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快速城市化与气候变化双重作用下,热岛效应与城市内涝成为最为突出的城市环境问题。绿化屋顶因能有效利用闲置屋面添緑、帮助城市缓解热岛和暴雨径流而受到关注。以往研究较多探讨单种气象条件下、单个小面积实验型绿化屋面的气候水文调节功能,本研究基于夏秋两季的微气候水文观测数据,定量分析不同气象条件下5种典型绿化屋顶的降温和径流削减效应。首先选择晴朗、多云、降雨3种典型夏日天气条件,分析草坪、裸土、菜地、小面积花园、大面积花园5种类型绿化屋顶与对照光屋顶之间的温度差日变化规律,探讨绿化屋顶热效应强度及时空特征;其次,选择暴雨、大雨、中雨及小雨4次典型降雨,分析大面积草坪与花园型绿化屋顶上的降雨-滞蓄过程及径流削减率。研究结果表明:绿化屋顶降温与升温效应并存,晴朗无风天气条件下,距离屋面10 cm和150 cm两个高度上,绿化屋顶最高可降低气温5.3℃和2.5℃,多云及降雨天气条件下降温强度下降,升温时段延长;白天草坪与裸土上的大气温度高于对照光屋顶,其它绿化屋顶的温度低于对照屋顶;夜间5个绿化屋顶的大气温度均低于对照屋顶,且降温效应按照大面积花园、草坪、小面积花园、裸土、菜地的顺序递减。绿化屋顶径流削减效益与绿化类型及降雨强度密切相关,花园型绿化对一次典型暴雨、大雨、中雨、小雨的径流削减率分别为50.8%、78%、100%、100%,简易型绿化的4次径流削减率分别为24.3%,58.6%,98.2%和100%。研究结果可为同气候区其他城市绿化屋顶环境设计及管理提供一定参考价值。
Under the dual action of rapid urbanization and climate change, the heat island effect and urban waterlogging have become the most prominent urban environmental problems. Green roofs are drawing attention for the efficient use of idle roofing to help green the city to ease heat islands and storm runoff. Previous researches mainly discussed the climate and hydrological regulation function of a single small-area experimental green roof under a single meteorological condition. Based on the data of microclimatic hydrological observation in summer and autumn, this study quantitatively analyzed the temperature reduction of five typical green roofs under different weather conditions And runoff reduction. Firstly, three typical summer weather conditions of sunny, cloudy and rainfall were selected to analyze the diurnal variation of temperature difference between five types of green roof and control roof of lawn, bare soil, vegetable garden, small area garden and large area garden Green roof thermal effect intensity and spatio-temporal characteristics; Secondly, four typical rainfalls of heavy rain, heavy rain, moderate rain and light rain were selected to analyze the rainfall-slumping process and runoff reduction rate on large-scale lawn and garden green roof. The results show that under the condition of sunny and windless weather, the green roofs can reduce the temperature by 5.3 ℃ and 2.5 ℃ at the height of 10 cm and 150 cm from the roof, and cool down under the cloudy and rainfall weather conditions The temperature of the other green roofs was lower than that of the control roof; the atmospheric temperature of the five green roofs at night was lower than that of the control roof, and the cooling effect was in accordance with Large area garden, lawn, small area garden, bare soil, vegetable order decreasing. The reduction effect of green roof runoff is closely related to the type of greening and rainfall intensity. The reduction of runoff for a typical storm, heavy rain, moderate rain and light rain for garden type landscaping is 50.8%, 78%, 100% and 100% respectively. The 4-fold runoff reduction rates were 24.3%, 58.6%, 98.2% and 100% respectively. The results can provide some reference value for the design and management of green roofs in other cities in the climate zone.