Envi-met-based urban landscape modeling for determining thermal comfort in open and green public spaces: The case of Afyonkarahisar city

Human settlements have historically been shaped by climatic conditions; natural surfaces, water resources, and vegetation have played a significant role in the formation of living spaces. However, today, accelerating urbanization, increasing impervious surfaces, and decreasing green spaces are altering the microclimate of cities, negatively impacting thermal comfort in public open spaces. This thesis was conducted to evaluate the microclimatic characteristics of public open spaces in Afyonkarahisar and to reveal the temporal and spatial changes in thermal comfort levels throughout the city. Three meteorological stations in the city constituted the study area. Meteorological data from these stations for the period 2020–2024 was obtained from the General Directorate of Meteorology, and Physiological Equivalent Temperature (PES) analyses were conducted. The resulting monthly, daytime, and nighttime averages were compared to assess the stations' thermal comfort conditions over a five-year period. The Regional Station was selected for micro-scale analyses due to its proximity to the city center, its importance in terms of open space density and pedestrian use. Five scenarios representing different vegetation levels were created for this station in the ENVI-met environment. The current situation was determined to contain approximately 10% vegetation; in addition, a completely vegetated scenario, along with scenarios with 30%, 50%, and 75% vegetation density, was prepared. All scenarios were run to represent the conditions on August 15, 2023, at 2:00 PM, and their effects on air temperature, mean radiant temperature (Tmrt), wind speed, and sensible temperature (SPH) were comparatively analyzed. The results show that the microclimate improved significantly as the vegetation rate increased. Scenario 5, where vegetation cover was increased to 75%, resulted in a 0.5°C decrease in air temperature and a 0.8°C decrease in mean temperature. In Scenario 2, where there was no vegetation, the temperature increased by 0.3°C. At the Tmrt value, Scenario 5 reduced the maximum value by 1°C and the mean value by 1.6°C. Scenario 5 also improved the sensible temperature (SPH) by approximately 0.9°C. These findings generally indicate that increasing plant density in public open spaces in Afyonkarahisar improves thermal comfort by reducing temperature and radiant heat values, especially in summer; however, since it reduces wind speed, layout, tree species, and tree structure should be carefully considered in design decisions.