Impacts of the Microclimate of a Large Urban Park on Its Surrounding Built Environment in the Summertime

Majid Amani-Beni,Biao Zhang,A Jacob Odgaard,Gao-Di Xie

doi:10.3390/rs13224703

Abstract

The cooling effect of green spaces as an ecological solution to mitigate urban climate change is well documented. However, the factors influencing the microclimate in the built environment around forest parks, diurnal variations of their impact and their degree of importance have not been explicitly addressed. We attempted to quantify how much various landscape parameters, including land cover and spatial location, impact the ambient air and surface temperature in the area around Beijing’s Olympic Forest Park. Data were taken along strategically located traverses inside and outside the park. We found: (1) The air temperature during the day was 1.0–3.5 °C lower in the park than in the surrounding area; the surface temperature was 1.7–4.8 °C lower; air humidity in the park increased by 8.7–15.1%; and the human comfort index reduced to 1.8–6.9, all generating a more comfortable thermal environment in the park than in the surrounding area. (2) The distance to the park and the green space ratio of the park’s surrounding area are significant factors for regulating its microclimate. A 1 km increase in distance to the park caused the temperature to increase by 0.83 °C; when the green space ratio increased by 10%, the temperature dropped by 0.16 °C on average. The impact of these two parameters was more obvious in the afternoon than in the middle of the day or in the morning. The green space ratio could be used for designing a more stable thermal environment. (3) Land cover affects surface temperature more than it does air temperature. Our data suggest that an urban plan with an even distribution of green space would provide the greatest thermal comfort.

Highlights

Urbanization and climate change are two main challenges and fundamental considerations in 21st-century urban planning [1]
The specific objectives of our study are: (1) to quantify the cooling effect of an urban park in its surrounding built environment, and (2) to explore how landscape parameters including land cover and spatial location contribute to the diurnal variations in air temperature in the area surrounding the park, and their degree of importance
Borders, like at the points with a higher ratio of green space, was significantly smaller than at other points. This is consistent with the findings of a recent study in Shenzhen, China, which showed that greater vegetation coverage could significantly reduce air temperature fluctuations and maintain a stable thermal environment for the dwellers [39]. These results suggest that an even distribution of small green spaces in the proximity of urban parks is an efficient way to improve the thermal environment, and confirm the importance of balancing the green space ratio in the built environment of cities through reasonable planning to obtain maximum thermal comfort for citizens

Summary

Introduction

Urbanization and climate change are two main challenges and fundamental considerations in 21st-century urban planning [1]. Over the past few decades, a major concentration of people has taken place in urban areas, especially in developing countries such as China. Over 50% of the world’s population lives in cities. This percentage is expected to increase to 66% by 2050 [2]. These rapid changes are causing a significant deterioration of the urban climate [3]. The urban heat island (UHI) is one of the most documented features of the urban environment, involving the increase in temperature relative to the surrounding non-urban areas [4]

Objectives

Methods

Findings

Discussion

Conclusion