Journal of the Korean Society of Environmental Restoration Technology (한국환경복원기술학회지)

The Korea Society of Environmental Restoration Technology (한국환경복원기술학회)
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Estimating the urban radiation heat flux distribution and the reduction effect of building and tree shade

건물과 수목의 그림자에 의한 도시의 열 분포 산정 및 저감효과 연구

  • Park, Chae-Yeon (Interdisciplinary Program in Landscape Architecture, Seoul National University) ;
  • Lee, Dong-Kun (Department of Landscape Architecture and Rural system Engineering, Seoul National University) ;
  • Yoon, June-Ha (Department of Landscape Architecture and Rural system Engineering, Seoul National University)
  • 박채연 (서울대학교 협동과정조경학) ;
  • 이동근 (서울대학교 조경.지역시스템 공학부) ;
  • 윤준하 (서울대학교 조경.지역시스템 공학부)
  • Received : 2018.09.28
  • Accepted : 2018.12.17
  • Published : 2018.12.31
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Abstract

Mapping radiation heat flux of urban area is essential for urban design and landscape planning. Because controlling urban geometry and generating green space are important urban design strategies for reducing urban heat, urban planner and designer need to recognize the micro urban heat distribution for adequate urban planning. This study suggests a new methodology for mapping urban radiation heat flux in a micro scale considering buildings and trees' shade. For doing that, firstly, we calculate net radiation for each urban surfaces (building, road (not shaded, building shaded, tree shaded), ground (not shaded, building shaded, tree shaded), tree (not shaded, building shaded)). Then, by multiplying the area ratio of surfaces to the net radiation, we can obtain the radiation heat flux in micro-scale. The estimated net radiation results were found to be robust with a $R^2$ of 90%, which indicates a strong explanatory power of the model. The radiation heat flux map for 12h $17^{th}$ August explains that areas under the building and tree have lower net radiation heat flux, indicating that shading is a good strategy for reducing incident radiation. This method can be used for developing thermal friendly urban plan.

Keywords

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Figure 1. Research Process and the model flow(1-2-3).

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Figure 2. Model geometry for estimating net radiation of urban surfaces.

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Figure 3. Urban surfaces types.

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Figure 4. Projection coordinate for calculating shade coordinates of tree and building.

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Figure 5. Field measurement sites.

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Figure 6. Comparison of model results (x axis) and measured net radiation fluxes. (y axis).

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Figure 7. Pilot site map and urban surfaces map.

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Figure 8. Net radiation map for 12:00 17th August.

Table 1. Input data for calculating net radiation.

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Table 3. The characteristics and net radiation of 4 locations (the locations are defined in Figure 8)

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References

  1. Armson, D..Stringer, P. and Ennos, A. R. 2012. The effect of tree shade and grass on surface and globe temperatures in an urban area. Urban Forestry and Urban Greening 11. Elsevier GmbH.: 245-255. doi:10.1016/j.ufug.2012.05.002.
  2. Bretagnon, P. and Francou, G. 1988. Planetary theories in rectangular and spherical variables-VSOP 87 solutions. Astronomy and Astrophysics 202: 309-315.
  3. Cao, X..Onishi, A..Chen, J. and Imura, H. 2010. Quantifying the cool island intensity of urban parks using ASTER and IKONOS data. Landscape and Urban Planning 96: 224-231. https://doi.org/10.1016/j.landurbplan.2010.03.008
  4. Gaitani, N..Burud, I..Thiis, T. and Santamouris, M. 2017. High-resolution spectral mapping of urban thermal properties with Unmanned Aerial Vehicles. Building and Environment 121. Elsevier Ltd: 215-224. doi:10.1016/j.buildenv.2017.05.027.
  5. Holst, J. and Mayer, H. 2011. Impacts of street design parameters on human-biometeorological variables. Meteorologische Zeitschrift 20: 541-552. doi:10.1127/0941-2948/2011/0254.
  6. Jamei, E..Rajagopalan, P..Seyedmahmoudian, M. and Jamei Y. 2016. Review on the impact of urban geometry and pedestrian level greening on outdoor thermal comfort. Renewable and Sustainable Energy Reviews 54. Elsevier: 1002-1017. doi:10.1016/j.rser.2015.10.104.
  7. Kim, J. S. and Kang, J. E. 2018. Effects of Compact Spatial Characteristics on the Urban Thermal Environment. Journal of the Urban Design Institute of Korea Urban Design. 19(1): 21-36. (in Korean with English summary)
  8. Kim, J. U..Lee, D. K..Oh, K. S. and Sung, H. C. 2003. A fundamental study on the relationship between riparian vegetation and surface temperature -Focused on Cheonggaecheon stream restoration-. Journal of Korea Society of Environmental Restoration Technology. 6(3): 79-85. (in Korean with English summary)
  9. Kosareo, L..A, R. R. 2007. Comparative en vironmental life cycle assessment of green roofs 42: 2606-2613. doi:10.1016/j.buildenv.2006.06.019.
  10. Krayenhoff, E. S..Christen, A..Martilli, A. and Oke, T. R. 2014. A Multi-layer Radiation Model for Urban Neighbourhoods with Trees. Boundary-Layer Meteorology 151: 139-178. doi:10.1007/s10546-013-9883-1.
  11. Lee, H..Kim, J..Lee, S. and Kang, Y. 2011. Heat-Flux Analysis of Solar Furnace Using the Monte Carlo Ray-Tracing Method. Journals of Mechanical Science and Technology B. 35(10): 989-996. (in Korean with English summary)
  12. Lee, H..Holst, J. and Mayer, H. 2013. Modification of human-biometeorologically significant radiant flux densities by shading as local method to mitigate heat stress in summer within urban street canyons. Advances in Meteorology 2013. doi:10.1155/2013/312572.
  13. Lee, S. 2011. Further Development of the Vegetated Urban Canopy Model Including a Grass-Covered Surface Parametrization and Photosynthesis Effects. Boundary-Layer Meteorology 140: 315-342. doi:10.1007/s10546-011-9603-7.
  14. Mazumder, S. and Ravishankar, M. 2012. General procedure for calculation of diffuse view factors between arbitrary planar polygons. International Journal of Heat and Mass Transfer 55: 23-24
  15. Napoli, M..Massetti, L..Brandani, G..Petralli, M. and Orlandini, S.. 2016. Modeling tree shade effect on urban ground surface temperature. Journal of Environmental Quality 45. The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.: 146-156. https://doi.org/10.2134/jeq2015.02.0097
  16. Park, C. Y..Lee, D. K..Kwon, E. and Her, M. 2017. Green-infra Strategies for Mitigating Urban Heat Island. Journal of Korean Environmental Restoration Technology 20(5): 69-83. doi:10.1016/j.ijheatmasstransfer.2012.07.066. (in Korean with English summary)
  17. Park, C. Y..Lee, D. K..Krayenhoff, E. S.. Heo, H. K..Ahn, S..Asawa, T.. Murakami, A. and Kim, H. G. 2018. A multilayer mean radiant temperature model for pedestrians in a street canyon with trees. Building and Environment 141: 298-309. doi:10.1016/j.buildenv.2018.05.058.
  18. Park, E. J. 2014. Selection of green roof initiative zone for improving adaptation capability against Urban Heat Island. Journal of Korea Society of Environmental Restoration Technology. 17(1): 135-146. doi:10.13087/kosert.2014.17.1.135. (in Korean with English summary)
  19. Rahman, M. A..A. Moser.T. Rotzer and S. Pauleit. 2017. Microclimatic differences and their influence on transpirational cooling of Tilia cordata in two contrasting street canyons in Munich, Germany. Agricultural and Forest Meteorology 232. Elsevier B.V.: 443-456. doi:10.1016/j.agrformet.2016.10.006.
  20. Ryu, Y. H..Bou-Zeid, E..Wang, Z. H. and Smith, J. A. 2016. Realistic Representation of Trees in an Urban Canopy Model. Boundary-Layer Meteorology 159. Springer Netherlands: 193-220. doi:10.1007/s10546-015-0120-y.
  21. Santamouris, M. 2014. Cooling the cities - A review of reflective and green roof mitigation technologies to fight heat island and improve comfort in urban environments. Solar Energy 103. Elsevier Ltd: 682-703. doi:10.1016/j.solener.2012.07.003.
  22. Takebayashi, H..Kimura, Y. and Kyogoku, S. 2014. Study on the appropriate selection of urban heat island measure technologies to urban block properties. Sustainable Cities and Society 13: 217-222. doi:10.1016/j.scs.2014.01.008.
  23. Taleghani, M..Tenpierik, M..Van Den DobbelsteenA. and Sailor, D. J. 2014. Heat in courtyards: A validated and calibrated parametric study of heat mitigation strategies for urban courtyards in the Netherlands. Solar Energy 103. Elsevier Ltd: 108-124. doi:10.1016/j.solener.2014.01.033.
  24. Wang, M..Chang, H. C..Merrick, J. R. and Amati, M. 2016. Assessment of solar radiation reduction from urban forests on buildings along highway corridors in Sydney. Urban Forestry and Urban Greening 15. Elsevier GmbH.: 225-235. doi:10.1016/j.ufug.2016.01.003.
  25. Wang, Y. and Akbari, H. 2014. Effect of Sky View Factor on Outdoor Temperature and Comfort in Montreal. environmental engineering science 31: 272-287. doi:10.1089/ees.2013.0430.
  26. Wu, Z. and Chen, L. 2017. Optimizing the spatial arrangement of trees in residential neighborhoods for better cooling effects: Integrating modeling with in-situ measurements. Landscape and Urban Planning 167: 463-472. https://doi.org/10.1016/j.landurbplan.2017.07.015
  27. Zheng, H. Y..Jin, Ri.Jin, W and Lee, K. 2012. A study on weekly variation of urban air temperature difference. Journal of Korea Society of Environmental Restor ati on Technology. 15(4): 13-21. (in Korean with English summary) https://data.kma.go.kr/cmmn/main.do https://doi.org/10.13087/kosert.2012.15.4.013