Effects of urbanization on the relationship between greenspace patterns and evolution of regional heat island in cities of Ethiopia

Green space(GS) is a central element of urban ecosystems while, urbanization is substantially changed green land into impervious ecosystems, which has then troubled the equilibrium of the surface thermal energy and the ecosystem services fluxes. This study was intended to explore the response of relative land surface temperature(RLST) intensities to the urban ecosystem-agglomeration dynamics as well as regional thermal environment(RTE) effects on green space in four major cities(i. e., Addis Ababa-Hawassa-Adama-Bahir Dar) of Ethiopia from 1990-2020, using a set of remote sensing images, single-channel algorism, and geospatial analyses. The results showed the trends of GS evolution were: GS loss > GS gain > GS exchange. Besides, the distinct ecosystems as high-temperature zones(RLST more than 2°C) were gradually augmented and significantly intensified between 2010-2020 in all cities, while the proportion of green space was significantly decreased.Due to this, the segregated urban heat islands were gradually inter-weaved and interacted with each other and forming regional heat islands. However, the newly established green space has fewer cooling effects than urban forest and greenery, because RLST of green space loss and gain are substantially disparate. We also confirmed that the regional thermal environment is not only prejudiced by ecosystem patterns and processes besides substantially conquered by the particular GS change processes as well as RHI dynamics and evolution rate.