Impact of urban spatial configuration on land surface temperature and urban heat islands: a case study of Mashhad, Iran

Urban heat islands (UHIs) are among important urban development issues in environmental and ecological climate changes. In this context, the urban spatial configuration is one of the factors that play a significant role in the formation of UHIs. This study investigates how urban spatial configuration affects land surface temperature (LST) and formation of UHI in Mashhad urban area, located in the northeast of Iran. The objectives of this study include (i) building quantitative relationships between LST and spatial configuration properties and (ii) representing the impacts of urban morphology on LST and climate changes. The methodology of this study is based on the space syntax and image processing theories and techniques. With respect to these two objectives, we (1) extracted the surface temperature (LST) by Landsat 7 ETM+ sensor image dated June 27, 2014, by ENVI 4.7 software, (2) provided an axial map of Mashhad city in Auto Cad 2007 environment, (3) analyzed spatial configuration by UCL Depthmap 10, and (4) employed transect model and gradient analysis and measured the measured the Pearson correlation coefficients and linear regression between LST and spatial configuration. The Pearson correlation coefficient between the two variables was found as R=-0.394, which demonstrates that the LST is negatively correlated with integration. The results showed that land surfaces with high temperature are spatially segregated from the whole urban configuration and the integrated urban space has less temperature than other spaces.