Where and how to cool through blue infrastructure? Large lake groups to ameliorate urban overheating in a typical inland multi-lake megacity

Abstract

Large lake groups have been recognized as important blue infrastructure to ameliorate urban overheating in inland megacities. Previous studies have evaluated climate regulation capabilities of large lakes on cities. However, how the specific location of lake groups affects thermal environments across extensive built-up areas through thermal and aerodynamic mechanisms remains unclear. Therefore, we conducted sensitivity experiments using the Weather Research and Forecasting (WRF) model to explore the intensity and spatial variation of air temperatures and wind fields influenced by lake groups—located in downtown areas, inner suburbs, and outer suburbs—under typical heatwave conditions in Wuhan. Results indicate that compared to similar-sized suburban lake groups, downtown lake groups exhibit higher and lower daytime lake-land differences in sensible and latent heat fluxes, respectively, resulting in greater lake cooling intensities (LCIs). Also, upwind lake groups cool more built-up areas since lake breeze circulations (LBCs) promote the spreading of lake cooling distances (LCDs). However, the development of LCIs, LCDs, and LBCs is asynchronous, with LCIs peaking around mid-morning before the generation of LBCs, and LCDs peaking in the afternoon once LBCs have developed vigorously. Moreover, we propose a planning framework integrating the cooling effects of lake groups to support cooler, healthier, and more sustainable cities.