Creating and managing urban green infrastructure is an essential part of the sustainable urban development initiative promoted by the EU governments. To achieve a synergistic development of urban green spaces in various countries, acquiring spatially explicit information on urban green areas on a continental scale in Europe thus becomes necessary. Yet, the currently available European urban land use/cover products may fail to provide this comprehensive view as, due to their coarse spatial resolutions, they only pick up the large patches of green but fail to account for sparsely distributed urban green types. To address this issue, we applied a support vector regression model trained on samples collected from 50 European cities to urban green space mapping on a subpixel scale based on Landsat imagery. The model was validated in 10 other European cities, yielding a robust model performance (RMSE for the modeled green area fractions ranging from 0.09 to 0.16). Thus, we successfully mapped the spatial distribution of European urban green areas in 1990, 2000, and 2015. Given these results, we obtained three major conclusions: (i) previous studies might have underestimated the green space growth in Eastern European countries; (ii) most European countries have been building new settlements with more green spaces as the primary way to increase their urban greenness; (iii) the gap in urban green space per capita is widening among European countries, and Southern European countries are experiencing a decrease in access to urban green spaces.

创建和管理城市绿色基础设施是可持续城市发展的重要组成部分由欧盟政府推动的倡议。因此，为了实现各国城市绿地的协同发展，获取欧洲大陆范围内城市绿地的空间明确信息是必要的。然而，目前可用的欧洲城市土地利用/覆盖产品可能无法提供这种全面的视图，因为它们的空间分辨率很粗糙，它们只能拾取大片绿地，而无法考虑分布稀疏的城市绿地类型。为了解决这个问题，我们将基于从 50 个欧洲城市收集的样本训练的支持向量回归模型应用于基于 Landsat 图像的亚像素尺度的城市绿地映射。该模型在其他 10 个欧洲城市进行了验证，产生了稳健的模型性能（建模绿地分数的 RMSE 范围从 0. 09 至 0.16）。因此，我们成功地绘制了 1990 年、2000 年和 2015 年欧洲城市绿地的空间分布图。鉴于这些结果，我们得出了三个主要结论：（i）以前的研究可能低估了东欧国家的绿地增长；(ii) 大多数欧洲国家一直在建造具有更多绿地的新定居点，作为增加城市绿化度的主要方式；(iii) 欧洲国家人均城市绿地的差距正在扩大，南欧国家的城市绿地使用率正在下降。(i) 以前的研究可能低估了东欧国家的绿色空间增长；(ii) 大多数欧洲国家一直在建造具有更多绿地的新定居点，作为增加城市绿化度的主要方式；(iii) 欧洲国家人均城市绿地的差距正在扩大，南欧国家的城市绿地使用率正在下降。(i) 以前的研究可能低估了东欧国家的绿色空间增长；(ii) 大多数欧洲国家一直在建造具有更多绿地的新定居点，作为增加城市绿化度的主要方式；(iii) 欧洲国家人均城市绿地的差距正在扩大，南欧国家的城市绿地使用率正在下降。