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

[Paula Doubrawa]

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
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