[gradsusr] Grads vertical derivative error with cdiff

[Jeff Duda]

It will work on all levels in your current dimension environment.
 Therefore, if you have a range set, it will compute the derivative for all
levels (you'd want to define a variable in that case instead of merely
displaying it).  If you have just one level set, it will only
define/display for that level.  Of course, make sure that you are always
referring to a level that exists, else you will get an error.  If your
z-dimension has indices from 1 to 30, you will want to restrict your
settings to levels 2 to 29 at most because if you keep the settings at 1
and 30 your command will try to refer to levels 31 and 0, neither of which
exist.

Jeff

On Sun, May 6, 2012 at 9:55 PM, Aishwarya <spaceaish at gmail.com> wrote:

>
> should i set a specific level for this or Just leave it as it is? Will it
> work on specific levels or all levels?
>
> Thank you,
> Aishwarya.
> On Sun, May 6, 2012 at 6:44 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>
>> You can't use cdiff in the vertical.  You must calculate the derivative
>> using a manual centered difference.  For example, 'd
>> 0.5*(geopot(z+1)-geopot(z-1))'
>>
>> Jeff Duda
>>
>> On Sun, May 6, 2012 at 7:32 PM, Aishwarya <spaceaish at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I'm trying to find vertical derivative of geopotential (geopt). I tried
>>> d cdiff(geopt,z), i find the error :
>>> Error from CDIFF:  Specified dimension non varying
>>> Operation Error:  Error from cdiff function
>>>   Error ocurred at column 1
>>> DISPLAY error:  Invalid expression
>>>   Expression = cdiff(u,z)
>>>
>>> Any help would be great!
>>>
>>> Thank you,
>>> -------
>>> *Aishwarya,
>>> Graduate Research Assistant,
>>> Atmospheric Sciences,
>>> University of Arizona,Tucson.*
>>>
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> Jeff Duda
>> Graduate research assistant
>> University of Oklahoma School of Meteorology
>> Center for Analysis and Prediction of Storms
>>
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
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>>
>>
>
>
> --
> *Aishwarya,
> Graduate Research Assistant,
> Atmospheric Sciences,
> University of Arizona,Tucson.*
>
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>


-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
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