The phenomenon of the urban heat island effect requires urban planning adaptation strategies that mitigate heat stress. While the cooling effect of urban green spaces has been well studied, knowledge gaps remain regarding the cooling potential of urban blue spaces. Particularly, how the cooling intensity of an urban blue space is influenced by its features and the context in which it occurs, such as its size, location, and more broadly the local climate and season, requires closer investigation. To address these gaps, we conducted a systematic review of studies exploring the thermal effect of urban blue spaces on the surrounding urban microclimate. We extracted the cooling or heating intensity of urban blue spaces, while considering how season, time of day, climate zone, water body size and methodological approach may influence results. Through analysis of 67 identified articles, we found that the thermal effect of blue spaces varies between seasons and time of day, with daytime temperatures in the surrounding urban climate cooled by 2.6 °C on average and maximum intensities observed during late spring and early summer. While at night-time in the summer, the thermal effect showed an average urban heating intensity of 0.6 °C. These values differ depending on the methodological approach used, with mean daytime cooling intensities varying considerably by method (field measurements: 1.4 °C; remote sensing: 3.4 °C; numerical modelling: 1.7 °C). The thermal effect also differed by climate zone, with results indicating a cooling intensity during the day with higher values in temperate climate zones. At night, both cooling and heating effects were observed in continental and temperate zones. The few studies reporting on water body size indicated a higher cooling intensity with greater size of the water body. These varying cooling or heating characteristics of urban blue spaces suggest they can be utilised in different planning contexts to achieve desired goals, depending on their features, the time and location, making them valuable nature-based solutions aimed at mitigating urban heat.

中文翻译：

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蓝色空间对不同气候区、白天和季节城市小气候的影响 – 系统评价


城市热岛效应现象需要缓解热应激的城市规划适应策略。虽然城市绿地的降温效果已经得到充分研究，但关于城市绿地的降温潜力仍然存在知识差距。特别是，城市蓝色空间的冷却强度如何受到其特征和发生环境（例如其大小、位置以及更广泛的当地气候和季节）的影响，需要更深入的研究。为了解决这些差距，我们对探索城市蓝色空间对周围城市小气候的热效应的研究进行了系统评价。我们提取了城市蓝色空间的制冷或供暖强度，同时考虑了季节、一天中的时间、气候区、水体大小和方法如何影响结果。通过对 67 篇已确定文章的分析，我们发现蓝色空间的热效应因季节和一天中的时间而异，周围城市气候的白天温度平均冷却 2.6 °C，在春末夏初观察到最大强度。而在夏季的夜间，热效应显示城市平均供暖强度为 0.6 °C。 这些值因所使用的方法而异，平均白天冷却强度因方法而异（现场测量：1.4 °C;遥感：3.4 °C;数值建模：1.7 °C）。热效应也因气候区而异，结果表明白天的冷却强度较高，温带气候区的值较高。在夜间，在大陆和温带地区观察到冷却和加热效应。 少数报告水体大小的研究表明，水体尺寸越大，冷却强度越高。城市蓝色空间的这些不同的制冷或供暖特性表明，根据其特点、时间和地点，它们可以在不同的规划环境中利用以实现预期目标，使其成为旨在缓解城市热量的有价值的基于自然的解决方案。