Abstract: A depth-averaged numerical model is introduced for aeolian sediment transport modeling. Model validity has been assessed using experimental data, and the results show that the major features of aeolian sediment transport can be well captured by the proposed model. Furthermore, based on the integral model, the recent theoretical work on the multiple time scales of fluvial processes is extended to aeolian processes, the corresponding time scales concerning the adaptation of sediment transport to equilibrium state are purposely defined and quantitatively analyzed. The results provide a theoretical justification for aeolian saltation that it can be adapted to equilibrium state very rapidly, while it is found that a much longer time and space is needed for aeolian suspension to adapt to equilibrium.