公园绿地可达性时空分异与影响机制研究——以深圳市为例

Spatial-temporal Differentiation and Influencing Mechanism of Accessibility of Park Green Spaces:A Case Study Based on Shenzhen City

公园绿地可达性可表征居民使用公园绿地的难易程度,是反映绿地合理布局与公平使用的重要指标。随着城市化的快速发展,建设用地无序扩张与人口需求持续增长导致公园绿地供需逐渐失衡。使用高斯两步移动搜索法、地理探测器与地理加权回归模型,分析了深圳市2013年与2020年公园绿地可达性的时空分异与影响机制。结果表明:2013年至2020年,1)建设用地范围内,深圳市公园绿地数量与面积持续增长,空间上呈现“西多东少”、“由关内向关外”南北向扩展的分布特征;2)公园绿地可达性整体呈上升趋势,关外可达性逐渐高于关内,其中社区公园可达性均值增幅最大,专类公园可达性空间差异性最大,综合公园可达性水平基本稳定;3)道路密度、公园面积占比、公园出入口密度为公园绿地可达性的主导因子,道路密度与公园面积占比在研究区东部影响更大,而公园出入口密度主要作用于研究区西部。充实了绿地可达性的切入视角,探究时空分异特征与影响机制的方法不仅可应用于城市公园绿地布局与规划,也可为其他地理现象可达性分析提供思路参考。

Park green space is an important part of urban natural ecosystem and public service facilities.The accessibility index of park green space can characterize the difficulty of using park green space for residents.In addition,it is an important index that reflects the rational layout and fair use of park green spaces.With the rapid development of urbanization,the unrestrained expansion of construction land and the continuously increasing demands of the population have led to a gradual imbalance between the supply and demand of park green spaces.In this study,the spatial-temporal differentiation characteristics of accessibility of multi-scale park green spaces in Shenzhen under multi-traffic modes from 2013 to 2020 were analyzed using the Gauss two-step mobile search method Ga2SFCA,which comprehensively considers both supply and demand.The influencing degree of each factor on the accessibility of park green space was studied with a geographical detector from the global scale,through which the dominant factors were screened.The spatial differentiation of action intensity of each dominant factor on the local scale was investigated using the geographical weighted regression(GWR)model.Results showed that from 2013 to 2020:1)Within the scope of construction land,the number and area of green parks in Shenzhen increased continuously.The number of community parks increased the greatest amount,and the area of comprehensive parks expanded the greatest amount.There was an imbalanced distribution pattern,which is characteristic of"more in the west and less in the east","from the inside to the outside of the pass",and expansion from south to north.2)The demand of residents for park green space was positively correlated with population density.The population density in the western region of Shenzhen was increasing gradually,and the population density in the eastern region was always low.The highvalue area of green space demand extended gradually from the inside to the outside of the pass.3)The accessibility of park green space generally presented a rising trend.The proportion of highvalue residential areas was increasing gradually.The accessibility of the outside area became gradually higher than that of the inside area.The average accessibility of community parks achieved the highest growth rate,while the accessibility of comprehensive parks was basically stable.The standard deviation of special parks increased the most,and the spatial differentiation was intensified.4)In 2013,the p-value of all influencing factors was 0,which passed the 0.01 significance test.In 2020,only the three factors of park area proportion,park entrance and exit density,and road density passed the 0.01 significance test,indicating that the spatial distribution of park accessibility from 2013 to 2020 was closely related to green space factors and road factors.The correlations of park accessibility with location,economy,and natural factors presented a downward trend with the development of science and economy.5)According to the determination power(q-value)of the dominant factor,the q-values of the proportion of park area,park entrance and exit density,and road density all showed a downward trend on the dynamic level.The factors can be ranked road density>proportion of park area>park entrance and exit density in terms of action intensity.This revealed that road density was a dominant factor in park accessibility,with an explanatory power of as high as 10%,which was much larger than that of other factors.The park entrance and exit density and the proportion of park area were important factors for park accessibility.6)The influences of different factors on the accessibility index of park green space have significant spatial differences.Road density(X4)and proportion of park area(X1)had a greater impact in the eastern study area,while park entrance and exit density(X2)had a greater impact in the western study area.The research enriches perspectives on green space accessibility.The method of exploring the spatial-temporal differentiation characteristics and influencing mechanism of green space accessibility not only can be applied to the layout and planning of urban park green spaces,but also provides a reference to analyze other forms of geographical accessibility.