Assessment of relationship between the surface temperatures and built-up urban environment in Ankara city center

Abstract

Aim: This study focuses on determining relationship between the surface temperatures of Ankara (Turkey) - thermal load in this regard - and built-up environment of city using Local Climate Zone system. Methodology: This study consists of two basic stages: formation of thermal load map and analysis of relationship between surface temperatures, the LCZs, and the built-up environment by determining these LCZs. Firstly, metadata from Landsat 8-OLI satellite images were used to perform the surface temperature analysis, than building surface fractions, and building height figures were analyzed, and the thermal load in the area was determined. Pearson's correlation analysis was performed to assess the relationship between surface temperature, building surface fraction and building height. One-way analysis of variance (ANOVA) was conducted to see difference between the surface temperatures regarding LCZs. Tukey's test, one of multiple comparison (Post Hoc) tests used in one-way variance analysis, was performed to compare the groups with each other. Results: According to assessment of surface temperatures by LCZs, the lowest temperature (33.0°C) was seen in LCZ-A with a dense tree pattern, while the highest value (44.5°C) was detected in LCZ-8 which had buildings with low stories on a broad base and impervious neighboring areas. This study evaluated whether there was a relationship between surface temperature, building fractions, and building height in terms of LCZs. A relationship was found between the surface temperatures and building surface fraction in LCZ-2 and LCZ-5, but no relationship was present in other zones. There was a relationship between the surface temperature and building height in LCZ-3 and LCZ-5, however, no relationship was found in other zones. Interpretation: The Local Climate Zone system developed by Oke and Stewart should be supported by technical research and field studies, and should be adapted in Turkish cities.