IGM Canonical Variable Names
These are the names used internally by IGM and referenced in all module needs/updates declarations and output configs. IGM follows the naming conventions of PISM where applicable.
The table covers the core modules. Additional variables may be defined by community modules or custom user modules.
| Variable | Shape | Description | Unit |
|---|---|---|---|
t |
() |
Simulation time (scalar) | yr |
dt |
() |
Current time step (scalar) | yr |
x |
(nx,) |
x-coordinate vector | m |
y |
(ny,) |
y-coordinate vector | m |
thk |
(ny, nx) |
Ice thickness | m |
topg |
(ny, nx) |
Bedrock (basal) topography | m |
usurf |
(ny, nx) |
Ice surface elevation | m |
smb |
(ny, nx) |
Surface mass balance (ice-equivalent) | m yr⁻¹ |
icemask |
(ny, nx) |
Mask restricting SMB computation to glacierized area | — |
ubar |
(ny, nx) |
Depth-averaged x-velocity | m yr⁻¹ |
vbar |
(ny, nx) |
Depth-averaged y-velocity | m yr⁻¹ |
U |
(nz, ny, nx) |
Horizontal x-velocity (3D) | m yr⁻¹ |
V |
(nz, ny, nx) |
Horizontal y-velocity (3D) | m yr⁻¹ |
W |
(nz, ny, nx) |
Vertical velocity (3D) | m yr⁻¹ |
wvelbase |
(ny, nx) |
Vertical velocity at the ice base | m yr⁻¹ |
wvelsurf |
(ny, nx) |
Vertical velocity at the ice surface | m yr⁻¹ |
divflux |
(ny, nx) |
Divergence of the ice flux | m yr⁻¹ |
arrhenius |
(ny, nx) |
Arrhenius (rate) factor for ice rheology | MPa⁻³ yr⁻¹ |
slidingco |
(ny, nx) |
Sliding coefficient | MPa m-1/3 yr1/3 |
E |
(nz, ny, nx) |
Ice enthalpy | J kg⁻¹ |
T |
(nz, ny, nx) |
Ice temperature | °C |
omega |
(nz, ny, nx) |
Water content (liquid fraction) | — |
basal_melt_rate |
(ny, nx) |
Basal melt rate | m yr⁻¹ |