جمیل امان اللهی

Landsat satellite images have been increasingly used in studying Urban Heat Island (UHI) indicated by Land Surface Temperature (LST) in last decade. In this study Landsat Thematic Mapper (TM) 5 in 18 May 1998 (Spring), Landsat Enhanced Thematic Mapper Plus (ETM+) in 8 July 2000 (Summer) and 10 January 2001(Winter) were utilized to study UHI in Tehran, Iran. The relationship between Normalized Differences Vegetation Index (NDVI) and LST were also studied using Non Linear Correlation Coefficient (NLCC) with polynomial equation in those three times. A result showed that the NLCC between NDVI and LST is weak and in the spring was higher compared to other seasons. The LST obtained in the city (Tehran) were lower and higher than surrounding areas with steppe and thick vegetation cover respectively. Natural Immersive Surface Area (ISA) in surrounding areas was observed warmer compared to ISA in the city in winter and spring. Moreover, in the summer, gravel and sandy lands were warmer than ISA in the city. This study reveals that in the semi arid climate having shrubs and steppe vegetation, the LST in the city is not higher than LST of the surrounding areas.