Abstract:

Aerodynamic entrainments one of the significant mechanisms of surface dust emission in soil wind erosion processes. Due to its high frequency and regular occurrence， it contributes significantly to regional and global atmospheric dust over long time scales. This study uses the dried lakebed sediments of Qehan Lake in Inner Mongolia of China as simulation subjects， conducting large-eddy simulations under ideal atmospheric boundary layer conditions with different atmospheric stability and background winds to explore the dynamics of turbulent dust emission from dried lakebed sediments and the influencing factors. The results indicate： （1） Intermittent turbulence generated by surface heating causes dust emission at the surface. （2） Sensible heat flux and friction velocity both positively affect surface dust emission and near-surface dust concentration. Increased wind speed and sensible heat flux result in higher surface dust emission and near-surface dust concentration. （3） Under weak background wind and strong surface sensible heat flux compared to the case of strong background wind and weak sensible heat flux， the formation of strong vertical eddies is more frequent， leading to significantly increased vertical velocity. Under the driving force of thermal convection and atmospheric instability， surface dust emission is more prone.

Key words: convective turbulence, large-eddy simulation, dust, sensible heat flux, rriction velocity, Qehan Lake