Study of the Cooling Effects of Urban Green Space in Harbin in Terms of Reducing the Heat Island Effect

Abstract

The urban heat island (UHI) effect might cause extreme weather, which would seriously affect people's health, increase energy consumption and cause other negative impacts. To construct urban green spaces is a feasible strategy to effectively weaken the UHI effect. In this study, the cooling effect of green spaces on the UHI effect was carefully investigated in summer and winter in Harbin city. Specifically, the vegetation index and surface temperature information were extracted by the grid method, and based on this data, the relationship between the urban green space and the UHI effect was analyzed quantitatively. In summer, the cooling effect is more significant. The average cooling extent reached 1.65 • C, the average maximum temperature change was 7.5 • C, and the cooling range was mainly 120 m. The cooling effect can be improved by adjusting the green space area, perimeter and shape. Increasing the green area (within 37 ha) or the green circumference (within 5300 m) can most economically improve its cooling effect. The shape factor would significantly affect the cooling effect within 0.03. The simpler the green space shape, the more obvious the cooling effect. In contrast, in winter the green spaces had a certain cooling effect when there was no snow cover or little snow cover, although this was still less significant compared with the situation in summer. The average cooling extent reached 0.48 • C, the average maximum temperature change was 4.25 • C, and the cooling range was mainly 90 m. However, there is no correlation between urban green space and the UHI effect in areas mainly covered by ice and snow. This work could provide protocols for urban green space design to effectively control the UHI effect of sub-frigid cities.

Nature-Based Designs to Mitigate Urban Heat: The Efficacy of Green Infrastructure Treatments in Portland, Oregon

“…Many studies of land surface temperature in urban areas have revealed the apparent cooling effects of green spaces and vegetation [67][68][69][70][71], as found in the present study. Taleghani et al's studies in both Los Angeles [60] and Portland [62] show that adding vegetation and increasing the albedo of the pavement can decrease air temperature at 1.5 m. The Los Angeles study [60] shows that green roofs specifically (as opposed to ground-level vegetation) have little cooling effect at 1.5 m height, but mainly provide cooling effects at heights above the pedestrian level (rooftop level).…”

Relation between Urban Volume and Land Surface Temperature: A Comparative Study of Planned and Traditional Cities in Japan

“…During the city planning process, green areas are considered as the main part of urban development [22]. Most studies related to modern cities have shown that urban green areas play an important role in reducing the LST, particularly inside the city area, by providing cooling [23,24]. Urban green spaces provide cooling to minimize the LST via shading and evaporation [25,26].…”

A Multi-Temporal Analyses of Land Surface Temperature Using Landsat-8 Data and Open Source Software: The Case Study of Modena, Italy

“…In this way, urban policies can be directed to those areas where the SUHI phenomenon is still present and creates discomfort in the population. Furthermore, the public administration could evaluate appropriate mitigation measures such as green roofs, cool materials, and green areas [64,65] that lead to a more sustainable life quality. In addition, using this methodology, it is possible to evaluate whether the policies entailed within the framework of the European Green Infrastructure Strategies are producing the desired results.…”