Investigation on Impervious Surface (ISA) and the Normalized Difference Vegetation Index (NDVI) as Representative Parameters of the Urban Heat Island by Using Satellite Imageries

Urban heat island phenomenon is generally caused by a reduction in latent heat and a rise in sensible heat in urban areas. Today, this is one of the major problems of the large cities which has attracted the attention of many researchers and experts in various fields. This study investigates heat island in Tehran metropolitan as the most densely populated city of Iran. This paper aims to use satellite imageries to compares the normalized difference vegetation index (NDVI) and impervious surface (ISA) as representative parameters that of surface urban heat island (SUHI) by examining their relationship with land surface temperature indices (LST) and land-use map. For this purpose, LANDSAT 5 TM imageries and Tehran1:2000 land use map and sub-pixels model has been used. The results show that there are a linear and strong relationship between LST and ISA, while the relationship between LST and NDVI is much weaker and in order to quantitative investigation of LST in urban heat island we used thermal remote sensing. Results indicated that ISA indicator is suitable than NDVI. Also, the investigation on percentage of impervious surfaces in each land-use represents that residential land uses has the highest percentage of impervious surfaces because having the surfaces like asphalt and concrete and vegetation is the lowest one.