Revealing the influence of the physical expansion process of Khorram Abad city on changes in surface albedo and boundary layer height

Aim: This research aims to reveal the expansion trend of the built-up up of Khorramabad city and its effects on the boundary layer height and surface albedo in the city. Material & Method: The data related to the 2 main factors as surface Albido (FAL) and boundary layer height (BLH), were also obtained from the ECMWF data of ERAS model for the statistical period of 1990-2020. Finding: The results indicated that the urban area of Khorramabad grew by 829 hectares during the 30-year period, which indicates that this city expanded by 47% during the last 30-year period. The climatic result of this physical expansion in 2 variables of surface albedo and boundary layer height represented that with the expansion of the physical built-up of the city, the amount of albedo has decreased significantly. This decrease in surface albedo has caused a further increase in radiation and an increase in the heat budget of the city, which has increased the height of the boundary layer during the statistical period of 1990-2020. Conclusion: The expansion of Khorramabad's physical built-up has significantly reduced the surface Albido and increased the height of the boundary layer in the city. Innovation: Investigating and revealing the effect of land use changes on the thermal factors of the lower atmosphere of the region (surface albedo, boundary layer height) is the most important innovation of this research. Changes in thermal factors such as albedo and boundary layer height have extensive effects on climatic comfort and environmental quality. Therefore, it is essential to reveal the impact of the physical texture of the city concerning the spatial distribution, green space and urban gardens and parks to adjust the city's thermal conditions.