Irrigating urban green space for cooling benefits: the mechanisms and management considerations
Irrigating urban green space for cooling benefits: the mechanisms and management considerations
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DOI：
10.1088/2752-5295/ac6e7c
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
Pui Kwan Cheung;K. Nice;S. Livesley
中科院分区：
文献类型：
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作者：
Pui Kwan Cheung;K. Nice;S. Livesley
蒸散发是城市绿地降温的重要机制。用饮用水、收集的雨水或回收的污水灌溉植被表面，有可能通过增加蒸发蒸腾来增加UGS的冷却效果。这种降温效果可能并不总是很强，因为蒸散发取决于当地和区域因素，如背景气候、季节性和植被类型。当使用灌溉降温时，城市管理者还需要考虑诸如灌溉供水和UGS的设施使用等管理问题。本研究旨在建立一个解释灌溉冷却效应的物理和能量机制的理论框架，并为城市管理者提供一个利用灌溉进行城市冷却的决策框架。这是通过回顾文献中报道的灌溉对当地气候的影响，并确定影响温暖季节灌溉降温效果的区域和局部因素来实现的。文献表明，根据天气条件和灌溉量的不同，灌溉可能使日最高气温和地表温度分别降低约2.5°C和4.9°C。背景气候是影响灌溉降温势的重要因素。气候干燥和温暖的城市，灌溉带来的降温潜力最大。降温势还受季节和天气、植被类型、灌溉时间和灌水量的影响。干旱和温暖季节的城市可以考虑使用灌溉来缓解UGS内的城市热量，因为这种气候条件可以增加冷却潜力。为了最大限度地提高灌溉降温效果，灌溉供水充足的城市可以使用土壤湿度控制灌溉制度，而供应有限的城市可以使用温度控制制度。需要更多的研究来了解灌溉小型单个UGS的冷却潜力。
Evapotranspiration is an important cooling mechanism in urban green space (UGS). Irrigating vegetated surfaces with potable water, collected stormwater or recycled sewage water has the potential to increase the cooling effect of UGS by increasing evapotranspiration. Such cooling effect may not always be strong because evapotranspiration is dependent on local and regional factors such as background climate, seasonality and vegetation type. When using irrigation for cooling, city managers also need to consider management issues such as irrigation water supply and amenity use of the UGS. This study aims to develop a theoretical framework that explains the physical and energetic mechanisms of irrigation cooling effect and a framework to assist city managers to make decision about the use of irrigation for urban cooling. This is achieved by reviewing the impacts of irrigation on local climate reported in the literature and identifying the regional and local factors that influence irrigation cooling effect in warm seasons. The literature suggests that irrigation can potentially reduce daily maximum air temperature and ground surface temperature by approximately 2.5 °C and 4.9 °C, respectively, depending on weather conditions and irrigation amount. Background climate is an important factor that influences the cooling potentials of irrigation. Cities with dry and warm climates have the highest cooling potentials from irrigation. The cooling potentials are also influenced by seasonality and weather, vegetation type, irrigation time of day and irrigation amount. Cities with a dry and warm season can consider using irrigation to mitigate urban heat within UGS because such climatic conditions can increase cooling potentials. To maximise irrigation cooling effect, cities with abundant irrigation water supply can use a soil moisture-controlled irrigation regime while those with limited supply can use a temperature-controlled regime. More studies are required to understand the cooling potentials of irrigating small, individual UGS.