Ayansina AYANLADE, Department of Geography and Regional Research, University of Vienna | Universitätsstraße 7/5, Austria
Lemlem F. WELDEMARIAM, Department of Geography and Regional Research, University of Vienna | Universitätsstraße 7/5, Austria
This study utilizes Remote Sensing and Geographic Information System (GIS) techniques to assess urban heat islands in four cities in south western Nigeria over a period of 30 years. This study focuses at examining the influences of difference in ecological zone on the variation of ULST and the intensity of UHI. Both satellite climate data and landuse/landcover data from 1986 and 2017 were used in this study, to assess the recent extreme weather events as evident in changes in urban land surface temperature (LST) and f urban heat island (UHI) in four selected cities in Nigeria. Contribution index (CI) and landscape index (LI) were used to estimate the LST contributions from non-urban and urban areas to UHI. The results show significant variation in the intensity of LST and UHI over cities in different ecological zones in the study area. Much UHI were observed in large cities with LI < 1.0, but this was much more during the dry seasons with LI < 0.12. The study further revealed the parameters that influence land surface temperature and consequently urban heat islands, including changes in vegetation cover, bare surface (considering soil moisture content), water bodies and population (hence built density and impervious surfaces) are examined in the study. The study concluded by stated the need for the cities’ planners to improve current and future development plans for the city through the formulation of the appropriate policy.
Mots clés : urban land surface temperature |Climate change|Remote Sensing |GIS|Nigeria