Large and comparatively compact European cities such as Bucharest and Leipzig struggle with considerable urban heat island (UHI) effects characterized by heat and drought together with high concentrations of air pollutants (NO₂, SO₂, O₃, CO₂). However, a healthy urban green infrastructure is necessary to reduce the impacts of UHI on human health. Therefore, continuous monitoring schemes are required for green infrastructure in order to improve human life in such cities. Satellite remote sensing can provide the means for monitoring urban vegetation status. In this study, vegetation indices, mostly based on the spectral bands located in the red-edge region, were computed from Sentinel-2 imagery, and land surface temperature (hereafter LST) was estimated from Landsat 8 data. The aim was to assess the individual and cumulative effects of both vicinity to roads and estimated LST on tree vegetation health in urban parks using analysis of variance. Vegetation indices indicated stressed vegetation. However, tracking urban tree health required a combination of indices, and therefore of spectral ranges, rather than one specific index alone, as the effect sizes varied between parks, cities and along the centre-periphery gradient. Therefore, spaceborne data can provide spatially-explicit indicators for stressed urban vegetation and, thus, decreasing ecosystem services delivery. Future studies are encouraged to decipher further the relation the spatial configuration of urban systems and remote sensing based stress indicators of urban trees using publicly available datasets to enable comparative studies.

中文翻译：

---

基于卫星图像的城市公园植被热与交通应力图-罗马尼亚布加勒斯特与德国莱比锡的比较

大型且相对紧凑的欧洲城市，例如布加勒斯特和莱比锡，在城市热岛效应（UHI）方面表现突出，其特征是热和干旱以及高浓度的空气污染物（NO ₂，SO ₂，O ₃，CO ₂）。但是，健康的城市绿色基础设施对于减少UHI对人类健康的影响是必要的。因此，绿色基础设施需要连续的监测方案，以改善此类城市的人类生活。卫星遥感可以提供监测城市植被状况的手段。在这项研究中，植被指数主要是基于Sentinel-2影像来计算的，其植被指数主要基于位于红边区域的光谱带，并且根据Landsat 8数据估算了地表温度（以下称LST）。目的是评估道路附近和估计的LST的个别和累积影响方差分析的城市公园树木植被健康状况 植被指数表明受压植被。然而，随着影响大小在公园，城市之间以及沿中心周边梯度变化，跟踪城市树木健康需要指标的组合，因此也需要光谱范围的组合，而不是单独的特定指标。因此，星载数据可以为受压的城市植被提供空间明晰的指标，从而减少生态系统服务的提供。鼓励未来的研究，使用可公开获得的数据集，进一步解读城市系统的空间配置与基于遥感的城市树木压力指标之间的关系，以进行比较研究。