Assessing the Impacts of Urbanization-Induced Land Use and Land Cover Changes on Urban Land Surface Temperature Using Spatial Metrics: A Case of Adama City, Central Ethiopia

Abstract

Changes in land use and land cover (LULC) as a result of urbanization have a substantial effect on local and regional climate. Understanding the interaction between the urbanization process and patterns of land surface temperature (LST) at both temporal and spatial scales is crucial for formulating strategies for the potential effects, but little is understood in the context of Ethiopian urban centers. The aim of this study is to examine the spatiotemporal variations in LST attributed to LULC changes due to urbanization between 1990 and 2020 in Adama City, a rapidly growing urban area. Through supervised classification using the support vector machine algorithm, decadal-scale LULC maps of the study area were prepared, and the spatiotemporal changes of LULC were investigated. Spatial metrics were utilized to analyze the dynamics of the landscape patterns. LST was extracted from the Landsat thermal band using emissivity corrected Inverted Planks Equation, and its changes over time were examined. Regression analysis was used to explore the relationship between the changes in LST and the dynamics of built-up areas and vegetation patterns. The findings show that the built-up area has undergone about 23% expansion annually in the past three decades. Furthermore, as evidenced by changes in the number of patches at the landscape level from 3248 in 1990 to 4807 in 2020, the landscape pattern structure became more fragmented. Percentage of Landscape (PLAND), Number of Patch (NP), and Patch Density (PD) of the built-up area have increased, indicating growing urbanization and aggregation with economic growth. In addition, barren land is characterized by the highest temperature followed by built-up areas, and the spatial pattern of the mean LST declined as one moved from the city center to the fringes. Moreover, the temporal changes in LST were directly correlated with the normalized difference built-up index and negatively correlated with the normalized difference vegetation index and vegetation land cover configuration. This research would assist planners in developing an effective land use plan to manage the effects of urbanization on LST, thereby supporting efforts to ensure the sustainable development of urban areas.