Document Type : Original Article
School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran, Tehran, Iran
The surface temperature is an essential parameter in controlling and evaluating the physical and chemical processes of the surface of the earth. The Surface Urban Heat Island (SUHI) is the difference in temperature between urban and suburban areas. This study aims to consider the heat island of the urban and suburban areas of 20 different regions in the world with different weather conditions. In order to calculate the surface temperature of the earth in the daytime, the segmentation of the urban and suburban areas and the acquisition of several spectral indices from the Landsat 8 data were used. To calculate the surface temperature of the earth at night, at the same time as Landsat 8 data acquisition at daytime, an Eight-day product of the Earth's surface temperature MODIS (MOD11A21) was used. Land Surface Temperature (LST) of Landsat 8 images was calculated using a split-window algorithm. The results of this study indicate that the heat island of the urban area varies from one region to another. For most of the Mediterranean and temperate regions, the SUHI was positive for both day and nighttimes. For the warm, dry, and desert weather conditions the SUHI was positive at night and negative at daytime. Just for Manama city, the SUHI was negative at night and positive at daytime. However, the positive or negative value of this phenomenon in these twenty regions has been stable over two study time. Also, the effect of spectral indices on this phenomenon was measured. The GVI vegetation index's correlation coefficient was calculated to be -0.823, and the IBI Built-Up Index's correlation coefficient was calculated as 0.761.