Spatio-temporal analysis of urban growth and heat island effects in Bahir Dar, Ethiopia

Abstract

In developing nations like Ethiopia, the pattern of land use is rapidly shifting from non-urban to urban (built-up) areas due to rapid urban growth. The study aims to evaluate the effect of urban growth on urban heat island (UHI) and ecological condition of Bahir Dar using time series Landsat data during 1984–2019. The current study evaluated the ecological consequences that urban growth has on urban heat islands in Bahir Dar and its adjacent areas from 1984 to 2019. The ecological effects of urban heat islands in the study area were measured using the Urban Thermal Field Variance Index (UTFVI). Built-up surfaces of Bahir Dar were occupied 1.14% (1984), 1.69% (1994), 8.29% (2009) and 11.9% (2019) during the study period. The maximum land surface temperature has been raised by 8.39 °C for the past three and half decades (1984–2019). UTFVI values of Bahir Dar for class 1–3 for all study years has been seen as excellent (< 0) in terms of ecological evaluation index (EEI). However, values for classes 4–6 of all study years depict the highest urban heat island effects with maximum values greater than the maximum threshold of UTFVI (> 0.020). This indicates the presence of the strongest UHI effects and ecologically worst problems. So, interventions are required to mitigate this ecological problem caused by high urban heat island effects in the present study area.