[MITgcm-support] top_Pres

[Jean-Michel Campin]

Hi Angela,

On Tue, Aug 30, 2016 at 12:26:10AM -0600, Angela Zalucha wrote:
> Hi,
> 
> I see that Ro_SeaLevel has been removed, and top_Pres has somehow
> replaced it.  I'm using r* (pressure) coordinates for the
> atmosphere.  So rather than specifying the pressure at sea level,
> now we specify the pressure at top of the atmosphere?  Do I now need
> to specify delR from the top down instead of from the bottom up?

You are right, I started to replace the setting of Ro_SeaLevel in favor of 
setting the pressure at the top "top_Pres", but nothing has changed regarding
delR setting, with pressure coords, still starting at the lowest level (k=1) 
and going up toward the top level (k=Nr).
Note that Ro_SeaLevel has not been removed yet (is still working as before)
to allow full backward compatibility.

> I was trying to use the 'verification/hs94.cs-32x32x5/input/data'
> file to check.  In the notes for the latest version it says "remove
> 'Ro_SeaLevel' setting and use default 'top_Pres' value (=0)".  Yet
> in the code itself, Ro_SeaLevel has indeed been removed, but
> top_Pres is nowhere in the namelist.  In set_defaults.F, top_Pres is
> unset.

This experiment has been changed to use the new way to set pressure
coords origin, and as you quote it, it uses the default value of 'top_Pres'
which is zero "(=0)", so that it does not need to be explicitly specified in "data".

> The documentation page for hs94.cs-32x32x5/input/data still contains
> Ro_SeaLevel and no mention of top_Pres.  What is gong on here?

As it sometime happens, the doc is lagging behind (will try to see if we 
can fix this part). However, doc about Ro_SeaLevel is not (yet) completely irrelevant 
since it can still be used as before (backward compatibility).

Cheers,
Jean-Michel

> 
> Thanks,
> 
> Angela
> 
> 
> -- 
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> Angela Zalucha, Ph.D.
> Principal Investigator
> SETI Institute
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