Spatial pattern of the green heat sink using patch- and network-based analysis: Implication for urban temperature alleviation

Abstract

Despite the evidence on the cooling effects of urban green spaces (UGS), little is known about how they function as an interconnected network of cold green patches or a green heat sink (GHS) within an urban landscape. This study aimed to analyze the general spatial pattern and connectivity of GHSs using the pertinent indices and Circuitcape tool in an Iranian urban area between 2000 and 2020. Initially, normalized differentiation vegetation index (NDVI) and land surface temperature (LST) maps were derived. To construct a network, GHS was extracted by Getis Ord Gi* statistic and the cost map was built by reversing the NDVI. The results showed that UGS and GHSs shrunk by 17% and 31%, respectively, and became highly fragmented, demonstrating smaller sizes but increased in number, density, and shape complexity. According to the network analysis, the overall connectivity of GHSs decreased over time. Finally, five high-priority locations were identified to increase the connectedness of vegetation cover that might improve the thermal environment of the city. This research can direct urban planning towards enhancing a green space network to mitigate the urban temperature within the urban landscape .