The impacts of land cover types on urban outdoor thermal environment: the case of Beijing, China

Journal of Environmental Health Science Engineering

Li Dong²  Hai Yan¹ 

[1] School of Landscape Architecture, Zhejiang Agriculture and Forestry University, Lin’an 311300, Zhejiang, China;College of Landscape Architecture, Beijing Forestry University, Beijing 100083, China

关键词: Land cover;    Air temperature;    Vegetation;    Urban park;    Urban heat island;   

Others  :  1216885
DOI  :  10.1186/s40201-015-0195-x

 received in 2014-02-23, accepted in 2015-05-04,  发布年份 2015

【 摘 要 】

Background

This study investigated the microclimatic behavior of different land cover types in urban parks and, the correlation between air temperature and land cover composition to understand how land cover affects outdoor thermal environment during hot summer.

Methods

To address this issue, air temperatures were measured on four different land cover types at four observation sites inside an urban park in Beijing, China, meanwhile, the land cover composition of each site was quantified with CAD, by drawing corresponding areas on the aerial photographs.

Results

The results showed that the average air temperature difference among four land cover types was large during the day and small during the night. At noon, the average air temperature differed significantly among four land cover types, whereas on night, there was no significant difference among different land cover types. Results of the linear regression indicated that during daytime, there was a strong negative correlation between air temperature and percent tree cover; while at nighttime, a significant negative correlation was observed between air temperature and percent lawn cover. It was shown that as the percent tree cover increased by 10 %, the air temperature decreased by 0.26 °C during daytime, while as the percent lawn cover increased by 10 %, the air temperature decreased by 0.56 °C during nighttime.

Conclusions

Results of this study help to clarify the effects of land cover on urban outdoor thermal environment, and can provide assistance to urban planner and designer for improving green space planning and design in the future.

【 授权许可】

   
2015 Yan and Dong; licensee BioMed Central.

【 图 表 】

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【 参考文献 】

• [1]Kalnay E, Cai M. Impact of urbanization and land-use change on climate. Nature. 2003; 423:528-31.
• [2]Oke TR. The energetic basis of the urban heat island. Q J Roy Meteorol Soc. 1982; 108:1-24.
• [3]Roshan G, Ghanghermeh A, Orosa JA. Thermal comfort and forecast of energy consumption in Northwest Iran. Arab J Geosci. 2014; 7(9):3657-74.
• [4]Orosa JA, Costa ÁM, Rodríguez-Fernández Á, Roshan G. Effect of climate change on outdoor thermal comfort in humid climates. J Environ Healt Sci Eng. 2014; 12:46. BioMed Central Full Text
• [5]Ca VT, Asaeda T, Abu EM. Reductions in air conditioning energy caused by a nearby park. Energ Buildings. 1998; 29(1):83-92.
• [6]Gill SE, Handley JF, Ennos AR, Pauleit S. Adapting cities for climate change: the role of the green infrastructure. Built Environ. 2007; 33(1):115-33.
• [7]Spronken-Smith RA, Oke TR. The thermal regime of urban parks in two cities with different summer climates. Int J Remote Sens. 1998; 19(1):2085-104.
• [8]Makhelouf A. The effect of green spaces on urban climate and pollution. Iran J Environ Healt Sci Eng. 2009; 6(1):35-40.
• [9]Hamada S, Ohta T. Seasonal variations in the cooling effect of urban green areas on surrounding urban areas. Urban For Urban Gree. 2010; 9(1):15-24.
• [10]Oliveira S, Andrade H, Vaz T. The cooling effect of green spaces as a contribution to the mitigation of urban heat: a case study in Lisbon. J Build Environ. 2011; 46(11):2186-94.
• [11]Jansson C, Jansson PE, Gustafsson D. Near surface climate in an urban vegetated park and its surroundings. Theor Appl Climatol. 2007; 89(3–4):185-93.
• [12]Jauregui E. Influence of a large urban park on temperature and convective precipitation in a tropical city. Energ Buildings. 1991; 15(3–4):457-63.
• [13]Chen Y, Wong NH. Thermal benefits of city parks. Energ Buildings. 2006; 38(2):105-20.
• [14]Barradas VL. Air temperature and humidity and human comfort index of some city parks of Mexico City. Int J Biometeorol. 1991; 35(1):24-8.
• [15]Cao X, Onishi A, Chen J. Quantifying the cool island intensity of urban parks using ASTER and IKONOS data. Landscape Urban Plan. 2010; 96(4):224-31.
• [16]Chang C, Li M, Chang S. A preliminary study on the local cool island intensity of Taipei city parks. Landscape Urban Plan. 2007; 80(4):386-95.
• [17]Yan H, Fan S, Guo C, Wu F, Zhang N, Dong L. Assessing the effects of landscape design parameters on intra-urban air temperature variability: the case of Beijing, China. Build Environ. 2014; 76:44-53.
• [18]Yan H, Fan S, Guo C, Hu J, Dong L. Quantifying the impact of land cover composition on intra-Urban air temperature variations at a mid-latitude city. Plos one. 2014; 9(7):e102124.
• [19]Krüger E, Givoni B. Outdoor measurements and temperature comparisons of seven monitoring stations: preliminary studies in Curitiba, Brazil. Build Environ. 2007; 42(4):1685-98.
• [20]Huang L, Li J, Zhao D, Zhu J. A fieldwork study on the diurnal changes of urban microclimate in four types of ground cover and urban heat island of Nanjing, China. Build Environ. 2008; 43(1):7-17.
• [21]Shashua-Bar L, Hoffman ME. Vegetation as a climatic component in the design of an urban street: an empirical model for predicting the cooling effect of urban green areas with trees. Energ Buildings. 2000; 31(3):221-35.
• [22]Potchter O, Cohen P, Bitan A. Climatic behavior of various urban parks during hot and humid summer in the Mediterranean city of Tel Aviv, Israel. Int J Climatol. 2006; 26(12):1695-711.