Ouédraogo Ahmeda Assann, Berthier Emmanuel, Ramier David, Tan Yanlin, Gromaire Marie-Christine
Equipe TEAM, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et Aménagement (Cerema), 12 rue Teisserenc de Bort, F 78190 Trappes, France.
Equipe TEAM, Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et Aménagement (Cerema), 12 rue Teisserenc de Bort, F 78190 Trappes, France.
Sci Total Environ. 2023 Dec 1;902:166135. doi: 10.1016/j.scitotenv.2023.166135. Epub 2023 Aug 8.
Evapotranspiration (ET) is an important process in green stormwater infrastructure (GSI) aiming to reduce urban drainage, to promote cooling and/or to contribute to an urban hydrological balance restoration closer to the natural one. However, on these structures and particularly on green roofs (GR), its evaluation remains challenging and subject to discussion. Estimates of ET by water balance, energy balance, and an ET chamber were performed on five different plots of a full-scale experimental green roof in Trappes (France). Compared to both water balance (90th percentile range of daily ET values: 0.8 mm/d to 3 mm/d) and chamber methods (90th percentile range of daily ET values: 1 mm/d to 1.5 mm/d), the energy balance (90th percentile range of daily ET values is between 1.8 mm and 3.7 mm) produces higher values, 1 to 2 times higher in cumulative values during common periods. The chamber ET displays a similar trend to the energy balance on an hourly basis, and its values remain within the same range as the water balance evaluations on a daily time-step. All three assessments consistently fell below the potential ET values estimated with the Penman-Monteith formula. Critical issues in ET estimation through experimentation have arisen. Sensible heat flux (H) significantly increases ET values when using the energy balance approach compared to the other two methods. The Water Balance method is practical, but on days following rainfall events, the Chamber method may prove more reliable, albeit more time and labour-intensive. The three methods indicated that the substrate thickness was the main contributing factor to increase ET, with well-maintained herbaceous plants providing higher ET values than sedums in thick (15 cm) substrates. In addition, the substrate's nature, especially its organic content, is another factor that promotes ET in green roofs.
蒸散（ET）是绿色雨水基础设施（GSI）中的一个重要过程，旨在减少城市排水、促进降温，和/或有助于恢复更接近自然状态的城市水文平衡。然而，对于这些结构，尤其是绿色屋顶（GR），其评估仍然具有挑战性且存在争议。在法国特拉普斯一个全尺寸实验性绿色屋顶的五个不同地块上，通过水平衡、能量平衡和蒸散室对蒸散进行了估算。与水平衡法（日蒸散值的第90百分位数范围：0.8毫米/天至3毫米/天）和蒸散室法（日蒸散值的第90百分位数范围：1毫米/天至1.5毫米/天）相比，能量平衡法（日蒸散值的第90百分位数范围在1.8毫米至3.7毫米之间）得出的值更高，在共同时间段内累积值高出1至2倍。蒸散室的蒸散在每小时的基础上与能量平衡呈现相似趋势，并且其值在日时间步长上与水平衡评估值处于同一范围内。所有这三种评估结果始终低于用彭曼 - 蒙特斯公式估算的潜在蒸散值。通过实验进行蒸散估算时出现了一些关键问题。与其他两种方法相比，在使用能量平衡方法时，显热通量（H）会显著增加蒸散值。水平衡法很实用，但在降雨事件后的日子里，蒸散室法可能更可靠，尽管它更耗时且劳动强度更大。这三种方法表明，基质厚度是增加蒸散的主要因素，在厚（15厘米）基质中，养护良好的草本植物比景天属植物提供更高的蒸散值。此外，基质的性质，尤其是其有机含量，是促进绿色屋顶蒸散的另一个因素。
