[MITgcm-support] obcs_apply_ptracer

[Taka Ito]

Hi Martin,

I do agree that the wet points right next to topography in open 
boundaries are unlikely to affect interior solution.  Would it make 
sense to do one of the following? 

(1) As you suggest, the obcs code can check if there is any topographic 
gradient at the beginning, and warn users saying they must prepare 
topography file which has no gradients at open boundaries. 

(2) Use maskC instead of maskW/S when applying obcs to tracers.  Is 
there any particular reason for not using maskC? 

Taka