Fig. 1. Topography of Beijing and surrounding areas

Fig. 2. Distribution of land use types in the WRF simulation area

Fig. 3. The technology roadmap

Fig. 4. Daily series of wind speed at 10 m in January and July 2019

Fig. 5. Evaluation of ventilation performance by maximum roughness length (z_{0_max}) based on USGS land use data (GLC2015)

Fig. 6. WRF-simulated mean wind speed and wind direction at 10 m above the ground

Fig. 7. WRF simulated mean surface temperature at 2 m above the ground (T₂)

Fig. 8. Dimensionless ventilation index (I_v) is determined by the order relation method of the surface temperature T₂ and roughness of z₀

Fig. 9. Comprehensive analysis of ventilation grades in Beijing