Day and night surface and atmospheric heat islands in a continental and temperate tropical environment

Urban areas cause several transformations in the landscape through the replacement of vegetation and permeable soils for buildings and waterproofing of surfaces. Such changes result in a different energy balance according to land use and occupation characteristics, contributing to the generation of heat islands. This research aims to compare and analyze the intensities of day and night atmospheric and surface urban heat islands in Presidente Prudente, Brazil, and in Rennes, France. These are medium-sized cities located in continental tropical and temperate climates, respectively. Air temperatures were recorded in urban built areas and in other representative areas of rural environments in both cities. Surface temperature maps were plotted using images from the Landsat 8 satellite, band 10, thermal infrared channel/TIRS 1, taken during the night and the day. The results show that atmospheric (UHI) and surface (SUHI) heat islands do not present the same characteristics and that the dynamics of each heat island varies not only throughout the day, but also depending on the region's climate, meteorological condition, location, and types of land use. The details of surface temperatures and air temperatures during the satellite passage time (day and night) through points with typical characteristics of each city show the effects of vegetation and less built-up areas on reducing the differences between air and surface temperatures, evidencing the effects of buildings on increasing air temperatures, especially at night, when atmospheric heat islands are more intense. This research is original because relations between air and surface temperatures during the day and night were not previously studied in these cities. Thus, the results of this study may contribute to improving knowledge on urban climate and surface and atmospheric heat islands aiming to provide information for the management and planning of cities with different climate and historical backgrounds.