Ensuring residents\' equal access to high quality urban greenspace is vital for urban environmental justice and sustainable urban development. However, most previous studies have mainly focused on greenspace quantity, overlooking its quality. Moreover, the national-level spatial distribution pattern of residential greenspace exposure (RGE) within urban areas remains unclear. Here, we have improved the existing RGE assessment framework by integrating both the quality and quantity of urban greenspace to evaluate RGE and its associated inequality across 119,692 blocks in 334 Chinese cities in 2020. We find that the spatial distribution pattern of RGE varies with urban size. Large cities exhibit a distinct clustering of low RGE in their central areas, whereas small cities tend to show a pronounced clustering of high RGE in the central areas. RGE in Chinese cities indicates extensive inequality, as the average RGE of high-exposed people is nearly four times greater than that of low-exposed people. Moreover, residents in larger cities are more prone to experiencing greater inequalities compared to those in smaller cities. We also find that the landscape metrics (i.e., connectance index and mean Euclidean nearest-neighbor distance) of greenspace possess a strong explanatory power (R2 = 0.431) for the observed inequality. Our study underscores the importance of optimizing the landscape structure of urban greenspace and enhancing equality in the quality of greenspace. These findings provide novel insights for urban greenspace planning and promoting urban environmental justice.

Under the background of frequent flood disasters and stock planning challenges, clarifying the relationship and mechanism of urban green space landscape patterns and flood retention efficiency at multiple spatial scales has become a critical scientific issue in realizing the maximum flood retention efficiency of limited urban green spaces and improving the capabilities of urban flood control. We reviewed and summarized the factors, mechanisms, and scale differences in the influence of green space landscape patterns on flood retention efficacy at the urban and block scales. Based on the causes for differences in conclusions and research deficiencies, we suggested that future studies should focus on watershed-scale research and expand the investigation into three-dimensional green space landscape patterns. Additionally, attention should be paid to urban and suburban areas separately, and a set of research indices with indicative significance for the flooding process should be established for different flood-sensitive areas and block structures. These measures will help quantitatively reveal how green space landscape patterns of urban and block scales affect flooding process, providing theoretical guidance for urban planning and establishing urban flood safety patterns.
在雨洪灾害频发和存量规划的背景下,阐明不同尺度下城市绿地景观格局与雨洪滞蓄效能间的关系与机制,成为实现有限城市绿地的最大雨洪滞蓄效能并提高城市防洪能力的关键科学问题。本文系统归纳了城市和街区尺度下绿地景观格局对雨洪滞蓄效能的影响要素、作用机制和尺度差异。并基于研究结论差异致因和研究不足,指出未来应增加流域尺度研究、拓展三维绿地景观格局的研究,还应分别聚焦城市和城郊区域,针对不同雨洪敏感区和街区结构,建立具有雨洪过程指示意义的研究指数集合,以定量揭示城市和街区尺度的绿地景观格局对雨洪过程作用机理,为城市规划及城市雨洪安全格局构建提供理论指导。.