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

Lyndz olagueralyndonmark429 at gmail.com
Fri Feb 8 08:21:16 MST 2019

```Hi Sir  Dennis,

Thanks a lot!
I was also looking at *conform* a while ago but didn't know how to use it.

Lyndz

On Sat, Feb 9, 2019 at 12:15 AM Dennis Shea <shea at ucar.edu> wrote:

> vr(ntim,klev,nlat,mlon)  ==> dimension numbers (0,1,2,3)
>              flat(nlat)
> -----
>      va = vr + *conform*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/conform.shtml>(vr,
> flat, 2) )    ; flat matched the '2-th' dimension of 'vr'
>
>      va at long_name = "absolute vorticity"
>      va at units     = "per second
>      *copy_VarCoords*
> <http://www.ncl.ucar.edu/Document/Functions/Contributed/copy_VarCoords.shtml>(u,
> va)
>
> or overwrite rather than create a new variable
>
>      vr = vr + *conform*
> <http://www.ncl.ucar.edu/Document/Functions/Built-in/conform.shtml>(vr,
> flat, 2) )    ; flat matched the '2-th' dimension of 'vr'
>
>      vr at long_name = "absolute vorticity"
>      vr at units     = "per second
>      *copy_VarCoords*
> <http://www.ncl.ucar.edu/Document/Functions/Contributed/copy_VarCoords.shtml>(u,
> vr)
> "
>
> Good luck
>
> On Fri, Feb 8, 2019 at 2:11 AM Lyndz <olagueralyndonmark429 at gmail.com>
> wrote:
>
>> 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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>
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