ASSESSMENT OF URBAN HEAT ISLAND IN BHILAI
DURG CITY USING REMOTE SENSING AND GIS
Dipak Bej*
*Junior Research Fellow, Chhattisgarh council of science and technology
Abstract
The urban air temperature is gradually rising in all cities in the world. One of the possible causes is the drastic
reduction in the greenery area in cities. The distinguished climatic condition termed ‘Urban Heat Island’ (UHI) is
developing in the rapidly urbanized cities. Bhilai-Durg city of Chhattisgarh is experiencing rapid urbanization that
has resulted in remarkable UHI. Understanding the distribution of Land Surface Temperature (LST) and its spatial
variation will be helpful to decipher its mechanism and find out possible solution. This study tries to investigate and
identify land use types which have the most influence to the increase of ambient temperature in Bhilai-Durg city.
For the present study Landsat 7 ETM+ images of 2002 and Landsat 8 TIRS image of 2017 was obtained from USGS
for the study area. Using bands 1- 4 and 7 of Landsat 7 ETM+ and 2-5 and 10, 11 of Landsat 8 TIRS for processing
the land use / cover pattern, Land surface temperature and NDVI. Eight classes considered for the study are Built-
upland, mixed Built-up, Water bodies, Agricultural fields, Tree clad area, Open land, Industry and River Sand.
Normalized Difference Vegetation Index (NDVI) image was developed. The digital number of thermal infrared
band is converted in to spectral radiance using the equation supplied by the Landsat user’s hand book. The effective
at-sensor brightness temperature is obtained from the spectral radiance using Plank’s inverse function. The surface
emissivity based on NDVI classes is used to retrieve the final LST. It was noted that maximum air temperature was
observed in built up areas of the city and minimum temperatures are observed in areas where vegetation cover is
more. Urban heat island phenomenon is evident from the LST images. NDVI is found to have negative correlation
with LST. The study reveals that appropriate strategies are necessary for the sustainable management of the urban
area.
Key words: Land Surface Temperature, Land Use/Cover, NDVI, Urban Heat Island
