wrfout omega direction

[Elaine_wrf]

Dear help,
I output a diagnostic for vertical velocity, whose unit is Pa/s
w = getvar(wrf_list, 'omega', timeidx=ALL_TIMES, method='cat')
I wonder if w>0,mean upward direction or downward direction
Thanks a lot
Yours sincerely.

 

[Pechudin]

Omega is positive downward (since if pressure is increasing, this means that we are descending). Basically, omega is opposite (in direction) to vertical velocity.

So: omega - positive; vertical velocity - negative and opposite, omega - negative, vertical velocity - positive.