Spatial distribution of urban heat island and intra-urban air temperature variability in high-density urban areas in Hong Kong
Refereed conference paper presented and published in conference proceedings

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AbstractHigh level of urbanization in Hong Kong causes urban heat island effect (UHI), which is considered as one of the major urban climatic problems in recent years. Understanding the spatial distribution of UHI intensity as well as intra-urban air temperature differences is the basis of urban climatic planning for UHI mitigation. Many studies have investigated the impacts of urban surface properties and geographical characteristics on UHI intensity. However, given the unique urban morphology and complicated geographical environment in Hong Kong, the climatic conditions and UHI pattern at local scale exhibit greater diversity compared to other cities. Thus, there is a need to investigate the spatial pattern of UHI intensity, identify its relationships with urban morphological parameters, and propose planning strategies for UHI mitigation.

This paper firstly examines ten years of meteorological observations (2002- 2012) from Hong Kong Observatory (HKO) automatic weather stations (AWSs) to understand the diurnal urban heat island profile, and find out the linkages of urban heat island intensity with cloud amount and wind speed. Base on the data analysis, UHI intensities are found to be maximized during nighttime with calm wind and clear sky conditions. Secondly, this paper analyzes air temperature data captured by six mobile traverse measurements at street level (2.3m above ground) during calm and clear summer nights (8PM to 10PM) in 2014 to study the UHI intensity pattern over four high-density areas: Kowloon peninsula, north part of Hong Kong Island, Tuen Mun and Yuen Long. Thirdly, urban morphological parameters, such as building height, ground coverage ratio, sky view factor, aspect ratio, calculated using GIS are reported and compared with the traverse measurement data. The results indicate that, the compact high-rise commercial area Mong Kok (in Kowloon), Causeway Bay (in Hong Kong Island), Castle Peak Road (in Yuen Long) are the hotspot areas with higher UHI intensity of 3-5 °C. Intra-urban air temperature difference are identified to be 1.5-3.5 °C due to the variations in urban geometry and geographical conditions. Finally, the discussion part of this paper makes summaries about the spatial characteristics of nocturnal urban heat island effect as well as intra-urban air temperature differences, and also presents UHI mitigation strategies through optimization in land-use planning and building design.
All Author(s) ListYingsheng ZHENG, Yuan SHI, Chao REN, Hung Lam, Steve YIM, Yuk Fo, Derrick LAI, Ka Lun, Kevin LAU
Name of Conference9th International Conference on Urban Climate
Start Date of Conference20/07/2015
End Date of Conference24/07/2015
Place of ConferenceToulouse
Country/Region of ConferenceFrance
Proceedings TitleProceedings of the Ninth International Conference on Urban Climate (ICUC9)
LanguagesEnglish-United Kingdom

Last updated on 2018-22-01 at 21:26