Abstract

In the present study, the most appropriate Landsat and ASTER Image spatial and spectral resolutions were selected to extract thermal infrared data in Doha City, Qatar from 1990-2015. Results indicated Urban Heat Island (UHI) calculated from Landsat sensor data was more consistent with ground truthed temperatures. Landsat TM thermal infrared data with low spatial resolution (60-120 m) was more appropriate for large-scale thermal studies, but was not suitable to assess complex urban thermal environments and establish Land Surface Temperatures (LSTs) for individual buildings. However, ASTER sensor, with a Thermal Infrared (TIR) subsystem of 90 m spatial resolution, showed more accurate determination of thermal patterns and LSTs. Landsat data revealed relatively high temperatures, which exhibited increased congruence with ground truthed measures. In Doha City, LST showed an increased trend from 1990 to 2015; low in 1990, moderate in 2000, to very high in 2015. Furthermore, our results confirmed accelerated urban sprawl during 1990-2015. The evaluated areas increased from 80 km2 in 1990 to 179 km2 in 2015. A strong positive relationship was observed between UHI and urban area intensity. Urban planning absence significantly affected the rural environment. Urbanized areas exhibited high thermal conductivity and radiation heat budgets, characterized by increased atmospheric and surface temperatures compared to surrounding rural areas. Therefore, rapid urbanization rates must undergo proper planning and management regimes to insure positive impacts on the local climate and environment.

Keywords: Urban heat island (UHI); Land surface temperature (LST); Doha (Qatar)