# [ncl-talk] Question about addition of coriolis parameter (1Darray) and a variable(4D-aray)

Lyndz olagueralyndonmark429 at gmail.com
Fri Feb 8 02:11:07 MST 2019

```Dear NCL-experts,

I am calculating vorticity tendency using the following equation (also
attached in this email):
I want to add the coriolis parameter (1D) and the calculated relative
vorticity (4D) before calculating its advection. These two parameters have
dimensions.

[image: Screenshot from 2019-02-08 18-02-16.png]

Below is the part  that calculates the vorticity using spherical harmonics
and the coriolis parameter.
;************************************************
; variable and file handling
;************************************************
f   = addfile("../ncep_6h_jan.nc","r")       ; open netcdf file
u   = f->U_GRD_2_ISBL(:,:,:,:)            ; pull u off file
v   = f->V_GRD_2_ISBL(:,:,:,:)            ; pull v off file
u = u(:,:,::-1,:)                         ;for speherical harmonics
v = v(:,:,::-1,:)
;************************************************
; calculate vorticity on a Fixed Grid
;************************************************
*  vr = uv2vrF_Wrap(u,v)*
printVarSummary(vr)

vr at long_name = "vorticity"
vr at units     = "per second"
;************************************************
;calculate coriolis parameter
;************************************************
lat = vr&lat
*  flat = coriolis_param(lat)*

[1] I apologize, I think this is a basic question. How do add the coriolis
parameter to the calculated vorticity? I already know how to get the
advection, I only got stuck in this part.

I'll appreciate any help.

Sincerely,

*Lyndz*
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```