This directory contains the original llc2160 bathymetry and mask files,
which includes several land lakes that have not been filled.

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)
DYC.data     :: Cell center separation in Y across southern cell wall (m)
DYG.data     :: Cell face separation in Y along western cell wall (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)
                length(hFacC(:,:,:,1)) = 35159453
                length(hFacC(:)) = 2493334940
hFacS.data   :: mask of v cell (0 is land, >0 is wet)
                length(hFacS(:,:,:,1)) = 35085831
                length(hFacS(:)) = 2486126499
hFacW.data   :: mask of u cell (0 is land, >0 is wet)
                length(hFacW(:,:,:,1)) = 35090587
                length(hFacW(:)) = 2486440609

Also look at ~dmenemen/MITgcm/model/inc/GRID.h for more details
The grid is lat/lon from 70S to 57N (jx=1441:5760;)