Lagrangian simulation of suspended particles in the neutrally stratified surface boundary layer

[1] The one-dimensional equation of motion for suspended particles in the neutral atmospheric surface boundary layer is solved for the particle motion assuming that the sequence of vertical fluid velocities at the (moving) particle location can be modeled by a generalized Langevin equation. This inertial particle model is used to produce concentration profiles above a reflecting lower boundary for neutrally buoyant particles with inertia and for heavy particles with gravitational settling. Near the ground, modeled particle number concentration profiles above an infinite plane depart from the standard power law solution predicted by diffusion models. We investigate effective settling velocity and the eddy diffusivity for particles in this turbulent boundary layer flow and find that, near the ground, both are reduced in relation to particle terminal velocity and the assumptions made in boundary layer diffusion models.