Interdisciplinary Journal of Civil Engineering

Interdisciplinary Journal of Civil Engineering

Investigating the Role of Caspian Sea-Level Decline in Intensifying Surface Urban Heat Islands in the Coastal Cities of Northern Iran

Document Type : Original Article

Authors
Department of Geoinformation and Geomatics Engineering, Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran
Abstract
Urban expansion and replacing natural land with impervious surfaces drive (UHI) formation. Along northern Iran, this phenomenon is influenced by urban development, hydrological fluctuations, and the Caspian Sea’s declining water level, which weakens its climatic moderating effect. This study examined ten-year changes in (LST) and Caspian Sea water extent (2015–2025) across Gilan, Mazandaran, and Golestan provinces. The framework relied on cloud computing and processing Landsat 8/9 imagery in GEE . Water bodies were delineated using the (MNDWI), while LST was retrieved from Landsat thermal bands. Satellite-derived temperatures were validated against NASA POWER data. Linear regression showed strong agreement (R^2 of 0.8376, 0.8699, and 0.8830 for Rasht, Sari,and Gorgan). Findings revealed a complex link between water extent shifts and thermal behavior. The most pronounced water retreat occurred in 2022, exposing barren coastal land and intensifying thermal hotspots. An exceptional thermal peak of 30.8 °C in 2021 potentially heightened evaporation and subsequent water retreat. Interprovincial comparisons demonstrated that Golestan experienced higher surface temperatures than Mazandaran and Gilan due to its drier climate and more pronounced shoreline retreat. Overall, Caspian Sea hydrological changes significantly drive thermal instability along northern Iran's coast.Consequently, sustainable planning for coastal cities must integrate sea-level decline scenarios and climate-adaptation strategies.
Keywords

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