Numerical simulation of the impact of lake size on the lake breeze over Bosten Lake, China

Lake–atmosphere interactions influence regional weather patterns and climate regulation. This study investigated the impact of lake size of Bosten Lake on the lake breeze and regional meteorological changes using the WRF-Lake model. Comparisons between the model and observations showed that the model effectively reproduced the diurnal variations in surface air temperature and wind speed during the lake breeze. The lake breeze developed between 10:00 and 20:00 BJT, persisting for approximately 10 h. Near-surface wind speeds ranged from 2 to 4 m·s −1 , while upper-level speeds reached 6 m·s −1 . The breeze attained peak intensity during 14:00–16:00 BJT, featuring winds diverging from the lake center, converging with the overland background airflow, ascending vertically, and forming a closed circulation cell with a thickness of up to 1,000 m. The horizontal penetration extended 17.77 km northward from the northern shore. Sensitivity experiments quantified lake size impacts on circulation dynamics: the horizontal penetration distance decreased by 29% during lake contraction and increased by 43% during lake expansion, whereas vertical thickness and temporal persistence remained unaffected. Thermal gradients exhibited asymmetric responses, with contraction weakening temperature contrasts (1–2 m·s −1 wind reduction), while expansion intensifying thermal-driven acceleration. Comparative analyses with no-lake scenarios revealed dual acceleration–cooling effects: lake-induced cooling vertically exceeded a 1-km altitude and horizontally extended 10–20 km inland, generating 0.4–3.2°C temperature reductions that decayed exponentially with altitude and distance. Wind modifications demonstrated context-dependent complexity, enhancing speeds by 2–4 m·s −1 within the 500-m layer through thermal-mechanical forcing while inducing downwind deceleration via flow-blocking mechanisms.