Construction of an urban cold island network under the perspective of local climate zones

Abstract

Urban blue–green spaces(BGS) exhibit a remarkable cold island (CI) effect, and research on heat mitigation measures based on CIs has attracted considerable attention. However, few studies have been conducted on mitigating urban overheating by connecting isolated CI patches to form CI networks. Therefore, this study aimed to explore the framework and specific processes for building an urban CI network in Hangzhou, China. The CI network construction framework consisted of “source identification-resistance surface construction-corridor construction”. Based on morphological spatial pattern analysis, local climate zone (LCZ) theory, connectivity index, and circuit theory, the CI sources and cooling corridors were identified and classified, and the pinch and barrier points in the network were determined. The results indicated that the CI network in Hangzhou comprised 69 CI sources, 134 cooling corridors, 36 pinch points, and 89 barrier points. Based on these results, we recommended that the LCZs in the CI network that are dominated by water (LCZG) and dense trees (LCZA) be protected and areas that are dominated by bare rock or pavement be improved. This study and methodology can provide new inspiration for future planning of urban BGS and sustainable urban cooling.