[MITgcm-devel] question about pkg/shelfice

[Jean-Michel Campin]

Hi Martin,

I was looking at pkg/shelfice code, and have few questions that came up:

1) From shelfice_check.F, seems that I cannot use SHELFICEconserve with useISOMIPTD
 but in shelfice_thermodynamics.F, in the "useISOMIPTD" block, I see some cFac there
 (lines 421 & 425) that could safely be removed (cFac is always = 0 if useISOMIPTD=T), 
 which means "rFac" is no longer needed neither. Is it right ?

2) The melting from ice-shelf contributes to sea-level variations only
  if useRealFreshWaterFlux=T,  (logical and expected) AND if SHELFICEBoundaryLayer=F
  (see shelfice_forcing_surf.F).
  Now regarding the recently merged PR #251 (obcs_balance_surface), it's not very clear
  to me what is done regarding pkg/shelfice contribution:
   a) with SHELFICEBoundaryLayer=F
    The comments within S/R SHELFICE_NETMASSFLUX_SURF, in file: 
    in file: shelfice_step_icemass.F, lines 185-189, describe accurately the balancing
    correction.
   b) with SHELFICEBoundaryLayer=T
    Things are less clear here, but I don't have the impression that it's not right,
    just not clear. May be we should add some documentation/comments fro this case ?

3) Could we try to change all the secondary isomip test to use SHELFICEBoundaryLayer=F
  (I am fine with keeping SHELFICEBoundaryLayer in the primary one and, for now, 
   the adjoint tests) ? I changed isomip.htd a while ago but no other have been switched 
  since and the new ones (isomip.obcs and Dan's shelfice_remeshing) are still using
  SHELFICEBoundaryLayer.

4) This bring me to Dan's modifs (within PR #124, "branch_remeshing"):
 Did you look at the 2 modifications/additions to pkg/shelfice that are not part of the
 remeshing, i.e., under #ifdef SHI_USTAR_TOPDR and when new param SHELFICErealFWflux=T ?
 Both are addressing issue within SHELFICEBoundaryLayer code (a bit of a hack to start 
 with) but the SHELFICEBoundaryLayer looks even more like a hack on a hack.

Let us now what your thought are.
Cheers,
Jean-Michel