Evaluation of Diurnal Variations in Urban Surface Temperature with Earth Observations System

Abstract

Rapid urbanisation causes the ‘heat island’ problem in megacities worldwide. The industrialisation has fuelled the increase in the urbanisation in Indian cities. This work measures and characterises Ahmedabad’s heat island variations (India). The study uses two satellite passes of the MODIS sensor over the summer for the last three years to assess urban heat island intensity (UHII). Sentinel-2B records are used to create a land-use map. The study considers the impact of land-use patterns on summer UHII diurnal fluctuations. Daily diurnal changes in land surface temperature (LST) are being analysed. Locations and land-use land-cover patterns affect UHII. Satellite observations show greater LST values during the day than at night, however, UHII is stronger at night. Urban UHII is stronger rural UHII. Lower vegetation cover area is one of the key causes of UHII development, as seen in the region’s Normalized Difference Vegetation Index (NDVI) values.