[MITgcm-support] north-south or south-north gridding?

[Mark Hadfield]

jschwarz at awi-bremerhaven.de wrote:
> Thanks for clarifying the convention - why do all you modellers think upside down?  What is that?!
>   
Yeah, Jill, like I've noticed all the maps on your wall have south at 
the top :-)
> Like i said (  (o;  )  the grid i define is read in by mitgcm as i intended - the co-ordinates that are listed in the run_output.txt go from -50 to -80, the area i see in grid.nc covers the geographic region i intended.
Just to clarify for the group, it's a spherical polar grid and the 
upside-down-ness has been achieved using negative values in the delY file.
>   Of course i can rewrite all my input files to run south to north, but i'm interested to know :-  will there be any repercussions in, for example, the direction the currents are calculated or anything bizarre that i might not be able to detect, or is MITgcm clever enough to calculate everything the correct way round regardless of whether j=0 is north or south of j=end  (given that it's got the right lat/lon so that the coriolis force is OK) ?
Aside from the interesting question of whether MITgcm is clever enough, 
there's the question of whether Jill's colleagues are clever enough to 
cope with all the conceptual head-standing required to understand the 
results.

-- 
Mark Hadfield          "Kei puwaha te tai nei, Hoea tahi tatou"
m.hadfield at niwa.co.nz
National Institute for Water and Atmospheric Research (NIWA)