Identification of Surface Urban Heat Islands in Pune City using Multi-date Landsat-8 TIRS Data
Urban Heat Islands (UHI) are areas with significantly warmer temperature than the surrounding areas, primarily formed due to increase in impervious surface area, a decline in vegetation cover, changing climatic conditions and anthropogenic heat discharge from industries. In the past few years, Pune city has witnessed rapid urbanization, making it the eighth-largest city of India. This rapid urbanization has caused significant changes in the land use/land cover (LULC) of the city, resulting in a marked alteration of the local thermal environment. This study attempts to identify such high-temperature zones within Pune city, by using optical and thermal infrared images acquired by Landsat 8 satellite. The study used data acquired during the months of April and May, coinciding with the local summer seasons, for years 2018, 2019 and 2020. The Land Surface Temperature (LST) of the study area was derived from Landsat 8 OLI/TIRS data using radiative transfer equation method. The vegetation cover of Pune city was assessed using Normalized Difference Vegetation Index (NDVI). The study observed that around 12% of the built-up regions within the city had a relatively higher temperature. The difference between high and low- temperature zones within the built-up area was around 8.59°C.
Keywords: Landsat - 8 OLI/TIRS, Urbanization, Climate change, Normalized Difference Vegetation Index, Land Surface Temperature