Spatio-temporal analysis of urban heat island dynamics in urban centers landscape of southwest Ethiopia

<p>Climate change is becoming a global threat to human well-being and the sustainability of the planet Earth. The central cores of urban centers are significantly observed warmer than their surrounding outskirts or rural areas, which is identified as the urban heat island (UHI) effect fueled by massive Land Use Land Cover (LULC) change. The main research aim was to examine the Spatio-temporal variation of UHI dynamics based on the land surface temperature (LST), Normalized Difference Vegetation Index (NDVI) and built-up density in the urban centers (Jimma, Bedelle, Bonga, and Sokorru) landscape using techniques of remote sensing. In this study, Landsat thematic mapper (TM) for 1987 and Landsat Operational Imagery (OLI) for 2018 in the extraction of LST were used for examining UHI. Also, LULC, NDVI and built-up density of the urban centers were analyzed. The results of the study showed that the urban core had greater LST and UHI values, due to an increase of built-up density and a decline of green space. The result of LST mean value range rose from 20.1 ℃ (Bonga) to 23.3 ℃ (Sokorru) in 1987 and 22.67 ℃ (Bedelle) to 24.74 ℃ (Bonga), and 24.72 ℃ (Sokorru) in 2018, while the maximum observed LST value range from 28.97 ℃ (Jimma) in 1987 to 32.61 ℃ (Bonga) in 2018. The maximum range of UHI mean value was from 11.23 ℃ (1987) to 14.04 ℃ (2018), while the maximum observed UHI value ranged from 19.63 ℃ in 1987 to 23.32 ℃ in 2018 over Jimma city. The computed correlation at 5% significance results showed LULC change has a significant association with surface air temperature (<em>r</em> = 0.621, Sig. (2-tailed) = 0.031) accompanied by UHI impacts. We recommended urban authorities, policymakers, and urban planners should consider the effects of LST and UHI in urban planning to realize climate-smart urban centers of tomorrow in urban centers of southwest Ethiopia.</p>