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

Abstract

Land Surface Temperature (LST) increment and Urban Heat Islands (UHI) variability are the major urban climatology problems arising in the urban development. Greening urban environment play vital role to combat the effects of micro-climate change. This study attempts to assess the effects of Urban Green Spaces in cooling and mitigating micro-climate change in Addis Ababa City. Three different dates of remotely sensed data from Landsat5 TM (1990) Landsat7 ETM+ (2005) and Landsat8 OLI/TIRS (2021) were used for the study. LST were retrieved from Landsat5 TM and Landsat7 ETM+ using mono window and Landsat8 OLI/TIRS were used split window algorithms. Regression and correlation analysis of LST, Normalized Vegetation Index (NDVI) were performed in SPSS V23. The Results from this study have shown that the proportion of Urban Green Space (UGS) to other LULC were reduced from 120.4 Km² in 1990 to 76.26 Km² in 2021. The Result of multiple linear regression analysis clearly indicates that built up and green vegetation contributed 92.2% of the LST variations in Addis Ababa City. The Cooling Efficiency (CE) and Threshold value (TVoE) of green space in Addis Ababa City were calculated as 4.5 ± 0.5 ha. This finding indicated that the city municipality implements urban planning, allocating a green space area of 4.5 ± 0.5 ha is the most efficient to reduce heat effects of the study area. The result of the study indicates that, strengthening of public participation in urban greening as an important strategy to mitigate the effects of micro-climate change and it is important to sustain urban development as well as to provide better quality of life on the urban population.