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:

  1. Strings (mostly file names),
  2. Scalars (a number representing a physical quantify, usually with units),
  3. Integers (an integer number, usually corresponding to a count),
  4. Booleans (True/False, on/off, yes/no),
  5. 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.

  1. input.file (string)
    Value:no default
    Option:-i
    Description:Input file name
  2. input.bootstrap (boolean)
    Value:no
    Option:-bootstrap
    Description:It true, use bootstrapping heuristics when initializing PISM.
  3. input.regrid.file (string)
    Value:no default
    Option:-regrid_file
    Description:Regridding (input) file name
  4. input.regrid.vars (string)
    Value:no default
    Option:-regrid_vars
    Description:Comma-separated list of variables to regrid. Leave empty to regrid all model state variables.
  5. age.enabled (boolean)
    Value:no
    Option:-age
    Description:Solve age equation (advection equation for ice age).
  6. age.initial_value (scalar)
    Value:0 (years)
    Description:Initial age of ice
  7. atmosphere.fausto_air_temp.c_ma (scalar)
    Value:-0.718900 (Kelvin / degree_north)
    Description:latitude-dependence coefficient for formula (1) in [1]
  8. atmosphere.fausto_air_temp.c_mj (scalar)
    Value:-0.158500 (Kelvin / degree_north)
    Description:latitude-dependence coefficient for formula (2) in [1]
  9. atmosphere.fausto_air_temp.d_ma (scalar)
    Value:314.980000 (Kelvin)
    Description:41.83+273.15; base temperature for formula (1) in [1]
  10. atmosphere.fausto_air_temp.d_mj (scalar)
    Value:287.850000 (Kelvin)
    Description:= 14.70+273.15; base temperature for formula (2) in [1]
  11. atmosphere.fausto_air_temp.gamma_ma (scalar)
    Value:-0.006309 (Kelvin / meter)
    Description:= -6.309 / 1km; mean slope lapse rate for formula (1) in [1]
  12. atmosphere.fausto_air_temp.gamma_mj (scalar)
    Value:-0.005426 (Kelvin / meter)
    Description:= -5.426 / 1km; mean slope lapse rate for formula (2) in [1]
  13. atmosphere.fausto_air_temp.kappa_ma (scalar)
    Value:0.067200 (Kelvin / degree_west)
    Description:longitude-dependence coefficient for formula (1) in [1]
  14. atmosphere.fausto_air_temp.kappa_mj (scalar)
    Value:0.051800 (Kelvin / degree_west)
    Description:longitude-dependence coefficient for formula (2) in [1]
  15. atmosphere.fausto_air_temp.summer_peak_day (integer)
    Value:196
    Description:day of year for July 15; used in corrected formula (4) in [1]
  16. atmosphere.given.file (string)
    Value:no default
    Option:-atmosphere_given_file
    Description:Name of the file containing climate forcing fields.
  17. atmosphere.given.period (integer)
    Value:0
    Option:-atmosphere_given_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  18. atmosphere.given.reference_year (integer)
    Value:0
    Option:-atmosphere_given_reference_year
    Description:Reference year to use when atmosphere.given.period is active.
  19. atmosphere.anomaly.file (string)
    Value:no default
    Option:-atmosphere_anomaly_file
    Description:Name of the file containing climate forcing fields.
  20. atmosphere.anomaly.period (integer)
    Value:0
    Option:-atmosphere_anomaly_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  21. atmosphere.anomaly.reference_year (integer)
    Value:0
    Option:-atmosphere_anomaly_reference_year
    Description:Reference year to use when atmosphere.anomaly.period is active.
  22. atmosphere.lapse_rate.file (string)
    Value:no default
    Option:-atmosphere_lapse_rate_file
    Description:Name of the file containing the reference surface elevation field (variable usurf).
  23. atmosphere.lapse_rate.period (integer)
    Value:0
    Option:-atmosphere_lapse_rate_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  24. atmosphere.lapse_rate.reference_year (integer)
    Value:0
    Option:-atmosphere_lapse_rate_reference_year
    Description:Reference year to use when atmosphere.lapse_rate.period is active.
  25. atmosphere.precip_exponential_factor_for_temperature (scalar)
    Value:0.070417 (Kelvin-1)
    Description:= 0.169/2.4; in SeaRISE-Greenland formula for paleo-precipitation from present; a 7.3% change of precipitation rate for every one degC of temperature change [2]
  26. atmosphere.pik.file (string)
    Value:no default
    Option:-atmosphere_pik_file
    Description:Name of the file containing the reference surface elevation field (variable usurf).
  27. atmosphere.pik.parameterization (keyword)
    Value:martin
    Choices:martin, huybrechts_dewolde, martin_huybrechts_dewolde, era_interim, era_interim_sin, era_interim_lon
    Option:-atmosphere_pik
    Description:Selects parameterizations of mean annual and mean summer near-surface air temperatures.
  28. atmosphere.lapse_rate.precipitation_lapse_rate (scalar)
    Value:0 ((m / year) / km)
    Option:-precip_lapse_rate
    Description:Elevation lapse rate for the surface mass balance
  29. atmosphere.uniform.precipitation (scalar)
    Value:1000 (kg m-2 year-1)
    Description:Precipitation used by the ‘uniform’ atmosphere model.
  30. atmosphere.uniform.temperature (scalar)
    Value:273.150000 (Kelvin)
    Description:Air temperature used by the ‘uniform’ atmosphere model.
  31. basal_resistance.beta_ice_free_bedrock (scalar)
    Value:1.800000e+09 (Pascal second meter-1)
    Description:value is for ice stream E from [95]; 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
  32. basal_resistance.plastic.regularization (scalar)
    Value:0.010000 (meter / year)
    Option:-plastic_reg
    Description:Set the value of \(\epsilon\) regularization of plastic till; this is the second \(\epsilon\) in formula (4.1) in [38]
  33. basal_resistance.pseudo_plastic.enabled (boolean)
    Value:no
    Option:-pseudo_plastic
    Description:Use the pseudo-plastic till model (basal sliding law).
  34. basal_resistance.pseudo_plastic.q (scalar)
    Value:0.250000 (pure number)
    Option:-pseudo_plastic_q
    Description:The exponent of the pseudo-plastic basal resistance model
  35. basal_resistance.pseudo_plastic.sliding_scale_factor (scalar)
    Value:-1 (1)
    Option:-sliding_scale_factor_reduces_tauc
    Description: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
  36. basal_resistance.pseudo_plastic.u_threshold (scalar)
    Value:100 (meter / year)
    Option:-pseudo_plastic_uthreshold
    Description:threshold velocity of the pseudo-plastic sliding law
  37. basal_yield_stress.add_transportable_water (boolean)
    Value:no
    Option:-tauc_add_transportable_water
    Description: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.
  38. basal_yield_stress.constant.value (scalar)
    Value:200000 (Pascal)
    Option:-tauc
    Description: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
  39. basal_yield_stress.ice_free_bedrock (scalar)
    Value:1000000 (Pascal)
    Option:-high_tauc
    Description:the ‘high’ yield stress value used in grounded ice-free areas.
  40. basal_yield_stress.model (keyword)
    Value:mohr_coulomb
    Choices:constant, mohr_coulomb
    Option:-yield_stress
    Description:The basal yield stress model to use when sliding is active.
  41. basal_yield_stress.mohr_coulomb.till_cohesion (scalar)
    Value:0 (Pascal)
    Option:-till_cohesion
    Description: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…’
  42. basal_yield_stress.mohr_coulomb.till_compressibility_coefficient (scalar)
    Value:0.120000 (pure number)
    Option:-till_compressibility_coefficient
    Description:coefficient of compressiblity of till; value from [86]
  43. basal_yield_stress.mohr_coulomb.till_effective_fraction_overburden (scalar)
    Value:0.020000 (pure number)
    Option:-till_effective_fraction_overburden
    Description:\(\delta\) 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 [86]; default value from Greenland and Antarctic model runs
  44. basal_yield_stress.mohr_coulomb.till_log_factor_transportable_water (scalar)
    Value:0.100000 (meters)
    Option:-till_log_factor_transportable_water
    Description:If basal_yield_stress.add_transportable_water = yes then the water amount in the transport system is added to tillwat in determining tauc. Normally only the water in the till is used. This factor multiplies the logarithm in that formula.
  45. basal_yield_stress.mohr_coulomb.till_phi_default (scalar)
    Value:30 (degrees)
    Option:-plastic_phi
    Description:fill value for till friction angle
  46. basal_yield_stress.mohr_coulomb.till_reference_effective_pressure (scalar)
    Value:1000 (Pascal)
    Description:reference effective pressure N_0; value from [86]
  47. basal_yield_stress.mohr_coulomb.till_reference_void_ratio (scalar)
    Value:0.690000 (pure number)
    Option:-till_reference_void_ratio
    Description:void ratio at reference effective pressure N_0; value from [86]
  48. basal_yield_stress.mohr_coulomb.topg_to_phi.enabled (boolean)
    Value:no
    Description:If THE OPTION -topg_to_phi IS SET THEN THIS WILL BE SET TO ‘yes’, and then MohrCoulombYieldStress will initialize the tillphi field using a piece-wise linear function of depth described by four parameters.
  49. basal_yield_stress.mohr_coulomb.topg_to_phi.phi_max (scalar)
    Value:15 (degrees)
    Description:upper value of the till friction angle; see the implementation of MohrCoulombYieldStress
  50. basal_yield_stress.mohr_coulomb.topg_to_phi.phi_min (scalar)
    Value:5 (degrees)
    Description:lower value of the till friction angle; see the implementation of MohrCoulombYieldStress
  51. basal_yield_stress.mohr_coulomb.topg_to_phi.topg_max (scalar)
    Value:1000 (meters)
    Description:the elevation at which the upper value of the till friction angle is used; see the implementation of MohrCoulombYieldStress
  52. basal_yield_stress.mohr_coulomb.topg_to_phi.topg_min (scalar)
    Value:-1000 (meters)
    Description:the elevation at which the lower value of the till friction angle is used; see the implementation of MohrCoulombYieldStress
  53. basal_yield_stress.slippery_grounding_lines (boolean)
    Value:no
    Option:-tauc_slippery_grounding_lines
    Description: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.
  54. bed_deformation.lc.elastic_model (boolean)
    Value:no
    Option:-bed_def_lc_elastic_model
    Description:Use the elastic part of the Lingle-Clark bed deformation model.
  55. bed_deformation.lc.grid_size_factor (integer)
    Value:4
    Description:The spectral grid size is (Z*(grid.Mx - 1) + 1, Z*(grid.My - 1) + 1) where Z is given by this parameter. See [88], [89]
  56. bed_deformation.mantle_density (scalar)
    Value:3300 (kg meter-3)
    Description:half-space (mantle) density used by the bed deformation model. See [88], [89]
  57. bed_deformation.lithosphere_flexural_rigidity (scalar)
    Value:5.000000e+24 (Newton meter)
    Description:lithosphere flexural rigidity used by the bed deformation model. See [88], [89]
  58. bed_deformation.mantle_viscosity (scalar)
    Value:1.000000e+21 (Pascal second)
    Description:half-space (mantle) viscosity used by the bed deformation model. See [88], [89]
  59. bed_deformation.model (keyword)
    Value:none
    Choices:none, iso, lc
    Option:-bed_def
    Description:Selects a bed deformation model to use. ‘iso’ is point-wise isostasy, ‘lc’ is the Lingle-Clark model (see [88], requires FFTW3).
  60. bed_deformation.update_interval (scalar)
    Value:10 (years)
    Description:Interval between bed deformation updates
  61. bed_deformation.bed_topography_delta_file (string)
    Value:no default
    Option:-topg_delta_file
    Description:The name of the file to read the topg_delta from. This field is added to the bed topography during initialization.
  62. bed_deformation.bed_uplift_file (string)
    Value:no default
    Option:-uplift_file
    Description:The name of the file to read the uplift (dbdt) from. Leave empty to read it from an input file or a regridding file.
  63. bootstrapping.defaults.bed (scalar)
    Value:1 (meters)
    Description:bed elevation value to use if topg (bedrock_altitude) variable is absent in bootstrapping file
  64. bootstrapping.defaults.bmelt (scalar)
    Value:0 (meter / second)
    Description:basal melt rate value to use if variable bmelt is absent in bootstrapping file
  65. bootstrapping.defaults.bwat (scalar)
    Value:0 (meters)
    Description:till water thickness value to use if variable tillwat is absent in bootstrapping file
  66. bootstrapping.defaults.bwp (scalar)
    Value:0 (Pascal)
    Description:basal water pressure value to use if variable bwp is absent in bootstrapping file; most hydrology models do not use this value because bwp is diagnostic
  67. bootstrapping.defaults.enwat (scalar)
    Value:0 (meters)
    Description:effective englacial water thickness value to use if variable enwat is absent in bootstrapping file
  68. bootstrapping.defaults.geothermal_flux (scalar)
    Value:0.042000 (Watt meter-2)
    Description:geothermal flux value to use if bheatflx variable is absent in bootstrapping file
  69. bootstrapping.defaults.ice_thickness (scalar)
    Value:0 (meters)
    Description:thickness value to use if thk (land_ice_thickness) variable is absent in bootstrapping file
  70. bootstrapping.defaults.tillwat (scalar)
    Value:0 (meters)
    Description:till water thickness value to use if variable tillwat is absent in bootstrapping file
  71. bootstrapping.defaults.uplift (scalar)
    Value:0 (meter / second)
    Description:uplift value to use if dbdt variable is absent in bootstrapping file
  72. bootstrapping.temperature_heuristic (keyword)
    Value:smb
    Choices:smb, quartic_guess
    Option:-boot_temperature_heuristic
    Description: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.
  73. calving.eigen_calving.K (scalar)
    Value:0 (meter second)
    Option:-eigen_calving_K
    Description:Set proportionality constant to determine calving rate from strain rates. Note references [75], [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.
  74. calving.float_kill.margin_only (boolean)
    Value:no
    Option:-float_kill_margin_only
    Description:Apply float_kill at ice margin cells only.
  75. calving.float_kill.calve_near_grounding_line (boolean)
    Value:yes
    Option:-float_kill_calve_near_grounding_line
    Description:Calve floating ice near the grounding line.
  76. calving.front_retreat.wrap_around (boolean)
    Value:false
    Option:-calving_wrap_around
    Description:If true, wrap around domain boundaries. This may be needed in some regional synthetic geometry setups.
  77. calving.front_retreat.use_cfl (boolean)
    Value:false
    Option:-calving_cfl
    Description:apply CFL criterion for eigen-calving rate front retreat
  78. calving.methods (string)
    Value:no default
    Option:-calving
    Description:comma-separated list of calving methods; one or more of ‘eigen_calving’, ‘ocean_kill’, ‘float_kill’, ‘thickness_calving’
  79. calving.ocean_kill.file (string)
    Value:no default
    Option:-ocean_kill_file
    Description:Input file containing ice thickness and bed elevation used to compute maximum ice extent.
  80. calving.thickness_calving.threshold (scalar)
    Value:50 (meters)
    Option:-thickness_calving_threshold
    Description:When terminal ice thickness of floating ice shelf is less than this threshold, it will be calved off.
  81. calving.thickness_calving.threshold_file (string)
    Value:no default
    Option:-thickness_calving_threshold_file
    Description:Name of the file containing the spatially-variable thickness calving threshold.
  82. calving.vonmises.sigma_max (scalar)
    Value:1000000 (Pa)
    Option:-vonmises_calving_sigma_max
    Description:Set maximum tensile stress. Note references [76] use 1.0e6 Pa.
  83. climate_forcing.buffer_size (integer)
    Value:60
    Description:number of 2D climate forcing records to keep in memory; = 5 years of monthly records
  84. climate_forcing.evaluations_per_year (integer)
    Value:52
    Description:length of the time-series used to compute temporal averages of forcing data (such as mean annual temperature)
  85. constants.fresh_water.density (scalar)
    Value:1000 (kg meter-3)
    Description:density of fresh water
  86. constants.fresh_water.latent_heat_of_fusion (scalar)
    Value:334000 (Joule / kg)
    Description:latent heat of fusion for water [65]
  87. constants.fresh_water.melting_point_temperature (scalar)
    Value:273.150000 (Kelvin)
    Description:melting point of pure water
  88. constants.fresh_water.specific_heat_capacity (scalar)
    Value:4170 (Joule / (kg Kelvin))
    Description:at melting point T_0 [65]
  89. constants.ice.beta_Clausius_Clapeyron (scalar)
    Value:7.900000e-08 (Kelvin / Pascal)
    Description:Clausius-Clapeyron constant relating melting temperature and pressure: \(\beta = dT / dP\) [96]
  90. constants.ice.density (scalar)
    Value:910 (kg meter-3)
    Description:\(\rho_i\); density of ice in ice sheet
  91. constants.ice.grain_size (scalar)
    Value:1 (mm)
    Option:-ice_grain_size
    Description:Default constant ice grain size to use with the Goldsby-Kohlstedt [67] flow law
  92. constants.ice.specific_heat_capacity (scalar)
    Value:2009 (Joule / (kg Kelvin))
    Description:specific heat capacity of pure ice at melting point T_0
  93. constants.ice.thermal_conductivity (scalar)
    Value:2.100000 (Joule / (meter Kelvin second))
    Description:= W m-1 K-1; thermal conductivity of pure ice
  94. constants.ideal_gas_constant (scalar)
    Value:8.314410 (Joule / (mol Kelvin))
    Description:ideal gas constant
  95. constants.sea_water.density (scalar)
    Value:1028 (kg meter-3)
    Description:density of sea water
  96. constants.sea_water.specific_heat_capacity (scalar)
    Value:3985 (Joule / (kg Kelvin))
    Description:at 35 psu, value taken from http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html
  97. constants.global_ocean_area (scalar)
    Value:3.625000e+14 (meter2)
    Description:area of the global ocean [97]
  98. constants.standard_gravity (scalar)
    Value:9.810000 (meter second-2)
    Description:acceleration due to gravity on Earth geoid
  99. energy.allow_temperature_above_melting (boolean)
    Value:no
    Description:If set to ‘yes’, allow temperatures above the pressure-malting point in the cold mode temperature code. Used by some verifiaction tests.
  100. energy.basal_melt.use_grounded_cell_fraction (boolean)
    Value:true
    Option:-subgl_basal_melt
    Description: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.
  101. energy.bedrock_thermal_conductivity (scalar)
    Value:3 (Joule / (meter Kelvin second))
    Description:= W m-1 K-1; for bedrock used in thermal model [5]
  102. energy.bedrock_thermal_density (scalar)
    Value:3300 (kg meter-3)
    Description:for bedrock used in thermal model
  103. energy.bedrock_thermal_specific_heat_capacity (scalar)
    Value:1000 (Joule / (kg Kelvin))
    Description:for bedrock used in thermal model [5]
  104. energy.drainage_maximum_rate (scalar)
    Value:1.584438e-09 (second-1)
    Description:0.05 year-1; maximum rate at which liquid water fraction in temperate ice could possibly drain; see [28]
  105. energy.drainage_target_water_fraction (scalar)
    Value:0.010000 (1)
    Description:liquid water fraction (omega) above which drainage occurs, but below which there is no drainage; see [28]
  106. energy.enabled (boolean)
    Value:yes
    Description:Solve energy conservation equations.
  107. energy.enthalpy.cold_bulge_max (scalar)
    Value:60270 (Joule / kg)
    Description:= (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
  108. energy.ch_warming.enabled (boolean)
    Value:no
    Description:Enable the cryo-hydrologic warming model
  109. energy.ch_warming.residual_water_fraction (scalar)
    Value:0.005000 (pure number)
    Description:residual water fraction in the cryo-hydrologic system at the end of a melt season
  110. energy.ch_warming.temperate_ice_thermal_conductivity_ratio (scalar)
    Value:1 (pure number)
    Description:ratio of thermal conductivities of temperate and cold ice in the cryo-hydrologic system
  111. energy.ch_warming.average_channel_spacing (scalar)
    Value:20 (meters)
    Description:Average spacing between elements of the cryo-hydrologic system (controls the rate of heat transfer from the CH system into the ice).
  112. energy.margin_ice_thickness_limit (scalar)
    Value:100 (meters)
    Description:use special margin treatment at grid points with a neighbor with the thickness below this limit.
  113. energy.margin_exclude_horizontal_advection (boolean)
    Value:yes
    Description:Exclude horizontal advection of energy at grid points near ice margins. See energy.margin_ice_thickness_limit.
  114. energy.margin_exclude_vertical_advection (boolean)
    Value:yes
    Description:Exclude vertical advection of energy at grid points near ice margins. See energy.margin_ice_thickness_limit.
  115. energy.margin_exclude_strain_heating (boolean)
    Value:yes
    Description:Exclude strain heating at grid points near ice margins. See energy.margin_ice_thickness_limit.
  116. energy.max_low_temperature_count (integer)
    Value:10
    Option:-max_low_temps
    Description:Maximum number of grid points with ice temperature below energy.minimum_allowed_temperature.
  117. energy.minimum_allowed_temperature (scalar)
    Value:200 (Kelvin)
    Option:-low_temp
    Description:Minimum allowed ice temperature
  118. energy.enthalpy.temperate_ice_thermal_conductivity_ratio (scalar)
    Value:0.100000 (pure number)
    Description:K in cold ice is multiplied by this fraction to give K0 in [28]
  119. energy.temperature_based (boolean)
    Value:no
    Description:Use cold ice (i.e. not polythermal) methods.
  120. energy.temperature_dependent_thermal_conductivity (boolean)
    Value:no
    Option:-vark
    Description:If yes, use varkenthSystemCtx class in the energy step. It is base on formula (4.37) in [49]. Otherwise use enthSystemCtx, which has temperature-independent thermal conductivity set by constant ice.thermal_conductivity.
  121. enthalpy_converter.T_reference (scalar)
    Value:223.150000 (Kelvin)
    Description:= T_0 in enthalpy formulas in [28]
  122. enthalpy_converter.relaxed_is_temperate_tolerance (scalar)
    Value:0.001000 (Kelvin)
    Description:Tolerance within which ice is treated as temperate (cold-ice mode and diagnostics).
  123. flow_law.Hooke.A (scalar)
    Value:4.421650e-09 (Pascal-3 second-1)
    Description:\(A_{\text{Hooke}} = (1/B_0)^n\) where n=3 and B_0 = 1.928 \(a^{1/3}\) Pa. See [70]
  124. flow_law.Hooke.C (scalar)
    Value:0.166120 (Kelvin^{flow_law.Hooke.k})
    Description:See [70]
  125. flow_law.Hooke.Q (scalar)
    Value:78800 (Joule / mol)
    Description:Activation energy, see [70]
  126. flow_law.Hooke.Tr (scalar)
    Value:273.390000 (Kelvin)
    Description:See [70]
  127. flow_law.Hooke.k (scalar)
    Value:1.170000 (pure number)
    Description:See [70]
  128. flow_law.Paterson_Budd.A_cold (scalar)
    Value:3.610000e-13 (Pascal-3 / second)
    Description:Paterson-Budd A_cold, see [66]
  129. flow_law.Paterson_Budd.A_warm (scalar)
    Value:1730 (Pascal-3 / second)
    Description:Paterson-Budd A_warm, see [66]
  130. flow_law.Paterson_Budd.Q_cold (scalar)
    Value:60000 (Joule / mol)
    Description:Paterson-Budd Q_cold, see [66]
  131. flow_law.Paterson_Budd.Q_warm (scalar)
    Value:139000 (Joule / mol)
    Description:Paterson-Budd Q_warm, see [66]
  132. flow_law.Paterson_Budd.T_critical (scalar)
    Value:263.150000 (Kelvin)
    Description:Paterson-Budd critical temperature, see [66]
  133. flow_law.Schoof_regularizing_length (scalar)
    Value:1000 (km)
    Description:Regularizing length (Schoof definition)
  134. flow_law.Schoof_regularizing_velocity (scalar)
    Value:1 (meter / year)
    Description:Regularizing velocity (Schoof definition)
  135. flow_law.gpbld.water_frac_coeff (scalar)
    Value:181.250000 (pure number)
    Description:coefficient in Glen-Paterson-Budd flow law for extra dependence of softness on liquid water fraction (omega) [49], [68]
  136. flow_law.gpbld.water_frac_observed_limit (scalar)
    Value:0.010000 (1)
    Description:maximum value of liquid water fraction omega for which softness values are parameterized by [68]; used in Glen-Paterson-Budd-Lliboutry-Duval flow law; compare [28]
  137. flow_law.isothermal_Glen.ice_softness (scalar)
    Value:3.168900e-24 (Pascal-3 second-1)
    Description:ice softness used by IsothermalGlenIce [27]
  138. fracture_density.constant_fd (boolean)
    Value:no
    Option:-constant_fd
    Description:FIXME
  139. fracture_density.constant_healing (boolean)
    Value:no
    Option:-constant_healing
    Description:Constant healing
  140. fracture_density.enabled (boolean)
    Value:no
    Option:-fractures
    Description:Calculation of fracture density according to stresses and strain rate field.
  141. fracture_density.fd2d_scheme (boolean)
    Value:no
    Option:-scheme_fd2d
    Description:FIXME
  142. fracture_density.fracture_weighted_healing (boolean)
    Value:no
    Option:-fracture_weighted_healing
    Description:Fracture weighted healing
  143. fracture_density.include_grounded_ice (boolean)
    Value:no
    Option:-do_frac_on_grounded
    Description:model fracture density in grounded areas
  144. fracture_density.lefm (boolean)
    Value:no
    Option:-lefm
    Description:FIXME
  145. fracture_density.max_shear_stress (boolean)
    Value:no
    Option:-max_shear
    Description:Use the max. shear stress criterion.
  146. fracture_density.phi0 (scalar)
    Value:0 (1)
    Option:-phi0
    Description:FIXME
  147. fracture_density.softening_lower_limit (scalar)
    Value:1 (1)
    Option:-fracture_softening
    Description:epsilon in equation (6) in Albrecht and Levermann, ‘Fracture-induced softening for large-scale ice dynamics’
  148. fracture_density.write_fields (boolean)
    Value:no
    Option:-write_fd_fields
    Description:Writing of fracture density related fields to nc-file.
  149. geometry.grounded_cell_fraction (boolean)
    Value:false
    Option:-subgl
    Description: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.
  150. geometry.ice_free_thickness_standard (scalar)
    Value:0.010000 (meters)
    Description:If ice is thinner than this standard then the mask is set to MASK_ICE_FREE_BEDROCK or MASK_ICE_FREE_OCEAN.
  151. geometry.part_grid.enabled (boolean)
    Value:no
    Option:-part_grid
    Description:apply partially filled grid cell scheme
  152. geometry.part_grid.max_iterations (integer)
    Value:10
    Description:maximum number of residual redistribution iterations
  153. geometry.remove_icebergs (boolean)
    Value:no
    Option:-kill_icebergs
    Description:identify and kill detached ice-shelf areas
  154. geometry.update.enabled (boolean)
    Value:yes
    Option:-mass
    Description:Solve the mass conservation equation
  155. geometry.update.use_basal_melt_rate (boolean)
    Value:yes
    Option:-bmr_in_cont
    Description:Include basal melt rate in the continuity equation
  156. grid.allow_extrapolation (boolean)
    Value:no
    Option:-allow_extrapolation
    Description:Allow extrapolation during regridding.
  157. grid.Lbz (scalar)
    Value:1000 (meters)
    Description:Thickness of the thermal bedrock layer. (Inactive if grid.Mbz < 2)
  158. grid.Lx (scalar)
    Value:1500000 (meters)
    Description:Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.
  159. grid.Ly (scalar)
    Value:1500000 (meters)
    Description:Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.
  160. grid.Lz (scalar)
    Value:4000 (meters)
    Option:-Lz
    Description:Height of the computational domain.
  161. grid.Mbz (integer)
    Value:1
    Description:Number of thermal bedrock layers; 1 level corresponds to no bedrock.
  162. grid.Mx (integer)
    Value:61
    Option:-Mx
    Description:Number of grid points in the x direction.
  163. grid.My (integer)
    Value:61
    Option:-My
    Description:Number of grid points in the y direction.
  164. grid.Mz (integer)
    Value:31
    Option:-Mz
    Description:Number of vertical grid levels in the ice.
  165. grid.recompute_longitude_and_latitude (boolean)
    Value:yes
    Description:Re-compute longitude and latitude using grid information and provided projection parameters. Requires PROJ.4.
  166. grid.ice_vertical_spacing (keyword)
    Value:quadratic
    Choices:quadratic, equal
    Option:-z_spacing
    Description:vertical spacing in the ice
  167. grid.lambda (scalar)
    Value:4 (pure number)
    Description:Vertical grid spacing parameter. Roughly equal to the factor by which the grid is coarser at an end away from the ice-bedrock interface.
  168. grid.max_stencil_width (integer)
    Value:2
    Description:Maximum width of the finite-difference stencil used in PISM.
  169. grid.registration (keyword)
    Value:center
    Choices:center, corner
    Description:horizontal grid registration
  170. grid.periodicity (keyword)
    Value:xy
    Choices:none, x, y, xy
    Option:-periodicity
    Description:horizontal grid periodicity
  171. hydrology.cavitation_opening_coefficient (scalar)
    Value:0.500000 (meter-1)
    Option:-hydrology_cavitation_opening_coefficient
    Description:c_1 in notes; coefficient of cavitation opening term in evolution of layer thickness in hydrology::Distributed
  172. hydrology.creep_closure_coefficient (scalar)
    Value:0.040000 (pure number)
    Option:-hydrology_creep_closure_coefficient
    Description:c_2 in notes; coefficient of creep closure term in evolution of layer thickness in hydrology::Distributed
  173. hydrology.gradient_power_in_flux (scalar)
    Value:1.500000 (pure number)
    Option:-hydrology_gradient_power_in_flux
    Description: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
  174. hydrology.hydraulic_conductivity (scalar)
    Value:0.001000 (\(m^{2 \beta - \alpha} s^{2 \beta - 3} kg^{1-\beta}\))
    Option:-hydrology_hydraulic_conductivity
    Description:= 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
  175. hydrology.maximum_time_step (scalar)
    Value:1 (years)
    Description:maximum allowed time step length used by hydrology::Routing and hydrology::Distributed
  176. hydrology.model (keyword)
    Value:null
    Choices:null, routing, distributed
    Option:-hydrology
    Description:Basal hydrology sub-model.
  177. hydrology.null_diffuse_till_water (boolean)
    Value:no
    Description:Diffuse stored till water laterally. See equation (11) of [22]
  178. hydrology.null_diffusion_distance (scalar)
    Value:20000 (meters)
    Description:diffusion distance for till water thickness; see equation (11) in [22]; only active if hydrology.null_diffuse_till_water is set
  179. hydrology.null_diffusion_time (scalar)
    Value:1000 (years)
    Description:diffusion time for till water thickness; see equation (11) in [22]; only active if hydrology.null_diffuse_till_water is set
  180. hydrology.null_strip_width (scalar)
    Value:-1 (meters)
    Description: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
  181. hydrology.regularizing_porosity (scalar)
    Value:0.010000 (pure number)
    Option:-hydrology_regularizing_porosity
    Description:phi_0 in notes; regularizes pressure equation by multiplying time derivative term
  182. hydrology.roughness_scale (scalar)
    Value:0.100000 (meters)
    Option:-hydrology_roughness_scale
    Description:W_r in notes; roughness scale determining maximum amount of cavitation opening in hydrology::Distributed
  183. hydrology.thickness_power_in_flux (scalar)
    Value:1.250000 (1)
    Option:-hydrology_thickness_power_in_flux
    Description: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
  184. hydrology.tillwat_decay_rate (scalar)
    Value:1 (mm / year)
    Option:-hydrology_tillwat_decay_rate
    Description:rate at which tillwat is reduced to zero, in absence of other effects like input
  185. hydrology.tillwat_max (scalar)
    Value:2 (meters)
    Option:-hydrology_tillwat_max
    Description:maximum effective thickness of the water stored in till
  186. hydrology.use_const_bmelt (boolean)
    Value:no
    Option:-hydrology_use_const_bmelt
    Description:if ‘yes’, subglacial hydrology model sees basal melt rate which is constant and given by hydrology.const_bmelt
  187. hydrology.distributed.init_p_from_steady (boolean)
    Value:no
    Option:-hydrology_init_p_form_steady
    Description:if ‘yes’, initialize subglacial water pressure from P(W) formula that applies in steady state
  188. hydrology.distributed.sliding_speed_file (string)
    Value:no default
    Option:-hydrology_sliding_speed_file
    Description:name of the file containing velbase_mag, the basal sliding speed to use with hydrology.distributed.init_p_from_steady
  189. hydrology.surface_input_file (string)
    Value:no default
    Description:Basal hydrology sub.surface_input_file.
  190. inverse.design.cH1 (scalar)
    Value:0 (1)
    Option:-inv_design_cH1
    Description:weight of derivative part of an H1 norm for inversion design variables
  191. inverse.design.cL2 (scalar)
    Value:1 (1)
    Option:-inv_design_cL2
    Description:weight of derivative-free part of an H1 norm for inversion design variables
  192. inverse.design.func (keyword)
    Value:sobolevH1
    Choices:sobolevH1, tv
    Option:-inv_design_func
    Description:functional used for inversion design variables
  193. inverse.design.param (keyword)
    Value:exp
    Choices:ident, trunc, square, exp
    Option:-inv_design_param
    Description:parameterization of design variables used during inversion
  194. inverse.design.param_hardav_eps (scalar)
    Value:10000 (Pascal second^(1/3))
    Description:tiny vertically-averaged hardness used as a substitute for 0 in some tauc parameterizations
  195. inverse.design.param_hardav_scale (scalar)
    Value:1.000000e+08 (Pascal second^(1/3))
    Description:typical size of ice hardness
  196. inverse.design.param_tauc_eps (scalar)
    Value:100 (Pascal)
    Description:tiny yield stress used as a substitute for 0 in some tauc parameterizations
  197. inverse.design.param_tauc_scale (scalar)
    Value:100000 (Pascal)
    Description:typical size of yield stresses
  198. inverse.design.param_trunc_hardav0 (scalar)
    Value:1000000 (Pascal second^(1/3))
    Description:transition point of change to linear behaviour for design variable parameterization type ‘trunc’
  199. inverse.design.param_trunc_tauc0 (scalar)
    Value:1000 (Pascal)
    Description:transition point of change to linear behaviour for design variable parameterization type ‘trunc’
  200. inverse.log_ratio_scale (scalar)
    Value:10 (pure number)
    Option:-inv_log_ratio_scale
    Description:Reference scale for log-ratio functionals
  201. inverse.ssa.hardav_max (scalar)
    Value:1.000000e+10 (Pascal second^(1/3))
    Description:Maximum allowed value of hardav for inversions with bound constraints
  202. inverse.ssa.hardav_min (scalar)
    Value:0 (Pascal second^(1/3))
    Description:Minimum allowed value of hardav for inversions with bound constraints
  203. inverse.ssa.length_scale (scalar)
    Value:50000 (meters)
    Description:typical length scale for rescaling derivative norms
  204. inverse.ssa.method (keyword)
    Value:tikhonov_lmvm
    Choices:sd, nlcg, ign, tikhonov_lmvm, tikhonov_cg, tikhonov_blmvm, tikhonov_lcl, tikhonov_gn
    Option:-inv_method
    Description:algorithm to use for SSA inversions
  205. inverse.ssa.tauc_max (scalar)
    Value:5.000000e+07 (Pascal)
    Description:Maximum allowed value of tauc for inversions with bound constraints
  206. inverse.ssa.tauc_min (scalar)
    Value:0 (Pascal)
    Description:Minimum allowed value of tauc for inversions with bound constraints
  207. inverse.ssa.tv_exponent (scalar)
    Value:1.200000 (pure number)
    Option:-inv_ssa_tv_exponent
    Description:Lebesgue exponent for pseudo-TV norm
  208. inverse.ssa.velocity_eps (scalar)
    Value:0.100000 (meter / year)
    Description:tiny size of ice velocities during inversion
  209. inverse.ssa.velocity_scale (scalar)
    Value:100 (meter / year)
    Description:typical size of ice velocities expected during inversion
  210. inverse.state_func (keyword)
    Value:meansquare
    Choices:meansquare, log_ratio, log_relative
    Option:-inv_state_func
    Description:functional used for inversion design variables
  211. inverse.target_misfit (scalar)
    Value:100 (meter / year)
    Option:-inv_target_misfit
    Description:desired root misfit for SSA inversions
  212. inverse.tikhonov.atol (scalar)
    Value:1.000000e-10 (meter / year)
    Option:-tikhonov_atol
    Description:absolute threshold for Tikhonov stopping criterion
  213. inverse.tikhonov.penalty_weight (scalar)
    Value:1 (1)
    Option:-tikhonov_penalty
    Description:penalty parameter for Tikhonov inversion
  214. inverse.tikhonov.ptol (scalar)
    Value:0.100000 (pure number)
    Option:-tikhonov_ptol
    Description:threshold for reaching desired misfit for adaptive Tikhonov algorithms
  215. inverse.tikhonov.rtol (scalar)
    Value:0.050000 (1)
    Option:-tikhonov_rtol
    Description:relative threshold for Tikhonov stopping criterion
  216. inverse.max_iterations (integer)
    Value:1000
    Option:-inv_max_it
    Description:maximum iteration count
  217. inverse.use_zeta_fixed_mask (boolean)
    Value:yes
    Option:-inv_use_zeta_fixed_mask
    Description:Enforce locations where the parameterized design variable should be fixed. (Automatically determined if not provided)
  218. inverse.use_design_prior (boolean)
    Value:yes
    Option:-inv_use_design_prior
    Description:Use prior from inverse data file as initial guess.
  219. ocean.anomaly.file (string)
    Value:no default
    Option:-ocean_anomaly_file
    Description:Name of the file containing shelf basal mass flux offset fields.
  220. ocean.anomaly.period (integer)
    Value:0
    Option:-ocean_anomaly_period
    Description:Length of the period of the ocean forcing data. Set to zero to disable.
  221. ocean.anomaly.reference_year (integer)
    Value:0
    Option:-ocean_anomaly_reference_year
    Description:Reference year to use when ocean.anomaly.period is active.
  222. ocean.given.file (string)
    Value:no default
    Option:-ocean_given_file
    Description:Name of the file containing climate forcing fields.
  223. ocean.given.period (integer)
    Value:0
    Option:-ocean_given_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  224. ocean.given.reference_year (integer)
    Value:0
    Option:-ocean_given_reference_year
    Description:Reference year to use when ocean.given.period is active.
  225. ocean.delta_sl_2d.file (string)
    Value:no default
    Description:Name of the file containing climate forcing fields.
  226. ocean.delta_sl_2d.period (integer)
    Value:0
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  227. ocean.delta_sl_2d.reference_year (integer)
    Value:0
    Description:Reference year to use when ocean.delta_sl_2d.period is active.
  228. ocean.th.file (string)
    Value:no default
    Option:-ocean_th_file
    Description:Name of the file containing climate forcing fields.
  229. ocean.th.period (integer)
    Value:0
    Option:-ocean_th_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  230. ocean.th.reference_year (integer)
    Value:0
    Option:-ocean_th_reference_year
    Description:Reference year to use when ocean.th.period is active.
  231. ocean.pico.file (string)
    Value:no default
    Option:-ocean_pico_file
    Description:Name of the file containing climate forcing fields.
  232. ocean.pico.period (integer)
    Value:0
    Option:-ocean_pico_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  233. ocean.pico.reference_year (integer)
    Value:0
    Option:-ocean_pico_reference_year
    Description:Reference year to use when ocean.pico.period is active.
  234. ocean.always_grounded (boolean)
    Value:no
    Option:-dry
    Description:Dry (ocean-less) simulation; ice is considered grounded regardless of ice thickness, bed elevation, and sea level.
  235. ocean.pik_melt_factor (scalar)
    Value:0.005000 (1)
    Option:-meltfactor_pik
    Description:dimensionless tuning parameter in the ‘-ocean pik’ ocean heat flux parameterization; see [3]
  236. ocean.constant.melt_rate (scalar)
    Value:0.051914 (m / year)
    Option:-shelf_base_melt_rate
    Description:default melt rate used by the ‘constant’ ocean model (computed as \(Q / (L \rho_i)\))
  237. ocean.constant.melange_back_pressure_fraction (scalar)
    Value:0 (1)
    Description:default melange back pressure fraction in the ‘contant’ ocean model
  238. ocean.cache.update_interval (integer)
    Value:10
    Option:-ocean_cache_update_interval
    Description:update interval of the ‘cache’ ocean modifier
  239. ocean.sub_shelf_heat_flux_into_ice (scalar)
    Value:0.500000 (W meter-2)
    Description:= J meter-2 second-1; naively chosen default value for heat from ocean; see comments in pism::ocean::Constant::shelf_base_mass_flux().
  240. ocean.three_equation_model_clip_salinity (boolean)
    Value:yes
    Option:-clip_shelf_base_salinity
    Description:Clip shelf base salinity so that it is in the range [4, 40] k/kg. See [9].
  241. ocean.pico.number_of_boxes (integer)
    Value:5
    Option:-number_of_boxes
    Description:Default maximum number of boxes (for the largest ice shelves)
  242. ocean.pico.continental_shelf_depth (scalar)
    Value:-800 (meters)
    Option:-continental_shelf_depth
    Description:Determines the edge of the continental shelf to calculate mean ocean properties
  243. ocean.pico.maximum_ice_rise_area (scalar)
    Value:100000 (km2)
    Description:Maximum ice rise area. Patches of grounded ice that are bugger than this are treated as continental ice sheets.
  244. ocean.pico.overturning_coefficent (scalar)
    Value:1000000 (meters6 seconds-1 kg-1)
    Option:-overturning_coeff
    Description:Overturning stregth coefficient
  245. ocean.pico.heat_exchange_coefficent (scalar)
    Value:0.000020 (meters second-1)
    Option:-gamma_T
    Description:Turbulent heat exchange coefficient
  246. ocean.pico.exclude_ice_rises (boolean)
    Value:yes
    Option:-exclude_icerises
    Description:Exclude ice rises for box calculation in PICO
  247. output.extra.file (string)
    Value:no default
    Option:-extra_file
    Description:Name of the output file containing spatially-variable diagnostics.
  248. output.extra.times (string)
    Value:no default
    Option:-extra_times
    Description:List or a range of times defining reporting intervals for spatially-variable diagnostics.
  249. output.extra.vars (string)
    Value:no default
    Option:-extra_vars
    Description:Comma-separated list of spatially-variable diagnostics.
  250. output.extra.split (boolean)
    Value:no
    Option:-extra_split
    Description:Save spatially-variable diagnostics to separate files (one per time record).
  251. output.extra.append (boolean)
    Value:no
    Option:-extra_append
    Description:Append to an existing output file.
  252. output.backup_interval (scalar)
    Value:1 (hours)
    Option:-backup_interval
    Description:wall-clock time between automatic backups
  253. output.backup_size (keyword)
    Value:small
    Choices:none, small, medium, big_2d, big
    Option:-backup_size
    Description:The ‘size’ of a backup file. See configuration parameters output.sizes.medium, output.sizes.big_2d, output.sizes.big
  254. output.fill_value (scalar)
    Value:-2.000000e+09 (none)
    Description:_FillValue used when saving diagnostic quantities
  255. output.format (keyword)
    Value:netcdf3
    Choices:netcdf3, netcdf4_parallel, pnetcdf
    Option:-o_format
    Description:The I/O format used for spatial fields; ‘netcdf3’ is the default, ‘netcd4_parallel’ is available if PISM was built with parallel NetCDF-4, and ‘pnetcdf’ is available if PISM was built with PnetCDF.
  256. output.ice_free_thickness_standard (scalar)
    Value:10 (meters)
    Description:If ice is thinner than this standard then a grid cell is considered ice-free for purposes of reporting glacierized area, volume, etc.
  257. output.runtime.area_scale_factor_log10 (integer)
    Value:6
    Option:-summary_area_scale_factor_log10
    Description:an integer; log base 10 of scale factor to use for area (in km^2) in summary line to stdout
  258. output.file_name (string)
    Value:unnamed.nc
    Option:-o
    Description:The file to save final model results to.
  259. output.runtime.time_unit_name (string)
    Value:year
    Description: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.)
  260. output.runtime.time_use_calendar (boolean)
    Value:yes
    Description:Whether to use the current calendar when printing model time in summary to stdout.
  261. output.runtime.viewer.size (integer)
    Value:320
    Option:-view_size
    Description:default diagnostic viewer size (number of pixels of the longer side)
  262. output.runtime.viewer.variables (string)
    Value:no default
    Option:-view
    Description:comma-separated list of map-plane diagnostic quantities to view at runtime
  263. output.runtime.volume_scale_factor_log10 (integer)
    Value:6
    Option:-summary_vol_scale_factor_log10
    Description:an integer; log base 10 of scale factor to use for volume (in km^3) in summary line to stdout
  264. output.snapshot.file (string)
    Value:no default
    Option:-save_file
    Description:Snapshot (output) file name (or prefix, if saving to individual files).
  265. output.snapshot.times (string)
    Value:no default
    Option:-save_times
    Description:List or a range of times to save model state snapshots at.
  266. output.snapshot.split (boolean)
    Value:no
    Option:-save_split
    Description:Save model state snapshots to separate files (one per time record).
  267. output.snapshot.size (keyword)
    Value:small
    Choices:none, small, medium, big_2d, big
    Option:-save_size
    Description:The ‘size’ of a snapshot file. See configuration parameters output.sizes.medium, output.sizes.big_2d, output.sizes.big
  268. output.size (keyword)
    Value:medium
    Choices:none, small, medium, big_2d, big
    Option:-o_size
    Description:The ‘size’ of an output file. See configuration parameters output.sizes.medium, output.sizes.big_2d, output.sizes.big
  269. output.sizes.big (string)
    Value:cts, liqfrac, temp, temp_pa, uvel, vvel, wvel, wvel_rel
    Description:Comma-separated list of variables to write to the output (in addition to model_state variables and variables listed in output.sizes.medium and output.sizes.big_2d) if ‘big’ output size is selected. Does not include fields written by sub-models.
  270. output.sizes.big_2d (string)
    Value:age, bfrict, bheatflx, bmelt, bwp, bwprel, dbdt, effbwp, enthalpybase, enthalpysurf, flux_divergence, hardav, hydroinput, lat, litho_temp, lon, nuH, ocean_kill_mask, rank, tempbase, tempicethk, tempicethk_basal, temppabase, tempsurf, thk, thksmooth, tillphi, topg, velbar, velbase, wallmelt, wvelbase
    Description:Comma-separated list of variables to write to the output (in addition to model_state variables and variables listed in output.sizes.medium) if ‘big_2d’ output size is selected. Does not include fields written by boundary models.
  271. output.sizes.medium (string)
    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
    Description:Comma-separated list of variables to write to the output (in addition to model_state variables) if ‘medium’ output size (the default) is selected. Does not include fields written by sub-models.
  272. output.timeseries.buffer_size (integer)
    Value:10000
    Description: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.
  273. output.timeseries.variables (string)
    Value:no default
    Option:-ts_vars
    Description:Requested scalar (time-series) diagnostics. Leave empty to save all available diagnostics.
  274. output.timeseries.append (boolean)
    Value:false
    Option:-ts_append
    Description:If true, append to the scalar time series output file.
  275. output.timeseries.filename (string)
    Value:no default
    Option:-ts_file
    Description:Name of the file to save scalar time series to. Leave empty to disable reporting scalar time-series.
  276. output.timeseries.times (string)
    Value:no default
    Option:-ts_times
    Description:List or range of times defining reporting time intervals.
  277. output.variable_order (keyword)
    Value:yxz
    Choices:xyz, yxz, zyx
    Option:-o_order
    Description:Variable order to use in output files.
  278. regional.no_model_strip (scalar)
    Value:5 (km)
    Option:-no_model_strip
    Description:Default width of the ‘no model strip’ in regional setups.
  279. regional.no_model_yield_stress (scalar)
    Value:1000 (kPa)
    Description:High yield stress used in the ‘no_model_mask’ area in the regional mode.
  280. regional.zero_gradient (boolean)
    Value:false
    Option:-zero_grad_where_no_model
    Description:Use zero ice thickness and ice surface gradient in the no_model_mask area.
  281. run_info.institution (string)
    Value:no default
    Option:-institution
    Description:Institution name. This string is written to output files as the ‘institution’ global attribute.
  282. run_info.title (string)
    Value:no default
    Option:-title
    Description:Free-form string containing a concise description of the current run. This string is written to output files as the ‘title’ global attribute.
  283. stress_balance.calving_front_stress_bc (boolean)
    Value:no
    Option:-cfbc
    Description:Apply CFBC condition as in [78], [30]. 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 [22].
  284. stress_balance.ice_free_thickness_standard (scalar)
    Value:10 (meters)
    Description:If ice is thinner than this standard then a cell is considered ice-free for purposes of computing ice velocity distribution.
  285. stress_balance.model (keyword)
    Value:sia
    Choices:none, prescribed_sliding, weertman_sliding, sia, ssa, prescribed_sliding+sia, weertman_sliding+sia, ssa+sia
    Option:-stress_balance
    Description:Stress balance model
  286. stress_balance.sia.Glen_exponent (scalar)
    Value:3 (pure number)
    Option:-sia_n
    Description:Glen exponent in ice flow law for SIA
  287. stress_balance.sia.bed_smoother.range (scalar)
    Value:5000 (meters)
    Option:-bed_smoother_range
    Description:half-width of smoothing domain for stressbalance::BedSmoother, in implementing [91] bed roughness parameterization for SIA; set value to zero to turn off mechanism
  288. stress_balance.sia.bed_smoother.theta_min (scalar)
    Value:0 (1)
    Description:minimum value of \(\theta\) in [91] bed roughness parameterization for SIA
  289. stress_balance.sia.e_age_coupling (boolean)
    Value:no
    Option:-e_age_coupling
    Description:Couple the SIA enhancement factor to age as in [29].
  290. stress_balance.sia.enhancement_factor (scalar)
    Value:1 (1)
    Option:-sia_e
    Description:Flow enhancement factor for SIA
  291. stress_balance.sia.enhancement_factor_interglacial (scalar)
    Value:1 (1)
    Option:-sia_e_interglacial
    Description:Flow enhancement factor for SIA; used for ice accumulated during interglacial periods.
  292. stress_balance.sia.flow_law (keyword)
    Value:gpbld
    Choices:arr, arrwarm, gk, gpbld, hooke, isothermal_glen, pb
    Option:-sia_flow_law
    Description:The SIA flow law.
  293. stress_balance.sia.grain_size_age_coupling (boolean)
    Value:no
    Option:-grain_size_age_coupling
    Description:Use age of the ice to compute grain size to use with the Goldsby-Kohlstedt [67] flow law
  294. stress_balance.sia.limit_diffusivity (boolean)
    Value:no
    Option:-limit_sia_diffusivity
    Description:Limit SIA diffusivity by \(stress_balance.sia.max_diffusivity\).
  295. stress_balance.sia.max_diffusivity (scalar)
    Value:100 (m2 s-1)
    Description:Maximum allowed diffusivity of the SIA flow. PISM stops with an error message if the SIA diffusivity exceeds this limit.
  296. stress_balance.sia.surface_gradient_method (keyword)
    Value:haseloff
    Choices:eta, haseloff, mahaffy
    Option:-gradient
    Description:method used for surface gradient calculation at staggered grid points
  297. stress_balance.ssa.Glen_exponent (scalar)
    Value:3 (pure number)
    Option:-ssa_n
    Description:Glen exponent in ice flow law for SSA
  298. stress_balance.ssa.compute_surface_gradient_inward (boolean)
    Value:no
    Description:If yes then use inward first-order differencing in computing surface gradient in the SSA objects.
  299. stress_balance.ssa.dirichlet_bc (boolean)
    Value:no
    Option:-ssa_dirichlet_bc
    Description:apply SSA velocity Dirichlet boundary condition
  300. stress_balance.ssa.enhancement_factor (scalar)
    Value:1 (1)
    Option:-ssa_e
    Description:Flow enhancement factor for SSA
  301. stress_balance.ssa.enhancement_factor_interglacial (scalar)
    Value:1 (1)
    Option:-ssa_e_interglacial
    Description:Flow enhancement factor for SSA; used for ice accumulated during interglacial periods.
  302. stress_balance.ssa.epsilon (scalar)
    Value:1.000000e+13 (Pascal second meter)
    Option:-ssa_eps
    Description: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 \(s^{1/3}\) [61] 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 [98], but with a tiny thickness \(H\) of about 1 cm.
  303. stress_balance.ssa.read_initial_guess (boolean)
    Value:yes
    Option:-ssa_read_initial_guess
    Description:Read the initial guess from the input file when re-starting.
  304. stress_balance.ssa.fd.brutal_sliding (boolean)
    Value:false
    Option:-brutal_sliding
    Description:Enhance sliding speed brutally.
  305. stress_balance.ssa.fd.brutal_sliding_scale (scalar)
    Value:1 (1)
    Option:-brutal_sliding_scale
    Description:Brutal SSA Sliding Scale
  306. stress_balance.ssa.fd.lateral_drag.enabled (boolean)
    Value:false
    Description:set viscosity at ice shelf margin next to ice free bedrock as friction parameterization
  307. stress_balance.ssa.fd.lateral_drag.viscosity (scalar)
    Value:5.000000e+15 (Pascal second)
    Option:-nu_bedrock
    Description:Staggered Viscosity used as side friction parameterization.
  308. stress_balance.ssa.fd.max_iterations (integer)
    Value:300
    Option:-ssa_maxi
    Description:Maximum number of iterations for the ice viscosity computation, in the SSAFD object
  309. stress_balance.ssa.fd.nuH_iter_failure_underrelaxation (scalar)
    Value:0.800000 (pure number)
    Option:-ssafd_nuH_iter_failure_underrelaxation
    Description:In event of ‘Effective viscosity not converged’ failure, use outer iteration rule nuH <- nuH + f (nuH - nuH_old), where f is this parameter.
  310. stress_balance.ssa.fd.relative_convergence (scalar)
    Value:0.000100 (1)
    Option:-ssa_rtol
    Description:Relative change tolerance for the effective viscosity in the SSAFD object
  311. stress_balance.ssa.fd.replace_zero_diagonal_entries (boolean)
    Value:yes
    Description:Replace zero diagonal entries in the SSAFD matrix with basal_resistance.beta_ice_free_bedrock to avoid solver failures.
  312. stress_balance.ssa.fd.max_speed (scalar)
    Value:500000 (m yr-1)
    Option:-ssafd_max_speed
    Description:Upper bound for the ice speed computed by the SSAFD solver.
  313. stress_balance.ssa.flow_law (keyword)
    Value:gpbld
    Choices:arr, arrwarm, gpbld, hooke, isothermal_glen, pb
    Option:-ssa_flow_law
    Description:The SSA flow law.
  314. stress_balance.ssa.method (keyword)
    Value:fd
    Choices:fd, fem
    Option:-ssa_method
    Description:Algorithm for computing the SSA solution.
  315. stress_balance.ssa.strength_extension.constant_nu (scalar)
    Value:9.486807e+14 (Pascal second)
    Description: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 \(Pa s^{1/3}\) [61] 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 [98].
  316. stress_balance.ssa.strength_extension.min_thickness (scalar)
    Value:50 (meters)
    Description: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.
  317. stress_balance.vertical_velocity_approximation (keyword)
    Value:centered
    Choices:centered, upstream
    Option:-vertical_velocity_approximation
    Description:Vertical velocity FD approximation. “Upstream” uses first-order finite difference to compute u_x and v_y. Uses basal velocity to make decisions.
  318. stress_balance.weertman_sliding.A (scalar)
    Value:1.800000e-16 (Pa-3 year-1 m-2)
    Description:Sliding parameter in the Weertman-style sliding parameterization [72]
  319. stress_balance.weertman_sliding.k (scalar)
    Value:0.200000 (1)
    Description:The ratio of the basal water pressure and the ice overburden pressure in the Weertman-style sliding parameterization.
  320. surface.cache.update_interval (integer)
    Value:10
    Description:Update interval (in years) for the \(-surface cache\) modifier.
  321. surface.force_to_thickness_file (string)
    Value:no default
    Option:-force_to_thickness_file
    Description:The name of the file to read the target ice thickness from.
  322. surface.force_to_thickness.alpha (scalar)
    Value:0.010000 (year-1)
    Option:-force_to_thickness_alpha
    Description:exponential coefficient in force-to-thickness mechanism
  323. surface.force_to_thickness.ice_free_alpha_factor (scalar)
    Value:1 (1)
    Option:-force_to_thickness_ice_free_alpha_factor
    Description:surface.force_to_thickness.alpha is multiplied by this factor in areas that are ice-free according to the target ice thickness and surface.force_to_thickness.ice_free_thickness_threshold
  324. surface.force_to_thickness.ice_free_thickness_threshold (scalar)
    Value:1 (meters)
    Option:-force_to_thickness_ice_free_thickness_threshold
    Description: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.
  325. surface.force_to_thickness.start_time (scalar)
    Value:-4.540000e+09 (years)
    Description:Starting time for the “force to thickness” modifier; the default is “start from the creation of the Earth.”
  326. surface.given.smb_max (scalar)
    Value:91000 (kg m-2 year-1)
    Description:Maximum climatic mass balance value (used to check input data). Corresponds to 100 m/year ice equivalent.
  327. surface.given.file (string)
    Value:no default
    Option:-surface_given_file
    Description:Name of the file containing climate forcing fields.
  328. surface.given.period (integer)
    Value:0
    Option:-surface_given_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  329. surface.given.reference_year (integer)
    Value:0
    Option:-surface_given_reference_year
    Description:Reference year to use when surface.given.period is active.
  330. surface.lapse_rate.file (string)
    Value:no default
    Option:-surface_lapse_rate_file
    Description:Name of the file containing the reference surface elevation field (variable usurf).
  331. surface.lapse_rate.period (integer)
    Value:0
    Option:-surface_lapse_rate_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  332. surface.lapse_rate.reference_year (integer)
    Value:0
    Option:-surface_lapse_rate_reference_year
    Description:Reference year to use when surface.lapse_rate.period is active.
  333. surface.anomaly.file (string)
    Value:no default
    Option:-surface_anomaly_file
    Description:Name of the file containing climate forcing fields.
  334. surface.anomaly.period (integer)
    Value:0
    Option:-surface_anomaly_period
    Description:Length of the period of the climate forcing data. Set to zero to disable.
  335. surface.anomaly.reference_year (integer)
    Value:0
    Option:-surface_anomaly_reference_year
    Description:Reference year to use when surface.anomaly.period is active.
  336. surface.pdd.method (keyword)
    Value:expectation_integral
    Choices:expectation_integral, repeatable_random_process, random_process
    Option:-pdd_method
    Description:PDD implementation method
  337. surface.pdd.air_temp_all_precip_as_rain (scalar)
    Value:275.150000 (Kelvin)
    Description: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
  338. surface.pdd.air_temp_all_precip_as_snow (scalar)
    Value:273.150000 (Kelvin)
    Description:threshold temperature below which all precipitation is snow
  339. surface.pdd.balance_year_start_day (integer)
    Value:274
    Description:day of year for October 1st, beginning of the balance year in northern latitudes.
  340. surface.pdd.factor_ice (scalar)
    Value:0.008791 (meter / (Kelvin day))
    Description:EISMINT-Greenland value [5]; = (8 mm liquid-water-equivalent) / (pos degree day)
  341. surface.pdd.factor_snow (scalar)
    Value:0.003297 (meter / (Kelvin day))
    Description:EISMINT-Greenland value [5]; = (3 mm liquid-water-equivalent) / (pos degree day)
  342. surface.pdd.fausto.T_c (scalar)
    Value:272.150000 (Kelvin)
    Description:= -1 + 273.15; for formula (6) in [1]
  343. surface.pdd.fausto.T_w (scalar)
    Value:283.150000 (Kelvin)
    Description:= 10 + 273.15; for formula (6) in [1]
  344. surface.pdd.fausto.beta_ice_c (scalar)
    Value:0.015000 (meter / (Kelvin day))
    Description:water-equivalent thickness; for formula (6) in [1]
  345. surface.pdd.fausto.beta_ice_w (scalar)
    Value:0.007000 (meter / (Kelvin day))
    Description:water-equivalent thickness; for formula (6) in [1]
  346. surface.pdd.fausto.beta_snow_c (scalar)
    Value:0.003000 (meter / (Kelvin day))
    Description:water-equivalent thickness; for formula (6) in [1]
  347. surface.pdd.fausto.beta_snow_w (scalar)
    Value:0.003000 (meter / (Kelvin day))
    Description:water-equivalent thickness; for formula (6) in [1]
  348. surface.pdd.fausto.latitude_beta_w (scalar)
    Value:72 (degree_north)
    Description:latitude below which to use warm case, in formula (6) in [1]
  349. surface.pdd.firn_compaction_to_accumulation_ratio (scalar)
    Value:0.750000 (1)
    Description:How much firn as a fraction of accumulation is turned into ice
  350. surface.pdd.firn_depth_file (string)
    Value:no default
    Option:-pdd_firn_depth_file
    Description:The name of the file to read the firn_depth from.
  351. surface.pdd.temperature_standard_deviation_file (string)
    Value:no default
    Option:-pdd_sd_file
    Description:The name of the file to read air_temp_sd from.
  352. surface.pdd.interpret_precip_as_snow (boolean)
    Value:no
    Description:Interpret precipitation as snow fall.
  353. surface.pdd.max_evals_per_year (integer)
    Value:52
    Description: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
  354. surface.pdd.positive_threshold_temp (scalar)
    Value:273.150000 (Kelvin)
    Description:temperature used to determine meaning of ‘positive’ degree day
  355. surface.pdd.refreeze (scalar)
    Value:0.600000 (1)
    Description:EISMINT-Greenland value [5]
  356. surface.pdd.refreeze_ice_melt (boolean)
    Value:yes
    Description:If set to ‘yes’, refreeze surface.pdd.refreeze fraction of melted ice, otherwise all of the melted ice runs off.
  357. surface.pdd.std_dev (scalar)
    Value:5 (Kelvin)
    Description:std dev of daily temp variation; = EISMINT-Greenland value [5]
  358. surface.pdd.std_dev_lapse_lat_base (scalar)
    Value:72 (degree_north)
    Description:std_dev is a function of latitude, with value surface.pdd.std_dev at this latitude; this value only active if surface.pdd.std_dev_lapse_lat_rate is nonzero
  359. surface.pdd.std_dev_lapse_lat_rate (scalar)
    Value:0 (Kelvin / degree_north)
    Description:std_dev is a function of latitude, with rate of change with respect to latitude given by this constant
  360. surface.pdd.std_dev_param_a (scalar)
    Value:-0.150000 (pure number)
    Description:Parameter a in Sigma = a*T + b, with T in degrees C. Used only if surface.pdd.std_dev_use_param is set to yes.
  361. surface.pdd.std_dev_param_b (scalar)
    Value:0.660000 (Kelvin)
    Description:Parameter b in Sigma = a*T + b, with T in degrees C. Used only if surface.pdd.std_dev_use_param is set to yes.
  362. surface.pdd.std_dev_use_param (boolean)
    Value:no
    Description: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.
  363. surface.pressure (scalar)
    Value:0 (Pascal)
    Description:atmospheric pressure; = pressure at ice surface
  364. surface.temp_to_runoff_a (scalar)
    Value:0.500000 (K-1)
    Description:a in runoff=a * temp + b
  365. time.calendar (keyword)
    Value:365_day
    Choices:standard, gregorian, proleptic_gregorian, noleap, 365_day, 360_day, julian, none
    Option:-calendar
    Description:The calendar to use.
  366. time.dimension_name (string)
    Value:time
    Description:The name of the time dimension in PISM output files.
  367. time.eemian_end (scalar)
    Value:-114500 (years)
    Description:End of the Eemian interglacial period. See [64].
  368. time.eemian_start (scalar)
    Value:-132000 (years)
    Description:Start of the Eemian interglacial period. See [64].
  369. time.holocene_start (scalar)
    Value:-11000 (years)
    Description:Start of the Holocene interglacial period. See [64].
  370. time.reference_date (string)
    Value:1-1-1
    Description:year-month-day; reference date used for calendar computations and in PISM output files
  371. time.run_length (scalar)
    Value:1000 (years)
    Description:Default run length
  372. time.start_year (scalar)
    Value:0 (years)
    Description:Start year.
  373. time_stepping.adaptive_ratio (scalar)
    Value:0.120000 (1)
    Option:-adapt_ratio
    Description:Adaptive time stepping ratio for the explicit scheme for the mass balance equation; [23], inequality (25)
  374. time_stepping.count_steps (boolean)
    Value:no
    Option:-count_steps
    Description: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.
  375. time_stepping.hit_extra_times (boolean)
    Value:yes
    Option:-extra_force_output_times
    Description:Modify the time-stepping mechanism to hit times requested using -extra_times.
  376. time_stepping.hit_multiples (scalar)
    Value:0 (years)
    Option:-timestep_hit_multiples
    Description:Hit every X years, where X is specified using this parameter. Use 0 to disable
  377. time_stepping.hit_save_times (boolean)
    Value:no
    Option:-save_force_output_times
    Description:Modify the time-stepping mechanism to hit times requested using -save_times.
  378. time_stepping.hit_ts_times (boolean)
    Value:no
    Description:Modify the time-stepping mechanism to hit times requested using -ts_times.
  379. time_stepping.maximum_time_step (scalar)
    Value:60 (years)
    Option:-max_dt
    Description:Maximum allowed time step length
  380. time_stepping.skip.enabled (boolean)
    Value:no
    Option:-skip
    Description:Use the temperature, age, and SSA stress balance computation skipping mechanism.
  381. time_stepping.skip.max (integer)
    Value:10
    Option:-skip_max
    Description:Number of mass-balance steps, including SIA diffusivity updates, to perform before a the temperature, age, and SSA stress balance computations are done

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