Seasonal and Multi-Decadal Dynamics of Land Surface Temperature and Urban Heat Island in a Semi-Arid Secondary City: A Case Study of Adama, Ethiopia

Ethiopia is experiencing rapid urbanization, which is drastically changing land use and land cover (LULC), increasing land surface temperature (LST), and aggravating urban heat island (UHI) effects. The paper provides a new seasonally disaggregated, multi-decadal analysis of UHI processes in a fast-growing secondary city in the semi-arid Rift Valley of Ethiopia, namely, Adama City. We measure seasonal and interannual patterns of LST based on multi-seasonal Landsat images of 1991, 2000, 2010, and 2022 and examine how this information is related to LULC changes and spectral indices (NDVI, NDBI). The Belg season is when peak heating takes place due to low vegetation and high solar radiation, and the Kiremt is a cooling influence of thick vegetation and moisture. Urban growth is the primary cause of the LST increase, with built-up areas experiencing a massive eightfold increase. Vegetation helps to mitigate the heat effects, as it modulates the temperatures on the surfaces in recent years. This research contributes to understanding urban climate seasonality and long-term trends beyond megacities, which is crucial for urban planning that aligns with climate-resistant development in semi-arid secondary cities.