RC.data      :: vertical coordinate of center of cell (m)
RF.data      :: vertical coordinate of face of cell (m)
DRC.data     :: Cell center separation along Z axis (m)
DRF.data     :: Cell face separation along Z axis (m)
RhoRef.data  :: vertical profile of reference density
PHrefC.data  :: reference potential density at cell centers
PHrefF.data  :: reference potential density at cell faces

XC.data      :: longitude East of center of grid cell
XG.data      :: longitude East of southwest corner of grid cell
YC.data      :: latitude North of center of grid cell
YG.data      :: latitude North of southwest corner of grid cell
DXC.data     :: Cell center separation in X across western cell wall (m)
DXG.data     :: Cell face separation in X along southern cell wall (m)
DXF.data     :: Cell face separation in X thru cell center (m)
DXV.data     :: V-point separation in X across south-west corner of cell (m)
DYC.data     :: Cell center separation in Y across southern cell wall (m)
DYG.data     :: Cell face separation in Y along western cell wall (m)
DYF.data     :: Cell face separation in Y thru cell center (m)
DYU.data     :: U-point separation in Y across south-west corner of cell (m)

Depth.data   :: Model bathymetry (m)

AngleCS.data :: cosine(alpha) relative to geographic direction at grid cell center
AngleSN.data :: sine(alpha) relative to geographic direction at grid cell center
                alpha = angle of model uVel direction vs geographical East
                      = angle of model vVel direction vs geographical North
                (AngleCS*uVelc - AngleSN*vVelc, AngleSN*uVelc + AngleCN*vVelc)
                rotates model velocity to geographical coordinates, where
                (uVelc,vVelc) is model velocity vector at center of grid cell
U2zonDir.data:: cosine of grid orientation angle at U point location
V2zonDir.data:: minus sine of  orientation angle at V point location

RAC.data     :: vertical face area of tracer cell (m^2)
RAS.data     :: vertical face area of v cell (m^2)
RAW.data     :: vertical face area of u cell (m^2)
RAZ.data     :: vertical face area of vorticity points (m^2)
hFacC.data   :: mask of tracer cell (0 is land, >0 is wet)
hFacS.data   :: mask of v cell (0 is land, >0 is wet)
hFacW.data   :: mask of u cell (0 is land, >0 is wet)

Also look at ~dmenemen/MITgcm/model/inc/GRID.h for more details
The grid is lat/lon from 70S to 57N (jx=2881:11520;)

============
Grid information can also be obtained from
~dmenemen/llc_4320/run_template/tile00[1-5].mitgrid

The advantage over the output diagnostic is that:
(1) they explicitly include northeast edges for each face
(2) they include values for dxF, dyF, dxV, and dyU
(3) there are no holes for land tiles

These files are real*8 and have dimension:
tile00[1-2].mitgrid  (nx+1)*(3*nx+1)*16
tile003.mitgrid  (nx+1)*(nx+1)*16
tile00[4-5].mitgrid  (3*nx+1)*(nx+1)*16
where nx=4320;
(ignore tile006.mitgrid --- it is not used)

The 16 grid information fields included are:
01    xC      :: X-coordinate of cell center f[X,Y] (deg)
02    yC      :: Y-coordinate of center of cell f[X,Y] (deg)
03    dxF     :: Cell face separation in X thru cell center (m)
04    dyF     :: Cell face separation in Y thru cell center (m)
05    rA      :: R-face area f[X,Y] ( m^2 ).
06    xG      :: X-coordinate of corner of cell (c-grid vorticity point) (deg)
07    yG      :: Y-coordinate of corner of cell (c-grid vorticity point) (deg)
08    dxV     :: V-point separation in X across south-west corner of cell (m)
09    dyU     :: U-point separation in Y across south-west corner of cell (m)
10    rAz     :: area of c-grid vorticity cell ( m^2 ).
11    dxC     :: Cell center separation in X across western cell wall (m)
12    dyC     :: Cell center separation in Y across southern cell wall (m)
13    rAw     :: area of c-grid Uvel cell ( m^2 ).
14    rAs     :: area of c-grid Vvel cell ( m^2 ).
15    dxG     :: Cell face separation in X along southern cell wall (m)
16    dyG     :: Cell face separation in Y along western cell wall (m)

See read_tile_mitgrid.m for an example of reading and using the tile* files.

See ini_curvilinear_grid.F after lines
   #else /* ifndef OLD_GRID_IO */
   ...
   #ifdef ALLOW_MDSIO
for more details.