Potential grading refrigeration system? Based on urban agglomeration thermal environment analysis perspective

Abstract

Urban heat stress is a critical issue impacting the sustainable development of urban agglomerations. Ecological land is an important factor in alleviating the heat environment stress of urban agglomerations. However, few scholars have taken a macro, interconnected perspective to consider the cooling effects of different ecological land. This study reveals that urban agglomerations have a potential hierarchical natural cooling system. Based on the heat environment assessment of the Beijing-Tianjin-Hebei (BTH) urban agglomeration and the Minimal cumulative resistance (MCR) model, we extracted the graded cooling patches and cooling corridors from 2005 to 2020. The research findings indicate that the heat environment intensity of the BTH urban agglomeration presents a spatial pattern of high intensity in the southeast and low intensity in the northwest, and the heat environment intensity of the urban agglomeration remains at a relatively high level. The number of graded patches and corridors shows a trend of first decreasing and then increasing, and the central and southern regions have relatively few corridors and patches, which require targeted optimization and improvement. Additionally, the overall length of corridors in the BTH urban agglomeration has increased, while the cooling effect of patches has decreased. The robustness and connectivity of the cooling system have both increased over 15 years, but further optimization and improvement are still needed to alleviate the heat environment intensity of urban agglomerations. This study quantifies the trends in urban agglomeration heat environment stress and the functional and topological properties of patches, corridors, and systems, providing valuable information for natural-based urban planning and management, as well as new solutions and research perspectives for alleviating heat environment stress in urban agglomerations.