Can improving the spatial equity of urban green space mitigate the effect of urban heat islands? An empirical study

Chao Xu; Guangdong Chen; Qianyuan Huang; Meirong Su; Qiangqiang Rong; Wencong Yue; Dagmar Haase

doi:10.1016/j.scitotenv.2022.156687

Can improving the spatial equity of urban green space mitigate the effect of urban heat islands? An empirical study

Sci Total Environ. 2022 Oct 1:841:156687. doi: 10.1016/j.scitotenv.2022.156687. Epub 2022 Jun 15.

Authors

Chao Xu¹, Guangdong Chen², Qianyuan Huang², Meirong Su³, Qiangqiang Rong², Wencong Yue², Dagmar Haase⁴

Affiliations

¹ Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Daxue Road 1, 523808 Dongguan, China; Institute of Geography, Humboldt University of Berlin, Rudower Chaussee 16, 12489 Berlin, Germany.
² Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Daxue Road 1, 523808 Dongguan, China.
³ Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Daxue Road 1, 523808 Dongguan, China. Electronic address: sumr@dgut.edu.cn.
⁴ Institute of Geography, Humboldt University of Berlin, Rudower Chaussee 16, 12489 Berlin, Germany; Department of Computational Landscape Ecology, Helmholtz Centre for Environmental Research - UFZ, Permoser Str. 15, 04318 Leipzig, Germany.

PMID: 35716736
DOI: 10.1016/j.scitotenv.2022.156687

Abstract

The role of urban green space (UGS) in mitigating the urban heat island (UHI) effect has been demonstrated in a growing body of literature. However, the potential influence of the spatial equity of UGS distribution on the UHI effect has largely been overlooked. The present study aims to identify this potential influence using the spatial equity of UGS and the land surface temperature (LST) as measures of UGS spatial distribution and UHIs, respectively. A comprehensive spatial distribution map of UGS was generated by combining the UGS coverage fraction data within urban impervious pixels and the green cover data outside urban impervious pixels. Then, the spatial equity of UGS distribution across all urban impervious pixels was determined using the Gini coefficient. In addition, an LST map was derived using the thermal infrared spectral bands of Landsat 8 OLI/TIRS products. A case study of Dongguan, a highly urbanized city in China, showed that (1) the distribution of both UGS and LSTs were spatially aggregated in all the towns of the city, (2) the LST of urban impervious pixels was negatively correlated with the area of surrounding UGS, and (3) the Gini coefficient of UGS was positively correlated with the proportion of hot and cool areas, but negatively correlated with the proportion of medium-hot and medium-cool areas. These findings indicate that increasing the amount of UGS is beneficial to the reduction of urban average LSTs, while promoting the spatial equity of UGS distribution is conducive to reducing the spatial aggregation of LSTs within urban areas, thereby improving the overall urban thermal environment. Therefore, as a nature-based solution, promoting the spatial equity of UGS distribution could enhance the overall cooling effect of UGS more effectively at the city scale, and thus further underpin the sustainable development of the urban environment.

Keywords: Dongguan city; Gini coefficient; Green space equity; Land surface temperature; Urban heat island.

MeSH terms

Cities
Cold Temperature
Environmental Monitoring
Hot Temperature*
Parks, Recreational*