• Title/Summary/Keyword: urban temperature

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Factors Affecting Temperature of Urban Parks (도시공원의 기온에 영향을 미치는 요인)

  • 윤용한;송태갑
    • Journal of the Korean Institute of Landscape Architecture
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    • v.28 no.2
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    • pp.39-48
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    • 2000
  • The purpose of this study is to investigate the factors affecting temperature of urban parks to grasp the relationship between the land coverage in open space as well as the forest condition and decreasing city temperature by difference of purposed are. Futhermore, this research interpreted the relationship between wind direction, air temperature, the land coverage of the green space, the number of tree, green volume, height of tree and the mitigation of city temperature with the revolution analysis. The result of this study is that cool air in open space move leeward and decreasing city temperature is influenced by the difference of the land coverage in open space. Specifically, in order of the arbo rarbor in the forest zone, the increase of the number of trees was related with temperature surrounding significantly. This study found that the use possibility of the green volume was recognized as the index of the green volume relative to air temperature surrounding. Green space of the city control area is more effective decreasing temperature than that of housing zone.

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Estimation of Air Temperature Changes due to Future Urban Growth in the Seoul Metropolitan Area (수도권지역 미래 도시성장에 따른 기온변화 추정)

  • Kim, Yoo-Keun;Kim, Hyun-Su;Jeong, Ju-Hee;Song, Sang-Keun
    • Journal of Environmental Science International
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    • v.19 no.2
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    • pp.237-245
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    • 2010
  • The relationship between air temperatures and the fraction of urban areas (FUA) and their linear regression equation were estimated using land-use data provided by the water management information system (WAMIS) and air temperatures by the Korea Meteorology Administration (KMA) in the Seoul metropolitan area (SMA) during 1975 through 2000. The future FUA in the SMA (from 2000 to 2030) was also predicted by the urban growth model (i.e., SLEUTH) in conjunction with several dataset (e.g., urban, roads, etc.) in the WAMIS. The estimated future FUA was then used as input data for the linear regression equation to estimate an annual mean minimum air temperature in the future (e.g., 2025 and 2030). The FUA in the SMA in 2000 simulated by the SLEUTH showed good agreement with the observations (a high accuracy (73%) between them). The urban growth in the SMA was predicted to increase by 16% of the total areas in 2025 and by 24% in 2030. From the linear regression equation, the annual mean minimum air temperature in the SMA increased about 0.02C/yr and it was expected to increase up to 8.3C in 2025 and 8.7C in 2030.

A Study on the Urban climate Mitigation Effects with Ecological Landscape Planning with reference to Namyang-Ju Walsanli Master-plan (환경생태계획의 도시기후 변화 대응 가능성 연구 -남양주 월산리 마스터플랜을 중심으로)

  • Moon, Soo Young;Kim, Hyun Soo;Lee, Kwang Bok
    • KIEAE Journal
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    • v.10 no.6
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    • pp.11-19
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    • 2010
  • To meet with the nation's policy of Green Growth, local governments are rushing to propose an ecological urban development plan. And although various studies stress on the need of ecological planning to harmonize development with preservation, we have come to a point in which a quantitative evaluation of how much ecological planning contributes to the environmental load is needed. Through the increasing tendency of making plans based on the development of IT technology, capability of gathering environmental data and scientific instrument, studies on ecological planning's effect towards environmental load has recently begun. This study aims to perform a quantitative evaluation on how ecological planning mitigate urban heat island in the region of Namyang-ju Wallsanli. Three theories were used to mitigate urban heat island ; White network, Green network and Blue network. As a result, the atmosphere temperature was reduced the whole site 1.1C and partly 7C and the mean radiant temperature was reduced the whole site 1.1C and partly 8.7C on the modified ecological landscape plan in summer. The PMV index is 0~1 in ecologically modified landscape plan otherwise almost 3 in landscape plan. This study has its limits on the fact that results may differ from the actual plan as the study was performed based on the land use plan and building plan. However, what is important is that it shows a quantitative result of the effect that ecological planning has on surrounding environment and reducing environmental load.

Improvement of Vegetation Cooling Effects in BioCAS for Better Estimation of Daily Maximum Temperature during Heat Waves - In Case of the Seoul Metropolitan Area - (식생냉각효과 적용을 통한 BioCAS의 폭염기간 일 최고기온 추정 개선 - 서울 및 수도권지역을 중심으로 -)

  • Lee, Hankyung;Yi, Chaeyeon;Kim, Kyu Rang;Cho, Changbum
    • Atmosphere
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    • v.29 no.2
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    • pp.131-147
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    • 2019
  • On the urban scale, Micro-climate analysis models for urban scale have been developed to investigate the atmospheric characteristics in urban surface in detail and to predict the micro-climate change due to the changes in urban structure. BioCAS (Biometeorological Climate Impact Assessment System) is a system that combines such analysis models and has been implemented internally in the Korea Meteorological Administration. One of role in this system is the analysis of the health impact by heat waves in urban area. In this study, the vegetation cooling models A and B were developed and linked with BioCAS and evaluated by the temperature drop at the vegetation areas during ten selected heat-wave days. Smaller prediction errors were found as a result of applying the vegetation cooling models to the heat-wave days. In addition, it was found that the effects of the vegetation cooling models produced different results according to the distribution of vegetation area in land cover near each observation site - the improvement of the model performance on temperature analysis was different according to land use at each location. The model A was better fitted where the surrounding vegetation ratio was 50% or more, whereas the model B was better where the vegetation ratio was less than 50% (higher building and impervious areas). Through this study, it should be possible to select an appropriate vegetation cooling model according to its fraction coverage so that the temperature analysis around built-up areas would be improved.

Variation of Green Space Cooling Effect Influenced by Its Composition and Surroundings in Suwon City (수원시 녹지 조성 및 주변 환경에 따른 녹지 냉각 효과의 변화)

  • Seung Yeon Lee;Seong Woo Jeon
    • Journal of Environmental Impact Assessment
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    • v.32 no.3
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    • pp.176-186
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    • 2023
  • Urban Heat Island (UHI) is caused by an energy imbalance in urban areas, where building design and land cover contribute to its amplification. To mitigate UHI, increasing green space is one of the well known and the most effective approach. This study aims aimed to identify specific components of green spaces that lower temperatures and demonstrate the cooling effects based on their size and composition. Forests within green spaces have had a greater impact on temperature reduction due to shading and blocking solar radiation. Although lakes also contributed to temperature reduction, the effect to cooling intensity was not significant. The cooling distance does not depended on green space size or composition. The study emphasizes that initial temperature has a strongerinfluence on cooling intensity than green space size, highlighting the importance of vegetation type within green spaces to achieve a cooling effect. These findings provide valuable insights for urban planning and the design of green spaces to mitigate the effects of the urban heat island.

Numerical Simulation on the Effect of the Land Coverage Change on the Urban Heat Budget (토지피복 변화가 도시열수지에 미치는 영향에 관한 수치시뮬레이션)

  • Kim, Sang-Ok;Yeo, In-Ae;Ha, Kyung-Min;Yee, Jurng-Jae;Yoon, Seong-Hwan
    • 한국태양에너지학회:학술대회논문집
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    • 2009.04a
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    • pp.176-179
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    • 2009
  • In this study, Urban Climate Simulation was performed using 3-Dimensional Urban Canopy Model. The characteristics of urban thermal environment was analyzed by classifying land coverage and increasing natural land coverage ratio. The results are as follows. The characteristics of the land coverage on urban thermal environment formation can be summarized by the effects like higher temperature on the artificial coverage, and the contrary effects on the natural coverage. When the water coverage 100% was made up, maximum temperature was declined by 5.5C, humidity by the 6.5g/kg, wind velocity by 0.6m/s, convective sensible heat by 400W/m2 and the evaporative latent heat was increased by 370W/m2 compared to when artificial coverage 100% was formed. These simulation results need to be constructed as DB which shows urban quantitative thermal characters by the urban physical structure. These can be quantitative base for suggesting combinations of the building and urban planning features at the point of the desirable urban thermal environment as well as analysing urban climate phenomenon.

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Analyzing Change of Discomfort Index for Transpiration of Street Tree (도시 가로수의 증산 작용으로 인한 불쾌지수 변화 분석)

  • Yun, Seok-Hwan;Lee, Dong-Kun;Park, Chae-Yeon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.23 no.5
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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.

A Study on a Comparison of Sky View Factors and a Correlation with Air Temperature in the City (하늘시계지수 비교 및 도시기온 상관성 연구: 강남 선정릉지역을 중심으로)

  • Yi, Chaeyeon;Shin, Yire;An, Seung Man
    • Atmosphere
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    • v.27 no.4
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    • pp.483-498
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    • 2017
  • Sky view factor can quantify the influence of complex obstructions. This study aims to evaluate the best available SVF method that represents an urban thermal condition with land cover in complex city of Korea and also to quantify a correlation between SVF and mean air temperature; the results are as follows. First, three SVF methods comparison result shows that urban thermal study should consider forest canopy induced effects because the forest canopy test (on/off) on SVF reveals significant difference range (0.8, between maximum value and minimum value) in comparison with the range (0.1~0.3) of SVFs (Fisheye, SOLWEIG and 3DPC) difference. The significance is bigger as a forest cover proportion become larger. Second, R-square between SVF methods and urban local mean air temperature seems more reliable at night than a day. And as the value of SVF increased, it showed a positive slope in summer day and a negative slope in winter night. In the SVF calculation method, Fisheye SVF, which is the observed value, is close to the 3DPC SVF, but the grid-based SWG SVF is higher in correlation with the temperature. However, both urban climate monitoring and model/analysis study need more development because of the different between SVF and mean air temperature correlation results in the summer night period, which imply other major factors such as cooling air by the forest canopy, warming air by anthropogenic heat emitted from fuel oil combustion and so forth.

Analysis on Effective Range of Temperature Observation Network for Evaluating Urban Thermal Environment (도시 열환경 평가를 위한 기온관측망 영향범위 분석)

  • Kim, Hyomin;Park, Chan;Jung, Seunghyun
    • KIEAE Journal
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    • v.16 no.6
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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.

LEED Certification and Its Effectiveness on Urban Heat Island Effect

  • Kim, Hwan-Yong;Gu, Dong-Hwan
    • Journal of KIBIM
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    • v.5 no.4
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    • pp.30-36
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    • 2015
  • The Leadership in Energy and Environmental Design (LEED) has provided abundant resources and guidelines for a new project to become a sustainable anchor in the neighborhood. Paired with a range of checklist, LEED has strong influence on the standards for a sustainable building, and it also has played an iconic role in energy-efficient architecture. However, it is still unclear as to whether or not an LEED certified building enhances environmental benefits to its surroundings. If an LEED certification promises a baseline for an eco-friendly building, then a group of these structures should ensure significant environmental benefits to the society. This is the main question of this study, and the authors answer this hypothesis by examining the relationship of LEED certificates and their influence on outdoor temperature, especially in terms of urban heat island effect. The goal of this paper is to analyze the influence of the LEED certification on urban temperature as an indicator of sustainable architecture's regional interactions. If an LEED certificate is regarded as a strong contributor to a sustainable built environment, then a group of these certificates should result in greater benefits to society. To this extent, the authors question if there is any possible relationship between a large concentration of LEED certified sites and the temperature of their surroundings. To properly assess the research direction, Global Moran's I analysis, Local Moran's I analysis, and Hot Spot analysis are implemented to find the clustered areas of LEED certified buildings. For examining relationships between clustered area and its temperature, correlation efficients are calculated.