Reassessing Urban Heat Island Intensity Using Vegetation-Based References in a Semi-Arid City: The Case of Diyarbakır

The Urban Heat Island (UHI) effect has intensified due to rapid urbanization and the expansion of impervious surfaces, a phenomenon particularly critical in semi-arid cities. This study investigates the relationship between Land Surface Temperature (LST) and vegetation density (NDVI) during the 2025 summer season (May–September) in the Diyarbakır metropolitan area, Türkiye. Landsat 8–9 thermal data and Sentinel-2 imagery were processed on the Google Earth Engine platform using spatial and statistical analyses. Quantitative results reveal that the mean surface temperature in urban areas was 53.7°C, compared to 45.6°C in vegetated rural reference areas. The study identified a maximum mean UHI intensity of 8.1°C during the peak summer month of July. Furthermore, regression analysis demonstrated a robust negative correlation between NDVI and LST (R² = 0.757), indicating that densely vegetated zones (NDVI > 0.3) were up to 10–15°C cooler than the urban core. These findings underscore the pivotal function of urban green spaces in moderating UHI intensity and provide a scientific basis for thermal comfort strategies in semi-arid urban contexts.