Physical and non-physical factors driving urban heat island: Case of Bangkok Metropolitan Administration, Thailand

Abstract

This study is focused on two aspects of the urban heat island (UHI). Firstly, the study is aimed at examining the difference in temperature between zones that are classified into different built areas and other land cover types instead of using the urban and rural classification, which is prevalent in the existing literature. Secondly, we consider the heat-intensity-related physical structure of the city such as the sky view, building coverage, building height, surface albedo, and pervious and impervious surfaces, as well as non-physical factors such as anthropogenic heat, travel demand, electricity consumption, and air pollutant concentration. The local climate zone (LCZ) is used as an approach for characterizing the landscape and physical structure of the study areas. The Bangkok Metropolitan Administration (BMA) is used as the case study and 2016 as the base year for examination. The LCZ is classified using Landsat data and the training areas are created using Google Earth and Google Street View. The heat intensity is studied by deriving the land surface temperature (LST) from the thermal band of the Landsat satellite images of March 3, April 4, and April 12, in 2016, which represent the summer season in Bangkok. The result shows that the industry building areas have the highest mean LST is 32.41 °C, while the lowest LST is 28.32 °C in areas of water bodies; the temperature difference was approximately 4 °C. The factors significantly influencing the warming in the BMA are pervious and impervious surfaces, the building coverage ratio, and the anthropogenic heat flux, while the sky view factor, vehicular traffic, and air pollutant concentration are the weak drivers of UHI.

Keywords: Heat intensity; Land surface temperature; Local climate zone; Non-physical factor; Physical factor; Urban heat island.