IMPACTS OF LAND USE/LAND COVER CHANGES ON SURFACE URBAN HEAT ISLANDS: A CASE STUDY OF COIMBATORE, INDIA

Abstract

Urban Heat Island (UHI) is a major urban environmental issue throughout the world. UHI is a climatic phenomenon where anthropogenic modification leads to increased air temperature in urban areas when compared to that of the surrounding rural areas. Over urbanisation leads to an increase in UHI, resulting in the decrease of human health and a healthy environment. Remote sensing plays a major role in mapping the UHI as it can sense the top of the atmosphere radiances. From brightness, temperatures can be derived using Planck’s constant. In this study, UHI of Coimbatore was determined by using the single channel algorithm during winter season. Landsat data of TM, ETM+ and OLI/TIRS were used. Thus, LST helps to identify the increase in heat due to expansion urban areas. Supervised classification with maximum likelihood technique was used to classify the imageries into five landuse classes.Based on this study, the result emphasies that the land use changes was observed to be 14.55 per cent, where as vegetation reduction was 11.6 per cent.Thus, by correlating all these scenario from the year 1990 to 2015 with a five-year interval, the rapid development that took place in the Coimbatore region led to decrease in vegetation and increase in built-up land and temperature. This study reveals that there was an increase of 3.8oC in land surface temperature during in the study periods. Also, the result indicates that there is a strong linearly negative correlation between land surface temperature and vegetation.