LULC dynamics and the effects of urban green spaces in cooling and mitigating micro-climate change and urban heat island effects: a case study in Addis Ababa City, Ethiopia
Mulugeta Demisse, Solomon Hishe, Kefelegn Getahun
Abstract
ABSTRACT Land surface temperature (LST) increase and urban heat islands (UHI) are significant issues in urban development. Urban green spaces are crucial in combating micro-climate change. This study assesses their effects on cooling and mitigating micro-climate change in Addis Ababa using remotely sensed data from Landsat 5 TM (1990), Landsat 7 ETM+ (2005), and Landsat 8 OLI/TIRS (2021). LST was retrieved using mono-window algorithms for Landsat 5 and Landsat 7, and the split-window algorithm for Landsat 8. Regression and correlation analyses of LST and Normalized Difference Vegetation Index (NDVI) were conducted using SPSS V23, STATA, and R Studio. Results showed a decrease in urban green space (UGS) from 120.4 km² in 1990 to 76.26 km² in 2021. Multiple linear regression analysis indicated that built-up areas and green vegetation accounted for 92.2% of LST variations. The cooling efficiency (CE) and threshold value (TVoE) of green space were calculated as 4.5 ± 0.5 hectares. This suggests that allocating green spaces of this size effectively reduces heat effects. Strengthening public participation in urban greening is crucial to mitigate micro-climate change, sustain urban development, and improve quality of life. Built-up areas and vegetation significantly impact LST more than surface water (NDWI), essential for urban green and land-use planning to minimize urbanization impacts.