Examining Relationships between Spatial Pattern of Green Infrastructure and Urban Heat Island (Case Study: Tehran Metropolis)

Abstract

Green infrastructure (GI) is one factor that reduces the intensity of Urban Heat Islands (UHI). The research results related to the relationship between the spatial pattern (composition/configuration) of urban GI and UHI show contradictory results. Some researchers emphasized the negative relationship between MPS and ED criteria, while other researchers found positive results in these criteria. Based on this, this study was conducted in the metropolis of Tehran, which is located in the center of Iran and has undergone many changes. The method is based on Local Climate Zone (LCZ) classification, measuring the landscape metrics (CA, ED, MPS, LSPI), and analyzing the relationships through Pearson correlation and partial Pearson correlation. The results show: (1) Areas with tree cover in two types of green spaces A/B have a negative effect on Land Surface Temperature by 0.46 and 0.84 at the 95% and 99% confidence levels, respectively, (2) Mean patch size (MPS) and largest patch index (LPI) of type A were important factors in reducing LST by 0.458 and 0.481 respectively at 99% confidence level, (3) The value of Edge Density (ED) in GI, including B/C type, has positive effects on LST and is 0.519 and 0.33 at the 95% confidence level. These results showed that it is possible to influence the reduction of LST by planning suitable GI spatial patterns, So that urban planners and designers should focus on creating green infrastructure with dense trees in urban centers, and on the other hand, pay attention to air circulation flows in Tehran metropolis based on the height of buildings.