An estimation of land surface temperatures from landsat ETM+ images for Durban, South Africa

Abstract

Population increase within urban environments especially in the developing  countries, has posed a need to understand the urban climates. While the importance of urban climates cannot be overemphasized, acquiring knowledge about  contributing factors to urban climates can be challenging. Measuring land surface temperatures is one of the ways to acquire such knowledge which could be an uphill task if done manually. However, satellite remote sensing data could be applied to  spatially estimate such factors. Land surface temperatures (LST) were estimated  from the thermal bands of the Landsat Enhanced Thermal Mapper Plus (ETM+) using remote sensing and geographic information system (GIS) techniques. In addition,  meteorological data which included air temperature and relative humidity for the  same satellite image dates were used in the analysis. Results showed that Durban  metropolitan area is experiencing a major heat island over the city centre with some  micro ones around the metro. Comparing the LST results to the landuse/cover of the  city showed the UHI phenomenon is a reality with a 3°C and 4°C LST increase over the city centre of Durban for winter and summer seasons respectively in 2012 and being attributed greatly to the human activities within the area that has led to increase thermal radiation from land surface over highly dense and paved areas.

Keywords: Urban growth, urban heat Island, land surface temperatures, satellite remote sensing