Assessment of Temperature Reduction and Evapotranspiration of Green Roof Planted with Zoysia japonica

한국잔디식재 옥상녹화의 온도저감 및 증발산량 평가

Kim, Se-Chang;Lee, Hyun-Jeong;Park, Bong-Ju

  • Received : 2013.03.14
  • Accepted : 2013.05.09
  • Published : 2013.11.29


This was an experimental study to evaluate temperature reduction and evapotranspiration of extensive green roof. Three test cells with a dimension of $1.2(W){\times}1.2(D){\times}1.0(H)$ meters were built using 4-inch concrete blocks. Ten-centimeter concrete slab was installed on top of each cell. The first cell was control cell with no green roof installed. The second and third cells were covered with medium-leaf type Zoysiagrass (Zoysia japonica) above a layer of soil. Soil thickness on the second cell was 10cm and that on the third cell was 20cm. Air temperature, relative humidity and solar irradiance were measured using AWS (automatic weather system). Temperature on top surface and ceiling of the control cell and temperature on top surface, below soil and ceiling of green roof cells was measured. Evapotranspiration of the green roof cells were measured using weight changes. Compared with temperature difference on the control cell, temperature difference was greater on green roof cells. Between two green roof cells, the temperature difference was greater on the third cell with a thicker soil layer. Temperature differences below soil and on ceilings of green roof cells were found greater than those of the control cell. Between the green roof cells, there was no difference in the temperature reduction effects below soil and on ceilings based on substrate depth. In summary, green roof was found effective in temperature reduction due to evapotranspiration and shading effect.


Urban heat island;Solar irradiance;Surface temperature;Shading effect;Zoysia japonica


  1. Bang, K. J., Ju, J. H., Kim, S. H., 2004, Effects of soil depth and irrigation period on some of the native plants in an artificial substrate of roof garden, Journal of the Korean Society of Environment Restoration Technology, 7(6), 75-83.
  2. Chen, Y., Teo, C. M., Wong, N. H., Tan, P. Y., 2004, Preliminary study of leaf area index and thermal protection of vegetation in the tropical climate, Built Environment and Environmental Buildings, 1, 221-226.
  3. Durhman, A. K., Rowe, D. B., Rugh, C. L., 2006, Effect of watering regimen on chlorophyll fluorescence and growth of selected green roof plant taxa, HortScience, 41, 1623-1628.
  4. Jim, C. Y., 2012, Effect of vegetation biomass structure on thermal performance of tropical green roof, Landscape and Ecological Engineering, 8(2), 173-187.
  5. Jones, C. A., Suckling, W., 1983, Comparison of the radiation balance of a rooftop lawn with that of a conventional rooftop surface, Archives for Meteorology, Geophysics, and Bioclimatology Series B, 33, 77-87.
  6. Kim, T. H., 2012, A study on thermal simulation for extensive green roof system using a plant canopy model, Journal of the Korean Society of Environment Restoration Technology, 15(2), 137-147.
  7. Koh, S. K., Shin, H. K., Tae, H. S., Kim, Y. S., Ahn, G. M., 2009. Effect of heating system on roof garden for turf growth, Kor. Turfgrass Sci., 23(2), 279-286.
  8. Lin, Y. J., Lin, H. T., 2011, Thermal performance of different planting substrates and irrigation frequencies in extensive tropical rooftop greeneries, Building and Environment, 46, 345-355.
  9. Ling, P., Kawamura, M., Nakane, K., 2011, Effect on rooftop temperatures and heat fluxes of a bamboo charcoal sublayer in rooftop greening soil at a factory office, International Journal of Environmental Protection, 1(3), 15-20.
  10. Ohno, T., Yamamoto, S., Maenaka, H., 2006, Evapotranspiration from sedum mat and cynodon turf, Journal of the Japanese Institute of Landscape Architecture, 69(5), 431-436.
  11. Onmura, S., Matsumoto, M., Hokoi, S., 2001, Study on evaporative cooling effect of roof lawn gardens, Energy and Building, 33, 653-666.
  12. Ono, K., Yanagi, M., Kudo, T., Teshirogi, J., Shibuya, Y., Koshimizu, H., 2005, Evapotranspiration of rooftop gardening plants and their effect on the thermal environment of building, The 2005 world sustainable building Conference, Tokyo, Japan, 771-776.
  13. Park, J. S., Ju, J. H., Kim, W. T., Yoon, Y. H., 2010, Application analysis of Vitex rotundifolia by difference of the shallow-extensive green roof system, Journal of the Korean Society of Environment Restoration Technology, 13(4), 10-17.
  14. Thuring, C. E., Verghage, R. D., Beattie, D. J., 2010, Green roof plant responses to different substrate types and depths under various drought conditions, HortTechnology, 20, 395-401.
  15. Wong, N. H., Chen, Y., Ong, C. L., Sia, A., 2003, Investigation of thermal benefits of rooftop garden in the tropical environment, Energy and Building, 38, 261-270.


Supported by : 충북대학교