Background and Objective: Cities have profoundly altered the characteristics of the Earth's surface through their development. These alterations have the potential to influence weather patterns on a local scale. Consequently, with the rise in temperatures, urban areas are confronted with a significant challenge known as the urban heat island effect. This study aims to investigate the spatiotemporal changes in regional temperature and the extent of the urban heat island within Tehran Province. A novel aspect of this research is the combined use of meteorological and remote sensing data.
Methods: Daily temperature data from synoptic stations in Tehran, Shemiran, Chitgar, Mehrabad, Abali, Firuzkuh, and Geophysics from 1996-2020 were obtained from the Meteorological Organization to examine temperature trends using the Mann-Kendall test. To calculate the regional average temperature, MODIS data monthly LST images from NASA's site during 2014-2024 were downloaded and calculated in Arc GIS Pro. To prepare the UHI map, profile, and extent, Landsat 8 satellite images from 2024 were obtained from the USGS site, and the thermal profile of Tehran areas (1, 9, 18, 22) based on the highest LST was drawn. For the vegetation index and LST trend maps between 2013-2024, the Climate Engine program was used.
Findings: The temperature pattern at the stations Shemiran, Chitgar, Mehrabad, Abali, Firuzkuh, and Geophysics showed an increasing trend except for Chitgar. The study of regional average temperatures of Tehran counties showed the highest regional temperatures in July and August. In 2015, the counties of Varamin and Rey experienced the highest land surface temperature at 52.50 degrees C°, which increased to 52.97 degrees C° in the same months in 2018. The study of the relationship between the vegetation index and LST showed a direct and inverse relationship. The examination of the UHI extent showed that the heat focus areas are in the south, southeast, west, southwest, and northern regions of Tehran. The climatic index of air temperature and LST both showed similar and consistent temperature change patterns in June and July.
Conclusion: This study reveals that climate change, driven by global warming, the establishment of the summer subtropical high-pressure system and downward over Iran, with increasing greenhouse gas emissions and land-use changes, and loss of Green cover, has significantly altered the spatiotemporal patterns of temperature in urban areas of Tehran. The findings of this research can be utilized in developing long-term plans for climate change adaptation within the framework of urban crisis management.
Type of Study:
Research |
Subject:
Special Received: 2024/11/21 | Accepted: 2025/03/2 | ePublished: 2025/09/19