Is terrain included in the Hysplit model and how accurate are surface trajectories computed for complex terrain?

Meteorological model output fields are interpolated to terrain following coordinate system. Resolution is the same as the native coordinate system. Your local terrain will not match model terrain, which is much smoother. In very complex terrain the model is probably not very accurate unless local wind flow is being driven by the large-scale synoptic conditions — strong winds.

Roland Draxler