Modeling of shade creation and radiation modification by four tree species in hot and humid areas: Case study of Guangzhou, China

Senlin Zheng, Jean Michel Guldmann, Zhixin Liu, Lihua Zhao*, Junsong Wang, Xueli Pan

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Shade creation and radiation modification by trees is an important way of alleviating the urban heat island and improving the outdoor thermal environment. However, a major challenge is still present in numerical models: How can shade creation and radiation modification by trees be realistically represented? To address this challenge, this paper proposes a new three-dimensional model of radiation modification by shade trees for four common tree species in Guangzhou, China: Ficus microcarpa, Mangifera indica, Michelia alba and Bauhinia blakeana. Its accuracy is verified with field measurements. The results show that the proposed model can accurately simulate the canopy attenuation of incoming solar radiation (SR) (d = 0.76∼0.93) and long-wave radiation (LWR) (RMSE = 2.7 W/m2∼12 W/m2) in the case of Ficus microcarpa, Mangifera indica, and Bauhinia blakeana. But for Michelia alba, the difference between measured and simulated values can be large (>60 W/m2), leading to a high RMSE (25 W/m2 ∼194 W/m2). The predictability of surface energy budget and thermal comfort in urban environments is enhanced by incorporating the proposed model into a heat balance model to obtain the mean radiant temperature (MRT). Future development and application of this numerical model will provide useful guidelines for urban landscape management and sustainable urban planning in terms of heat island mitigation.

Original languageEnglish
Article number126545
Pages (from-to)1-14
Number of pages14
JournalUrban Forestry and Urban Greening
Early online date21 Nov 2019
Publication statusPublished - 1 Jan 2020



  • Radiation modification
  • Subtropical climate
  • Tree radiation model
  • Tree shading
  • Urban heat island

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