Study on the influence of topography on wind shear numerical simulations based on WRF–CALMET

Abstract. This study focuses on the critical issue of low-altitude wind shear, which is vital for aircraft safety during takeoff and landing. Using the WRF–CALMET model, we assess the impact of topography on low-level wind shear at Zhongchuan Airport. CALMET outperforms WRF, showing improved simulation accuracy. CALMET's simulation highlights diurnal variations in vertical wind shear, which are especially pronounced from 13:00 to 24:00 CST (China standard time, UTC+8). Notably, CALMET indicates wind shear that is one to two hazard levels higher for aircraft operations compared to WRF over a significant area. Terrain sensitivity experiments reveal CALMET's responsiveness to terrain changes during high-wind-shear periods, with reduced impact at higher altitudes. CALMET's incorporation of kinematic terrain influences, blocking effects, slope flow, and strengthened diversion of near-surface airflow on complex terrain contribute to these findings. This study confirms the efficacy of CALMET in simulating low-altitude wind shear, emphasizing its superiority in capturing terrain influences and reducing the aviation safety threat posed by low-altitude wind shear.