• 한국조경학회지
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• 제30권3호
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• pp.25-34
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• 2002

The purpose of this paper is to discuss the function of microclimate amelioration of urban trees regarding the environmental benefits of street trees in summer, focusing on the heat pollution-urban heat island, tropical climate day's phenomenon and air pollution. We measured the diurnal variation of air/ground temperatures and humidity within the vegetation canopy with the meteorological tower observation system. Summertime air temperatures within the vegetation canopy layer were 1-2$^{\circ}C$ cooler than in places with no vegetation. Due to lack of evaporation, the ground surface temperatures of footpaths were, at a midafternoon maximum, 8$^{\circ}C$ hotter than those under trees. This means that heat flows from a place with no vegetation to a vegetation canopy layer during the daytime. The heat is consumed as a evaporation latent heat. These results suggest that the extension of vegetation canopy bring about a more pleasant urban climate. Diurnal variation of air/ground temperatures and humidity within the vegetation canopy were measured with the meteorological tower observation system. According to the findings, summertime air temperatures under a vegetation canopy layer were 1-2$^{\circ}C$ cooler than places with no vegetation. Due mainly to lack of evaporation the ground surface temperature of footpaths were up to 8$^{\circ}C$ hotter than under trees during mid-afternoon. This means that heat flows from a place where there is no vegetation to another place where there is a vegetation canopy layer during the daytime. Through the energy redistribution analysis, we ascertain that the major part of solar radiation reaching the vegetation cover is consumed as a evaporation latent heat. This result suggests that the expansion of vegetation cover creates a more pleasant urban climate through the cooling effect in summer. Vegetation plays an important role because of its special properties with energy balance. Depended on their evapotranspiration, vegetation cover and water surfaces diminish the peaks of temperature during the day. The skill to make the best use of the vegetation effect in urban areas is a very important planning device to optimize urban climate. Numerical simulation study to examine the vegetation effects on urban climate will be published in our next research paper.

• 한국지리정보학회지
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• 제20권2호
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• pp.75-88
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• 2017

본 연구에서는 대구시를 사례로 도시내에서의 공간지형적 특성에 따른 국지적 바람유동성을 분석하였다. 분석은 3단계로 이루어졌는데, 1단계에서는 지역풍향(종관풍)과 국지적 바람유동간의 기상학적 관계를 비교하였다. 2단계에서는 도심지역과 교외지역으로 구분하여 국지적 바람유동의 변화를 비교 분석하였다. 3단계에서는 KLAM_21을 활용하여 국지적 바람유동과 도시공간전체의 바람길 형성 및 유동과의 공간적 관계에 대하여 비교 검증하였다. 연구결과를 요약하면 다음과 같다. 첫째, 지역의 대표풍향(종관풍)과 국지적 바람유동 사이에는 기상학적으로 상관성이 낮았다. 둘째, 도심지역 5개와 교외지역 2개 측정지점에서의 국지적 바람유동에 대한 관측결과에서는 지점별로 다양한 풍향을 나타내었다. 이는 측정지점 인근에서의 공간지형적 특성이 국지적 바람유동에 영향을 미치고 있음을 보여주고 있다. 셋째, KLAM_21을 활용하여 분석한 결과를 AWS 측정자료와 비교 검증한 결과 수치모델링분석의 신뢰도를 확인할 수 있었다. 본 연구를 통해 검증한 도시의 국지적 바람유동은 도시열섬현상의 개선을 위한 공간적 기능과 역할을 할 수 있는 요소가 될것으로 판단된다. 즉, 도시계획 수립시 공간지형적 특성에 따른 국지적 바람유동을 체계적으로 파악하고 이를 도시열섬발생지역과 공간적으로 연계될 수 있는 계획적 기법을 적용한다면 도시열섬 현상을 효과적이며 지속적으로 개선할 수 있을 것으로 기대된다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2006년도 춘계학술대회 논문집
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• pp.90-90
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• 2006

• 한국지구과학회지
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• 제42권2호
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• pp.135-148
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• 2021

본 연구는 기상청 현업모델(LDAPS)로부터 예측된 서울의 도시열섬 강도와 지상 기온을 AWS 관측과 비교 평가하였다. 관측된 서울의 열섬 강도는 봄과 겨울동안 증가하며 여름동안 감소한다. 열섬 강도의 시간적 변동 경향은 새벽 시간 최대, 오후에 최소를 보인다. 기상청 국지기상예측시스템(LDAPS)으로부터 예측된 열섬 강도는 여름철 과대모의, 겨울철 과소모의 특징을 보인다. 특히 여름철은 주간에 과대 모의 경향이 증가하며, 겨울은 새벽 시간 과소 모의 오차가 크게 나타난다. LDAPS에서 예측된 지면 기온의 오차는 여름철 감소하며 겨울철 증가한다. 겨울철 열섬 강도의 과소 모의는 도시 기온의 과소 모의와 관련되었으며, 여름철 열섬 강도의 과대 모의는 교외 지역 기온의 과소 모의로부터 기인하는것으로 판단된다. 도시 열섬강도 예측성 개선을 위하여 도시효과를 고려하는 도시캐노피모델을 LDAPS와 결합하여 2017년 여름 기간동안 모의하였다. 도시캐노피모델 적용 후 도시의 지면 기온의 오차는 개선되었다. 특히 오전시간 과소모의되는 기온의 오차 개선 효과가 뚜렷하였다. 도시캐노피모델은 여름동안 과대 모의하는 도시열섬강도를 약화시키는 개선 효과를 보였다.

• 대한원격탐사학회지
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• 제27권3호
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• pp.339-351
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• 2011

This study investigates the potentials of satellite, ground measurement data, and geo-spatial information within an urban area for the mapping of the Urban Environmental Quality (UEQ) parameters. The UEQ indicates a complex and various parameters resulting from both human and natural factors, which are greenness, climate, air pollution, the urban infrastructure, and etc. Multi-spectral remote sensing data from the Landsat ETM and TM sensors for the mapping of air pollution by the Haze Optimized Transform (HOT) technique, Urban Heat Island (UHO using the emissivity-fusion method in Seoul from 2000 to 2006 in fine resolution (30m) were analyzed for the estimation of UEQ index. Although the UHI values are similar ($8.4^{\circ}C{\sim}9.1^{\circ}C$) during these years, the spatial coverage of "hot" surface temperature (> $24^{\circ}C$) significantly increased from 2000 to 2006 due to the rapid urban development. Furthermore, high correlations between vegetation index and land surface temperature were achieved with a correlation coefficients of 0.85 (2000), 0.81 (2001), 0.84 (2002), and 0.89 (2006), respectively. It was found that the proposed method was successfully analyzed spatial structure of the UEQ and the scenarios of the best and worst areas within the city were also identified. Based on the quantifiable fine resolution satellite image parameters, UEQ can promote the understanding of the complex and dynamic factors controlling urban environment.

• 한국환경복원기술학회지
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• 제19권2호
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• pp.55-69
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• 2016

Significant efforts are being devoted in mitigating the urban heat island effect, and extensive green roofs are an option for mitigation. The purpose of this study was to compare the surface temperature, vegetation types, and plant species on an extensive green roof. Test beds were created in May 2015, and the surface temperature was monitored from June to August. The test beds comprised polyculture and monoculture. Polyculture was divided into three types, and monoculture comprised eight plant species. An extensive green roof is effective in reducing temperature by forming a shade and preventing sunlight from falling on the surface of buildings, which mitigates the urban heat island effect. Consequently, the surface temperature of the green roof and that of concrete during summer reduced from $17.8^{\circ}C$ to $7.3^{\circ}C$. The temperature reduction was greater on using polyculture than on using monoculture, but monocultures of Sedum takesimense, Hemerocallis dumortieri, Allium senescens, Aster yomena, Belamcanda chinensis, and Aster koraiensis also produced good results. The temperature reduction effects of Polygonatum odoratum var. pluriflorum f. variegatum, Phlox subulata, and Thymus quinquecostatus var. japonica were excellent compared with those of concrete but were less than those of other plant species. Careful attention is needed for the management of extensive green roofs. Studies on the plant species and types of extensive green roof should continue to mitigate the urban heat island effect.

• 한국지구과학회지
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• 제43권2호
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• pp.253-264
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• 2022

본 연구에서는 2019년에서 2021년까지, 매년 2월에서 5월 동안 대전광역시 6개 지점(기준지역 1곳 포함)의 기온 데이터를 바탕으로 COVID-19로 인한 인간 활동의 감소가 대전 지역의 도시열섬강도에 미친 영향에 대하여 분석하였다. 관측 지점에 따라 차이는 있으나 도시열섬강도는 COVID-19 전인 2019년에 비해 2020년과 2021년에 약 20% 이상 감소되었다. 인간 활동 감소는 야간의 도시열섬을 증가시키고 주간의 도시열섬을 감소시켰다. 그 결과 도시열섬강도의 일변동 폭은 지점에 관계없이 2019년에 비해 2020년 및 2021년 모두 약 20% 이상 증가하였다. 도시열섬강도 감소는 풍속과 같은 자연적 요인 및 사회적 거리두기 단계와는 큰 관련성이 없는 것으로 보인다. 반면에 COVID-19 이후 시행된 사회적 거리두기 및 확연히 감소된 대기오염물질과 관계가 있는 것으로 나타났으며, 특히 NO₂와 가장 유의미한 상관관계를 보였다.

• 한국환경복원기술학회지
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• 제23권5호
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• pp.29-43
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• 2020

Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. The cooling effect of street tree is regarded as a effective way to ameliorate the urban heat environment. The effect is largely made up of shadow formation and transpiration. This study aims to identify how the transpiration affects the discomfort index by analyzing comprehensive impact of the transpiration on the air temperature and relative humidity. The changes in the amount of transpiration, air temperature, and relative humidity were estimated for Seogyo-dong area which has a lot of floating population in Seoul, at 2 p.m. in dry day in July and August. On average, the transpiration of the street tree decreased the temperature 0.3℃ and increased the relative humidity 2.6% in an hour. As a result of these changes in temperature and humidity, the discomfort index rose mostly(0.036 on average). It was always get rise especially on the day when the discomfort index was above 80(0.05 on average). However, compared with the significant change in temperature and humidity, the variation of the discomfort index itself was very slight(up to 0.107). Therefore, the effect of transpiration by the street trees might not be effective in the planning to improve the thermal environment(especially on the day when the discomfort index is high). It is necessary to select the species of trees and planting location considering the cooling effect of shade formation synthetically.

• KIEAE Journal
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• 제16권6호
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• pp.69-75
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• 2016

Climate change has resulted in the urban heat island (UHI) effect throughout the globe, contributing to heat-related illness and fatalities. In order to reduce such damage, it is necessary to improve the climate observation network for precise observation of the urban thermal environment and quick UHI forecasting system. Purpose: This study analyzed the effective range of the climate observation network and the distribution of the existing Automatic Weather Stations (AWS) in Seoul to propose optimal locations for additional installment of AWS. Method: First, we performed quality analysis to pinpoint missing values and outliers within the high-density temperature data measured. With the result from the analysis, a spatial autocorrelation structure in the temperature data was tested to draw the effective range and correlation distance for each major time period. Result: As a result, it turned out that the optimal effective range for the climate observation network in Seoul in July was a radius of 2.8 kilometers. Based on this result, population density, and temperature data, we selected the locations for additional installment of AWS. This study is expected to be used to generate urban temperature maps, select and move measurement locations since it is able to suggest valid, specific spatial ranges when the data measured in point is converted into surface data.

• KIEAE Journal
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• 제17권1호
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• pp.49-54
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• 2017

Purpose: Temperature in urban areas increase much more than suburban areas and it is called urban heat island (UHI) phenomenon. There are several solutions to control UHI phenomenon such as green roof system, water space construction, and cool roof system. However, application of green roof system and cool roof system to some of the buildings which compose the city has a critical limit. Therefore, in order to diminish the temperature rising and UHI phenomenon due to climate change of the city, it needs to approach from the viewpoint of site or city, rather than the viewpoint of individual buildings. This study is aims at analyzing UHI phenomenon by characteristics of surface materials and suggesting the solutions to reduce UHI phenomenon by types of complex. Method: Literature reviews were conducted to analyze the cause, mitigating plan, and recent trends of UHI phenomenon. For the simulation analysis, the type of complex was classified 3 representative complex. Based on measured reflectivity, simulation about UHI phenomenon was conducted by setting 4 strategies; albedo of roof, road pavement, green roof system, and vegetating around buildings. Result: As the results of simulating the UHI reduction factor by types of complex, it showed that the effect of temperature reduction on the building roof layer is more effective than adjusting the reflectivity of buildings such as green roof system, planting near the buildings in both the detached house complex, apartment complex, and commercial complex.