HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hello.

Within the 'Initial CONTROL File Section,' I understand that if a given file does not have a vertical wind speed variable, the vertical motion will be computed from the velocity divergence. Now I understand that this is a vertical integration of the horizontal velocity divergence, but what is the exact calculation/equation used here?

Thank you.

Wη = (-∂η/∂t - u ∂η/∂x - v ∂η/∂y) / (∂η/∂z)