Percentage of impervious areas in core cities (2015), Jan. 2019

This data shows the information on the percentage of impervious areas in core cities in Europe.

The area of soil sealing is taken from the Copernicus pan-European soil-sealing layer 2015. The reference unit for the processing is the core city based on UrbanAudit from Eurostat and the Urban Morphological Zone (UMZ) from EEA.To compute the mean soil-sealing degree of city’s urban area by means of zonal statistics, the soil-sealing mosaic of Europe was overlaid with the extent of UMZ within the core city.

The percentage of sealed area in the city affects the impacts of climate-related hazards. Heavy rainfall may lead to flooding, if the water can not infiltrate into the ground, and if its amount exceeds the capacity of the drainage system. Also, artificial surfaces tend to get hotter than vegetation, contributing to the urban heat island effect. Therefore, it is important to consider the amount of sealed surfaces in the city, in particular in the most densely built-up areas, in order to plan adaptation.

本数据集展示了欧洲核心城市不透水区域占比的相关信息。
本数据集的地表封闭（soil sealing）面积数据源自哥白尼计划（Copernicus）2015年泛欧洲地表封闭图层。本次处理的参考单元为基于欧盟统计局（Eurostat）城市审计（UrbanAudit）项目定义的核心城市，以及欧洲环境局（EEA）提出的城市形态区（Urban Morphological Zone, UMZ）。为通过分区统计方法计算城市建成区的平均地表封闭程度，需将欧洲地表封闭镶嵌图与核心城市范围内的城市形态区范围进行叠加分析。
城市封闭区域占比会影响气候相关灾害的影响程度。当降水无法渗入地下且总量超过排水系统承载能力时，强降雨便可能引发洪涝灾害。此外，人工地表的温度通常高于植被覆盖区域，会加剧城市热岛效应。因此，在制定气候适应规划时，需重点考量城市封闭地表的占比情况，尤其是人口与建筑高度密集的建成区域。