Detecting the Cool Island Effect of Urban Parks in Wuhan: A City on Rivers.

Qijiao Xie,Jing Li

doi:10.3390/ijerph18010132

Qijiao Xie, Jing Li

Open Access

https://doi.org/10.3390/ijerph18010132

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Abstract

As a nature-based solution, development of urban blue-green spaces is widely accepted for mitigating the urban heat island (UHI) effect. It is of great significance to determine the main driving factors of the park cool island (PCI) effect for optimizing park layout and achieving a maximum cooling benefit of urban parks. However, there have been obviously controversial conclusions in previous studies due to varied case contexts. This study was conducted in Wuhan, a city with high water coverage, which has significant differences in context with the previous case cities. The PCI intensity and its correlation with park characteristics were investigated based on remote sensing data. The results indicated that 36 out of 40 urban parks expressed a PCI effect, with a PCI intensity of 0.08~7.29 °C. As expected, larger parks with enough width had stronger PCI intensity. An increased density of hardened elements in a park could significantly weaken PCI effect. Noticeably, in this study, water bodies in a park contributed the most to the PCI effect of urban parks, while the vegetated areas showed a negative impact on the PCI intensity. It implied that in a context with higher water coverage, the cooling effect of vegetation was weakened or even masked by water bodies, due to the interaction effect of different variables on PCI intensity.

Highlights

Worldwide, the urban heat island (UHI) effect has been detected in megacities and in small towns in recent years [1,2]
This study investigated the impact of urban parks on park cool island (PCI) intensity in the perspective of park design
Larger parks with enough width were more efficient for improving the PCI effect

Summary

Introduction

The urban heat island (UHI) effect has been detected in megacities and in small towns in recent years [1,2]. The UHI effect usually leads to a series of adverse economic and environmental consequences [3,4]. More anthropogenic heat and pollutants are released into the atmosphere from industries and energy plants, which intensifies the UHI effect and raises the air pollution level in urban areas [8]. The air pollutant concentration in urban areas was approximately 10 times that in a clean environment [9]. The superposition of heat stress and air pollution in urban areas may exacerbate the negative impacts on an urban residential environment [10,11]. The worsening thermal environment significantly leads to high morbidity and mortality of the heat-related diseases, especially in extreme heat events [4,12]. How to mitigate the UHI effect has been extensively discussed in many studies [3,13,14,15,16]

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