Sky View Factor-based correlation of landscape morphology and the thermal environment of street canyons: A case study of Harbin, China

China’s rapid and extraordinary urbanisation has resulted in a dichotomy between the urban form of historic districts and that of new urban areas. Unlike the new planning of new urban areas, the optimisation of the thermal environment in historic districts is achieved through an important means of regulating the shading effectiveness of trees in street canyons, without destruction of current buildings in existing districts. In this paper, the sky view factor, an index for evaluating the shading capacity of street canyons, is used to calculate the shading efficiency of trees and reveal their influence mechanism by using a convolutional neural network (SegNet) to segment the Baidu street view images. The results show that: (1) tree shading in Harbin’s historic districts has a significant impact on the thermal environment of street canyons, with an average shade effectiveness of 56.3%; (2) based on geospatial autocorrelation analysis and a typological reconstruction of street canyons, the study reveals that tree shading has significant spatial aggregation characteristics in historic districts and proposes guidelines for the planning and design of different types of street canyon trees. The study provides important data and strategic support for optimising the thermal environment of urban historic districts in Northeast China.

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Positional error modeling of sky‐view factor measurements within urban street canyons

Transactions in GIS ◽

10.1111/tgis.12761 ◽

2021 ◽

Author(s):

Zian Wang ◽

Guoan Tang ◽

Guonian Lü ◽

Cheng Ye ◽

Fangzhuo Zhou ◽

...

Keyword(s):

Error Modeling ◽

View Factor ◽

Positional Error ◽

Street Canyons ◽

Urban Street ◽

Sky View Factor ◽

Urban Street Canyons

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Review of methods used to estimate the sky view factor in urban street canyons

Building and Environment ◽

10.1016/j.buildenv.2019.106497 ◽

2020 ◽

Vol 168 ◽

pp. 106497 ◽

Cited By ~ 8

Author(s):

Chunping Miao ◽

Shuai Yu ◽

Yuanman Hu ◽

Huiwen Zhang ◽

Xingyuan He ◽

...

Keyword(s):

View Factor ◽

Street Canyons ◽

Urban Street ◽

Sky View Factor ◽

Urban Street Canyons

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Measurement and Analysis of Summer Outdoor Thermal Environment of Campus Open Space in Guangzhou

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.4680 ◽

2011 ◽

Vol 121-126 ◽

pp. 4680-4684

Author(s):

Guang Chen ◽

Li Hua Zhao ◽

Qiong Li

Keyword(s):

Energy Saving ◽

Open Space ◽

Thermal Environment ◽

Great Influence ◽

View Factor ◽

Environment Design ◽

Sky View Factor ◽

Hot Environment ◽

Outdoor Thermal Environment ◽

Measurement And Analysis

Open space is an important part of Campus, also has an important influence to the thermal environment of campus. The measurement of summer outdoor thermal environment of campus open space showed that: the piloti can effectively improve the thermal environment in hot summer; underlying surface materials, sky view factor has a great influence on the outdoor thermal environment. Using appropriate surface structure, increasing piloti and increasing square shading are suggested as outdoor thermal environment optimizing measures based the measure results. Advices were given for hot environment design and passive energy saving design

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Effect of the position of the visible sky in determining the sky view factor on micrometeorological and human thermal comfort conditions in urban street canyons

Theoretical and Applied Climatology ◽

10.1007/s00704-016-2023-3 ◽

2017 ◽

Vol 131 (3-4) ◽

pp. 1083-1100 ◽

Cited By ~ 9

Author(s):

Adeb Qaid ◽

Hasanuddin Bin Lamit ◽

Dilshan Remaz Ossen ◽

Mohd Hisyam Rasidi

Keyword(s):

Thermal Comfort ◽

View Factor ◽

Street Canyons ◽

Urban Street ◽

Human Thermal Comfort ◽

Sky View Factor ◽

Urban Street Canyons

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Optimization Strategy of Traditional Block Form Based on Field Investigation—A Case Study of Xi’an Baxian’an, China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182010895 ◽

2021 ◽

Vol 18 (20) ◽

pp. 10895

Author(s):

Wei Feng ◽

Wei Ding ◽

Yingdi Yin ◽

Qixian Lin ◽

Meng Zheng ◽

...

Keyword(s):

Wind Speed ◽

Air Temperature ◽

Speed Ratio ◽

View Factor ◽

Rapid Urbanization ◽

Architectural Form ◽

Building Density ◽

Building Height ◽

Sky View Factor

Rapid urbanization has caused environmental problems such as the urban heat island and air pollution, which are unfavorable to residents. Urban traditional blocks are facing the dual challenges of restoration and protection. This paper proposes adaptive transformation strategies for improving the microclimate of traditional areas. We selected Baxian’an Block in Xi’an city, simulated the air temperature and wind speed during summer and winter using ENVI-met, and studied the correlationship between morphological parameters (average building height, building density, enclosure degree, height fall, aspect ratio, and sky view factor) and air temperature and wind speed ratio. The case study revealed that the wind speed ratio of Baxian’an is relatively different in summer, reaching a maximum of 0.61, meaning that the ventilation capacity is significantly affected by the architectural form of the block. Finally, suggestions for the optimal design of the block’s form are provided: the building density should be less than 50%, the average building height should be more than 50 m, the enclosure degree should be less than 0.2, the height fall should be more than 41.7 m, and the sky view factor should be less than 0.5. This study can provide data and support for improving the planning and design standards of traditional residential areas.

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The Influence of Sky View Factor on Daytime and Nighttime Urban Land Surface Temperature in Different Spatial-Temporal Scales: A Case Study of Beijing

Remote Sensing ◽

10.3390/rs13204117 ◽

2021 ◽

Vol 13 (20) ◽

pp. 4117

Author(s):

Qiang Chen ◽

Qianhao Cheng ◽

Yunhao Chen ◽

Kangning Li ◽

Dandan Wang ◽

...

Keyword(s):

Surface Temperature ◽

Land Surface Temperature ◽

Land Surface ◽

Thermal Environment ◽

Experimental Results ◽

View Factor ◽

Temporal Scales ◽

Building Height ◽

Sky View Factor ◽

The Impact

Urban building morphology has a significant impact on the urban thermal environment (UTE). The sky view factor (SVF) is an important structure index of buildings and combines height and density attributes. These factors have impact on the land surface temperature (LST). Thus, it is crucial to analyze the relationship between SVF and LST in different spatial-temporal scales. Therefore, we tried to use a building vector database to calculate the SVF, and we used remote sensing thermal infrared band to retrieve LST. Then, we analyzed the influence between SVF and LST in different spatial and temporal scales, and we analyzed the seasonal variation, day–night variation, and the impact of building height and density of the SVF–LST relationship. We selected the core built-up area of Beijing as the study area and analyzed the SVF–LST relationship in four periods in 2018. The temporal experimental results indicated that LST is higher in the obscured areas than in the open areas at nighttime. In winter, the maximum mean LST is in the open areas. The spatial experimental results indicate that the SVF and LST relationship is different in the low SVF region, with 30 m and 90 m pixel scale in the daytime. This may be the shadow cooling effect around the buildings. In addition, we discussed the effects of building height and shading on the SVF–LST relationship, and the experimental results show that the average shading ratio is the largest at 0.38 in the mid-rise building area in winter.

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Tree planting indices and their effects on summer park thermal environment: A case study of a subtropical satellite city, China

Indoor and Built Environment ◽

10.1177/1420326x20977614 ◽

2020 ◽

pp. 1420326X2097761

Author(s):

Wei Guo ◽

Bin Cheng ◽

Chunlu Wang ◽

Xinyu Tang

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Thermal Environment ◽

Urban Forestry ◽

Urban Environments ◽

Tree Planting ◽

View Factor ◽

Radiation Level ◽

Area Index ◽

Sky View Factor

Urban residents are suffering from serious thermal stress resulting from urban heat island and global warming. Investigators have explored several methods to address this issue. Vegetation, especially trees, were found to play a vital part in urban environments. It produces a cooling effect by reducing temperature and radiation levels. To find thermal performances of trees in detail, this study physically measured two urban parks during August 2019 in a satellite city of China regarding their thermal environments relevant to tree planting indices. There were three planting indices used, sky view factor, leaf area index and enclosure area. Through associating them with thermal indicators by linear regression, all of the indices were confirmed to have significant thermal effects. Every 0.1 increase in sky view factor resulted in an increase of 1°C air temperature, 0.16 m/s air velocity, 40 W/m2 solar radiation level and 1.6°C mean radiant temperature. Same effects were found in nearly 0.4 leaf area index decrease and approximately 20 m2 enclosure area increase. These results provide very optimistic directions for future urban forestry planning and landscaping.

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