Reducing the Effects of City Heat Islands Through Cool Pavement Materials (Case Study: District 8 of Tabriz Metropolis)

In today's society, the urban heat island is considered as one of the most important emerging natural hazards. It is in the form of a difference in the surface temperature of urban areas compared to the surrounding areas due to various ecological, morphological and topographical reasons. This research investigated the thermal islands of Tabriz city, as one of the most important population and industrial centers of Iran, in its 8th region as a case study, using Landsat 8 images. The objectives of this research included extracting, locating and analyzing the phenomenon of urban heat islands in the study area by using specific algorithms and preparing relevant maps and checking with the type of materials used, identifying two hot heat islands in the center and west with a temperature of 33.48 degrees Celsius and one island It followed a cold temperature in the north of the region with a temperature of 20.02 degrees Celsius. In the following, the influential indicators in the heat islands of the urban land were evaluated in the study area. According to the review of key and referenced articles and the review of other sources and authoritative books, in this study, the factors affecting the urban heat island are divided into two categories of uncontrollable climatic factors, controllable factors of urbanization and city construction, and factors related to and influenced by urbanization. which consists of: 1- Uncontrollable climatic factors: these factors include solar radiation, speed and intensity and direction of wind, height above sea level, direction of slope, vegetation cover, green space per capita and proximity to large bodies of water such as rivers and the sea. 2-Controllable factors of urban development and city construction and affected by urban development: which include street width, building height, building orientation, building occupation level, building density, building facade, building roof and open space per capita. The amount of positive or negative effects of the mentioned factors on urban heat islands requires a comprehensive investigation of the factors through field visits. Now, in this research, after examining the influencing indicators and determining the heat islands, the impact of surface materials as one of the effective components on urban heat islands compared to other components is comprehensively evaluated. After analyzing the 15 main factors determined for the 8th area of ​​Tabriz and field observations of the main materials used in the area, which were mostly cement and clay, and determining the albedo, thermal radiation emission rate, heat capacity and solar reflectance of the colors in the area, we came to the conclusion that with More or less the entire region is one of the most effective indicators of heat islands, the main difference in urban temperature difference can be seen in the type of pavement materials used and its color in the designated heat islands. Where the cold thermal island i.e. the covered market of Tabriz, despite the almost identical conditions with the existing heating islands in most of the determined indicators, the main difference was in the new paving materials that marble and light reflective materials were used. Therefore, urban shell materials play the most important role in reducing heat intake, storage and transfer to the urban environment. Finally, practical solutions have been presented in connection with the use of cool materials in the construction of designated thermal islands in District 8 of Tabriz city.