From: Bogdan Antonescu <bogdan.antonescu_at_nyahnyahspammersnyahnyah>
Date: Fri Apr 19 2013 - 02:14:25 MDT

Hi,

Thank you very much for your help. I have managed to calculate
from shea_util. Now I want to calculate Miller frontogenesis using WRF
output data. Basically I want to calculate these therms: dtheta/dx,
dtheta/dy, du/dx, du/dy, dv/dx, dv/dy. I am not sure how to do this, and
I don't think that I can use the spherical harmonic functions with WRF.

Thank you very much,
Bogdan

On 10/12/12 16:43, Dennis Shea wrote:
> Forgot to mention ....
>
> If you do use the spherical harmonic functions, they do
> require that the grids be ordered south->north.
>
> Likely, the GFS are N->S. Use NCL syntax to reorder
>
> if x(time,lev,lat,lon)
>
> x = x(:,:,::-1,:)
>
> if x(time,lat,lon)
>
> x = x(:,::-1,:)
>
> printVarSummary(x)
>
> On 12/10/12 8:56 AM, Dennis Shea wrote:
>> There is no builtin Petterssen frontogenesis equation.
>>
>> However, the GFS is a global grid and the spherical harmonic
>> functions could be used to accurately calculate some of the
>> various terms.
>>
>> gradient terms: du/dx, dv/dx, dy/dy, du/dy
>>
>> There is an **unsupported** function in shea_util.ncl
>>
>> ,gridType[1]:integer, con[1]:numeric \
>> ,long_name:string, units:string,
>> iopt[1]:integer)
>> ;
>> ; : U*(dX/dlon) + V*(dX/dlat)
>> ======
>> The documentation is embedded in the library. You can read vis:
>>
>> %> less \$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl
>>
>>
>> Don't know about the calculation of the angles.
>>
>>
>> On 12/9/12 3:56 AM, Adrian Antonescu wrote:
>>> Hi,
>>>
>>> Does anyone have a NCL script to calculate Petterssen frontogenesis?
>>> I am trying to calculate Petterssen frontogenesis using the GFS 0.5
>>> degrees data.
>>>
>>> Thank you so much.
>>>
>>> Bogdan Antonescu
>>>
>>> The University of Manchester
>>> Manchester, M13 9PL, United Kingdom
>>> Room 3.16, Simon Building
>>> +44 (0)161 306 3911
>>> _______________________________________________
>>> ncl-talk mailing list
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>

--
Bogdan Antonescu
Postdoctoral Research Associate
Centre for Atmospheric Science
School of Earth, Atmospheric and Environmental Sciences
The University of Manchester