城市湖泊在降低城市热岛效应方面有着重要影响。选取湖南烈士公园湖泊作为研究对象,采用定点实测和CFD模拟相结合的方法,重点分析了湖泊面积和湖泊形状指数对湖泊降温效应的影响程度。研究结果表明:①湖泊面积是湖泊降温效应的主要影响因子,面积越小湖泊降温效应越弱,当研究区域无湖泊时区域内整体平均升温1.8 ℃,湖泊区域绿地最大可升温4.1 ℃;②湖泊形状指数的大小对湖泊降温效应的影响微弱,湖泊降温效应随着形状指数的增大而略微增大;③湖泊面积不变的前提下,形状指数过大影响水体的整体性,从而减弱湖泊的降温效应。研究结论对于加深对城市湖泊在降低城市热岛效应方面的认识,以及城市湖泊区域的规划设计等均具有重要的参考价值。

Urban lake plays an important role in reducing the urban heat island effect. With the lake in the martyr park of Hunan Province as study object, we probed into the influences of lake area and lake shape index (perimeter-to-area ratio) on the lake cooling effect through field measurement and CFD (Computational Fluid Dynamics) simulation. Results show that: 1) Lake area is the major factor that affects the cooling effect of lake. The smaller lake area, the weaker the cooling effect. In the control area (area for comparison with no lake), the mean temperature increases by 1.8 ℃ in general, and the green land in lake increases by 4.1 ℃ to the maximum. 2) Lake shape index has a weak influence on the cooling effect of lake which increases slightly with the increase of shape index. 3) Under the condition that lake area remains unchanged, an excessive shape index will greatly affect the integrity of the water body, thus weakening the cooling effect.