Urban morphology and landscape structure effect on land surface temperature: Evidence from Shiraz, a semi-arid city

Abstract

Urbanization process contributes to more urban climate changes, specifically the land surface temperature (LST). Higher LST of urban areas compared to the surroundings is regarded as the side effect of urban morphology and landscape structure features. The primary purpose of the study is to investigate the relationship between the pattern of built-up areas and land surface temperature in a semi-arid urban environment. In this study, spectral and landscape indices, such as Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), Shannon’s Diversity Index (SHDI), Landscape Shape Index (LSI), Fractal Dimension Index (FRAC), and Landscape Division Index (DIVISION), along with morphological variables (parcel density, housing density, road density, Floor area ratio, Mass-Space proportion, land use pattern, and distance to CBD) were applied to investigate the correlation of urban morphology with LST. Landscape and morphological variables are provided from Landsat 5, statistical center of Iran and Shiraz’s master plan and also gathered at the census district level. The results revealed that all the variables had a relatively strong correlation with LST except for distance to CBD. While landscape diversity and fragmentation had the highest correlation with LST, housing and parcel density were the most effective morphological variables. Also, while SHDI, DIVISION, FRAC, LSI, and road density had positive correlation coefficient, NDBI, housing and parcel density, FAR and Mass-Space proportion were negative. Moreover, examining land use pattern and its relation to LST revealed that bare lands, industrial and green spaces had a remarkable negative effect on LST. Also, residential areas with moderate and high building density alleviated the surface temperature. Alongside that, dense gardens, lower road density, and more developed districts declined LST in Shiraz, a semi-arid urban environment in Iran.