[Wrf-users] Sigma levels to geopotential heights (in meters)

[Paula Doubrawa]

Oh, sorry Seyed, I think I got confused myself. Perhaps that is not what
you want. Try looking at your sigma levels spatially, vertically and
horizontally (you should have that as a variable, staggered and
unstaggered, in your model output), and perhaps that will help you
understand?


On Wed, Mar 26, 2014 at 12:48 PM, Paula Doubrawa <pdoubraw at indiana.edu>wrote:

> Hi, Seyed
>
> I do understand what you mean. Sigma levels are terrain following
> coordinates so a sigma level will never be the same height or pressure
> along its sigma surface. You will need to interpolate the " dust " . Say
> you have a variable called dust at sigma levels, and a variable called
> heights, also at sigma levels. Let desired_height = 500. Then
>
> dust_height_levels =
> wrf_user_intrp3d(dust,heights,"h",desired_height,0.0,False)
>
> Will give you dust at the desired level. You can use pressures instead of
> heights, in which case instead of desired_height you should specify some
> desired_pressure, say 500 mb.
>
>
> On Wed, Mar 26, 2014 at 12:38 PM, Seyed Omid Nabavi <omid.nabavy at gmail.com
> > wrote:
>
>> Dear Paula,
>>
>> First of all, thanks for your time.
>>
>> I also use NCL to map data and I am sure this command will help in next
>> steps of the study.
>> But at the moment, I want to produce dust maps in geopotential layers not
>> vertical interpolation. As you know, we analyze atmospheric data more based
>> on constant pressure layers. for example wind streams in 500 hPa. Since,  I
>> want to convert sigma layers to geopotential heights (in meters) and then
>> depict dust particles in any single layers.
>> For instance: the concentration of dust particles in 850 hPa not in sigma
>> layer 4,5, 15..... etc.
>>
>> Thanks again,
>>
>>
>>
>> On Wed, Mar 26, 2014 at 5:11 PM, Paula Doubrawa <pdoubraw at indiana.edu>wrote:
>>
>>> Hi, Seyed
>>>
>>> You can use your geopotential heights at the sigma levels to interpolate
>>> your variables... I always do it with ncl, and it's very easy with the
>>> function
>>>
>>> wrf_user_intrp3d (see here<http://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_intrp3d.shtml>
>>> )
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, Mar 26, 2014 at 11:43 AM, Seyed Omid Nabavi <
>>> omid.nabavy at gmail.com> wrote:
>>>
>>>> Dear all,
>>>> I am trying to map forecasted dust storms in different geopotential
>>>> heights , not sigma levels, from wrfout file.
>>>> I used formula hPa=PH+PHB/g to calculate this parameter, but as you
>>>> absolutely know it returns geo-heights in sigma levels. While I am trying
>>>> to replace sigma level by geo-heights and sort forecasted data based on it.
>>>>
>>>> Maybe it is a commonplace command, but unfortunately I could not find
>>>> it on the net,
>>>> Thanks in Advance,
>>>> --
>>>>
>>>> ===========================================
>>>>
>>>> Seyed Omid Nabavi;
>>>>
>>>> PhD student, University of Vienna,
>>>>
>>>> Faculty of Earth Sciences, Geography and Astronomy
>>>>
>>>> Department of Geography and Regional Research
>>>>
>>>> UZA II Althanstrasse 14 A-1010 Vienna
>>>>
>>>> Uni. Email: a1276905 at unet.univie.ac.at
>>>>
>>>> ===========================================
>>>>
>>>> _______________________________________________
>>>> Wrf-users mailing list
>>>> Wrf-users at ucar.edu
>>>> http://mailman.ucar.edu/mailman/listinfo/wrf-users
>>>>
>>>>
>>>
>>>
>>> --
>>> *Paula Doubrawa*
>>> PhD Student
>>> Atmospheric Sciences Program
>>> Department of Geological Sciences
>>> Indiana University
>>>
>>
>>
>>
>> --
>>
>> ===========================================
>>
>> Seyed Omid Nabavi;
>>
>> PhD student, University of Vienna,
>>
>> Faculty of Earth Sciences, Geography and Astronomy
>>
>> Department of Geography and Regional Research
>>
>> UZA II Althanstrasse 14 A-1010 Vienna
>>
>> Uni. Email: a1276905 at unet.univie.ac.at
>>
>> ===========================================
>>
>
>
>
> --
> *Paula Doubrawa*
> PhD Student
> Atmospheric Sciences Program
> Department of Geological Sciences
> Indiana University
>



-- 
*Paula Doubrawa*
PhD Student
Atmospheric Sciences Program
Department of Geological Sciences
Indiana University
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