Background and Objective: Urban Heat Islands (UHI) are an important environmental consequence of urban expansion and changes in land surface characteristics, particularly the growth of built-up areas and reduction of vegetation cover. This study aims to investigate the spatio-temporal changes in urban heat islands and identify the factors influencing their intensity in Baqubah City, Iraq, using remote sensing and Geographic Information Systems (GIS). The analysis focuses on three periods, 1985, 2005, and 2025, to assess changes in the thermal characteristics of the urban environment and their relationship with major environmental and physical indicators.
Methodology: Landsat satellite imagery was used to derive Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), and Urban Heat Island (UHI) indicators. In addition, Air Quality Index (AQI) and Relative Humidity (RH) were incorporated as environmental variables. Spatial analysis and map preparation were conducted using remote sensing and GIS techniques. Multivariate linear regression was applied to examine the relationships between UHI intensity and the explanatory variables during the three study periods.
Results and findings: The results indicate that the intensity of the urban heat island in Baqubah increased over the study period. The influence of NDBI on UHI increased from 0.47 in 1985 to 0.70 in 2025, while the effect of LST increased from 0.58 to 0.80. In contrast, NDVI showed a negative relationship with UHI, with its coefficient increasing from −0.25 to −0.38, indicating a persistent cooling effect of vegetation. The explanatory power of the regression models also increased over time, with R² rising from 0.67 in 1985 to 0.85 in 2025. These findings demonstrate that increasing urbanization and expansion of built-up surfaces have intensified thermal stress in Baqubah, whereas vegetation has played an important mitigating role. The results highlight the importance of protecting and expanding green spaces and integrating green infrastructure into urban planning to reduce UHI impacts.