Abstract
We have studied the effect of mountain wave on the transport of Yellow Sand by 2-dimensional simulation. The advection-diffusion equation of scalar concentration is solved to simulate the transport of Yellow Sand. Two different models are employed, one is a one-layer model in which the density gradient is constant in the entire domain, and the other is a two-layer model in which the density gradient changes at 11 km altitude. In the both models the air parcel at a high altitude starts descending toward the ground behind the mountain as the atmospheric stability increases. In the two-layer model, trapped mountain waves become strong and rotors are also generated. The scalar concentration diffuses strongly in wave breaking and rotor regions. The ground scalar concentrations of the two-layer model are very large, compared with those by the one-layer model.
