An investigation of the influence of ground surface properties and shading on outdoor thermal comfort in a high-altitude residential area

Abstract

Landscape elements in residential areas can effectively improve the outdoor thermal environment, with different outcomes depending on the climate conditions. This study explores how the ground surface and shading properties affect the outdoor thermal environment in a high-altitude plateau climate where few studies have been conducted. The measurements were conducted during summer and winter in a residential area in Lhasa, Tibet. Without natural shading such as trees, there is a positive correlation between Sky-view factor (SVF) and Physiological equivalent temperature (PET) during winter and a negative correlation during summer. When SVF exceeds 0.65 in summer, it may cause human discomfort. Compared to artificial shading such as a tensioned membrane, deciduous trees are superior at improving human comfort, as they can increase PET by 10.56 °C in winter and decrease it by 9.73 °C in summer. During summer, high-reflection water-permeable bricks can reduce the PET by 1.08 °C, and lawns can reduce the mean radiation temperature (Tmrt) by 1.65 °C; however, the lawns may produce a microclimate with a high air temperature. The results from this paper can be used as a reference for landscape planning and design in residential areas in high-altitude cold-climate regions.

Keywords

• High altitude cold area
• Residential area
• Shading
• Ground surface properties
• Outdoor thermal comfort