cdiff not working for z dim!?

[Arturo Pucillo]

Hello!

Try with the following:

"define dt=t(z-1)-t(z+1)"

However I think there's another post with discussion of this matter.

Regards

Arturo



Thomas Spengler wrote:
> Dear all,
>
> I am trying to calculate vertical gradients using the 'cdiff' function.
>
> For example for my variabte t (temperature) I write:
>
> ga-> set z 1 21
> LEV set to 1 1000
> ga-> define dt=cdiff(t,z)
>
> and get the following result/error message:
>
> Error from CDIFF:  Specified dimension non varying
> Operation Error:  Error from cdiff function
>   Error ocurred at column 1
> DEFINE error:  Invalid expression.
>
> when trying to use lev as the vertical dim:
>
> ga-> define dt=cdiff(t,lev)
> Error from CDIFF:  Invalid dimension argument
>   2nd argument must be X, Y, Z, or T
> Operation Error:  Error from cdiff function
>   Error ocurred at column 1
> DEFINE error:  Invalid expression.
>
> Would be great if someone has a suggestion on how to calculate vertical
> differentials in GrADS.
>
> Thanks for your help!
>
> Cheers,
> Thomas
>
>

--

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Arturo PUCILLO

ARPA FVG - Settore OSMER
Osservatorio Meteorologico Regionale
Regional Meteorological Observatory
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I-33040 Visco (UD) Italy
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e-mail: arturo.pucillo at osmer.fvg.it
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