Cooling Island Effect of Blue-Green Corridors: Quantitative Comparison of Morphological Impacts

Abstract

The patterns of green corridors in urban riverfront districts provide different synergistic cooling effects of blue-green space in urban areas. The purpose of this study is to quantify the spatial morphological impact of green corridors in riverfront block-scale area on the cooling effect. Three representative patterns (radiate, grid and dendritic) were selected in the study. The comprehensive influences analysis between multi-dimensional factors of spatial structure and morphology of green corridors and Ta (air temperature) distribution are processed by Envi-met4.4.5 simulation data and statistical analysis methods, such as regression tree model (BRT), were combined. The results showed that the D (distance from riverbank) has the greatest impact on the cooling effect of each belt green space. The D in the range of 600–750 m was affected by the cooling effect of blue-green space; The orientation with parallel to (southeast–northwest) or roughly the same as the prevailing wind direction (north–south) green corridors had relatively better cooling effect. When the width of green corridor was 20–25 m, the ME (marginal effect) of cooling was the largest; at 30–35 m (corridor width), the overall ME of cooling was the best; When the dPC (decreased probability connectivity, here the index was adapted to describe the connectivity degree) of green corridors was in the range of 0.5–1.5, the cooling effect of green corridor could be significantly improved. When dPC is 1.5, its marginal effect on temperature reached the maximum. The study provided a quantitative correlation technology for the morphological influence of blue-green space on the distribution of UCI (urban cooling island), which can guide the spatial layout control of green corridors in the planning and design of urban riverfront district.

Regulating sensitivity analysis of spatial patterns of high-density urban riverfront areas to the river cooling effect: a case study of the Grand Canal in Hangzhou, China

“…Ultimately, the processed RCE contour was obtained. Jiang's method (Jiang et al 2021) was as reference to calculate RCI by computing the LST along the contour, and various indices of RCD were calculated using the minimum distance method. The study area was selected as the area within 1000 meters surrounding the Hangzhou section of the Grand Canal of Beijing-Hangzh ou , as the largest observed extent of RCE is 1000m (Su n et al 2012).…”

“…In terms of land use types, the RCE effect in the case of a fixed water surface can be influenced by the vegetation proportion (Du et al 2016), as well as the size and connectivity of the green space. Irregularl y shaped areas and those that are parallel to the dominant wind direction with respect to the building space tend to receive a relatively high cooling effect from the river (Jiang et al 2021). A large-scale study of the Yangtze River basin in China identified six urban development and construction indicators that are closely linked to surface temperatu re changes in the riverfront area: percentage of vegetation area, distance from the river, bui lding density, building height, percentage of water area, and average green space patch area (Wang et al 2022).…”

Clustering Business Models of Heterogeneous Nature-Based Solutions Implementing Innovative Governance and Financing Concepts

“…This NBS type allows a reduction in energy consumption and an increase in urban resilience [32][33][34]. The target of the NBS type "Accessible green corridors (PI)" is to make post-industrial sites and renatured river corridors accessible for local residents [35,36]. The NBS type "Local environmental compensation processes (EC)" aims to consider green infrastructures, NBS, and participatory co-design and co-implementation processes inherently into urban planning procedures starting at the local level of municipalities [37][38][39][40][41].…”

Zoning Optimization Method of a Riverfront Greenspace Service Function Oriented to the Cooling Effect: A Case Study in Shanghai

“…High vegetation coverage can strengthen the cooling of riverbanks, and the maximum cooling occurs in places with a large number of trees covering and shading both sides of the banks [ 20 ]. The greenspace network mode with high connectivity is conducive to the cold air transportation of urban rivers to produce a better CI [ 21 , 22 ]. Interconnected greenspaces provide a higher CI to adjacent areas [ 23 , 24 ].…”

“…At present, the commonly used software platforms are ENVI-met, fluent, WRF, Airpark, etc. Among them, ENVI-met is widely used to simulate the microclimate of different pattern of blue–green spaces [ 21 , 22 ]. However, the maximum simulation grid scale of ENVI-met software is limited to 2 km × 2 km, which is more suitable for the microscale [ 18 , 37 ].…”