[MITgcm-support] MITgcmutil - cubed sphere - creating a broken line file

[Flynn Ames]

Dear MITgcm people,

Hello - I've run the MITgcm in a cubed sphere configuration for two different resolutions: cs32 and cs96. I am in the process of analysing the output, specifically computing the meridional overturning streamfunction, and have been using the MITgcmutils cubed-sphere MATLAB functions for this.

To compute the overturning streamfunction, a 'broken line' file is required. I have one of these for cs32 (given to me by my supervisor) and have used this successfully to compute the overturning streamfunction (see attached figure). I don't have a broken line file for the cs96 configuration, so I created an isoline for this configuration using 'mk_isolat_bkl.m'.

My problem: I get nonsense output when trying to compute the overturning stream function from my cs96 configuration, using the broken line file I created.
Furthermore, as a test, I tried recreating the broken line file for the cs32 configuration. When I use this file (instead of the file I had been given which works), I get nonsense output here too (see attached figure). This suggests there is something wrong with how I'm creating the file.

My question: Does anyone have any ideas for what could be going wrong?

Inspecting the broken line files, the only major difference I can see is that the parameter bkl_IJuv (which lists the indexes of velocity points to assign to a broken line file) looks quite different when I plot it (see attached figures). Not sure if this would be causing the issue without delving in deeper.

I use the same number of points in latitude for creating the cs32 broken line file (59) as the working file I was given, so would have expected the two files to be practically identical.


Thanks in advance!
Flynn
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