$ 공간해상도의 Landsat-7 ETM+ 영상과 $1m{\times}1m$의 고해상도 위성영상을 구축하였으며 tasselled cap 변환과 식생지수(NDVI) 변환을 수행하여 다양한 예측변수를 고려하였다. 수집된 학습자료에 분류 및 회귀트리를 적용하여 불투수층 추정모델을 구성하였고, 이를 지도화하여 중랑천 유역의 불투수층을 나타냈다.

• 한국지반환경공학회 논문집
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• 제10권4호
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• pp.5-13
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• 2009

최근 지속적이고 건전한 물 관리를 위하여 침투형 우수유출 저감시설이 고려되고 있는 실정이다. 그러나 침투형 우수유출저감시설의 실제 적용에는 많은 문제점에 대한 개선이 필요하다. 본 연구에서는 침투형 우수유출 저감시설에 대한 개선 방법으로 침투-저류 시스템(ISS)을 제안하고, 수리모형 실험에 의해 우수유출 저감효과를 분석하였다. 본 연구에서 새로 제안된 우수유출 저감시설의 침투 특성을 분석하기 위해 다양한 강우 조건과 택지 개발 및 도시화를 고려하기 위해 실제 택지 개발시 이용되는 표면재료를 적용하였다. 본 연구에서는 수리모형 실험결과에 따라, 하부층의 누가 침투량에 의해서 침투-저류 시스템(ISS)은 부가적인 저감효과를 나타냈으며, 강우강도가 증가함에 따라 누가 침투율도 증가하였다. 그러므로 침투-저류 시스템(ISS)은 침투율이 증가하므로 기존 우수유출 저감시설보다 더 효과적으로 나타났다. 이러한 결과는 침투-저류 시스템(ISS)의 우수유출저감시설로써 적용에 대한 타당성을 확보할 수 있으며, 향후 관련 연구가 수행되면 침투-저류시스템(ISS)은 실제 우수유출 저감시설로써 활용될 수 있을 것이다.

• 한국조경학회지
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• 제21권2호
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• pp.17-33
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• 1993

This paper is the on-site case study of the shaping of townscape of port towns in Korea. Inchon has been experienced the rapid urbanization after the opening of a port. Inchon is selected because of the relatively rapid process, the apparent event and influence, and the enough referneces of data about the landscape formation and transformation. As the value of historical landscape, it is very significant to study Inchon and the causes of change in townscape depend on the external element-the opening of a port, Japan colonial policy, economic progress, nationwide development. The main purpose of this study is scrutinized the process, the cause and effect, and the contents and the form of shaping of townscape. The result of the interpretation of landscape is never perfect but only a starting point. Finally this study will be applied to the pragmatic task as a basic tool which construct the desirable image of the city.

• 한국환경복원기술학회지
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• 제20권3호
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• pp.45-54
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• 2017

With rapid urbanization and reckless urban development in the 21st century, the urban environment has gradually gotten worse, and urban heat island effect has been dramatically intensified. Thus, the importance of street greenery that can mitigate the urban heat island effect has further been highlighted. In this regard, this study was aimed at selecting suitable plant species for street greenery to reduce the urban heat island effect. Towards this end, five roads located in Seocho-gu, Seoul were selected as study sites, and plant species composition and difference of surface temperature were compared and analyzed in relation to the light transmittance. The street with the greatest temperature difference is Bangbae-ro(Platanus occidentalis). On the other hand, the road with the lowest temperature difference is Nambusunhwan-doro(Metasequoia Glyptostroboides). The effect of temperature reduction was found to be associated with light transmittance.Bangbae-ro(Platanus occidentalis) with the lowest light transmittance showed the highest temperature difference and Nambusunhwan-doro(Metasequoia Glyptostroboides) with the highest light transmittance showed the lowest temperature difference. It is analyzed that there are most differences in temperature when the amount of lights coming in between the crown is small. The temperature reduction effect can be obtained by planting deciduous broad-leaved trees. Also species with dense crown and broad width of crown will be able to maximize the effect of temperature reduction. In future studies, it will be necessary to expand the other species of trees in the street, and analyze the germicidal trees and shrubs as well as the differences in the packaging materials.