Global climate impact on major urban agglomerations from MODIS UVEG-TES products: analysis of 56 cities (2003–2023)

Extended abstract / summary of an ongoing research article prepared for submission to a peer-reviewed scientific journal. This article presents a comprehensive multiscale analysis of surface urban heat islands (SUHI) over 56 major cities distributed globally during the 2003–2023 period, using validated Level 3 thermal products derived from the MODIS UVEG-TES processing chain. The methodology integrates Land Surface Temperature (LST) and emissivity retrievals validated against MOD21/MYD21 operational products with an uncertainty of approximately 1 K. A seasonal framework comparing May–September (Northern Hemisphere) and November–March (Southern Hemisphere) conditions provides climatic coherence across hemispheres. Four Level 3 indicators were generated and evaluated: SUHI intensity, Urban Thermal Field Variance Index (UTFVI), Discomfort Index (DI), and urban thermal hotspot density. Results demonstrate consistent nocturnal SUHI intensities between 3 and 5 K across the global sample, with pronounced variability linked to climate zone (Köppen–Geiger classification), surface elevation and urban density. Arid and semi-arid regions exhibit stronger warming signals (reaching rates above +2.0 K per decade), whilst coastal and tropical cities show moderated thermal amplification. Decadal trend analysis reveals progressive intensification in urban thermal signatures, indicating growing exposure to heat stress in expanding metropolitan areas. The coherent and reproducible methodology supports the establishment of a global reference database for urban thermal monitoring and provides a foundation for climate adaptation strategies in cities across all continents.