Re: Regridding POP gx1v6 resolution data

The CESM folks responded and sent me a mapping file from the following link:
http://www.cgd.ucar.edu/oce/bates/tmp/map_gx1v6_to_0.5x0.5_aave_da_c111021.nc
This uses an area averaging that is conservative.

I am now trying to do example #4
http://www.ncl.ucar.edu/Applications/Scripts/pop2lat_4.ncl

Thank you,

Scott

On 10/22/2011 08:03 AM, Dennis Shea wrote:
> 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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Received on Mon Oct 24 12:51:06 2011