Assessing the impacts of urbanization on the thermal environment of Ranchi City (India) using geospatial technology

Understanding, monitoring and mitigating the effects of increasing urbanization on the environment is essential for sustainable development. The objective of this study is to find out how and at what extent the spatio-temporal dynamics of Land Surface Temperature of Ranchi, Jharkhand (India) is affected by urbanization. In this study, the temporal Landsat images were used to derive the land use/land covers (LULC), Land Surface Temperatures (LST) and the spatio-temporal dynamics of urban expansion and Urban Heat Island Intensity (UHII) for three dates of 1992, 2001 and 2013. The impact of urbanization to the UHII is assessed using land use trajectories from 1992 to 2013. The results show that, with the urban built up growth of 251.89% in between 1992 to 2013, the increase in UHII is as high as 1.42 K. This is an alarming signal of deteriorating thermal environment of the city which happens to be cooler due to its relatively higher altitude. The result shows that in Ranchi, the Contribution to UHII (CUHII) of different urbanization trajectories are different and by 2013, the land transformed from agriculture to urban has highest CUHII than any other types of transformations. The results provide valuable insights into the effect of urbanization on thermal environmental and are very useful for decision making and planning of Ranchi, to make it an environmentally smart city.