The data request

The criteria the checker applies are not written into its code. They live in two CSV files bundled with the package:

isschecker/data/ISMIP7_variable_request.csv

one row per variable — its dimensions, type, units, standard_name, whether it is mandatory, and the value range allowed in each region.

isschecker/data/experiments_ismip7.csv

one row per experiment — the nominal start years it may begin at, the year it ends, and how long it runs.

The tables on this page are generated from those two files when these pages are built, so they say what the checker enforces rather than what someone remembered to copy across. A release of the checker that changes the data request changes this page with it; if you are chasing a disagreement between the docs and a run, compare ismip7-compliance-checker --version against the version in the sidebar.

Both files can be inspected directly in the repository (variable request, experiments) — they are ordinary CSV and open in a spreadsheet.

Variables

Variables are grouped by their dimensions, since that is what decides which checks apply: the gridded variables are checked against the grid extents and resolutions, the scalars are not, and x,y,z,t carries sparse snapshots rather than an annual time series.

Type is ST for a state variable — a snapshot — or FL for a flux, which is an annual average; the two are timestamped differently, as described in Time encoding. Mandatory says whether a submission must include the variable at all: a missing mandatory variable is an error, while a missing optional one is a warning you can quiet by declaring it, as described in Variables your model does not represent.

Gridded variables (x,y,t)

Variable	Long name	Type	Units	Mandatory	standard_name
lithk	Ice thickness	ST	m	yes	land_ice_thickness
orog	Surface elevation	ST	m	yes	surface_altitude
topg	Bedrock elevation	ST	m	yes	bedrock_altitude
base	Ice base elevation	ST	m	yes	—
hfgeoubed	Geothermal heat flux	FL	W m-2	no	upward_geothermal_heat_flux_in_land_ice
acabf	Surface mass balance flux	FL	kg m-2 s-1	yes	land_ice_surface_specific_mass_balance_flux
libmassbfgr	Basal mass balance flux beneath grounded ice	FL	kg m-2 s-1	yes	land_ice_basal_specific_mass_balance_flux
libmassbffl	Basal mass balance flux beneath floating ice	FL	kg m-2 s-1	yes	land_ice_basal_specific_mass_balance_flux
dlithkdt	Ice thickness imbalance	FL	m s-1	yes	tendency_of_land_ice_thickness
xvelsurf	Surface velocity in x	ST	m s-1	no	land_ice_surface_x_velocity
yvelsurf	Surface velocity in y	ST	m s-1	no	land_ice_surface_y_velocity
zvelsurf	Surface velocity in z	ST	m s-1	no	land_ice_surface_upward_velocity
xvelbase	Basal velocity in x	ST	m s-1	no	land_ice_basal_x_velocity
yvelbase	Basal velocity in y	ST	m s-1	no	land_ice_basal_y_velocity
zvelbase	Basal velocity in z	ST	m s-1	no	land_ice_basal_upward_velocity
xvelmean	Mean velocity in x	ST	m s-1	yes	land_ice_vertical_mean_x_velocity
yvelmean	Mean velocity in y	ST	m s-1	yes	land_ice_vertical_mean_y_velocity
litemptop	Surface temperature	ST	K	no	temperature_at_top_of_ice_sheet_model
litempavg	Depth average temperature	ST	K	no	—
litempbotgr	Basal temperature beneath grounded ice sheet	ST	K	no	temperature_at_base_of_ice_sheet_model
litempbotfl	Basal temperature beneath floating ice shelf	ST	K	no	temperature_at_base_of_ice_sheet_model
strbasemag	Basal drag	ST	Pa	yes	land_ice_basal_drag
licalvf	Calving flux	FL	kg m-2 s-1	yes	land_ice_specific_mass_flux_due_to_calving
ligroundf	Grounding line flux	FL	kg m-2 s-1	yes	—
lifmassbf	Ice front melt flux	FL	kg m-2 s-1	yes	—
sftgif	Land ice area fraction	ST	1	yes	land_ice_area_fraction
sftgrf	Grounded ice sheet area fraction	ST	1	yes	grounded_ice_sheet_area_fraction
sftflf	Floating ice sheet area fraction	ST	1	yes	floating_ice_shelf_area_fraction
thdrflf	Thermal forcing at the ice base under floating ice shelves	ST	K	no	—
deltag	Anomaly in geopotential height from reference geoid	ST	m	no	geopotential_height_anomaly

Comments from the data request

lithk

Ice thickness of the ice sheet

orog

Surface elevation of the ice sheet

topg

The bedrock topography (may change during the projections)

base

Should get standard name land_ice_temperature

hfgeoubed

Geothermal Heat flux at the ice interface

acabf

Surface Mass Balance flux

libmassbfgr

Basal mass balance flux (only beneath grounded ice)

libmassbffl

Basal mass balance flux (only beneath floating ice)

dlithkdt

dHdt

xvelsurf

u-velocity at land ice surface

yvelsurf

v-velocity at land ice surface

zvelsurf

w-velocity at land ice surface

xvelbase

u-velocity at land ice base

yvelbase

v-velocity at land ice base

zvelbase

w-velocity at land ice base

xvelmean

Vertical mean land ice velocity

yvelmean

The vertical mean land ice velocity is the average from the bedrock to the surface of the ice

litemptop

Ice temperature at surface

litempavg

Should get standard name land_ice_temperature

litempbotgr

Ice temperature at base of grounded ice sheet

litempbotfl

Ice temperature at base of floating ice shelf

strbasemag

Basal drag

licalvf

Ice mass change resulting from iceberg calving. Only for grid cells in contact with ocean

ligroundf

Flux of ice mass across the grounding line. Only for grounding line grid cells. Should get standard name: land_ice_specific_grounding_line_flux

lifmassbf

Ice mass change resulting from ice front melting. Only for grid cells in contact with ocean. Should get standard name: land_ice_specific_mass_flux_due_to_ice_front_melting

sftgif

Fraction of grid cell covered by land ice (ice sheet, ice shelf, ice cap, glacier)

sftgrf

Fraction of grid cell covered by grounded ice sheet, where grounded indicates that the quantity correspond to the ice sheet that flows over bedrock

sftflf

Fraction of grid cell covered by ice sheet flowing over seawater

thdrflf

Thermal forcing (thermal driving) interpolated to the ice draft under floating ice shelves (fill value for purely grounded ice or not ice)

deltag

The change in geoid height should be relative to the reference geoid

Three-dimensional variables (x,y,z,t)

Variable	Long name	Type	Units	Mandatory	standard_name
litemp	Ice temperature	ST	K	no	land_ice_temperature

Comments from the data request

litemp

3D temperature snapshots at (1900 if in historical), initial state, 2014, 2100, 2200, and 2300. Output on the model native vertical coordinate. Only for models that have 3D temperature calculation

Time-independent gridded variables (x,y)

Variable	Long name	Type	Units	Mandatory	standard_name
refgeoid	Reference geoid	ST	m	no	geoid_height_above_reference_ellipsoid

Comments from the data request

refgeoid

This field is calculated with respect to the WGS84 reference ellipsoid

Scalar variables (t)

Variable	Long name	Type	Units	Mandatory	standard_name
lim	Total ice mass	ST	kg	yes	land_ice_mass
limnsw	Mass above floatation	ST	kg	yes	land_ice_mass_not_displacing_sea_water
iareagr	Grounded ice area	ST	m^2	yes	grounded_ice_sheet_area
iareafl	Floating ice area	ST	m^2	yes	floating_ice_shelf_area
tendacabf	Total SMB flux	FL	kg s-1	yes	tendency_of_land_ice_mass_due_to_surface_mass_balance
tendlibmassbfgr	Total BMB flux beneath grounded ice	FL	kg s-1	yes	tendency_of_land_ice_mass_due_to_basal_mass_balance
tendlibmassbffl	Total BMB flux beneath floating ice	FL	kg s-1	yes	tendency_of_land_ice_mass_due_to_basal_mass_balance
tendlicalvf	Total calving flux	FL	kg s-1	yes	tendency_of_land_ice_mass_due_to_calving
tendlifmassbf	Total ice front melting flux	FL	kg s-1	yes	—
tendligroundf	Total grounding line flux	FL	kg s-1	yes	—

Comments from the data request

lim

spatial integration, volume times density

limnsw

spatial integration, volume times density

iareagr

spatial integration

iareafl

spatial integration

tendacabf

spatial integration

tendlibmassbfgr

spatial integration

tendlibmassbffl

spatial integration (computed beneath floating ice only)

tendlicalvf

spatial integration

tendlifmassbf

spatial integration, should get standard name: tendency_of_land_ice_mass_due_to_ice_front_melting

tendligroundf

spatial integration, should get a standard name

Value ranges

Every value in a file must lie within the range its variable and region allow. The bounds differ between Antarctica and Greenland where the ice sheets differ, and the severity column says whether exceeding them fails the file or is only reported — see Value ranges for why that is a per-variable question.

Variable	Units	AIS min	AIS max	GrIS min	GrIS max	Severity
lithk	m	0	5500	0	5000	error
orog	m	0	5500	0	4500	error
topg	m	-7000	5500	-4000	4000	error
base	m	-4000	4000	-4000	4000	error
hfgeoubed	W m-2	0	0.3	0	0.3	error
acabf	kg m-2 s-1	-0.0006	0.001	-0.0006	0.001	error
libmassbfgr	kg m-2 s-1	-0.0003	0.0001	-0.0003	0.0001	error
libmassbffl	kg m-2 s-1	-0.008	0.001	-0.008	0.001	error
dlithkdt	m s-1	-0.0001	0.0001	-0.0001	0.0001	error
xvelsurf	m s-1	-0.0004	0.0004	-0.0008	0.0008	error
yvelsurf	m s-1	-0.0004	0.0004	-0.0008	0.0008	error
zvelsurf	m s-1	-4.00E-06	4.00E-06	-8.00E-06	8.00E-06	error
xvelbase	m s-1	-0.0004	0.0004	-0.0008	0.0008	error
yvelbase	m s-1	-0.0004	0.0004	-0.0008	0.0008	error
zvelbase	m s-1	-5.00E-06	5.00E-06	-8.00E-06	8.00E-06	error
xvelmean	m s-1	-0.0008	0.0008	-0.0008	0.0008	error
yvelmean	m s-1	-0.0008	0.0008	-0.0008	0.0008	error
litemptop	K	183	290	183	290	error
litempavg	K	183	290	183	290	error
litempbotgr	K	183	290	183	290	error
litempbotfl	K	183	290	183	290	error
strbasemag	Pa	0	1.00E+06	0	1.00E+06	error
licalvf	kg m-2 s-1	-1.00E+11	0	-1.00E+11	0	error
ligroundf	kg m-2 s-1	-1.00E+09	1.00E+11	-1.00E+09	1.00E+11	error
lifmassbf	kg m-2 s-1	-1.00E+11	0	-1.00E+11	0	error
sftgif	1	0	1	0	1	error
sftgrf	1	0	1	0	1	error
sftflf	1	0	1	0	1	error
thdrflf	K	-1	30	-1	30	error
deltag	m	-4000	4000	-4000	4000	error
refgeoid	m	-500	500	-500	500	error
litemp	K	183	274	183	274	error
lim	kg	0	1.00E+25	0	1.00E+25	error
limnsw	kg	0	1.00E+25	0	1.00E+25	error
iareagr	m^2	0	1.00E+25	0	1.00E+25	error
iareafl	m^2	0	1.00E+25	0	1.00E+25	error
tendacabf	kg s-1	0	1.00E+25	0	1.00E+25	error
tendlibmassbfgr	kg s-1	0	1.00E+25	0	1.00E+25	error
tendlibmassbffl	kg s-1	0	1.00E+25	0	1.00E+25	error
tendlicalvf	kg s-1	0	1.00E+25	0	1.00E+25	error
tendlifmassbf	kg s-1	0	1.00E+25	0	1.00E+25	error
tendligroundf	kg s-1	0	1.00E+25	0	1.00E+25	error

Missing values

Where each variable is defined, and so where a fill value is the right thing to find, is given by the fill_policy column of the data request; what the checker does about it is described in Errors and warnings.

fill_policy	The variable is	Variables
forbidden	defined everywhere; no missing values anywhere	lithk, dlithkdt, licalvf, ligroundf, lifmassbf, sftgif, sftgrf, sftflf, lim, limnsw, iareagr, iareafl, tendacabf, tendlibmassbfgr, tendlibmassbffl, tendlicalvf, tendlifmassbf, tendligroundf
outside_domain	defined throughout the computational domain, including where there is no ice; missing outside it	orog, topg, base, hfgeoubed, acabf, thdrflf, deltag, refgeoid
no_grounded_ice	defined only where there is grounded ice (sftgrf > 0)	libmassbfgr, litempbotgr
no_floating_ice	defined only where there is floating ice (sftflf > 0)	libmassbffl, litempbotfl
no_ice	defined only where there is ice (sftgif > 0)	xvelsurf, yvelsurf, zvelsurf, xvelbase, yvelbase, zvelbase, xvelmean, yvelmean, litemptop, litempavg, strbasemag, litemp

Experiments

An experiment’s row fixes the nominal years its files may cover, and with them the time axis every annual file must carry. historical is the one experiment whose start year the modeler chooses, so its duration follows from that choice rather than being fixed here; every projection runs from 2015 to a fixed end year.

Experiment	Earliest start year	Latest start year	End year	Duration (years)
historical	1850	2014	2014	set by the start year
ssp370	2015	2015	2100	86
ssp126	2015	2015	2300	286
ssp585	2015	2015	2300	286
ctrl	2015	2015	2300	286

The nominal years in this table are what a filename’s YYYY-YYYY range refers to, and what the timestamps inside the file are derived from — not the same thing, and Time encoding explains the difference.