关键词: 视觉指数, 居住区, 城市热环境, 城市热岛效应

Abstract: The thermal environment in residential areas is closely related to the thermal comfort and safety of residents. With Tongshan District in Xuzhou City as a case, we explored the influencing patterns and potential mechanisms of residential compositions (quantified by visual indices) on the thermal environment parameters (air tempera-ture, relative humidity, and thermal-humidity index) at different periods in sunny summer days. The results showed that residential compositions were associated with the thermal environment parameters, and that the composition of residential areas influenced thermal environments by affecting energy flow. In the forenoon, residential compositions primarily regulated the thermal environment through ventilation. The construction view index (VI_C) showed a reduction in cooling. The green view index (VI_G) exhibited reductions in cooling and humidification. The sky view index (VI_S) showed an increase in cooling, respectively. VI_C and VI_S contributed 9.9% and 26.4% independent effects to the air temperature between the residential areas, and 10.0% and 8.7% to the relative humidity, respectively. Meanwhile, VI_S contributed a 20.2% independent effect to the temperature-humidity index. In the afternoon, heat released from constructions and vegetation evapotranspiration dominated the thermal environment, contributing 13.5% and 15.3% independent effects to the air temperature differences among the residential areas, 8.8% and 17.8% to the relative humidity, and 10.8% and 8.3% to the temperature-humidity index, respectively. Further analysis showed that VI_C∈(0.13, 0.14), VI_G∈[0, 0.15)∪(0.45, 1] and VI_S∈[0, 0.04)∪(0.24, 1] could effectively improve the thermal environment. Our results could provide quantitative references for residential area design.

Key words: visual index, residential area, urban thermal environment, urban heat island effect