Urban Heat Island and Its Impact On Impervious Surfaces During Two Seasons: A Case Study Of Bangalore

One of the major challenges faced in the 21
^st
century is urbanization and industrialization resulting in Urban Heat Island (UHI). Urban areas also exhibit a greater amount of anthropogenic heat and the increase in temperature can have very serious effects on public health, environment and energy use. This study attempts to understand the effect of impervious surfaces and green spaces on surface temperature. Here, Land Surface Temperature (LST) of Bangalore was derived using band 10 of Landsat-8 data for the month of March and November, 2020. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) were computed from the spectral bands and their correlation with LST were determined. NDVI and LST showed a negative correlation of -0.32 and -0.11 for March and November, 2020 respectively. In case of built-up, LST showed high correlation of 0.63 in March and relatively low value of 0.28 in November, 2020. The results showed that the effect of UHI is more in summer than in winters. LST of Land Use Land Cover (LULC) map of the study area was created with 4 classes namely built-up, vegetation, water and bare soil (including open areas and fallow land). This was used to find out the temperature variations amongst the classes. In case of built-up (including roads, residential buildings, commercial complexes etc.) mean LST was 36.18 °C and 22.40 °C in March and November respectively. Temperature variation was seen more within the 4 classes in November than in March. The mean temperature of vegetation and water was found to be lesser than other two classes. This study strongly advocates presence of urban green spaces for healthy environment of residents.