How is the output variable "W" calculated?

[Xipeng Jin]

Hi,

'w' (described as z-wind component) is the true vertical velocity by its conventional definition (dz/dt). I think it consists of two parts: 1) the model-resolved vertical motion ww; and 2) the sub-grid parameterized vertical velocity w0AVG (such as the Cumulus parameterization scheme KF).
I wonder how it is calculated in the WRF model? by w=ww+w0AVG or w=dz/dt? In which F files can I find the relevant code?

Any help will be appreciated.

 

[Ming Chen]

Hi, Xipeng,
Please take a look at the code dyn_em/module_big_step_utilities_em.F, in which you can find the subroutine 'diagnose_w'.
geopotential equation is applied to diagnose vertical velocity w.