[gradsusr] How to calculate the pressure gradient?

[Djordje Romanic]

Thanks Jeff...

Cheers,
Djordje



On Thu, Aug 9, 2012 at 6:30 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:

> Djordje,
> Since cdiff performs a centered difference, if you use the expressions
> suggested by another Grads user on this thread, you would only want to use
> dx since 2*dx is already implied in the definition.
>
> Jeff
>
>
> On Thu, Aug 9, 2012 at 1:50 AM, Djordje Romanic <djordje8 at gmail.com>wrote:
>
>> Thanks,
>>
>> Since I only need the pressure gradient, and not the pressure gradient
>> force, I should exclude 1/rho. Just one clarification. When I use cdiff
>> function for pressure (e.g. in LON direction), should I divide it with dx
>> or 2*dx. I believe that 2*dx would be correct.
>>
>> Regards,
>> Djordje
>>
>>
>> On Wed, Aug 8, 2012 at 7:08 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> The pressure gradient is simply 1/rho * del(p), where del(p) is the
>>> gradient operator, which can be displayed in Grads using the mathematical
>>> decomposition of the gradient operator (i.e., derivatives in the x- and
>>> y-directions).  Use cdiff for those derivatives.  Note, you'll have to
>>> define your x- and y- grid spacing values as well.  See the examples on the cdiff
>>> help page <http://www.iges.org/grads/gadoc/gradfunccdiff.html> for how
>>> to do that.
>>>
>>> Jeff Duda
>>>
>>> On Wed, Aug 8, 2012 at 5:48 AM, Djordje Romanic <djordje8 at gmail.com>wrote:
>>>
>>>> Dear Users,
>>>>
>>>> I have to calculate the pressure gradient in a given area (Southeast
>>>> Europe) and I have a pressure date at 2.5 x 2.5 degrees (reanalysis data).
>>>> Does anyone know how to calculate it in GrADS and how to show the results
>>>> in the vector form?
>>>>
>>>> Thanks in advance.
>>>>
>>>> Regards,
>>>> Djordje Romanic
>>>> M.Sc. in Meteorology
>>>> Cell: +38164 254 3539
>>>> www.linkedin.com (Djordje Romanic profile)
>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> Jeff Duda
>>> Graduate research assistant
>>> University of Oklahoma School of Meteorology
>>> Center for Analysis and Prediction of Storms
>>>
>>>
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>>>
>>
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>
>
> --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
>
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