Incorporating cool networks to optimize urban thermal environment patterns: A case study of the Central Plains Urban Agglomeration, China

The main factor contributing to the increasing thermal environment risk is rapid urbanization; therefore, to improve the thermal environment and enhance the sustainability of cities to ensure that they can adapt to climate change, it is crucial to analyze the spatial structure characteristics of the thermal environment from the perspective of networks. This study constructed, optimized, and evaluated the cool network of the Central Plains Urban Agglomeration (CPUA) from 2000 to 2020 from a connectivity perspective. First, the morphological spatial pattern analysis (MSPA) theory was used to identify the heat sources and evaluate their significance. Second, the cool network was created by identifying key nodes and corridors using circuit theory. To reduce the urban heat island effect (UHI), the cool network was finally optimized using node and corridor reduction, and its overall connectivity was assessed using alpha, beta, and gamma. The results indicate that the number of heat sources in the CPUA increased from 10 to 23 between 2000 and 2020. There is a distinct north-south pattern in the study area's heat island resistance spatial distribution, with higher values in the north and lower values in the south. Between 2000 and 2020, the number of corridors rose from 20 to 61. From 2000 to 2020, the overall connectivity of the cool network of the CPUA increased, and the efficiency of heat transfer between the source sites of the thermal environment rose. The number of cold corridors after optimization (2020) is nearly cut in half, the overall connectivity of the cool network is decreased, and the transfer efficiency of heat between network sources is reduced. The study aims to provide new perspectives and development strategies for promoting healthy urban development and climate adaptation planning.