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. Inferential and descriptive statistics were applied to examine the spatial and temporal patterns of UHI and the relationships between the Land Surface Temperature (LST), building volume density 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 between 2000 and 2024. Furthermore, within the urban-rural gradient, significant fluctuations in both LST and UHI are observed, with urban zones exhibiting substantially higher averages than peri-urban and rural zones. LST and UHI variations in the peri-urban areas also differ from those in the rural areas. Moreover, the LST variations are significantly correlated with the building volume density and vegetation density. 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 be a key solution to reduce the impact of UHI.