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Output of pow2 in diag_table off by some factor?


Jessica S Kenigson
New Member
When outputting a squared variable using "pow2" in the diag_table, the resulting output seems to be off by some large factor. (I have verified this by manually calculating the same squared quantity in MOM_diagnostics). Is there a known way to correct the output produced by pow2? Thanks a lot for any advice.


Neeraja Bhamidipati
New Member
In my own analysis of NeverWorld2 output (idealised configuration with a spherical grid), I found that the diagnostics using "pow2" were always off, especially when dealing with time-averages. One example is the diagnostic `e2` in the averages file which is the square of the interface height. Unfortunately, there are some issues with FMS, which lead to `e2` being off by a factor of (72/86400) in the 1/4 degree run, (192/86400) in the 1/8 degree run and (540/86400) in 1/16 degree run. I found that the ratio of the "off-factor" is inversely proportional to the the time-step in each run (DT=1200 in 1/4 degree, DT=450 in 1/8 degree, DT=160 in 1/16 degree).

I found this through trial-and-error so unfortunately don’t have a general solution that works in all cases.