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Urban Street Planting Scenarios Simulation for Micro-scale Urban Heat Island Effect Mitigation in Seoul

미시적 열섬현상 저감을 위한 도시 가로수 식재 시나리오별 분석 - 서울시를 대상으로 -

  • Kwon, You Jin (Interdisciplinary Program in Landscape Architecture, Seoul National University) ;
  • Lee, Dong Kun (Department of Landscape Architecture and Rural System Engineering, Seoul National University) ;
  • Ahn, Saekyul (Graduate School, Seoul National University)
  • 권유진 (서울대학교 협동조경학과) ;
  • 이동근 (서울대학교 조경시스템공학부) ;
  • 안새결 (서울대학교 조경시스템공학)
  • Received : 2018.09.22
  • Accepted : 2019.01.22
  • Published : 2019.02.28

Abstract

Global warming becomes a serious issue that poses subsidiary issues like a sea level rise or a capricious climate over the world. Because of severe heat-wave of the summer in Korea in 2016, a big attention has been focused on urban heat island since then. Not just about heat-wave itself, many researches have been concentrated on how to adapt in this trendy warming climate and weather in a small scope. A big part of existing studies is mitigating "Urban Heat Island effect" and that is because of huge impervious surface in urban area where highly populated areas do diverse activities. It is a serious problem that this thermal context has a high possibility causing mortality by heat vulnerability. However, there have been many articles of a green infrastructures' cooling impact in summer. This research pays attention to measure cooling effect of a street planting considering urban canyon and type of green infrastructures in neighborhood scale. This quantitative approach was proceeded by ENVI-met simulation with a spatial scope of a commercial block in Seoul, Korea. We found the dense double-row planting is more sensitive to change in temperature than that of the single-row. Among the double-row planting scenarios, shrubs which have narrow space between the plant and the land surface were found to store heat inside during the daytime and prevent emitting heat so as to have a higher temperature at night. The quantifying an amount of vegetated spaces' cooling effect research is expected to contribute to a study of the cost and benefit for the planting scenarios' assessment in the future.

Keywords

Urban canyon;Heat balance;ENVI-met;Heat wave;Cooling impact

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Figure 1. Study area street views (a, b, c) & Key map plan (d) (photos : Naver.com map street view)

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Figure 2. (a) Seasonal mean temperature, (b) location of CBD in Seoul (Seo 2014; Seoul Institute 2016)

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Figure 3. A: a domain of 3D view and B: a schematic plan for ENVI-met simulation

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Figure 4. Seven scenarios a. VS (Single-row tree), b. VM (Straight single-row shrub), c. TT (Twisted double-row tree), d. SDT (Straight doublerow tree), e. TM (Twisted double-row tree and shrub), f. TS (Twisted double-row shrub), g. VSD (Straight doublerow shrub), profiles and sections of AA’~GG’

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Figure 5. ENVI-met Simulation flow chart for seven scenarios (a process from input data using DATABASE to output data)

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Figure 6. Hourly temperature shift of 7 scenarios presenting a different gap between day and night

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Figure 7. Temperature shift in 6 scenarios (VM, VSD, SDT, TS, TM, TT), a. Temperature shift in day time (15h), b. Temperature shift in night time (23h)

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Figure 8. Heat flux diagram of TS & TT : At night TS and TT indicate that the storage heat is released from the surface of the earth and there is a difference in the numerical value of the emission heat under shrubs and trees.

Table 1. Input parameters for a scenarios’ at ENVI-met simulation

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Table 2. Temperature shift & standard deviation on each scenario at day & night (unit: ℃)

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Table 3. TT & TS significance test

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Acknowledgement

Supported by : 국토교통부

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