Spatiotemporal Variability of the Urban Heat Island of Almaty Based on Satellite Monitoring Data

The urban heat island (UHI) effect represents a significant environmental challenge for cities located in regions with complex topography and a continental climate, such as Almaty. This study analyzes the spatiotemporal variability of the urban heat island of Almaty using satellite observations and geographic information system (GIS) analysis methods.
Land surface temperature fields were derived from VIIRS (daytime and nighttime observations), MODIS, and Landsat satellite data in the thermal infrared range. Satellite data processing was performed using cloud-based technologies within the Google Earth Engine platform, enabling a consistent analysis of monthly, seasonal, and diurnal characteristics, as well as a long-term analysis based on MODIS data. To enhance the robustness of the results, temperature fields were normalized relative to two reference cold areas located within urban green zones, allowing the identification of relative thermal anomalies across the urban area.
The results indicate pronounced spatial heterogeneity of the urban heat island, characterized by persistent high-temperature zones associated with dense urban development, industrial areas, and extensive impervious surfaces. Park areas, river corridors, and mountainous regions form stable low-temperature zones. Despite its limited temporal resolution, Landsat data enable detailed identification of local thermal anomalies, while VIIRS and MODIS data provide reliable representation of the overall UHI structure and its seasonal evolution.
The identified spatiotemporal patterns provide a basis for further analysis of the relationship between the urban heat island, synoptic conditions, and urban morphology, and may also be used as input data for numerical modeling and the development of adaptation strategies aimed at improving the urban climate of Almaty.