Re: Regridding POP gx1v6 resolution data

It is unfortunate when 'CESM folks' do not respond.

The official weight files are at the site below. All are bilinear and
none do what you want.

---
Have you looked at the CDO (Climate Data Operators) from Max Planck?
    https://code.zmaw.de/projects/cdo
---
The following is a possible approach:
POP files have scalar and vector quantities.
The CDO documentation states that it will look at the 1st variable
encountered and use the latitude and longitude coordinates
associated with that variable for the entire file.
So ... how to proceed? One approach follows:
[1] Pick a scalar variable (say SALT) which uses TLAT and TLONG as 
coordinates
     Pick the one you want to plot or remap. Create an array with just 
necessary variables.
%> ncrcat -v SALT,TLAT,TLONG HR_POP.nc HR_POP.SALT.nc
[2] Generate the weights. Here bilinear but you can generate 
conservative weights also.
%> cdo genbil,r3600x2400 HR_POP.SALT.nc HR_POP.bilwgt_r3600x2400.nc &
[3] Apply the weights and generate a new grid:
%> cdo remap,r3600x2400,HR_POP.bilwgt_r3600x2400.nc \
           HR_POP.SALT.nc \
           HR_SALT.r3600x2400.nc.nc
==========================
[1] Pick a vector pair quantity (say UVEL, VVEL). Must perform
     the rotation using ANGLE ... somehow.
%> ncrcat -v UVEL,VVEL,ULAT,ULONG,ANGLE HR_POP.nc HR_POP.UVA.nc
[2] Generate weights for the  the vector components and ANGLE ???
     The following is for a 1x1 grid
%> cdo genbil,r360x180 HR_POP.UVA.nc HR_vector.bilwgt_r360x180.nc &
[3] Remap
cdo remap,r360x180,HR_vector.bilwgt_r360x180.nc \
          HR_POP.UVA.nc \
          HR_POP.UVA.r360x180.nc
Somehow how the rotation must be applied
+++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++
Finally, the next release of NCL [ 6.1.0] will include
the ESMF remap capabilities. There will be many examples.
ESMF is superior to SCRIP.
Can you please send us an example of the SODA model?
ftp ftp.cgd.ucar.edu
anonymous
email
cd incoming
put ....
quit
Le
D
On 10/21/11 11:07 PM, Scott Capps wrote:
> Greetings,
>
> I am trying to regrid CESM1 POP output from the ESG at gx1v6 resolution
> to match the 0.5x0.5 degree resolution of the Simple Ocean Data
> Assimilation Model (SODA).  My purpose is not for plotting.  I intend to
> perturb the SODA data with POP differences so, they need to be on the
> same grid at all levels.  Since I am interested in regridding all
> levels, I would like to use NCL example #4 on the POP regrid webpage:
> http://www.ncl.ucar.edu/Applications/Scripts/pop2lat_4.ncl
>
> So, I need to generate a weight file using the SCRIP routine.  However,
> I cannot locate the input grid file for this particular grid that SCRIP
> requires.  I have contacted the CESM folks but, they have not
> responded.  Further, I have not located any weight files for these
> resolutions as listed on:
> http://www.ncl.ucar.edu/Applications/popwgtfiles.shtml
>
> Can anyone point me in the right direction?
>
> Thank you,
>
> Scott
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