Configuration parameters¶
Every parameter corresponds to a command-line option; some options map to a combination of parameters.
There are five kinds of options and parameters:
Strings (mostly file names),
Scalars (a number representing a physical quantify, usually with units),
Integers (an integer number, usually corresponding to a count),
Flags (True/False, on/off, yes/no),
Keywords (one of a given set of strings).
Each parameter can be set using the command-line option consisting of a dash followed by the parameter name. For example,
-constants.standard_gravity 10
sets the acceleration due to gravity (parameter constants
.standard_gravity
) to
\(10\). Options listed below are shortcuts, added for convenience.
The following are equivalent and choose the temperature-based (as opposed to enthalpy-based) energy balance model:
-energy.temperature_based
-energy.temperature_based on
-energy.temperature_based yes
-energy.temperature_based true
-energy.temperature_based True
The following are also equivalent: they disable updating geometry by performing a step of the mass-continuity equation:
-geometry.update.enabled off
-geometry.update.enabled no
-geometry.update.enabled false
-geometry.update.enabled False
-no_geometry.update.enabled
The -no_
prefix is still supported for compatibility with older scripts, but will be
removed in a later PISM version.
age.enabled
Solve age equation (advection equation for ice age).
- Type
- flag
- Default value
no
- Option
-age
age.initial_value
Initial age of ice
- Type
- number
- Default value
0 (years)
atmosphere.anomaly.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-atmosphere_anomaly_file
atmosphere.anomaly.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_anomaly_period
atmosphere.anomaly.reference_year
Reference year to use when
atmosphere
.anomaly
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_anomaly_reference_year
atmosphere.delta_P.file
Name of the file containing scalar precipitation offsets.
- Type
- string
- Default value
empty
- Option
-atmosphere_delta_P_file
atmosphere.delta_P.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_delta_P_period
atmosphere.delta_P.reference_year
Reference year to use when
atmosphere
.delta_P
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_delta_P_reference_year
atmosphere.delta_T.file
Name of the file containing temperature offsets.
- Type
- string
- Default value
empty
- Option
-atmosphere_delta_T_file
atmosphere.delta_T.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_delta_T_period
atmosphere.delta_T.reference_year
Reference year to use when
atmosphere
.delta_T
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_delta_T_reference_year
atmosphere.elevation_change.file
Name of the file containing the reference surface elevation field (variable
usurf
).- Type
- string
- Default value
empty
- Option
-atmosphere_lapse_rate_file
atmosphere.elevation_change.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_lapse_rate_period
atmosphere.elevation_change.precipitation.lapse_rate
Elevation lapse rate for the surface mass balance
- Type
- number
- Default value
0 ((kg m-2 / year) / km)
- Option
-precip_lapse_rate
atmosphere.elevation_change.precipitation.method
Choose the precipitation adjustment method.
scale
: use temperature-change-dependent scaling factor.shift
: use the precipitation lapse rate.- Type
- keyword
- Default value
shift
- Choices
scale, shift
- Option
-precip_adjustment
atmosphere.elevation_change.reference_year
Reference year to use when
atmosphere
.elevation_change
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_lapse_rate_reference_year
atmosphere.elevation_change.temperature_lapse_rate
Elevation lapse rate for the surface temperature
- Type
- number
- Default value
0 (Kelvin / km)
- Option
-temp_lapse_rate
atmosphere.fausto_air_temp.c_ma
latitude-dependence coefficient for formula (1) in [1]
- Type
- number
- Default value
-0.7189 (Kelvin / degree_north)
atmosphere.fausto_air_temp.c_mj
latitude-dependence coefficient for formula (2) in [1]
- Type
- number
- Default value
-0.1585 (Kelvin / degree_north)
atmosphere.fausto_air_temp.d_ma
41.83+273.15; base temperature for formula (1) in [1]
- Type
- number
- Default value
314.98 (Kelvin)
atmosphere.fausto_air_temp.d_mj
= 14.70+273.15; base temperature for formula (2) in [1]
- Type
- number
- Default value
287.85 (Kelvin)
atmosphere.fausto_air_temp.gamma_ma
= -6.309 / 1km; mean slope lapse rate for formula (1) in [1]
- Type
- number
- Default value
-0.006309 (Kelvin / meter)
atmosphere.fausto_air_temp.gamma_mj
= -5.426 / 1km; mean slope lapse rate for formula (2) in [1]
- Type
- number
- Default value
-0.005426 (Kelvin / meter)
atmosphere.fausto_air_temp.kappa_ma
longitude-dependence coefficient for formula (1) in [1]
- Type
- number
- Default value
0.0672 (Kelvin / degree_west)
atmosphere.fausto_air_temp.kappa_mj
longitude-dependence coefficient for formula (2) in [1]
- Type
- number
- Default value
0.0518 (Kelvin / degree_west)
atmosphere.fausto_air_temp.summer_peak_day
day of year for July 15; used in corrected formula (4) in [1]
- Type
- integer
- Default value
196 (ordinal day number)
atmosphere.frac_P.file
Name of the file containing scalar precipitation scaling.
- Type
- string
- Default value
empty
- Option
-atmosphere_frac_P_file
atmosphere.frac_P.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_frac_P_period
atmosphere.frac_P.reference_year
Reference year to use when
atmosphere
.frac_P
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_frac_P_reference_year
atmosphere.given.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-atmosphere_given_file
atmosphere.given.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_given_period
atmosphere.given.reference_year
Reference year to use when
atmosphere
.given
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_given_reference_year
atmosphere.models
Comma-separated list of atmosphere melt models and modifiers.
- Type
- string
- Default value
given
- Option
-atmosphere
atmosphere.one_station.file
Specifies a file containing scalar time-series
precipitation
andair_temp
.- Type
- string
- Default value
empty
- Option
-atmosphere_one_station_file
atmosphere.orographic_precipitation.background_precip_post
Background precipitation \(P_{\mathrm{post}}\) added after the truncation.
- Type
- number
- Default value
0 (mm/hr)
- Option
-background_precip_post
atmosphere.orographic_precipitation.background_precip_pre
Background precipitation \(P_{\mathrm{pre}}\) added before the truncation.
- Type
- number
- Default value
0 (mm/hr)
- Option
-background_precip_pre
atmosphere.orographic_precipitation.conversion_time
Cloud conversion time \(\tau_c\)
- Type
- number
- Default value
1000 (s)
- Option
-conversion_time
atmosphere.orographic_precipitation.coriolis_latitude
Latitude used to compute Coriolis force
- Type
- number
- Default value
0 (degrees_N)
- Option
-coriolis_latitude
atmosphere.orographic_precipitation.fallout_time
Fallout time \(\tau_f\)
- Type
- number
- Default value
1000 (s)
- Option
-fallout_time
atmosphere.orographic_precipitation.grid_size_factor
The size of the extended grid is
(Z*(grid.Mx - 1) + 1, Z*(grid.My - 1) + 1)
whereZ
is given by this parameter.- Type
- integer
- Default value
2 (count)
atmosphere.orographic_precipitation.lapse_rate
Lapse rate \(\gamma\)
- Type
- number
- Default value
-5.8 (K / km)
- Option
-lapse_rate
atmosphere.orographic_precipitation.moist_adiabatic_lapse_rate
Moist adiabatic lapse rate \(\Gamma_m\)
- Type
- number
- Default value
-6.5 (K / km)
- Option
-moist_adiabatic_lapse_rate
atmosphere.orographic_precipitation.moist_stability_frequency
Moist stability frequency \(N_m\)
- Type
- number
- Default value
0.05 (1/s)
- Option
-moist_stability_frequency
atmosphere.orographic_precipitation.reference_density
Reference density \(\rho_{S_{\text{ref}}}\)
- Type
- number
- Default value
0.0074 (kg m-3)
- Option
-reference_density
atmosphere.orographic_precipitation.scale_factor
Precipitation scaling factor \(S\).
- Type
- number
- Default value
1 (1)
- Option
-scale_factor
atmosphere.orographic_precipitation.smoothing_standard_deviation
Standard deviation of the Gaussian filter used to smooth surface elevation or zero if disabled
- Type
- number
- Default value
0 (m)
atmosphere.orographic_precipitation.truncate
Truncate precipitation at 0, disallowing negative precipitation values.
- Type
- flag
- Default value
true
- Option
-truncate
atmosphere.orographic_precipitation.water_vapor_scale_height
Water vapor scale height \(H_w\)
- Type
- number
- Default value
2500 (m)
- Option
-water_vapor_scale_height
atmosphere.orographic_precipitation.wind_direction
The direction the wind is coming from
- Type
- number
- Default value
270 (degrees)
- Option
-wind_direction
atmosphere.orographic_precipitation.wind_speed
The wind speed.
- Type
- number
- Default value
10 (m/s)
- Option
-wind_speed
atmosphere.pik.file
Name of the file containing the reference surface elevation field (variable
usurf
).- Type
- string
- Default value
empty
- Option
-atmosphere_pik_file
atmosphere.pik.parameterization
Selects parameterizations of mean annual and mean summer near-surface air temperatures.
- Type
- keyword
- Default value
martin
- Choices
martin, huybrechts_dewolde, martin_huybrechts_dewolde, era_interim, era_interim_sin, era_interim_lon
- Option
-atmosphere_pik
atmosphere.precip_exponential_factor_for_temperature
= 0.169/2.4; in SeaRISE-Greenland formula for precipitation correction using air temperature offsets relative to present; a 7.3% change of precipitation rate for every one degC of temperature change [2]
- Type
- number
- Default value
0.0704167 (Kelvin-1)
atmosphere.precip_scaling.file
Name of the file containing temperature offsets to use for a precipitation correction.
- Type
- string
- Default value
empty
- Option
-atmosphere_precip_scaling_file
atmosphere.precip_scaling.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_precip_scaling_period
atmosphere.precip_scaling.reference_year
Reference year to use when
atmosphere
.precip_scaling
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-atmosphere_precip_scaling_reference_year
atmosphere.searise_greenland.file
Name of the file containing a precipitation field.
- Type
- string
- Default value
empty
- Option
-atmosphere_searise_greenland_file
atmosphere.uniform.precipitation
Precipitation used by the
uniform
atmosphere model.- Type
- number
- Default value
1000 (kg m-2 year-1)
atmosphere.uniform.temperature
Air temperature used by the
uniform
atmosphere model.- Type
- number
- Default value
273.15 (Kelvin)
atmosphere.yearly_cycle.file
Name of the file containing mean annual and mean July temperatures (
air_temp_mean_annual
andair_temp_mean_summer
) and theprecipitation
field.- Type
- string
- Default value
empty
- Option
-atmosphere_yearly_cycle_file
atmosphere.yearly_cycle.scaling.file
Name of the file containing amplitude scaling (
amplitude_scaling
) for the near-surface air temperature.- Type
- string
- Default value
empty
- Option
-atmosphere_yearly_cycle_scaling_file
atmosphere.yearly_cycle.scaling.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
atmosphere.yearly_cycle.scaling.reference_year
Reference year to use when
atmosphere
.yearly_cycle
.scaling
.period
is active.- Type
- integer
- Default value
0 (years)
basal_resistance.beta_ice_free_bedrock
value is for ice stream E from [97]; thus sliding velocity, but we hope it doesn’t matter much; at 100 m/year the linear sliding law gives 57040 Pa basal shear stress
- Type
- number
- Default value
1.8e+09 (Pascal second meter-1)
basal_resistance.beta_lateral_margin
high value of \(\beta\) used to simulate drag at lateral ice margins (fjord walls, etc); the default value is chosen to disable flow in the direction along a margin
- Type
- number
- Default value
1e+19 (Pascal second meter-1)
basal_resistance.plastic.regularization
Set the value of \(\epsilon\) regularization of plastic till; this is the second \(\epsilon\) in formula (4.1) in [41]
- Type
- number
- Default value
0.01 (meter / year)
- Option
-plastic_reg
basal_resistance.pseudo_plastic.enabled
Use the pseudo-plastic till model (basal sliding law).
- Type
- flag
- Default value
no
- Option
-pseudo_plastic
basal_resistance.pseudo_plastic.q
The exponent of the pseudo-plastic basal resistance model
- Type
- number
- Default value
0.25 (pure number)
- Option
-pseudo_plastic_q
basal_resistance.pseudo_plastic.sliding_scale_factor
divides pseudo-plastic tauc (yield stress) by given factor; this would increase sliding by given factor in absence of membrane stresses; not used if negative or zero; not used by default
- Type
- number
- Default value
-1 (1)
- Option
-sliding_scale_factor_reduces_tauc
basal_resistance.pseudo_plastic.u_threshold
threshold velocity of the pseudo-plastic sliding law
- Type
- number
- Default value
100 (meter / year)
- Option
-pseudo_plastic_uthreshold
basal_yield_stress.add_transportable_water
If “yes” then the water amount in the transport system is added to tillwat in determining tauc (in the Mohr-Coulomb relation). Normally only the water in the till is used.
- Type
- flag
- Default value
no
- Option
-tauc_add_transportable_water
basal_yield_stress.constant.value
fill value for yield stress for basal till (plastic or pseudo-plastic model); note \(2 \times 10^5\) Pa = 2 bar is quite strong and little sliding should occur
- Type
- number
- Default value
200000 (Pascal)
- Option
-tauc
basal_yield_stress.ice_free_bedrock
the “high” yield stress value used in grounded ice-free areas.
- Type
- number
- Default value
1e+06 (Pascal)
- Option
-high_tauc
basal_yield_stress.model
The basal yield stress model to use when sliding is active.
- Type
- keyword
- Default value
mohr_coulomb
- Choices
constant, mohr_coulomb
- Option
-yield_stress
basal_yield_stress.mohr_coulomb.delta.file
Name of the file containing space- and time-dependent variable
mohr_coulomb_delta
to use instead ofbasal_yield_stress
.mohr_coulomb
.till_effective_fraction_overburden
.- Type
- string
- Default value
empty
- Option
-mohr_coulomb_delta_file
basal_yield_stress.mohr_coulomb.delta.period
Length of the period. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-mohr_coulomb_delta_period
basal_yield_stress.mohr_coulomb.delta.reference_year
Reference year to use when
basal_yield_stress
.mohr_coulomb
.delta
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-mohr_coulomb_delta_reference_year
basal_yield_stress.mohr_coulomb.tauc_to_phi.file
File containing the basal yield stress field that should be used to recover the till friction angle distribution.
- Type
- string
- Default value
empty
- Option
-tauc_to_phi
basal_yield_stress.mohr_coulomb.till_cohesion
cohesion of till; = \(c_0\) in most references; note Schoof uses zero but Paterson pp 168–169 gives range 0–40 kPa; but Paterson notes that “… all the pairs \(c_0\) and \(\phi\) in the table would give a yield stress for Ice Stream B that exceeds the basal shear stress there…”
- Type
- number
- Default value
0 (Pascal)
- Option
-till_cohesion
basal_yield_stress.mohr_coulomb.till_compressibility_coefficient
coefficient of compressiblity of till; value from [89]
- Type
- number
- Default value
0.12 (pure number)
- Option
-till_compressibility_coefficient
basal_yield_stress.mohr_coulomb.till_effective_fraction_overburden
\(\delta\) in notes; \(N_0 = \delta P_o\) where \(P_o\) is overburden pressure; \(N_0\) is reference (low) value of effective pressure (i.e. normal stress); \(N_0\) scales with overburden pressure unlike [89]; default value from Greenland and Antarctic model runs
- Type
- number
- Default value
0.02 (pure number)
- Option
-till_effective_fraction_overburden
basal_yield_stress.mohr_coulomb.till_log_factor_transportable_water
If
basal_yield_stress
.add_transportable_water
is set then the water amount in the transport system is added totillwat
in determiningtauc
. Normally only the water in the till is used. This factor multiplies the logarithm in that formula.- Type
- number
- Default value
0.1 (meters)
- Option
-till_log_factor_transportable_water
basal_yield_stress.mohr_coulomb.till_phi_default
fill value for till friction angle
- Type
- number
- Default value
30 (degrees)
- Option
-plastic_phi
basal_yield_stress.mohr_coulomb.till_reference_effective_pressure
reference effective pressure \(N_0\); value from [89]
- Type
- number
- Default value
1000 (Pascal)
basal_yield_stress.mohr_coulomb.till_reference_void_ratio
void ratio at reference effective pressure \(N_0\); value from [89]
- Type
- number
- Default value
0.69 (pure number)
- Option
-till_reference_void_ratio
basal_yield_stress.mohr_coulomb.topg_to_phi.enabled
If the option
-topg_to_phi
is set then this will be set to “yes”, and thenMohrCoulombYieldStress
will initialize thetillphi
field using a piece-wise linear function of depth described by four parameters.- Type
- flag
- Default value
no
basal_yield_stress.mohr_coulomb.topg_to_phi.phi_max
upper value of the till friction angle; see the implementation of MohrCoulombYieldStress
- Type
- number
- Default value
15 (degrees)
basal_yield_stress.mohr_coulomb.topg_to_phi.phi_min
lower value of the till friction angle; see the implementation of MohrCoulombYieldStress
- Type
- number
- Default value
5 (degrees)
basal_yield_stress.mohr_coulomb.topg_to_phi.topg_max
the elevation at which the upper value of the till friction angle is used; see the implementation of MohrCoulombYieldStress
- Type
- number
- Default value
1000 (meters)
basal_yield_stress.mohr_coulomb.topg_to_phi.topg_min
the elevation at which the lower value of the till friction angle is used; see the implementation of MohrCoulombYieldStress
- Type
- number
- Default value
-1000 (meters)
basal_yield_stress.slippery_grounding_lines
If yes, at icy grounded locations with bed elevations below sea level, within one cell of floating ice or ice-free ocean, make tauc as low as possible from the Mohr-Coulomb relation. Specifically, at such locations replace the normally-computed tauc from the Mohr-Coulomb relation, which uses the effective pressure from the modeled amount of water in the till, by the minimum value of tauc from Mohr-Coulomb, i.e. by using the effective pressure corresponding to the maximum amount of till-stored water. Does not alter the modeled or reported amount of till water, nor does this mechanism affect water conservation.
- Type
- flag
- Default value
no
- Option
-tauc_slippery_grounding_lines
bed_deformation.bed_topography_delta_file
The name of the file to read the
topg_delta
from. This field is added to the bed topography during initialization.- Type
- string
- Default value
empty
- Option
-topg_delta_file
bed_deformation.bed_uplift_file
The name of the file to read the uplift (dbdt) from. Leave empty to read it from an input file or a regridding file.
- Type
- string
- Default value
empty
- Option
-uplift_file
bed_deformation.lc.elastic_model
Use the elastic part of the Lingle-Clark bed deformation model.
- Type
- flag
- Default value
yes
- Option
-bed_def_lc_elastic_model
bed_deformation.lc.grid_size_factor
The spectral grid size is
(Z*(grid.Mx - 1) + 1, Z*(grid.My - 1) + 1)
whereZ
is given by this parameter. See [91], [23].- Type
- integer
- Default value
4 (count)
bed_deformation.lc.update_interval
Interval between updates of the Lingle-Clark model
- Type
- number
- Default value
10 (years)
bed_deformation.lithosphere_flexural_rigidity
lithosphere flexural rigidity used by the bed deformation model. See [91], [23]
- Type
- number
- Default value
5e+24 (Newton meter)
bed_deformation.mantle_density
half-space (mantle) density used by the bed deformation model. See [91], [23]
- Type
- number
- Default value
3300 (kg meter-3)
bed_deformation.mantle_viscosity
half-space (mantle) viscosity used by the bed deformation model. See [91], [23]
- Type
- number
- Default value
1e+21 (Pascal second)
bed_deformation.model
Selects a bed deformation model to use.
iso
is point-wise isostasy,lc
is the Lingle-Clark model (see [91], requires FFTW).- Type
- keyword
- Default value
none
- Choices
none, iso, lc
- Option
-bed_def
bootstrapping.defaults.bed
bed elevation value to use if
topg
(bedrock_altitude
) variable is absent in bootstrapping file- Type
- number
- Default value
1 (meters)
bootstrapping.defaults.bmelt
basal melt rate value to use if variable
bmelt
is absent in bootstrapping file- Type
- number
- Default value
0 (meter / second)
bootstrapping.defaults.bwat
till water thickness value to use if variable tillwat is absent in bootstrapping file
- Type
- number
- Default value
0 (meters)
bootstrapping.defaults.bwp
basal water pressure value to use if variable
bwp
is absent in bootstrapping file; most hydrology models do not use this value becausebwp
is diagnostic- Type
- number
- Default value
0 (Pascal)
bootstrapping.defaults.enwat
effective englacial water thickness value to use if variable enwat is absent in bootstrapping file
- Type
- number
- Default value
0 (meters)
bootstrapping.defaults.geothermal_flux
geothermal flux value to use if bheatflx variable is absent in bootstrapping file
- Type
- number
- Default value
0.042 (Watt meter-2)
bootstrapping.defaults.ice_thickness
thickness value to use if thk (land_ice_thickness) variable is absent in bootstrapping file
- Type
- number
- Default value
0 (meters)
bootstrapping.defaults.tillwat
till water thickness value to use if variable tillwat is absent in bootstrapping file
- Type
- number
- Default value
0 (meters)
bootstrapping.defaults.uplift
uplift value to use if dbdt variable is absent in bootstrapping file
- Type
- number
- Default value
0 (meter / second)
bootstrapping.temperature_heuristic
The heuristic to use to initialize ice temperature during bootstrapping:
smb
uses the surface mass balance, surface temperature, and the geothermal flux,quartic_guess
uses the surface temperature and the geothermal flux.- Type
- keyword
- Default value
smb
- Choices
smb, quartic_guess
- Option
-boot_temperature_heuristic
calving.eigen_calving.K
Set proportionality constant to determine calving rate from strain rates. Note references [78], [3] use K in range \(10^{9}\) to \(3 \times 10^{11}\) m a, that is, \(3 \times 10^{16}\) to \(10^{19}\) m s.
- Type
- number
- Default value
0 (meter second)
- Option
-eigen_calving_K
calving.float_kill.calve_near_grounding_line
Calve floating ice near the grounding line.
- Type
- flag
- Default value
yes
- Option
-float_kill_calve_near_grounding_line
calving.float_kill.margin_only
Apply float_kill at ice margin cells only.
- Type
- flag
- Default value
no
- Option
-float_kill_margin_only
calving.hayhurst_calving.B_tilde
Effective damage rate [98]
- Type
- number
- Default value
65 ((MPa)^r / year)
calving.hayhurst_calving.exponent_r
Damage law exponent [98]
- Type
- number
- Default value
0.43 (1)
calving.hayhurst_calving.sigma_threshold
Damage threshold stress [98]
- Type
- number
- Default value
0.17 (MPa)
calving.methods
comma-separated list of calving methods; one or more of
eigen_calving
,float_kill
,thickness_calving
- Type
- string
- Default value
empty
- Option
-calving
calving.thickness_calving.threshold
When terminal ice thickness of floating ice shelf is less than this threshold, it will be calved off.
- Type
- number
- Default value
50 (meters)
- Option
-thickness_calving_threshold
calving.thickness_calving.threshold_file
Name of the file containing the spatially-variable thickness calving threshold.
- Type
- string
- Default value
empty
- Option
-thickness_calving_threshold_file
calving.vonmises_calving.Glen_exponent
Glen exponent in ice flow law for von Mises calving
- Type
- number
- Default value
3 (pure number)
- Option
-vonmises_calving_n
calving.vonmises_calving.enhancement_factor
Flow enhancement factor used by the flow law in the von Mises stress computation
- Type
- number
- Default value
1 (1)
calving.vonmises_calving.enhancement_factor_interglacial
Flow enhancement factor used by the flow law in the von Mises stress computation (for ice accumulated during interglacial periods).
- Type
- number
- Default value
1 (1)
calving.vonmises_calving.flow_law
The custom flow law for the von Mises stress computation
- Type
- keyword
- Default value
gpbld
- Choices
arr, arrwarm, gpbld, hooke, isothermal_glen, pb
calving.vonmises_calving.sigma_max
Set maximum tensile stress. Note references [79] use 1.0e6 Pa.
- Type
- number
- Default value
1e+06 (Pa)
- Option
-vonmises_calving_calving_sigma_max
calving.vonmises_calving.threshold_file
Name of the file containing the spatially-variable vonmises_calving calving threshold.
- Type
- string
- Default value
empty
- Option
-vonmises_calving_threshold_file
calving.vonmises_calving.use_custom_flow_law
Use custom flow law in the von Mises stress computation
- Type
- flag
- Default value
no
- Option
-vonmises_calving_use_custom_flow_law
constants.fresh_water.density
density of fresh water
- Type
- number
- Default value
1000 (kg meter-3)
constants.fresh_water.latent_heat_of_fusion
latent heat of fusion for water [68]
- Type
- number
- Default value
334000 (Joule / kg)
constants.fresh_water.melting_point_temperature
melting point of pure water
- Type
- number
- Default value
273.15 (Kelvin)
constants.fresh_water.specific_heat_capacity
at melting point T_0 [68]
- Type
- number
- Default value
4170 (Joule / (kg Kelvin))
constants.global_ocean_area
area of the global ocean [99]
- Type
- number
- Default value
3.625e+14 (meter2)
constants.ice.beta_Clausius_Clapeyron
Clausius-Clapeyron constant relating melting temperature and pressure: \(\beta = dT / dP\) [100]
- Type
- number
- Default value
7.9e-08 (Kelvin / Pascal)
constants.ice.density
\(\rho_i\); density of ice in ice sheet
- Type
- number
- Default value
910 (kg meter-3)
constants.ice.grain_size
Default constant ice grain size to use with the Goldsby-Kohlstedt [70] flow law
- Type
- number
- Default value
1 (mm)
- Option
-ice_grain_size
constants.ice.specific_heat_capacity
specific heat capacity of pure ice at melting point T_0
- Type
- number
- Default value
2009 (Joule / (kg Kelvin))
constants.ice.thermal_conductivity
= W m-1 K-1; thermal conductivity of pure ice
- Type
- number
- Default value
2.1 (Joule / (meter Kelvin second))
constants.ideal_gas_constant
ideal gas constant
- Type
- number
- Default value
8.31441 (Joule / (mol Kelvin))
constants.sea_water.density
density of sea water
- Type
- number
- Default value
1028 (kg meter-3)
constants.sea_water.salinity
salinity of sea water
- Type
- number
- Default value
35 (g / kg)
constants.sea_water.specific_heat_capacity
at 35 psu, value taken from Kaye and Laby, section 2.7.9
- Type
- number
- Default value
3985 (Joule / (kg Kelvin))
constants.standard_gravity
acceleration due to gravity on Earth geoid
- Type
- number
- Default value
9.81 (meter second-2)
energy.allow_temperature_above_melting
If set to “yes”, allow temperatures above the pressure-malting point in the cold mode temperature code. Used by some verifiaction tests.
- Type
- flag
- Default value
no
energy.basal_melt.use_grounded_cell_fraction
If geometry.grounded_cell_fraction is set, use the fractional floatation mask to interpolate the basal melt rate at the grounding line between grounded and floating values.
- Type
- flag
- Default value
true
- Option
-subgl_basal_melt
energy.bedrock_thermal.conductivity
= W m-1 K-1; for bedrock used in thermal model [7]
- Type
- number
- Default value
3 (Joule / (meter Kelvin second))
energy.bedrock_thermal.density
for bedrock used in thermal model
- Type
- number
- Default value
3300 (kg meter-3)
energy.bedrock_thermal.file
Name of the file containing the geothermal flux field
bheatflx
. Leave empty to read it from theinput
.file
.- Type
- string
- Default value
empty
energy.bedrock_thermal.specific_heat_capacity
for bedrock used in thermal model [7]
- Type
- number
- Default value
1000 (Joule / (kg Kelvin))
energy.ch_warming.average_channel_spacing
Average spacing between elements of the cryo-hydrologic system (controls the rate of heat transfer from the CH system into the ice).
- Type
- number
- Default value
20 (meters)
energy.ch_warming.enabled
Enable the cryo-hydrologic warming model
- Type
- flag
- Default value
no
energy.ch_warming.residual_water_fraction
residual water fraction in the cryo-hydrologic system at the end of a melt season
- Type
- number
- Default value
0.005 (pure number)
energy.ch_warming.temperate_ice_thermal_conductivity_ratio
ratio of thermal conductivities of temperate and cold ice in the cryo-hydrologic system
- Type
- number
- Default value
1 (pure number)
energy.drainage_maximum_rate
0.05 year-1; maximum rate at which liquid water fraction in temperate ice could possibly drain; see [31]
- Type
- number
- Default value
1.58444e-09 (second-1)
energy.drainage_target_water_fraction
liquid water fraction (omega) above which drainage occurs, but below which there is no drainage; see [31]
- Type
- number
- Default value
0.01 (1)
energy.enabled
Solve energy conservation equations.
- Type
- flag
- Default value
yes
energy.enthalpy.cold_bulge_max
= (2009 J kg-1 K-1) * (30 K); maximum amount by which advection can reduce the enthalpy of a column of ice below its surface enthalpy value
- Type
- number
- Default value
60270 (Joule / kg)
energy.enthalpy.temperate_ice_thermal_conductivity_ratio
K in cold ice is multiplied by this fraction to give K0 in [31]
- Type
- number
- Default value
0.1 (pure number)
energy.margin_exclude_horizontal_advection
Exclude horizontal advection of energy at grid points near ice margins. See
energy
.margin_ice_thickness_limit
.- Type
- flag
- Default value
yes
energy.margin_exclude_strain_heating
Exclude strain heating at grid points near ice margins. See
energy
.margin_ice_thickness_limit
.- Type
- flag
- Default value
yes
energy.margin_exclude_vertical_advection
Exclude vertical advection of energy at grid points near ice margins. See
energy
.margin_ice_thickness_limit
.- Type
- flag
- Default value
yes
energy.margin_ice_thickness_limit
use special margin treatment at grid points with a neighbor with the thickness below this limit.
- Type
- number
- Default value
100 (meters)
energy.max_low_temperature_count
Maximum number of grid points with ice temperature below energy.minimum_allowed_temperature.
- Type
- integer
- Default value
10 (count)
- Option
-max_low_temps
energy.minimum_allowed_temperature
Minimum allowed ice temperature
- Type
- number
- Default value
200 (Kelvin)
- Option
-low_temp
energy.temperature_based
Use cold ice (i.e. not polythermal) methods.
- Type
- flag
- Default value
no
energy.temperature_dependent_thermal_conductivity
If yes, use varkenthSystemCtx class in the energy step. It is base on formula (4.37) in [52]. Otherwise use enthSystemCtx, which has temperature-independent thermal conductivity set by constant ice.thermal_conductivity.
- Type
- flag
- Default value
no
- Option
-vark
enthalpy_converter.T_reference
= T_0 in enthalpy formulas in [31]
- Type
- number
- Default value
223.15 (Kelvin)
enthalpy_converter.relaxed_is_temperate_tolerance
Tolerance within which ice is treated as temperate (cold-ice mode and diagnostics).
- Type
- number
- Default value
0.001 (Kelvin)
flow_law.Hooke.A
\(A_{\text{Hooke}} = (1/B_0)^n\) where n=3 and B_0 = 1.928 \(a^{1/3}\) Pa. See [73]
- Type
- number
- Default value
4.42165e-09 (Pascal-3 second-1)
flow_law.Hooke.C
See [73]
- Type
- number
- Default value
0.16612 (Kelvin^{flow_law.Hooke.k})
flow_law.Hooke.Q
Activation energy, see [73]
- Type
- number
- Default value
78800 (Joule / mol)
flow_law.Hooke.Tr
See [73]
- Type
- number
- Default value
273.39 (Kelvin)
flow_law.Hooke.k
See [73]
- Type
- number
- Default value
1.17 (pure number)
flow_law.Paterson_Budd.A_cold
Paterson-Budd A_cold, see [69]
- Type
- number
- Default value
3.61e-13 (Pascal-3 / second)
flow_law.Paterson_Budd.A_warm
Paterson-Budd A_warm, see [69]
- Type
- number
- Default value
1730 (Pascal-3 / second)
flow_law.Paterson_Budd.Q_cold
Paterson-Budd Q_cold, see [69]
- Type
- number
- Default value
60000 (Joule / mol)
flow_law.Paterson_Budd.Q_warm
Paterson-Budd Q_warm, see [69]
- Type
- number
- Default value
139000 (Joule / mol)
flow_law.Paterson_Budd.T_critical
Paterson-Budd critical temperature, see [69]
- Type
- number
- Default value
263.15 (Kelvin)
flow_law.Schoof_regularizing_length
Regularizing length (Schoof definition)
- Type
- number
- Default value
1000 (km)
flow_law.Schoof_regularizing_velocity
Regularizing velocity (Schoof definition)
- Type
- number
- Default value
1 (meter / year)
flow_law.gpbld.water_frac_coeff
coefficient in Glen-Paterson-Budd flow law for extra dependence of softness on liquid water fraction (omega) [52], [71]
- Type
- number
- Default value
181.25 (pure number)
flow_law.gpbld.water_frac_observed_limit
maximum value of liquid water fraction omega for which softness values are parameterized by [71]; used in Glen-Paterson-Budd-Lliboutry-Duval flow law; compare [31]
- Type
- number
- Default value
0.01 (1)
flow_law.isothermal_Glen.ice_softness
ice softness used by IsothermalGlenIce [30]
- Type
- number
- Default value
3.1689e-24 (Pascal-3 second-1)
fracture_density.constant_fd
FIXME
- Type
- flag
- Default value
no
- Option
-constant_fd
fracture_density.constant_healing
Constant healing
- Type
- flag
- Default value
no
- Option
-constant_healing
fracture_density.enabled
Calculation of fracture density according to stresses and strain rate field.
- Type
- flag
- Default value
no
- Option
-fractures
fracture_density.fd2d_scheme
FIXME
- Type
- flag
- Default value
no
- Option
-scheme_fd2d
fracture_density.fracture_weighted_healing
Fracture weighted healing
- Type
- flag
- Default value
no
- Option
-fracture_weighted_healing
fracture_density.include_grounded_ice
model fracture density in grounded areas
- Type
- flag
- Default value
no
- Option
-do_frac_on_grounded
fracture_density.lefm
FIXME
- Type
- flag
- Default value
no
- Option
-lefm
fracture_density.max_shear_stress
Use the max. shear stress criterion.
- Type
- flag
- Default value
no
- Option
-max_shear
fracture_density.phi0
FIXME
- Type
- number
- Default value
0 (1)
- Option
-phi0
fracture_density.softening_lower_limit
epsilon in equation (6) in Albrecht and Levermann, “Fracture-induced softening for large-scale ice dynamics”
- Type
- number
- Default value
1 (1)
- Option
-fracture_softening
frontal_melt.constant.melt_rate
default melt rate used by the
constant
frontal_melt model- Type
- number
- Default value
1 (m / day)
- Option
-frontal_melt_rate
frontal_melt.discharge_given.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-frontal_melt_discharge_given_file
frontal_melt.discharge_given.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_discharge_given_period
frontal_melt.discharge_given.reference_year
Reference year to use when
frontal_melt
.discharge_given
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_discharge_given_reference_year
frontal_melt.given.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-frontal_melt_given_file
frontal_melt.given.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_given_period
frontal_melt.given.reference_year
Reference year to use when
frontal_melt
.given
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_given_reference_year
frontal_melt.include_floating_ice
Apply frontal melt to all grid icy cells next to ocean cells
- Type
- flag
- Default value
no
frontal_melt.models
Comma-separated list of frontal melt models and modifiers. (Leave empty to disable.)
- Type
- string
- Default value
empty
- Option
-frontal_melt
frontal_melt.routing.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-frontal_melt_routing_file
frontal_melt.routing.parameter_a
parameter A in eqn. 1 in [101]
- Type
- number
- Default value
0.0003 (m-alpha day^(alpha-1) Celsius-beta)
frontal_melt.routing.parameter_b
parameter B in eqn. 1 in [101]
- Type
- number
- Default value
0.15 (m day^(alpha-1) Celsius-beta)
frontal_melt.routing.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_routing_period
frontal_melt.routing.power_alpha
exponent \(\alpha\) in eqn. 1 in [101]
- Type
- number
- Default value
0.39 (1)
frontal_melt.routing.power_beta
exponent \(\beta\) in eqn. 1 in [101]
- Type
- number
- Default value
1.18 (1)
frontal_melt.routing.reference_year
Reference year to use when
frontal_melt
.routing
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-frontal_melt_routing_reference_year
geometry.front_retreat.prescribed.file
Name of the file containing the maximum ice extent mask \(land_ice_area_fraction_retreat\)
- Type
- string
- Default value
empty
- Option
-front_retreat_file
geometry.front_retreat.prescribed.period
Length of the period of the front retreat data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
geometry.front_retreat.prescribed.reference_year
Reference year to use when \(geometry.front_retreat.prescribed.period\) is active.
- Type
- integer
- Default value
0 (years)
geometry.front_retreat.use_cfl
apply CFL criterion for eigen-calving rate front retreat
- Type
- flag
- Default value
false
- Option
-front_retreat_cfl
geometry.front_retreat.wrap_around
If true, wrap around domain boundaries. This may be needed in some regional synthetic geometry setups.
- Type
- flag
- Default value
false
- Option
-front_retreat_wrap_around
geometry.grounded_cell_fraction
Linear interpolation scheme (“LI” in Gladstone et al. 2010) expanded to two dimensions is used if switched on in order to evaluate the position of the grounding line on a subgrid scale.
- Type
- flag
- Default value
false
- Option
-subgl
geometry.ice_free_thickness_standard
If ice is thinner than this standard then the mask is set to MASK_ICE_FREE_BEDROCK or MASK_ICE_FREE_OCEAN.
- Type
- number
- Default value
0.01 (meters)
geometry.part_grid.enabled
apply partially filled grid cell scheme
- Type
- flag
- Default value
no
- Option
-part_grid
geometry.part_grid.max_iterations
maximum number of residual redistribution iterations
- Type
- integer
- Default value
10 (count)
geometry.remove_icebergs
identify and kill detached ice-shelf areas
- Type
- flag
- Default value
no
- Option
-kill_icebergs
geometry.update.enabled
Solve the mass conservation equation
- Type
- flag
- Default value
yes
- Option
-mass
geometry.update.use_basal_melt_rate
Include basal melt rate in the continuity equation
- Type
- flag
- Default value
yes
- Option
-bmr_in_cont
grid.Lbz
Thickness of the thermal bedrock layer. (Inactive if
grid
.Mbz
< 2)- Type
- number
- Default value
1000 (meters)
- Option
-Lbz
grid.Lx
Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.
- Type
- number
- Default value
1.5e+06 (meters)
grid.Ly
Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.
- Type
- number
- Default value
1.5e+06 (meters)
grid.Lz
Height of the computational domain.
- Type
- number
- Default value
4000 (meters)
- Option
-Lz
grid.Mbz
Number of thermal bedrock layers; 1 level corresponds to no bedrock.
- Type
- integer
- Default value
1 (count)
- Option
-Mbz
grid.Mx
Number of grid points in the x direction.
- Type
- integer
- Default value
61 (count)
- Option
-Mx
grid.My
Number of grid points in the y direction.
- Type
- integer
- Default value
61 (count)
- Option
-My
grid.Mz
Number of vertical grid levels in the ice.
- Type
- integer
- Default value
31 (count)
- Option
-Mz
grid.allow_extrapolation
Allow extrapolation during regridding.
- Type
- flag
- Default value
no
- Option
-allow_extrapolation
grid.ice_vertical_spacing
vertical spacing in the ice
- Type
- keyword
- Default value
quadratic
- Choices
quadratic, equal
- Option
-z_spacing
grid.lambda
Vertical grid spacing parameter. Roughly equal to the factor by which the grid is coarser at an end away from the ice-bedrock interface.
- Type
- number
- Default value
4 (pure number)
grid.max_stencil_width
Maximum width of the finite-difference stencil used in PISM.
- Type
- integer
- Default value
2 (count)
grid.periodicity
horizontal grid periodicity
- Type
- keyword
- Default value
xy
- Choices
none, x, y, xy
- Option
-periodicity
grid.recompute_longitude_and_latitude
Re-compute longitude and latitude using grid information and provided projection parameters. Requires PROJ.
- Type
- flag
- Default value
yes
grid.registration
horizontal grid registration
- Type
- keyword
- Default value
center
- Choices
center, corner
hydrology.add_water_input_to_till_storage
Add surface input to water stored in till. If no it will be added to the transportable water.
- Type
- flag
- Default value
yes
hydrology.cavitation_opening_coefficient
c_1 in notes; coefficient of cavitation opening term in evolution of layer thickness in hydrology::Distributed
- Type
- number
- Default value
0.5 (meter-1)
- Option
-hydrology_cavitation_opening_coefficient
hydrology.creep_closure_coefficient
c_2 in notes; coefficient of creep closure term in evolution of layer thickness in hydrology::Distributed
- Type
- number
- Default value
0.04 (pure number)
- Option
-hydrology_creep_closure_coefficient
hydrology.distributed.init_p_from_steady
if “yes”, initialize subglacial water pressure from P(W) formula that applies in steady state
- Type
- flag
- Default value
no
- Option
-hydrology_init_p_form_steady
hydrology.distributed.sliding_speed_file
name of the file containing velbase_mag, the basal sliding speed to use with
hydrology.distributed.init_p_from_steady
- Type
- string
- Default value
empty
- Option
-hydrology_sliding_speed_file
hydrology.gradient_power_in_flux
power \(\beta\) in Darcy’s law \(q = - k W^{\alpha} |\nabla \psi|^{\beta-2} \nabla \psi\), for subglacial water layer; used by hydrology::Routing and hydrology::Distributed
- Type
- number
- Default value
1.5 (pure number)
- Option
-hydrology_gradient_power_in_flux
hydrology.hydraulic_conductivity
= k in notes; lateral conductivity, in Darcy’s law, for subglacial water layer; units depend on powers alpha = hydrology.thickness_power_in_flux and beta = hydrology_potential_gradient_power_in_flux; used by hydrology::Routing and hydrology::Distributed
- Type
- number
- Default value
0.001 (`m^{2 \beta - \alpha} s^{2 \beta - 3} kg^{1-\beta}`)
- Option
-hydrology_hydraulic_conductivity
hydrology.maximum_time_step
maximum allowed time step length used by hydrology::Routing and hydrology::Distributed
- Type
- number
- Default value
1 (years)
hydrology.model
Basal hydrology sub-model.
- Type
- keyword
- Default value
null
- Choices
null, routing, steady, distributed
- Option
-hydrology
hydrology.null_diffuse_till_water
Diffuse stored till water laterally. See equation (11) of [25]
- Type
- flag
- Default value
no
hydrology.null_diffusion_distance
diffusion distance for till water thickness; see equation (11) in [25]; only active if hydrology.null_diffuse_till_water is set
- Type
- number
- Default value
20000 (meters)
hydrology.null_diffusion_time
diffusion time for till water thickness; see equation (11) in [25]; only active if hydrology.null_diffuse_till_water is set
- Type
- number
- Default value
1000 (years)
hydrology.null_strip_width
if negative then mechanism is inactive; width of strip around computational domain in which water velocity and water amount are set to zero; used by hydrology::Routing and hydrology::Distributed
- Type
- number
- Default value
-1 (meters)
hydrology.regularizing_porosity
phi_0 in notes; regularizes pressure equation by multiplying time derivative term
- Type
- number
- Default value
0.01 (pure number)
- Option
-hydrology_regularizing_porosity
hydrology.roughness_scale
W_r in notes; roughness scale determining maximum amount of cavitation opening in hydrology::Distributed
- Type
- number
- Default value
0.1 (meters)
- Option
-hydrology_roughness_scale
hydrology.routing.include_floating_ice
Route subglacial water under ice shelves. This may be appropriate if a shelf is close to floatation. Note that this has no effect on ice flow.
- Type
- flag
- Default value
no
hydrology.steady.flux_update_interval
interval between updates of the steady state flux
- Type
- number
- Default value
1 (years)
hydrology.steady.input_rate_scaling
input rate scaling
- Type
- number
- Default value
1e+07 (seconds)
hydrology.steady.n_iterations
maxinum number of iterations to use in while estimating steady-state water flux
- Type
- integer
- Default value
7500 (count)
hydrology.steady.potential_delta
potential adjustment used to fill sinks (smaller values require more iterations but produce fewer artifacts)
- Type
- number
- Default value
10000 (Pa)
hydrology.steady.potential_n_iterations
maxinum number of iterations to take while pre-processing hydraulic potential
- Type
- integer
- Default value
1000 (count)
hydrology.steady.volume_ratio
water volume ratio used as the stopping criterion
- Type
- number
- Default value
0.1 (1)
hydrology.surface_input.file
Name of the file containing
water_input_rate
, the rate at which water from the ice surface is added to the subglacial hydrology system- Type
- string
- Default value
empty
hydrology.surface_input.period
Length of the period of the water input rate. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
hydrology.surface_input.reference_year
Reference year to use when
hydrology
.surface_input
.period
is active.- Type
- integer
- Default value
0 (years)
hydrology.surface_input_from_runoff
Use surface runoff as surface input.
- Type
- flag
- Default value
no
hydrology.thickness_power_in_flux
power \(\alpha\) in Darcy’s law \(q = - k W^{\alpha} |\nabla \psi|^{\beta-2} \nabla \psi\), for subglacial water layer; used by hydrology::Routing and hydrology::Distributed
- Type
- number
- Default value
1.25 (1)
- Option
-hydrology_thickness_power_in_flux
hydrology.tillwat_decay_rate
rate at which tillwat is reduced to zero, in absence of other effects like input
- Type
- number
- Default value
1 (mm / year)
- Option
-hydrology_tillwat_decay_rate
hydrology.tillwat_max
maximum effective thickness of the water stored in till
- Type
- number
- Default value
2 (meters)
- Option
-hydrology_tillwat_max
hydrology.use_const_bmelt
if “yes”, subglacial hydrology model sees basal melt rate which is constant and given by hydrology.const_bmelt
- Type
- flag
- Default value
no
- Option
-hydrology_use_const_bmelt
input.bootstrap
It true, use bootstrapping heuristics when initializing PISM.
- Type
- flag
- Default value
no
- Option
-bootstrap
input.file
Input file name
- Type
- string
- Default value
empty
- Option
-i
input.forcing.buffer_size
number of 2D climate forcing records to keep in memory; = 5 years of monthly records
- Type
- integer
- Default value
60 (count)
input.forcing.evaluations_per_year
length of the time-series used to compute temporal averages of forcing data (such as mean annual temperature)
- Type
- integer
- Default value
52 (count)
input.regrid.file
Regridding (input) file name
- Type
- string
- Default value
empty
- Option
-regrid_file
input.regrid.vars
Comma-separated list of variables to regrid. Leave empty to regrid all model state variables.
- Type
- string
- Default value
empty
- Option
-regrid_vars
inverse.design.cH1
weight of derivative part of an H1 norm for inversion design variables
- Type
- number
- Default value
0 (1)
- Option
-inv_design_cH1
inverse.design.cL2
weight of derivative-free part of an H1 norm for inversion design variables
- Type
- number
- Default value
1 (1)
- Option
-inv_design_cL2
inverse.design.func
functional used for inversion design variables
- Type
- keyword
- Default value
sobolevH1
- Choices
sobolevH1, tv
- Option
-inv_design_func
inverse.design.param
parameterization of design variables used during inversion
- Type
- keyword
- Default value
exp
- Choices
ident, trunc, square, exp
- Option
-inv_design_param
inverse.design.param_hardav_eps
tiny vertically-averaged hardness used as a substitute for 0 in some tauc parameterizations
- Type
- number
- Default value
10000 (Pascal second^(1/3))
inverse.design.param_hardav_scale
typical size of ice hardness
- Type
- number
- Default value
1e+08 (Pascal second^(1/3))
inverse.design.param_tauc_eps
tiny yield stress used as a substitute for 0 in some tauc parameterizations
- Type
- number
- Default value
100 (Pascal)
inverse.design.param_tauc_scale
typical size of yield stresses
- Type
- number
- Default value
100000 (Pascal)
inverse.design.param_trunc_hardav0
transition point of change to linear behaviour for design variable parameterization type
trunc
- Type
- number
- Default value
1e+06 (Pascal second^(1/3))
inverse.design.param_trunc_tauc0
transition point of change to linear behaviour for design variable parameterization type
trunc
- Type
- number
- Default value
1000 (Pascal)
inverse.log_ratio_scale
Reference scale for log-ratio functionals
- Type
- number
- Default value
10 (pure number)
- Option
-inv_log_ratio_scale
inverse.max_iterations
maximum iteration count
- Type
- integer
- Default value
1000 (count)
- Option
-inv_max_it
inverse.ssa.hardav_max
Maximum allowed value of hardav for inversions with bound constraints
- Type
- number
- Default value
1e+10 (Pascal second^(1/3))
inverse.ssa.hardav_min
Minimum allowed value of hardav for inversions with bound constraints
- Type
- number
- Default value
0 (Pascal second^(1/3))
inverse.ssa.length_scale
typical length scale for rescaling derivative norms
- Type
- number
- Default value
50000 (meters)
inverse.ssa.method
algorithm to use for SSA inversions
- Type
- keyword
- Default value
tikhonov_lmvm
- Choices
sd, nlcg, ign, tikhonov_lmvm, tikhonov_cg, tikhonov_blmvm, tikhonov_lcl, tikhonov_gn
- Option
-inv_method
inverse.ssa.tauc_max
Maximum allowed value of tauc for inversions with bound constraints
- Type
- number
- Default value
5e+07 (Pascal)
inverse.ssa.tauc_min
Minimum allowed value of tauc for inversions with bound constraints
- Type
- number
- Default value
0 (Pascal)
inverse.ssa.tv_exponent
Lebesgue exponent for pseudo-TV norm
- Type
- number
- Default value
1.2 (pure number)
- Option
-inv_ssa_tv_exponent
inverse.ssa.velocity_eps
tiny size of ice velocities during inversion
- Type
- number
- Default value
0.1 (meter / year)
inverse.ssa.velocity_scale
typical size of ice velocities expected during inversion
- Type
- number
- Default value
100 (meter / year)
inverse.state_func
functional used for inversion design variables
- Type
- keyword
- Default value
meansquare
- Choices
meansquare, log_ratio, log_relative
- Option
-inv_state_func
inverse.target_misfit
desired root misfit for SSA inversions
- Type
- number
- Default value
100 (meter / year)
- Option
-inv_target_misfit
inverse.tikhonov.atol
absolute threshold for Tikhonov stopping criterion
- Type
- number
- Default value
1e-10 (meter / year)
- Option
-tikhonov_atol
inverse.tikhonov.penalty_weight
penalty parameter for Tikhonov inversion
- Type
- number
- Default value
1 (1)
- Option
-tikhonov_penalty
inverse.tikhonov.ptol
threshold for reaching desired misfit for adaptive Tikhonov algorithms
- Type
- number
- Default value
0.1 (pure number)
- Option
-tikhonov_ptol
inverse.tikhonov.rtol
relative threshold for Tikhonov stopping criterion
- Type
- number
- Default value
0.05 (1)
- Option
-tikhonov_rtol
inverse.use_design_prior
Use prior from inverse data file as initial guess.
- Type
- flag
- Default value
yes
- Option
-inv_use_design_prior
inverse.use_zeta_fixed_mask
Enforce locations where the parameterized design variable should be fixed. (Automatically determined if not provided)
- Type
- flag
- Default value
yes
- Option
-inv_use_zeta_fixed_mask
ocean.always_grounded
Dry (ocean-less) simulation; ice is considered grounded regardless of ice thickness, bed elevation, and sea level.
- Type
- flag
- Default value
no
- Option
-dry
ocean.anomaly.file
Name of the file containing shelf basal mass flux offset fields.
- Type
- string
- Default value
empty
- Option
-ocean_anomaly_file
ocean.anomaly.period
Length of the period of the ocean forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_anomaly_period
ocean.anomaly.reference_year
Reference year to use when
ocean
.anomaly
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_anomaly_reference_year
ocean.cache.update_interval
update interval of the
cache
ocean modifier- Type
- integer
- Default value
10 (years)
- Option
-ocean_cache_update_interval
ocean.constant.melt_rate
default melt rate used by the
constant
ocean model (computed as \(Q / (L \rho_i)\))- Type
- number
- Default value
0.0519142 (m / year)
- Option
-shelf_base_melt_rate
ocean.delta_T.file
Name of the file containing temperature offsets.
- Type
- string
- Default value
empty
- Option
-ocean_delta_T_file
ocean.delta_T.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_T_period
ocean.delta_T.reference_year
Reference year to use when
ocean
.delta_T
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_T_reference_year
ocean.delta_mass_flux.file
Name of the file containing sub-shelf mass flux offsets.
- Type
- string
- Default value
empty
- Option
-ocean_delta_mass_flux_file
ocean.delta_mass_flux.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_mass_flux_period
ocean.delta_mass_flux.reference_year
Reference year to use when
ocean
.delta_mass_flux
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_mass_flux_reference_year
ocean.delta_sl.file
Name of the file containing sea level offsets.
- Type
- string
- Default value
empty
- Option
-ocean_delta_sl_file
ocean.delta_sl.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_sl_period
ocean.delta_sl.reference_year
Reference year to use when
ocean
.delta_sl
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_delta_sl_reference_year
ocean.delta_sl_2d.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
ocean.delta_sl_2d.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
ocean.delta_sl_2d.reference_year
Reference year to use when
ocean
.delta_sl_2d
.period
is active.- Type
- integer
- Default value
0 (years)
ocean.frac_MBP.file
Name of the file containing melange back-pressure scaling.
- Type
- string
- Default value
empty
- Option
-ocean_frac_MBP_file
ocean.frac_MBP.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_frac_MBP_period
ocean.frac_MBP.reference_year
Reference year to use when
ocean
.frac_MBP
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_frac_MBP_reference_year
ocean.frac_mass_flux.file
Name of the file containing sub-shelf mass flux scaling.
- Type
- string
- Default value
empty
- Option
-ocean_frac_mass_flux_file
ocean.frac_mass_flux.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_frac_mass_flux_period
ocean.frac_mass_flux.reference_year
Reference year to use when
ocean
.frac_mass_flux
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_frac_mass_flux_reference_year
ocean.given.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-ocean_given_file
ocean.given.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_given_period
ocean.given.reference_year
Reference year to use when
ocean
.given
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_given_reference_year
ocean.melange_back_pressure_fraction
default melange back pressure fraction
- Type
- number
- Default value
0 (1)
ocean.models
Comma-separated list of ocean models and modifiers.
- Type
- string
- Default value
constant
- Option
-ocean
ocean.pico.continental_shelf_depth
Specifies the depth up to which oceanic input temperatures and salinities are averaged over the continental shelf areas in front of the ice shelf cavities.
- Type
- number
- Default value
-800 (meters)
- Option
-continental_shelf_depth
ocean.pico.exclude_ice_rises
If set to true, grounding lines of ice rises are excluded in the geometrical routines that determine the ocean boxes; using this option is recommended.
- Type
- flag
- Default value
yes
- Option
-exclude_icerises
ocean.pico.file
Specifies the NetCDF file containing potential temperature (
theta_ocean
), salinity (salinity_ocean
) and ocean basins (basins
).- Type
- string
- Default value
empty
- Option
-ocean_pico_file
ocean.pico.heat_exchange_coefficent
Sets the coefficient for turbulent heat exchange from the ambient ocean across the boundary layer beneath the ice shelf base.
- Type
- number
- Default value
2e-05 (meters second-1)
- Option
-gamma_T
ocean.pico.maximum_ice_rise_area
Specifies an area threshold that separates ice rises from continental regions.
- Type
- number
- Default value
100000 (km2)
ocean.pico.number_of_boxes
For each ice shelf the number of ocean boxes is determined by interpolating between 1 and number_of_boxes depending on its size and geometry such that larger ice shelves are resolved with more boxes; a value of 5 is suitable for the Antarctic setup.
- Type
- integer
- Default value
5 (pure number)
- Option
-number_of_boxes
ocean.pico.overturning_coefficent
Sets the overturning strength coefficient.
- Type
- number
- Default value
1e+06 (meters6 seconds-1 kg-1)
- Option
-overturning_coeff
ocean.pico.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_pico_period
ocean.pico.reference_year
Reference year to use when
ocean
.pico
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_pico_reference_year
ocean.pik_melt_factor
dimensionless tuning parameter in the
-ocean pik
ocean heat flux parameterization; see [3]- Type
- number
- Default value
0.005 (1)
- Option
-meltfactor_pik
ocean.runoff_to_ocean_melt_b
parameter B in eqn. 1 in [102]
- Type
- number
- Default value
0.15 (1)
ocean.runoff_to_ocean_melt_power_alpha
exponent \(\alpha\) in eqn. 1 in [101]
- Type
- number
- Default value
0.54 (1)
ocean.runoff_to_ocean_melt_power_beta
exponent \(\beta\) in eqn. 1 in [101]
- Type
- number
- Default value
1.17 (1)
ocean.sub_shelf_heat_flux_into_ice
= J meter-2 second-1; naively chosen default value for heat from ocean; see comments in pism::ocean::Constant::shelf_base_mass_flux().
- Type
- number
- Default value
0.5 (W meter-2)
ocean.th.clip_salinity
Clip shelf base salinity so that it is in the range [4, 40] k/kg. See [11].
- Type
- flag
- Default value
yes
- Option
-clip_shelf_base_salinity
ocean.th.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-ocean_th_file
ocean.th.gamma_S
Turbulent salt transfer coefficient. See [11].
- Type
- number
- Default value
5.05e-07 (m s-1)
- Option
-gamma_T
ocean.th.gamma_T
Turbulent heat transfer coefficient. See [11].
- Type
- number
- Default value
0.0001 (m s-1)
- Option
-gamma_T
ocean.th.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-ocean_th_period
ocean.th.reference_year
Reference year to use when
ocean
.th
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-ocean_th_reference_year
output.ISMIP6
Follow ISMIP6 conventions (units, variable names, “standard names”) when writing output variables.
- Type
- flag
- Default value
false
output.ISMIP6_extra_variables
Comma-separated list of fields reported by models participating in ISMIP6 simulations.
- Type
- string
- Default value
lithk, orog, topg, hfgeoubed, acabf, libmassbfgr, libmassbffl, dlithkdt, velsurf, zvelsurf, velbase, zvelbase, velmean, litemptop, litempbotgr, litempbotfl, strbasemag, licalvf, lifmassbf, sftgif, sftgrf, sftflf
output.ISMIP6_ts_variables
Comma-separated list of scalar variables (time series) reported by models participating in ISMIP6 simulations.
- Type
- string
- Default value
lim, limnsw, iareagr, iareafl, tendacabf, tendlibmassbf, tendlibmassbffl, tendlicalvf, tendlifmassbf
output.backup_interval
wall-clock time between automatic backups
- Type
- number
- Default value
1 (hours)
- Option
-backup_interval
output.backup_size
The “size” of a backup file. See parameters
output
.sizes
.medium
,output
.sizes
.big_2d
,output
.sizes
.big
- Type
- keyword
- Default value
small
- Choices
none, small, medium, big_2d, big
- Option
-backup_size
output.compression_level
Compression level for 2D and 3D output variables (if supported by
output
.format
)- Type
- integer
- Default value
0 (count)
output.extra.append
Append to an existing output file.
- Type
- flag
- Default value
no
- Option
-extra_append
output.extra.file
Name of the output file containing spatially-variable diagnostics.
- Type
- string
- Default value
empty
- Option
-extra_file
output.extra.split
Save spatially-variable diagnostics to separate files (one per time record).
- Type
- flag
- Default value
no
- Option
-extra_split
output.extra.stop_missing
Stop if requested variable is not available instead of warning.
- Type
- flag
- Default value
yes
- Option
-extra_stop_missing
output.extra.times
List or a range of times defining reporting intervals for spatially-variable diagnostics.
- Type
- string
- Default value
empty
- Option
-extra_times
output.extra.vars
Comma-separated list of spatially-variable diagnostics.
- Type
- string
- Default value
empty
- Option
-extra_vars
output.file_name
The file to save final model results to.
- Type
- string
- Default value
unnamed.nc
- Option
-o
output.fill_value
_FillValue used when saving diagnostic quantities
- Type
- number
- Default value
-2e+09 (none)
output.format
The I/O format used for spatial fields;
netcdf3
is the default,netcd4_parallel
is available if PISM was built with parallel NetCDF-4, andpnetcdf
is available if PISM was built with PnetCDF.- Type
- keyword
- Default value
netcdf3
- Choices
netcdf3, netcdf4_serial, netcdf4_parallel, pnetcdf, pio_pnetcdf, pio_netcdf4p, pio_netcdf4c, pio_netcdf
- Option
-o_format
output.ice_free_thickness_standard
If ice is thinner than this standard then a grid cell is considered ice-free for purposes of reporting glacierized area, volume, etc.
- Type
- number
- Default value
10 (meters)
output.pio.base
Rank of the first I/O task
- Type
- integer
- Default value
0 (count)
output.pio.n_writers
Number of I/O tasks to use
- Type
- integer
- Default value
1 (count)
output.pio.stride
Offset between I/O tasks
- Type
- integer
- Default value
1 (count)
output.runtime.area_scale_factor_log10
an integer; log base 10 of scale factor to use for area (in km^2) in summary line to stdout
- Type
- integer
- Default value
6 (pure number)
- Option
-summary_area_scale_factor_log10
output.runtime.time_unit_name
Time units used when printing model time, time step, and maximum horizontal velocity at summary to stdout. Must be valid udunits for time. (E.g. choose from year,month,day,hour,minute,second.)
- Type
- string
- Default value
year
output.runtime.time_use_calendar
Whether to use the current calendar when printing model time in summary to stdout.
- Type
- flag
- Default value
yes
output.runtime.viewer.size
default diagnostic viewer size (number of pixels of the longer side)
- Type
- integer
- Default value
320 (count)
- Option
-view_size
output.runtime.viewer.variables
comma-separated list of map-plane diagnostic quantities to view at runtime
- Type
- string
- Default value
empty
- Option
-view
output.runtime.volume_scale_factor_log10
an integer; log base 10 of scale factor to use for volume (in km^3) in summary line to stdout
- Type
- integer
- Default value
6 (pure number)
- Option
-summary_vol_scale_factor_log10
output.size
The “size” of an output file. See parameters
output
.sizes
.medium
,output
.sizes
.big_2d
,output
.sizes
.big
- Type
- keyword
- Default value
medium
- Choices
none, small, medium, big_2d, big
- Option
-o_size
output.sizes.big
Comma-separated list of variables to write to the output (in addition to
model_state
variables and variables listed inoutput
.sizes
.medium
andoutput
.sizes
.big_2d
) ifbig
output size is selected. Does not include fields written by sub-models.- Type
- string
- Default value
cts, liqfrac, temp, temp_pa, uvel, vvel, wvel, wvel_rel
output.sizes.big_2d
Comma-separated list of variables to write to the output (in addition to
model_state
variables and variables listed inoutput
.sizes
.medium
) ifbig_2d
output size is selected. Does not include fields written by boundary models.- Type
- string
- Default value
age, bfrict, bheatflx, bmelt, bwp, bwprel, dbdt, effbwp, enthalpybase, enthalpysurf, flux_divergence, hardav, hydroinput, lat, litho_temp, lon, nuH, rank, tempbase, tempicethk, tempicethk_basal, temppabase, tempsurf, thk, thksmooth, tillphi, topg, velbar, velbase, wallmelt, wvelbase
output.sizes.medium
Comma-separated list of variables to write to the output (in addition to
model_state
variables) ifmedium
output size (the default) is selected. Does not include fields written by sub-models.- Type
- string
- Default value
bwat, bwatvel, climatic_mass_balance, diffusivity, enthalpy, flux, flux_mag, ice_surface_temp, liqfrac, mask, schoofs_theta, strain_rates, taub_mag, tauc, taud_mag, temp_pa, tillwat, topgsmooth, usurf, velbar_mag, velbase_mag, velsurf, velsurf_mag, wvelsurf
output.snapshot.file
Snapshot (output) file name (or prefix, if saving to individual files).
- Type
- string
- Default value
empty
- Option
-save_file
output.snapshot.size
The “size” of a snapshot file. See parameters
output
.sizes
.medium
,output
.sizes
.big_2d
,output
.sizes
.big
- Type
- keyword
- Default value
small
- Choices
none, small, medium, big_2d, big
- Option
-save_size
output.snapshot.split
Save model state snapshots to separate files (one per time record).
- Type
- flag
- Default value
no
- Option
-save_split
output.snapshot.times
List or a range of times to save model state snapshots at.
- Type
- string
- Default value
empty
- Option
-save_times
output.timeseries.append
If true, append to the scalar time series output file.
- Type
- flag
- Default value
false
- Option
-ts_append
output.timeseries.buffer_size
Number of scalar diagnostic time-series records to hold in memory before writing to disk. (PISM writes this many time-series records to reduce I/O costs.) Send the USR2 signal to flush time-series.
- Type
- integer
- Default value
10000 (count)
output.timeseries.filename
Name of the file to save scalar time series to. Leave empty to disable reporting scalar time-series.
- Type
- string
- Default value
empty
- Option
-ts_file
output.timeseries.times
List or range of times defining reporting time intervals.
- Type
- string
- Default value
empty
- Option
-ts_times
output.timeseries.variables
Requested scalar (time-series) diagnostics. Leave empty to save all available diagnostics.
- Type
- string
- Default value
empty
- Option
-ts_vars
output.use_MKS
Use MKS units in output files.
- Type
- flag
- Default value
false
regional.no_model_strip
Default width of the “no model strip” in regional setups.
- Type
- number
- Default value
5 (km)
- Option
-no_model_strip
regional.no_model_yield_stress
High yield stress used in the
no_model_mask
area in the regional mode.- Type
- number
- Default value
1000 (kPa)
regional.zero_gradient
Use zero ice thickness and ice surface gradient in the no_model_mask area.
- Type
- flag
- Default value
false
- Option
-zero_grad_where_no_model
run_info.institution
Institution name. This string is written to output files as the
institution
global attribute.- Type
- string
- Default value
empty
- Option
-institution
run_info.title
Free-form string containing a concise description of the current run. This string is written to output files as the
title
global attribute.- Type
- string
- Default value
empty
- Option
-title
sea_level.models
Comma-separated list of sea level models and modifiers.
- Type
- string
- Default value
constant
- Option
-sea_level
stress_balance.calving_front_stress_bc
Apply CFBC condition as in [81], [33]. May only apply to some stress balances; e.g. SSAFD as of May 2011. If not set then a strength-extension is used, as in [25].
- Type
- flag
- Default value
no
- Option
-cfbc
stress_balance.ice_free_thickness_standard
If ice is thinner than this standard then a cell is considered ice-free for purposes of computing ice velocity distribution.
- Type
- number
- Default value
10 (meters)
stress_balance.model
Stress balance model
- Type
- keyword
- Default value
sia
- Choices
none, prescribed_sliding, weertman_sliding, sia, ssa, prescribed_sliding+sia, weertman_sliding+sia, ssa+sia
- Option
-stress_balance
stress_balance.prescribed_sliding.file
The name of the file containing prescribed sliding velocity (variable names:
ubar
,vbar
).- Type
- string
- Default value
empty
stress_balance.sia.Glen_exponent
Glen exponent in ice flow law for SIA
- Type
- number
- Default value
3 (pure number)
- Option
-sia_n
stress_balance.sia.bed_smoother.range
half-width of smoothing domain for stressbalance::BedSmoother, in implementing [93] bed roughness parameterization for SIA; set value to zero to turn off mechanism
- Type
- number
- Default value
5000 (meters)
- Option
-bed_smoother_range
stress_balance.sia.bed_smoother.theta_min
minimum value of \(\theta\) in [93] bed roughness parameterization for SIA
- Type
- number
- Default value
0 (1)
stress_balance.sia.e_age_coupling
Couple the SIA enhancement factor to age as in [32].
- Type
- flag
- Default value
no
- Option
-e_age_coupling
stress_balance.sia.enhancement_factor
Flow enhancement factor for SIA
- Type
- number
- Default value
1 (1)
- Option
-sia_e
stress_balance.sia.enhancement_factor_interglacial
Flow enhancement factor for SIA; used for ice accumulated during interglacial periods.
- Type
- number
- Default value
1 (1)
- Option
-sia_e_interglacial
stress_balance.sia.flow_law
The SIA flow law.
- Type
- keyword
- Default value
gpbld
- Choices
arr, arrwarm, gk, gpbld, hooke, isothermal_glen, pb
- Option
-sia_flow_law
stress_balance.sia.grain_size_age_coupling
Use age of the ice to compute grain size to use with the Goldsby-Kohlstedt [70] flow law
- Type
- flag
- Default value
no
- Option
-grain_size_age_coupling
stress_balance.sia.limit_diffusivity
Limit SIA diffusivity by
stress_balance
.sia
.max_diffusivity
.- Type
- flag
- Default value
no
- Option
-limit_sia_diffusivity
stress_balance.sia.max_diffusivity
Maximum allowed diffusivity of the SIA flow. PISM stops with an error message if the SIA diffusivity exceeds this limit.
- Type
- number
- Default value
100 (m2 s-1)
stress_balance.sia.surface_gradient_method
method used for surface gradient calculation at staggered grid points
- Type
- keyword
- Default value
haseloff
- Choices
eta, haseloff, mahaffy
- Option
-gradient
stress_balance.ssa.Glen_exponent
Glen exponent in ice flow law for SSA
- Type
- number
- Default value
3 (pure number)
- Option
-ssa_n
stress_balance.ssa.compute_surface_gradient_inward
If yes then use inward first-order differencing in computing surface gradient in the SSA objects.
- Type
- flag
- Default value
no
stress_balance.ssa.dirichlet_bc
apply SSA velocity Dirichlet boundary condition
- Type
- flag
- Default value
no
- Option
-ssa_dirichlet_bc
stress_balance.ssa.enhancement_factor
Flow enhancement factor for SSA
- Type
- number
- Default value
1 (1)
- Option
-ssa_e
stress_balance.ssa.enhancement_factor_interglacial
Flow enhancement factor for SSA; used for ice accumulated during interglacial periods.
- Type
- number
- Default value
1 (1)
- Option
-ssa_e_interglacial
stress_balance.ssa.epsilon
Initial amount of regularization in computation of product of effective viscosity and thickness (\(\nu H\)). This default value for \(\nu H\) comes e.g. from a hardness for the Ross ice shelf (\(\bar B\)) = 1.9e8 Pa \(s^{1/3}\) [64] and a typical strain rate of 0.001 1/year for the Ross ice shelf, giving \(\nu = (\bar B) / (2 \cdot 0.001^{2/3})\) = 9.49e+14 Pa s ~ 30 MPa year, the value in [103], but with a tiny thickness \(H\) of about 1 cm.
- Type
- number
- Default value
1e+13 (Pascal second meter)
- Option
-ssa_eps
stress_balance.ssa.fd.brutal_sliding
Enhance sliding speed brutally.
- Type
- flag
- Default value
false
- Option
-brutal_sliding
stress_balance.ssa.fd.brutal_sliding_scale
Brutal SSA Sliding Scale
- Type
- number
- Default value
1 (1)
- Option
-brutal_sliding_scale
stress_balance.ssa.fd.flow_line_mode
Set \(v\) (the \(y\) component of the ice velocity) to zero when assembling the system
- Type
- flag
- Default value
false
stress_balance.ssa.fd.lateral_drag.enabled
set viscosity at ice shelf margin next to ice free bedrock as friction parameterization
- Type
- flag
- Default value
false
stress_balance.ssa.fd.lateral_drag.viscosity
Staggered Viscosity used as side friction parameterization.
- Type
- number
- Default value
5e+15 (Pascal second)
- Option
-nu_bedrock
stress_balance.ssa.fd.max_iterations
Maximum number of Picard iterations for the ice viscosity computation, in the SSAFD object
- Type
- integer
- Default value
300 (count)
- Option
-ssafd_picard_maxi
stress_balance.ssa.fd.max_speed
Upper bound for the ice speed computed by the SSAFD solver.
- Type
- number
- Default value
300000 (km s-1)
- Option
-ssafd_max_speed
stress_balance.ssa.fd.nuH_iter_failure_underrelaxation
In event of “Effective viscosity not converged” failure, use outer iteration rule nuH <- nuH + f (nuH - nuH_old), where f is this parameter.
- Type
- number
- Default value
0.8 (pure number)
- Option
-ssafd_nuH_iter_failure_underrelaxation
stress_balance.ssa.fd.relative_convergence
Relative change tolerance for the effective viscosity in the SSAFD object
- Type
- number
- Default value
0.0001 (1)
- Option
-ssafd_picard_rtol
stress_balance.ssa.fd.replace_zero_diagonal_entries
Replace zero diagonal entries in the SSAFD matrix with :config:’basal_resistance.beta_ice_free_bedrock’ to avoid solver failures.
- Type
- flag
- Default value
yes
stress_balance.ssa.flow_law
The SSA flow law.
- Type
- keyword
- Default value
gpbld
- Choices
arr, arrwarm, gpbld, hooke, isothermal_glen, pb
- Option
-ssa_flow_law
stress_balance.ssa.method
Algorithm for computing the SSA solution.
- Type
- keyword
- Default value
fd
- Choices
fd, fem
- Option
-ssa_method
stress_balance.ssa.read_initial_guess
Read the initial guess from the input file when re-starting.
- Type
- flag
- Default value
yes
- Option
-ssa_read_initial_guess
stress_balance.ssa.strength_extension.constant_nu
The SSA is made elliptic by use of a constant value for the product of viscosity (nu) and thickness (H). This value for nu comes from hardness (bar B)=1.9e8 \(Pa s^{1/3}\) [64] and a typical strain rate of 0.001 year-1: \(\nu = (\bar B) / (2 \cdot 0.001^{2/3})\). Compare the value of 9.45e14 Pa s = 30 MPa year in [103].
- Type
- number
- Default value
9.48681e+14 (Pascal second)
stress_balance.ssa.strength_extension.min_thickness
The SSA is made elliptic by use of a constant value for the product of viscosity (nu) and thickness (H). At ice thicknesses below this value the product nu*H switches from the normal vertical integral to a constant value. The geometry itself is not affected by this value.
- Type
- number
- Default value
50 (meters)
stress_balance.vertical_velocity_approximation
Vertical velocity FD approximation. “Upstream” uses first-order finite difference to compute u_x and v_y. Uses basal velocity to make decisions.
- Type
- keyword
- Default value
centered
- Choices
centered, upstream
- Option
-vertical_velocity_approximation
stress_balance.weertman_sliding.A
Sliding parameter in the Weertman-style sliding parameterization [75]
- Type
- number
- Default value
1.8e-16 (Pa-3 year-1 m-2)
stress_balance.weertman_sliding.k
The ratio of the basal water pressure and the ice overburden pressure in the Weertman-style sliding parameterization.
- Type
- number
- Default value
0.2 (1)
surface.anomaly.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-surface_anomaly_file
surface.anomaly.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-surface_anomaly_period
surface.anomaly.reference_year
Reference year to use when
surface
.anomaly
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-surface_anomaly_reference_year
surface.cache.update_interval
Update interval (in years) for the \(-surface cache\) modifier.
- Type
- integer
- Default value
10 (year)
surface.delta_T.file
Name of the file containing temperature offsets.
- Type
- string
- Default value
empty
- Option
-surface_delta_T_file
surface.delta_T.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-surface_delta_T_period
surface.delta_T.reference_year
Reference year to use when
surface
.delta_T
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-surface_delta_T_reference_year
surface.elevation_change.file
Name of the file containing the reference surface elevation field (variable
usurf
).- Type
- string
- Default value
empty
- Option
-surface_elevation_change_file
surface.elevation_change.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-surface_elevation_change_period
surface.elevation_change.reference_year
Reference year to use when
surface
.elevation_change
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-surface_elevation_change_reference_year
surface.elevation_change.smb.exp_factor
Exponential for the surface mass balance.
- Type
- number
- Default value
0 (Kelvin-1)
- Option
-smb_exp_factor
surface.elevation_change.smb.lapse_rate
Lapse rate for the surface mass balance.
- Type
- number
- Default value
0 ((m / year) / km)
- Option
-smb_lapse_rate
surface.elevation_change.smb.method
Choose the SMB adjustment method.
scale
: use temperature-change-dependent scaling factor.shift
: use the SMB lapse rate.- Type
- keyword
- Default value
shift
- Choices
scale, shift
- Option
-smb_adjustment
surface.elevation_change.temperature_lapse_rate
Lapse rate for the temperature at the top of the ice.
- Type
- number
- Default value
0 (K / km)
- Option
-temp_lapse_rate
surface.force_to_thickness.alpha
exponential coefficient in force-to-thickness mechanism
- Type
- number
- Default value
0.01 (year-1)
- Option
-force_to_thickness_alpha
surface.force_to_thickness.ice_free_alpha_factor
surface
.force_to_thickness
.alpha
is multiplied by this factor in areas that are ice-free according to the target ice thickness andsurface
.force_to_thickness
.ice_free_thickness_threshold
- Type
- number
- Default value
1 (1)
- Option
-force_to_thickness_ice_free_alpha_factor
surface.force_to_thickness.ice_free_thickness_threshold
threshold of ice thickness in the force-to-thickness target field. Used to determine whether to use
surface
.force_to_thickness
.ice_free_alpha_factor
.- Type
- number
- Default value
1 (meters)
- Option
-force_to_thickness_ice_free_thickness_threshold
surface.force_to_thickness.start_time
Starting time for the “force to thickness” modifier; the default is “start from the creation of the Earth.”
- Type
- number
- Default value
-4.54e+09 (years)
surface.force_to_thickness_file
The name of the file to read the target ice thickness from.
- Type
- string
- Default value
empty
- Option
-force_to_thickness_file
surface.given.file
Name of the file containing climate forcing fields.
- Type
- string
- Default value
empty
- Option
-surface_given_file
surface.given.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-surface_given_period
surface.given.reference_year
Reference year to use when
surface
.given
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-surface_given_reference_year
surface.given.smb_max
Maximum climatic mass balance value (used to check input data). Corresponds to 100 m/year ice equivalent.
- Type
- number
- Default value
91000 (kg m-2 year-1)
surface.ismip6.file
Name of the file containing climate forcing anomaly fields.
- Type
- string
- Default value
empty
- Option
-surface_ismip6_file
surface.ismip6.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-surface_ismip6_period
surface.ismip6.reference_file
Name of the file containing reference climate forcing fields.
- Type
- string
- Default value
empty
- Option
-surface_ismip6_reference_file
surface.ismip6.reference_year
Reference year to use when
surface
.ismip6
.period
is active.- Type
- integer
- Default value
0 (years)
surface.models
Comma-separated list of surface models and modifiers.
- Type
- string
- Default value
given
- Option
-surface
surface.pdd.air_temp_all_precip_as_rain
threshold temperature above which all precipitation is rain; must exceed
surface
.pdd
.air_temp_all_precip_as_snow
to avoid division by zero, because difference is in a denominator- Type
- number
- Default value
275.15 (Kelvin)
surface.pdd.air_temp_all_precip_as_snow
threshold temperature below which all precipitation is snow
- Type
- number
- Default value
273.15 (Kelvin)
surface.pdd.balance_year_start_day
day of year for October 1st, beginning of the balance year in northern latitudes.
- Type
- integer
- Default value
274 (ordinal day number)
surface.pdd.factor_ice
EISMINT-Greenland value [7]; = (8 mm liquid-water-equivalent) / (pos degree day)
- Type
- number
- Default value
0.00879121 (meter / (Kelvin day))
surface.pdd.factor_snow
EISMINT-Greenland value [7]; = (3 mm liquid-water-equivalent) / (pos degree day)
- Type
- number
- Default value
0.0032967 (meter / (Kelvin day))
surface.pdd.fausto.T_c
= -1 + 273.15; for formula (6) in [1]
- Type
- number
- Default value
272.15 (Kelvin)
surface.pdd.fausto.T_w
= 10 + 273.15; for formula (6) in [1]
- Type
- number
- Default value
283.15 (Kelvin)
surface.pdd.fausto.beta_ice_c
water-equivalent thickness; for formula (6) in [1]
- Type
- number
- Default value
0.015 (meter / (Kelvin day))
surface.pdd.fausto.beta_ice_w
water-equivalent thickness; for formula (6) in [1]
- Type
- number
- Default value
0.007 (meter / (Kelvin day))
surface.pdd.fausto.beta_snow_c
water-equivalent thickness; for formula (6) in [1]
- Type
- number
- Default value
0.003 (meter / (Kelvin day))
surface.pdd.fausto.beta_snow_w
water-equivalent thickness; for formula (6) in [1]
- Type
- number
- Default value
0.003 (meter / (Kelvin day))
surface.pdd.fausto.enabled
Set PDD parameters using formulas (6) and (7) in [1]
- Type
- flag
- Default value
false
- Option
-pdd_fausto
surface.pdd.fausto.latitude_beta_w
latitude below which to use warm case, in formula (6) in [1]
- Type
- number
- Default value
72 (degree_north)
surface.pdd.firn_compaction_to_accumulation_ratio
How much firn as a fraction of accumulation is turned into ice
- Type
- number
- Default value
0.75 (1)
surface.pdd.firn_depth_file
The name of the file to read the firn_depth from.
- Type
- string
- Default value
empty
- Option
-pdd_firn_depth_file
surface.pdd.interpret_precip_as_snow
Interpret precipitation as snow fall.
- Type
- flag
- Default value
no
surface.pdd.max_evals_per_year
maximum number of times the PDD scheme will ask for air temperature and precipitation to build location-dependent time series for computing (expected) number of positive degree days and snow accumulation; the default means the PDD uses weekly samples of the annual cycle; see also
surface
.pdd
.std_dev
- Type
- integer
- Default value
52 (count)
surface.pdd.method
PDD implementation method
- Type
- keyword
- Default value
expectation_integral
- Choices
expectation_integral, repeatable_random_process, random_process
- Option
-pdd_method
surface.pdd.positive_threshold_temp
temperature used to determine meaning of “positive” degree day
- Type
- number
- Default value
273.15 (Kelvin)
surface.pdd.refreeze
EISMINT-Greenland value [7]
- Type
- number
- Default value
0.6 (1)
surface.pdd.refreeze_ice_melt
If set to “yes”, refreeze
surface
.pdd
.refreeze
fraction of melted ice, otherwise all of the melted ice runs off.- Type
- flag
- Default value
yes
surface.pdd.std_dev
std dev of daily temp variation; = EISMINT-Greenland value [7]
- Type
- number
- Default value
5 (Kelvin)
surface.pdd.std_dev.file
The name of the file to read
air_temp_sd
(standard deviation of air temperature) from.- Type
- string
- Default value
empty
- Option
-pdd_sd_file
surface.pdd.std_dev.period
Length of the period of the climate forcing data. Set to zero to disable.
- Type
- integer
- Default value
0 (years)
- Option
-pdd_sd_period
surface.pdd.std_dev.reference_year
Reference year to use when
surface
.pdd
.std_dev
.period
is active.- Type
- integer
- Default value
0 (years)
- Option
-pdd_sd_reference_year
surface.pdd.std_dev_lapse_lat_base
std_dev is a function of latitude, with value
surface
.pdd
.std_dev
at this latitude; this value only active ifsurface
.pdd
.std_dev_lapse_lat_rate
is nonzero- Type
- number
- Default value
72 (degree_north)
surface.pdd.std_dev_lapse_lat_rate
std_dev is a function of latitude, with rate of change with respect to latitude given by this constant
- Type
- number
- Default value
0 (Kelvin / degree_north)
surface.pdd.std_dev_param_a
Parameter \(a\) in \(\Sigma = aT + b\), with \(T\) in degrees C. Used only if
surface
.pdd
.std_dev_use_param
is set to yes.- Type
- number
- Default value
-0.15 (pure number)
surface.pdd.std_dev_param_b
Parameter \(b\) in \(\Sigma = aT + b\), with \(T\) in degrees C. Used only if
surface
.pdd
.std_dev_use_param
is set to yes.- Type
- number
- Default value
0.66 (Kelvin)
surface.pdd.std_dev_use_param
Parameterize standard deviation as a linear function of air temperature over ice-covered grid cells. The region of application is controlled by
geometry
.ice_free_thickness_standard
.- Type
- flag
- Default value
no
surface.pressure
atmospheric pressure; = pressure at ice surface
- Type
- number
- Default value
0 (Pascal)
surface.temp_to_runoff_a
a in runoff=a * temp + b
- Type
- number
- Default value
0.5 (K-1)
time.calendar
The calendar to use.
- Type
- keyword
- Default value
365_day
- Choices
standard, gregorian, proleptic_gregorian, noleap, 365_day, 360_day, julian, none
- Option
-calendar
time.dimension_name
The name of the time dimension in PISM output files.
- Type
- string
- Default value
time
time.eemian_end
End of the Eemian interglacial period. See [67].
- Type
- number
- Default value
-114500 (years)
time.eemian_start
Start of the Eemian interglacial period. See [67].
- Type
- number
- Default value
-132000 (years)
time.holocene_start
Start of the Holocene interglacial period. See [67].
- Type
- number
- Default value
-11000 (years)
time.reference_date
year-month-day; reference date used for calendar computations and in PISM output files
- Type
- string
- Default value
1-1-1
time.run_length
Default run length
- Type
- number
- Default value
1000 (years)
time.start_year
Start year.
- Type
- number
- Default value
0 (years)
time_stepping.adaptive_ratio
Adaptive time stepping ratio for the explicit scheme for the mass balance equation; [26], inequality (25)
- Type
- number
- Default value
0.12 (1)
- Option
-adapt_ratio
time_stepping.count_steps
If yes, IceModel::run() will count the number of time steps it took. Sometimes useful for performance evaluation. Counts all steps, regardless of whether processes (mass continuity, energy, velocity, …) occurred within the step.
- Type
- flag
- Default value
no
- Option
-count_steps
time_stepping.hit_extra_times
Modify the time-stepping mechanism to hit times requested using
output
.extra
.times
.- Type
- flag
- Default value
yes
- Option
-extra_force_output_times
time_stepping.hit_multiples
Hit every X years, where X is specified using this parameter. Use 0 to disable.
- Type
- number
- Default value
0 (years)
- Option
-timestep_hit_multiples
time_stepping.hit_save_times
Modify the time-stepping mechanism to hit times requested using
output
.snapshot
.times
.- Type
- flag
- Default value
no
- Option
-save_force_output_times
time_stepping.hit_ts_times
Modify the time-stepping mechanism to hit times requested using
output
.timeseries
.times
.- Type
- flag
- Default value
no
time_stepping.maximum_time_step
Maximum allowed time step length
- Type
- number
- Default value
60 (years)
- Option
-max_dt
time_stepping.skip.enabled
Use the temperature, age, and SSA stress balance computation skipping mechanism.
- Type
- flag
- Default value
no
- Option
-skip
time_stepping.skip.max
Number of mass-balance steps, including SIA diffusivity updates, to perform before a the temperature, age, and SSA stress balance computations are done
- Type
- integer
- Default value
10 (count)
- Option
-skip_max
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