Impact of Nanjing Urban Development on the Boundary Layer

Abstract

AbstractIn order to understand how urban development changes the local urban boundary layer structure, the high‐resolution satellite observation data have been used to get detailed information of land‐use types, surface albedo, vegetation index and so on for regional boundary layer simulation. It is proved that this is an effective method and these data will help to get more reasonable simulation which are close to the realities. The numerical results illustrate that with the urban developing, the surface albedo decreases, the vegetation cover decreases and the surface wetness decreases, so surface sensible heat flux increases with a maximum of 140 W/m2, and less vegetation will lead to decrease of latent heat consumption and increase the Bowen ratio in urban areas. The kinetic heat flux will increase and the turbulence exchange will be stronger, at 14:00 the mixing layer is even lifted by a 500 m. The decreases of both kinetic moisture flux and vapor concentration cause that more energy will heat the earth surface and atmosphere, the diurnal change of earth surface temperature and atmospheric temperature will increase.