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(RESOLVED) ERROR: Gaussian_latitude_computation

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tmazzett

New member
Howdy.
I am working on the Cheyenne system. With WPSV3.7.1
I am using the era5 data set from the RDA section of glade/hpss in .grb format.
I need to save storage space by not storing the entire globe of reanalysis.

so, I used the following copygb.exe function from the UPP distro to take a subset of the global era5 data set over a portion of north America for all of the sfc and pl files involved.

./copygb.exe -g "255 4 142 53 50000 -135000 128 35000 -95000 281 320 0 255" -x GLOBAL.grb SUBSET.grb
the closest i can get to taking a direct subset of the origional file by this method.
If there are any other methods that can do better, that would be great.


I received the following error because my gaussian grid is no longer a global data set

Oops, something is not right with the Gaussian latitude computation.
The input data gave the starting latitude as 50.000.
This routine computed the starting latitude as +- 89.785.
The difference is larger than 0.01 degrees, which is not expected.
ERROR: Gaussian_latitude_computation

the grb files I have shrunk and using as imput are in
/gpfs/fs1/p/uwyo/wyom0004/tmazzett/WPS_3.7.1/tst/data/

do you guys see any way to work around this issue?
I want to introduce as little changes to the reanalysis data as possible in order to not skew my experimentation results.

If there is a simple way to just use the .nc format of the era5 data that is in the glade RDA space that would be great so i do not have to take up space in my quota to store the era5 .grb files.
 
Hi,
Yes, unfortunately, WPS is incapable of processing subsets of data on a Gaussian grid (as you found out with the error message). It is possible to use the *.nc data and write the data into intermediate file format (which is what the metgrid program expects). You can read more about that here:
http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/v4.0/users_guide_chap3.html#_Writing_Meteorological_Data
I can also provide a fortran script that was used previously for this purpose (to write data from NetCDF format, to intermediate format). This script was given to us by a user, so keep in mind that it was written specifically for their purpose and would need to be modified for yours.

Kelly
 

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What would you suggest about having the output of my copygb function being a lat lon grid instead of a gaussian grid?
Would WPS accept this kind of data?
Would there be any noticeable differences in the initialization created from a gaussian global grid vs a lat lon grid?
 
Hi,
I would like to apologize for the very long delay in response. This got placed in an incorrect email folder, and overlooked. Were you able to get this working? I believe using a regional subset that is in a lat-lon grid should be okay, as the accepted regional data sets are Mercator, Lambert conformal, polar stereographic, and cylindrical equidistant (which is a lat-lon projection).
 
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