Abstract: Selecting Tongsheng Lake in Changsha City as the research object and using parallel fixed-point actual measurement method combined with computational fluid dynamics (CFD) scenario simulation, the changing law of "wet island effect" in suburban lakes and the influence of architectural factors on "wet island effect" in summer are studied. The results show that:(1) The suburban lakes have a humidifying effect on their surrounding environment in summer, with the increasing of average daily humidifying intensity of 0.99 percentage point and the maximum increasing of humidifying intensity as 2.02 percentage point; (2) The humidifying effect of the lake water body is significantly and positively correlated with the distance from the lake shore, with its maximum at a distance of 0 m, and their humidifying effect on downwind area is far higher than on upwind and vertical areas; (3) Architectural factors (height, retreat distance, spacing, etc.) are the major factors affecting the size of "wet island effect" of lakes, resulting in the difference in the distribution characteristics and changing law of "wet island effect". For every 100 and 200 m far away from lake shore, the relative humidity in the northwestern area of the lakes increases by 0.27-1.40 percentage point, and humidifying scope is enlarged by 100-300 m. For an increase of height by 10 and 20 m, the relative humidity above the water bodies of the lakes decreases by 0.60-0.87 percentage point, with their humidifying scope in the northwestern area being reduced by 50-100 m. The relative humidity in the southeastern region decreases by 0.59-0.81 percentage point when the distance between buildings increases by 2 times, and water bodies of the lakes can affect the northwestern area 500-600 m far away.

Key words: wet island effect, cold island effect, lakes in urban suburbs, CFD scenario simulation, Tongsheng Lake