Interaction of Urban Rivers and Green Space Morphology to Mitigate the Urban Heat Island Effect: Case-Based Comparative Analysis

Abstract

The spatial morphology of waterfront green spaces helps generate cooling effects to mitigate the urban heat island effect (UHI) in metropolis cities. To explore the contribution and influence of multi-dimensional spatial indices on the mitigation of UHIs, the green space of the riparian buffer along 18 river channels in Shanghai was considered as a case study. The spatial distribution data of the land surface temperature (LST) in the study area were obtained by using remote sensing images. By selecting the related spatial structure morphological factors of the waterfront green space as the quantitative description index, the growth regression tree model (BRT) was adapted to analyze the contribution of various indexes of the waterfront green space on the distribution of the LST and the marginal effect of blue–green synergistic cooling. In addition, mathematical statistical analysis and spatial analysis methods were used to study the influence of the morphological group (MG) types of riparian green spaces with different morphological characteristics on the LST. The results showed that in terms of the spatial structure variables between blue and green spaces, the contribution of river widths larger than 30 m was more notable in decreasing the LST. In the case of a larger river width, the marginal effect of synergistic cooling could be observed in farther regions. The green space that had the highest connectivity degree and was located in the leeward direction of the river exhibited the lowest LST. In terms of the spatial morphology, the fractional cover values of the vegetation (Fv) and area (A) of the green space were the main factors affecting the cooling effect of the green space. For all MG types, a large green patch that had a high green coverage and connectivity degree, as well as was distributed in the leeward direction of the river, corresponded to the lowest LST. The research presented herein can provide methods and development suggestions for optimizing spatial thermal comfort in climate adaptive cities.

Evaluation of the Thermal Environmental Effects of Urban Ecological Networks—A Case Study of Xuzhou City, China

“…Considering the land use, urban thermal environment improvement should properly consider the interconnection between various land uses and corresponding forms, participate in the balance of ecological land at the overall level of the city, and increase the proportion of ecological land within a reasonable range [113,117], considering the land use types and spatial distribution in adjacent areas of ecological land [118][119][120][121] to maximize the cooling effect of ecological land, and avoid the formation of industrial concentration areas with a single land use type. Alternatively, G, E1, E2 and other land use types should be distributed at an appropriate scale and form, with landscaped ecological land [24,67,[122][123][124][125][126] in industrial concentration areas to achieve thermal environment regulation.…”

Dominance of Influencing Factors on Cooling Effect of Urban Parks in Different Climatic Regions

“…Previous studies have revealed the relationship between the PCE and various influencing factors [ 18 , 19 , 36 , 41 , 49 ]. In this study, 10 influencing factors that have been widely used in past studies were selected, and no strong correlation existed between any two influencing factors.…”

“…The existing research has primarily focused on analyzing the PCE in a single city and subsequently discussed the relationship between the PCE and influencing factors, which has a certain guiding role in the case of urban park planning [ 19 , 20 , 40 , 41 , 42 , 43 ]. However, the number and types of urban parks in a single city may have limitations, and studies on the PCE based on climatic regions are scarce [ 19 ].…”

Quantification of the Thermal Environmental Value of Urban Pores: A Case Study of Nanjing

“…Few studies have measured the impact of their spatial distribution on the thermal environment at the urban scale. It has proven that the distribution of urban pores, such as water, vegetation or forests (which can also actually be considered a type of urban pores) is quite important, since these pores' distribution have great cooling effects (Wang et al, 2019, Jiang et al,2021. Based on this, it is also assumed that the overall spatial distribution of other types of urban pores, such as open spaces, parks or urban roads, will also impact the urban thermal environment.…”