Urban expansion, vegetation patterns and surface heat distribution in Luanda, Angola

Urban growth can significantly affect the characteristics of land cover and surface thermal properties, especially in rapidly expanding African cities, where spatial data is scarce. This study aims at evaluating urban expansion, land surface temperature (LST), vegetation conditions and built-up intensity of Luanda, Angola based on geospatial analysis of satellite-based data. The Global Human Settlement Layer (GHSL) Multi-temporal Urban Extent data were used for investigating the spatial expansion between 2000 and 2025, the Landsat 8 and Landsat 9 Collection 2 Level 2 (CR-LS2025) data were processed for the year 2025 to derive LST, the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Built-up Index (NDBI). Spatial outputs were created using Google Earth Engine and QGIS, and pixel based statistical analysis was used to investigate the relationship between vegetation density and surface temperature after removing water pixels and implausible values. The results show a significant increase in Luanda urban sprawl as well as strong spatial variations in surface temperature and the presence of large high temperature regions within areas of high urban density and low vegetation cover. The analysis of NDVI and LST showed a weak negative correlation (r = −0.168; R2 = 0.028), implying that higher vegetation density is generally correlated with lower surface temperature, but the amount of thermal variation that can be explained by the vegetation is limited. The results reveal the need of incorporating urban greening, land-cover management and heat-sensitive spatial planning in the future development of Luanda, a city with a fast urbanization rate.