Analysis of Spatio-Temporal Patterns of Urban Heat Islands in Kisangani City Using MODIS Imagery: Urban-Rural Gradient, Building Volume Density, and Vegetation Effects

The Urban Heat Island (UHI) effect has emerged in the literature as a major challenge to urban well-being, primarily driven by increasing urbanization. To address this challenge, this study investigates the spatio-temporal pattern of the UHI in the fast-growing city of Kisangani and within its urban-rural gradient from 2000 to 2024, using Land Surface Temperature (LST) data from the MODIS MOD11A2 V6.1 product. Inferential and descriptive statistics were applied to examine the patterns of UHI and the relationships between the LST, building volume density (BVD) as well as vegetation density expressed by the Normalized Difference Vegetation Index (NDVI). Results showed that the spatial extent of the moderate UHI gradually increased from 16 km² to 38 km², while the high UHI increased from 9 km² to 19 km². Furthermore, although high UHI values (0.2°C<UHI≤0.3°C) are observed in urban areas and significant differences in UHI variations are detected across urban, peri-urban, and rural zones, the results indicate that the mean UHI in Kisangani’s urban areas remains below 0.2°C. Therefore, based on average UHI variations, Kisangani’s urban zones exhibit moderate disparities in LST compared to rural areas. Moreover, the LST variations are significantly correlated with the building volume and vegetation densities. However, the influence of vegetation density as a predictor of LST gradually decreases while the influence of building volume density increases over time, suggesting the need to implement a synergistic development pathway to manage the interactions between urbanization, landscape change, and ecosystem service provision. This integrated approach may represent a crucial solution for mitigating the UHI effect in regions categorized as high-temperature zones.