TIME SERIES STUDY ON URBAN HEAT ISLANDS

Abstract

URBAN HEAT ISLAND (UHI) refers to the observed temperature difference between the urban region and the surrounding rural regions. Local-climate changes due to urbanization are characterized by the urban heat island (UHI). There are various parameters which are considered while computing LST. The parameters like Spectral Radiance and At-Satellite Temperature plays an important role in LST computations. In this study, Delhi NCR region is selected for analysis of urban heat island (UHI) effect. The analysis is carried out using Landsat TM, ETM+ and OLI data from 1992 to 2016 over the study region. The relation between normalized difference vegetation index (NDVI) and LST is studied and it shows that there exists negative correlation between NDVI and LST. Moreover, there exists a negative correlation between emissivity and LST which implies NDVI and emissivity are positively correlated. Land use classification is also studied in order to showcase the % change in each land cover class from 1992 to 2016 and how LST is increasing in various land cover classes over the time frame. It can clearly be concluded that urban areas tend to increase in the temperature range particularly from 35-40 0C to 45-50 0C in the consequent years and moreover, urban areas with the temperature >45 0C also increase which shows there has been an increase in the core urban areas of Delhi NCR (study area) as well