Dispersion outside PBL

[macpeter]

Hi,
i`m doing dispersion simulation, letting particles start both in the boundary layer and outside. How is it computed the particle`s motion outside the BL? Does it have a random component, or just follow the wind as in the trajectory case? What happens when a particle goes down from the free layer to the BL?
Sorry, but I didn`t find the answers in the model`s documents.
Thank you.

[ariel.stein]

The transport and dispersion of the particles either outside or inside the PBL are calculated with the same equations. The only thing that changes is the meteorological environment given by the meteorological data driver (meteorological model). Given that the meteorological conditions above the PBL tend to produce a less turbulent environment the particles will indeed experience a lower degree of mixing but they will still have an associated random component to simulate its dispersion.