Remote sensing of land cover’s effect on surface temperatures : a case study of the urban heat island in Bangalore, India

Urbanization has substantially altered the earth’s surface, and cities’ impervious surfaces for anthropogenic activities often generate an urban heat island (UHI). This paper analyses the effects of the UHI in Bangalore, which in recent years has witnessed tremendous in-migration of people and expansion of infrastructure due to rapid growth of its information technology, biotechnology and manufacturing sectors. Temperature values extracted from the Landsat satellite’s Enhanced Thematic Mapper Plus (ETM+) thermal bands and a “Normalized Difference Vegetation Index” (NDVI) were used to ascertain the relationship between vegetation cover and temperature. Results indicate that the city core has a significantly lower mean temperature than the city’s outgrowth zones. The presence of water bodies and vegetation in the city’s core helped to maintain lower temperatures than those found in the city’s outskirts, even though within the city core temperatures varied from 1 to 7° C within different land cover classes. The continued expansion of urban infrastructure and new, residential neighborhoods which lack vegetation seem to be contributing substantially to higher temperatures in the outgrowth zones.