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. Flags (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. age.enabled (flag)

    Value

    no

    Option

    -age

    Description

    Solve age equation (advection equation for ice age).

  2. age.initial_value (number)

    Value

    0 (years)

    Description

    Initial age of ice

  3. atmosphere.anomaly.file (string)

    Value

    no default

    Option

    -atmosphere_anomaly_file

    Description

    Name of the file containing climate forcing fields.

  4. 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.

  5. atmosphere.anomaly.reference_year (integer)

    Value

    0

    Option

    -atmosphere_anomaly_reference_year

    Description

    Reference year to use when atmosphere.anomaly.period is active.

  6. atmosphere.delta_P.file (string)

    Value

    no default

    Option

    -atmosphere_delta_P_file

    Description

    Name of the file containing scalar precipitation offsets.

  7. atmosphere.delta_P.period (integer)

    Value

    0

    Option

    -atmosphere_delta_P_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  8. atmosphere.delta_P.reference_year (integer)

    Value

    0

    Option

    -atmosphere_delta_P_reference_year

    Description

    Reference year to use when atmosphere.delta_P.period is active.

  9. atmosphere.delta_T.file (string)

    Value

    no default

    Option

    -atmosphere_delta_T_file

    Description

    Name of the file containing temperature offsets.

  10. atmosphere.delta_T.period (integer)

    Value

    0

    Option

    -atmosphere_delta_T_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  11. atmosphere.delta_T.reference_year (integer)

    Value

    0

    Option

    -atmosphere_delta_T_reference_year

    Description

    Reference year to use when atmosphere.delta_T.period is active.

  12. atmosphere.elevation_change.file (string)

    Value

    no default

    Option

    -atmosphere_lapse_rate_file

    Description

    Name of the file containing the reference surface elevation field (variable usurf).

  13. atmosphere.elevation_change.period (integer)

    Value

    0

    Option

    -atmosphere_lapse_rate_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  14. atmosphere.elevation_change.precipitation.lapse_rate (number)

    Value

    0 ((kg m-2 / year) / km)

    Option

    -precip_lapse_rate

    Description

    Elevation lapse rate for the surface mass balance

  15. atmosphere.elevation_change.precipitation.method (keyword)

    Value

    shift

    Choices

    scale, shift

    Option

    -precip_adjustment

    Description

    Choose the precipitation adjustment method. scale: use temperature-change-dependent scaling factor. shift: use the precipitation lapse rate.

  16. atmosphere.elevation_change.reference_year (integer)

    Value

    0

    Option

    -atmosphere_lapse_rate_reference_year

    Description

    Reference year to use when atmosphere.elevation_change.period is active.

  17. atmosphere.elevation_change.temperature_lapse_rate (number)

    Value

    0 (Kelvin / km)

    Option

    -temp_lapse_rate

    Description

    Elevation lapse rate for the surface temperature

  18. atmosphere.fausto_air_temp.c_ma (number)

    Value

    -0.718900 (Kelvin / degree_north)

    Description

    latitude-dependence coefficient for formula (1) in [1]

  19. atmosphere.fausto_air_temp.c_mj (number)

    Value

    -0.158500 (Kelvin / degree_north)

    Description

    latitude-dependence coefficient for formula (2) in [1]

  20. atmosphere.fausto_air_temp.d_ma (number)

    Value

    314.980000 (Kelvin)

    Description

    41.83+273.15; base temperature for formula (1) in [1]

  21. atmosphere.fausto_air_temp.d_mj (number)

    Value

    287.850000 (Kelvin)

    Description

    = 14.70+273.15; base temperature for formula (2) in [1]

  22. atmosphere.fausto_air_temp.gamma_ma (number)

    Value

    -0.006309 (Kelvin / meter)

    Description

    = -6.309 / 1km; mean slope lapse rate for formula (1) in [1]

  23. atmosphere.fausto_air_temp.gamma_mj (number)

    Value

    -0.005426 (Kelvin / meter)

    Description

    = -5.426 / 1km; mean slope lapse rate for formula (2) in [1]

  24. atmosphere.fausto_air_temp.kappa_ma (number)

    Value

    0.067200 (Kelvin / degree_west)

    Description

    longitude-dependence coefficient for formula (1) in [1]

  25. atmosphere.fausto_air_temp.kappa_mj (number)

    Value

    0.051800 (Kelvin / degree_west)

    Description

    longitude-dependence coefficient for formula (2) in [1]

  26. atmosphere.fausto_air_temp.summer_peak_day (integer)

    Value

    196

    Description

    day of year for July 15; used in corrected formula (4) in [1]

  27. atmosphere.frac_P.file (string)

    Value

    no default

    Option

    -atmosphere_frac_P_file

    Description

    Name of the file containing scalar precipitation scaling.

  28. atmosphere.frac_P.period (integer)

    Value

    0

    Option

    -atmosphere_frac_P_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  29. atmosphere.frac_P.reference_year (integer)

    Value

    0

    Option

    -atmosphere_frac_P_reference_year

    Description

    Reference year to use when atmosphere.frac_P.period is active.

  30. atmosphere.given.file (string)

    Value

    no default

    Option

    -atmosphere_given_file

    Description

    Name of the file containing climate forcing fields.

  31. 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.

  32. atmosphere.given.reference_year (integer)

    Value

    0

    Option

    -atmosphere_given_reference_year

    Description

    Reference year to use when atmosphere.given.period is active.

  33. atmosphere.models (string)

    Value

    given

    Option

    -atmosphere

    Description

    Comma-separated list of atmosphere melt models and modifiers.

  34. atmosphere.one_station.file (string)

    Value

    no default

    Option

    -atmosphere_one_station_file

    Description

    Specifies a file containing scalar time-series ‘precipitation’ and ‘air_temp’.

  35. atmosphere.orographic_precipitation.background_precip_post (number)

    Value

    0 (mm/hr)

    Option

    -background_precip_post

    Description

    Adding background precipitation after truncation

  36. atmosphere.orographic_precipitation.background_precip_pre (number)

    Value

    0 (mm/hr)

    Option

    -background_precip_pre

    Description

    Adding background precipitation before truncation

  37. atmosphere.orographic_precipitation.conversion_time (number)

    Value

    1000 (s)

    Option

    -conversion_time

    Description

    Cloud conversion time

  38. atmosphere.orographic_precipitation.coriolis_latitude (number)

    Value

    0 (degrees_N)

    Option

    -coriolis_latitude

    Description

    Latitude used to compute Coriolis force

  39. atmosphere.orographic_precipitation.fallout_time (number)

    Value

    1000 (s)

    Option

    -fallout_time

    Description

    Fallout time

  40. atmosphere.orographic_precipitation.grid_size_factor (integer)

    Value

    2

    Description

    The spectral grid size is (Z*(grid.Mx - 1) + 1, Z*(grid.My - 1) + 1) where Z is given by this parameter.

  41. atmosphere.orographic_precipitation.lapse_rate (number)

    Value

    -5.800000 (K / km)

    Option

    -lapse_rate

    Description

    Lapse rate

  42. atmosphere.orographic_precipitation.moist_adiabatic_lapse_rate (number)

    Value

    -6.500000 (K / km)

    Option

    -moist_adiabatic_lapse_rate

    Description

    Water vapor scale height

  43. atmosphere.orographic_precipitation.moist_stability_frequency (number)

    Value

    0.050000 (1/s)

    Option

    -moist_stability_frequency

    Description

    Moist stability frequency

  44. atmosphere.orographic_precipitation.reference_density (number)

    Value

    0.007400 (kg m-3)

    Option

    -reference_density

    Description

    Water vapor scale height

  45. atmosphere.orographic_precipitation.scale_factor (number)

    Value

    1 (1)

    Option

    -scale_factor

    Description

    Precipitation scaling factor

  46. atmosphere.orographic_precipitation.truncate (flag)

    Value

    true

    Option

    -truncate

    Description

    Truncate precipitation at 0

  47. atmosphere.orographic_precipitation.water_vapor_scale_height (number)

    Value

    2500 (m)

    Option

    -water_vapor_scale_height

    Description

    Water vapor scale height

  48. atmosphere.orographic_precipitation.wind_direction (number)

    Value

    270 (degrees)

    Option

    -wind_direction

    Description

    The direction the wind is coming from

  49. atmosphere.orographic_precipitation.wind_speed (number)

    Value

    10 (m/s)

    Option

    -wind_speed

    Description

    The direction the wind is coming from

  50. atmosphere.pik.file (string)

    Value

    no default

    Option

    -atmosphere_pik_file

    Description

    Name of the file containing the reference surface elevation field (variable usurf).

  51. 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.

  52. atmosphere.precip_exponential_factor_for_temperature (number)

    Value

    0.070417 (Kelvin-1)

    Description

    = 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]

  53. atmosphere.precip_scaling.file (string)

    Value

    no default

    Option

    -atmosphere_precip_scaling_file

    Description

    Name of the file containing temperature offsets to use for a precipitation correction.

  54. atmosphere.precip_scaling.period (integer)

    Value

    0

    Option

    -atmosphere_precip_scaling_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  55. atmosphere.precip_scaling.reference_year (integer)

    Value

    0

    Option

    -atmosphere_precip_scaling_reference_year

    Description

    Reference year to use when atmosphere.precip_scaling.period is active.

  56. atmosphere.searise_greenland.file (string)

    Value

    no default

    Option

    -atmosphere_searise_greenland_file

    Description

    Name of the file containing a precipitation field.

  57. atmosphere.uniform.precipitation (number)

    Value

    1000 (kg m-2 year-1)

    Description

    Precipitation used by the ‘uniform’ atmosphere model.

  58. atmosphere.uniform.temperature (number)

    Value

    273.150000 (Kelvin)

    Description

    Air temperature used by the ‘uniform’ atmosphere model.

  59. atmosphere.yearly_cycle.file (string)

    Value

    no default

    Option

    -atmosphere_yearly_cycle_file

    Description

    Name of the file containing mean annual and mean July temperatures (\(air_temp_mean_annual\) and \(air_temp_mean_summer\)) and the \(precipitation\) field.

  60. atmosphere.yearly_cycle.scaling.file (string)

    Value

    no default

    Option

    -atmosphere_yearly_cycle_scaling_file

    Description

    Name of the file containing amplitude scaling (\(amplitude_scaling\)) for the near-surface air temperature.

  61. atmosphere.yearly_cycle.scaling.period (integer)

    Value

    0

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  62. atmosphere.yearly_cycle.scaling.reference_year (integer)

    Value

    0

    Description

    Reference year to use when atmosphere.yearly_cycle.scaling.period is active.

  63. basal_resistance.beta_ice_free_bedrock (number)

    Value

    1.800000e+09 (Pascal second meter-1)

    Description

    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

  64. basal_resistance.beta_lateral_margin (number)

    Value

    1.000000e+19 (Pascal second meter-1)

    Description

    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

  65. basal_resistance.plastic.regularization (number)

    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 [41]

  66. basal_resistance.pseudo_plastic.enabled (flag)

    Value

    no

    Option

    -pseudo_plastic

    Description

    Use the pseudo-plastic till model (basal sliding law).

  67. basal_resistance.pseudo_plastic.q (number)

    Value

    0.250000 (pure number)

    Option

    -pseudo_plastic_q

    Description

    The exponent of the pseudo-plastic basal resistance model

  68. basal_resistance.pseudo_plastic.sliding_scale_factor (number)

    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

  69. basal_resistance.pseudo_plastic.u_threshold (number)

    Value

    100 (meter / year)

    Option

    -pseudo_plastic_uthreshold

    Description

    threshold velocity of the pseudo-plastic sliding law

  70. basal_yield_stress.add_transportable_water (flag)

    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.

  71. basal_yield_stress.constant.value (number)

    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

  72. basal_yield_stress.ice_free_bedrock (number)

    Value

    1000000 (Pascal)

    Option

    -high_tauc

    Description

    the ‘high’ yield stress value used in grounded ice-free areas.

  73. 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.

  74. basal_yield_stress.mohr_coulomb.delta.file (string)

    Value

    no default

    Option

    -mohr_coulomb_delta_file

    Description

    Name of the file containing space- and time-dependent variable \(mohr_coulomb_delta\) to use instead of \(basal_yield_stress.mohr_coulomb.till_effective_fraction_overburden\).

  75. basal_yield_stress.mohr_coulomb.delta.period (integer)

    Value

    0

    Option

    -mohr_coulomb_delta_period

    Description

    Length of the period. Set to zero to disable.

  76. basal_yield_stress.mohr_coulomb.delta.reference_year (integer)

    Value

    0

    Option

    -mohr_coulomb_delta_reference_year

    Description

    Reference year to use when basal_yield_stress.mohr_coulomb.delta.period is active.

  77. basal_yield_stress.mohr_coulomb.tauc_to_phi.file (string)

    Value

    no default

    Option

    -tauc_to_phi

    Description

    File containing the basal yield stress field that should be used to recover the till friction angle distribution.

  78. basal_yield_stress.mohr_coulomb.till_cohesion (number)

    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…’

  79. basal_yield_stress.mohr_coulomb.till_compressibility_coefficient (number)

    Value

    0.120000 (pure number)

    Option

    -till_compressibility_coefficient

    Description

    coefficient of compressiblity of till; value from [89]

  80. basal_yield_stress.mohr_coulomb.till_effective_fraction_overburden (number)

    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 [89]; default value from Greenland and Antarctic model runs

  81. basal_yield_stress.mohr_coulomb.till_log_factor_transportable_water (number)

    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.

  82. basal_yield_stress.mohr_coulomb.till_phi_default (number)

    Value

    30 (degrees)

    Option

    -plastic_phi

    Description

    fill value for till friction angle

  83. basal_yield_stress.mohr_coulomb.till_reference_effective_pressure (number)

    Value

    1000 (Pascal)

    Description

    reference effective pressure N_0; value from [89]

  84. basal_yield_stress.mohr_coulomb.till_reference_void_ratio (number)

    Value

    0.690000 (pure number)

    Option

    -till_reference_void_ratio

    Description

    void ratio at reference effective pressure N_0; value from [89]

  85. basal_yield_stress.mohr_coulomb.topg_to_phi.enabled (flag)

    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.

  86. basal_yield_stress.mohr_coulomb.topg_to_phi.phi_max (number)

    Value

    15 (degrees)

    Description

    upper value of the till friction angle; see the implementation of MohrCoulombYieldStress

  87. basal_yield_stress.mohr_coulomb.topg_to_phi.phi_min (number)

    Value

    5 (degrees)

    Description

    lower value of the till friction angle; see the implementation of MohrCoulombYieldStress

  88. basal_yield_stress.mohr_coulomb.topg_to_phi.topg_max (number)

    Value

    1000 (meters)

    Description

    the elevation at which the upper value of the till friction angle is used; see the implementation of MohrCoulombYieldStress

  89. basal_yield_stress.mohr_coulomb.topg_to_phi.topg_min (number)

    Value

    -1000 (meters)

    Description

    the elevation at which the lower value of the till friction angle is used; see the implementation of MohrCoulombYieldStress

  90. basal_yield_stress.slippery_grounding_lines (flag)

    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.

  91. 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.

  92. 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.

  93. bed_deformation.lc.elastic_model (flag)

    Value

    yes

    Option

    -bed_def_lc_elastic_model

    Description

    Use the elastic part of the Lingle-Clark bed deformation model.

  94. 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 [91], [23]

  95. bed_deformation.lc.update_interval (number)

    Value

    10 (years)

    Description

    Interval between updates of the Lingle-Clark model

  96. bed_deformation.lithosphere_flexural_rigidity (number)

    Value

    5.000000e+24 (Newton meter)

    Description

    lithosphere flexural rigidity used by the bed deformation model. See [91], [23]

  97. bed_deformation.mantle_density (number)

    Value

    3300 (kg meter-3)

    Description

    half-space (mantle) density used by the bed deformation model. See [91], [23]

  98. bed_deformation.mantle_viscosity (number)

    Value

    1.000000e+21 (Pascal second)

    Description

    half-space (mantle) viscosity used by the bed deformation model. See [91], [23]

  99. 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 [91], requires FFTW3).

  100. bootstrapping.defaults.bed (number)

    Value

    1 (meters)

    Description

    bed elevation value to use if topg (bedrock_altitude) variable is absent in bootstrapping file

  101. bootstrapping.defaults.bmelt (number)

    Value

    0 (meter / second)

    Description

    basal melt rate value to use if variable bmelt is absent in bootstrapping file

  102. bootstrapping.defaults.bwat (number)

    Value

    0 (meters)

    Description

    till water thickness value to use if variable tillwat is absent in bootstrapping file

  103. bootstrapping.defaults.bwp (number)

    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

  104. bootstrapping.defaults.enwat (number)

    Value

    0 (meters)

    Description

    effective englacial water thickness value to use if variable enwat is absent in bootstrapping file

  105. bootstrapping.defaults.geothermal_flux (number)

    Value

    0.042000 (Watt meter-2)

    Description

    geothermal flux value to use if bheatflx variable is absent in bootstrapping file

  106. bootstrapping.defaults.ice_thickness (number)

    Value

    0 (meters)

    Description

    thickness value to use if thk (land_ice_thickness) variable is absent in bootstrapping file

  107. bootstrapping.defaults.tillwat (number)

    Value

    0 (meters)

    Description

    till water thickness value to use if variable tillwat is absent in bootstrapping file

  108. bootstrapping.defaults.uplift (number)

    Value

    0 (meter / second)

    Description

    uplift value to use if dbdt variable is absent in bootstrapping file

  109. 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.

  110. calving.eigen_calving.K (number)

    Value

    0 (meter second)

    Option

    -eigen_calving_K

    Description

    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.

  111. calving.float_kill.calve_near_grounding_line (flag)

    Value

    yes

    Option

    -float_kill_calve_near_grounding_line

    Description

    Calve floating ice near the grounding line.

  112. calving.float_kill.margin_only (flag)

    Value

    no

    Option

    -float_kill_margin_only

    Description

    Apply float_kill at ice margin cells only.

  113. calving.hayhurst_calving.B_tilde (number)

    Value

    65 ((MPa)^r / year)

    Description

    Effective damage rate [98]

  114. calving.hayhurst_calving.exponent_r (number)

    Value

    0.430000 (1)

    Description

    Damage law exponent [98]

  115. calving.hayhurst_calving.sigma_threshold (number)

    Value

    0.170000 (MPa)

    Description

    Damage threshold stress [98]

  116. calving.methods (string)

    Value

    no default

    Option

    -calving

    Description

    comma-separated list of calving methods; one or more of ‘eigen_calving’, ‘float_kill’, ‘thickness_calving’

  117. calving.thickness_calving.threshold (number)

    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.

  118. 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.

  119. calving.vonmises_calving.Glen_exponent (number)

    Value

    3 (pure number)

    Option

    -vonmises_calving_n

    Description

    Glen exponent in ice flow law for von Mises calving

  120. calving.vonmises_calving.enhancement_factor (number)

    Value

    1 (1)

    Description

    Flow enhancement factor used by the flow law in the von Mises stress computation

  121. calving.vonmises_calving.enhancement_factor_interglacial (number)

    Value

    1 (1)

    Description

    Flow enhancement factor used by the flow law in the von Mises stress computation (for ice accumulated during interglacial periods).

  122. calving.vonmises_calving.flow_law (keyword)

    Value

    gpbld

    Choices

    arr, arrwarm, gpbld, hooke, isothermal_glen, pb

    Description

    The custom flow law for the von Mises stress computation

  123. calving.vonmises_calving.sigma_max (number)

    Value

    1000000 (Pa)

    Option

    -vonmises_calving_calving_sigma_max

    Description

    Set maximum tensile stress. Note references [79] use 1.0e6 Pa.

  124. calving.vonmises_calving.threshold_file (string)

    Value

    no default

    Option

    -vonmises_calving_threshold_file

    Description

    Name of the file containing the spatially-variable vonmises_calving calving threshold.

  125. calving.vonmises_calving.use_custom_flow_law (flag)

    Value

    no

    Option

    -vonmises_calving_use_custom_flow_law

    Description

    Use custom flow law in the von Mises stress computation

  126. constants.fresh_water.density (number)

    Value

    1000 (kg meter-3)

    Description

    density of fresh water

  127. constants.fresh_water.latent_heat_of_fusion (number)

    Value

    334000 (Joule / kg)

    Description

    latent heat of fusion for water [68]

  128. constants.fresh_water.melting_point_temperature (number)

    Value

    273.150000 (Kelvin)

    Description

    melting point of pure water

  129. constants.fresh_water.specific_heat_capacity (number)

    Value

    4170 (Joule / (kg Kelvin))

    Description

    at melting point T_0 [68]

  130. constants.global_ocean_area (number)

    Value

    3.625000e+14 (meter2)

    Description

    area of the global ocean [99]

  131. constants.ice.beta_Clausius_Clapeyron (number)

    Value

    7.900000e-08 (Kelvin / Pascal)

    Description

    Clausius-Clapeyron constant relating melting temperature and pressure: \(\beta = dT / dP\) [100]

  132. constants.ice.density (number)

    Value

    910 (kg meter-3)

    Description

    \(\rho_i\); density of ice in ice sheet

  133. constants.ice.grain_size (number)

    Value

    1 (mm)

    Option

    -ice_grain_size

    Description

    Default constant ice grain size to use with the Goldsby-Kohlstedt [70] flow law

  134. constants.ice.specific_heat_capacity (number)

    Value

    2009 (Joule / (kg Kelvin))

    Description

    specific heat capacity of pure ice at melting point T_0

  135. constants.ice.thermal_conductivity (number)

    Value

    2.100000 (Joule / (meter Kelvin second))

    Description

    = W m-1 K-1; thermal conductivity of pure ice

  136. constants.ideal_gas_constant (number)

    Value

    8.314410 (Joule / (mol Kelvin))

    Description

    ideal gas constant

  137. constants.sea_water.density (number)

    Value

    1028 (kg meter-3)

    Description

    density of sea water

  138. constants.sea_water.specific_heat_capacity (number)

    Value

    3985 (Joule / (kg Kelvin))

    Description

    at 35 psu, value taken from Kaye and Laby, section 2.7.9

  139. constants.standard_gravity (number)

    Value

    9.810000 (meter second-2)

    Description

    acceleration due to gravity on Earth geoid

  140. energy.allow_temperature_above_melting (flag)

    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.

  141. energy.basal_melt.use_grounded_cell_fraction (flag)

    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.

  142. energy.bedrock_thermal.conductivity (number)

    Value

    3 (Joule / (meter Kelvin second))

    Description

    = W m-1 K-1; for bedrock used in thermal model [7]

  143. energy.bedrock_thermal.density (number)

    Value

    3300 (kg meter-3)

    Description

    for bedrock used in thermal model

  144. energy.bedrock_thermal.file (string)

    Value

    no default

    Description

    Name of the file containing the geothermal flux field bheatflx. Leave empty to read it from the input.file.

  145. energy.bedrock_thermal.specific_heat_capacity (number)

    Value

    1000 (Joule / (kg Kelvin))

    Description

    for bedrock used in thermal model [7]

  146. energy.ch_warming.average_channel_spacing (number)

    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).

  147. energy.ch_warming.enabled (flag)

    Value

    no

    Description

    Enable the cryo-hydrologic warming model

  148. energy.ch_warming.residual_water_fraction (number)

    Value

    0.005000 (pure number)

    Description

    residual water fraction in the cryo-hydrologic system at the end of a melt season

  149. energy.ch_warming.temperate_ice_thermal_conductivity_ratio (number)

    Value

    1 (pure number)

    Description

    ratio of thermal conductivities of temperate and cold ice in the cryo-hydrologic system

  150. energy.drainage_maximum_rate (number)

    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 [31]

  151. energy.drainage_target_water_fraction (number)

    Value

    0.010000 (1)

    Description

    liquid water fraction (omega) above which drainage occurs, but below which there is no drainage; see [31]

  152. energy.enabled (flag)

    Value

    yes

    Description

    Solve energy conservation equations.

  153. energy.enthalpy.cold_bulge_max (number)

    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

  154. energy.enthalpy.temperate_ice_thermal_conductivity_ratio (number)

    Value

    0.100000 (pure number)

    Description

    K in cold ice is multiplied by this fraction to give K0 in [31]

  155. energy.margin_exclude_horizontal_advection (flag)

    Value

    yes

    Description

    Exclude horizontal advection of energy at grid points near ice margins. See energy.margin_ice_thickness_limit.

  156. energy.margin_exclude_strain_heating (flag)

    Value

    yes

    Description

    Exclude strain heating at grid points near ice margins. See energy.margin_ice_thickness_limit.

  157. energy.margin_exclude_vertical_advection (flag)

    Value

    yes

    Description

    Exclude vertical advection of energy at grid points near ice margins. See energy.margin_ice_thickness_limit.

  158. energy.margin_ice_thickness_limit (number)

    Value

    100 (meters)

    Description

    use special margin treatment at grid points with a neighbor with the thickness below this limit.

  159. 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.

  160. energy.minimum_allowed_temperature (number)

    Value

    200 (Kelvin)

    Option

    -low_temp

    Description

    Minimum allowed ice temperature

  161. energy.temperature_based (flag)

    Value

    no

    Description

    Use cold ice (i.e. not polythermal) methods.

  162. energy.temperature_dependent_thermal_conductivity (flag)

    Value

    no

    Option

    -vark

    Description

    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.

  163. enthalpy_converter.T_reference (number)

    Value

    223.150000 (Kelvin)

    Description

    = T_0 in enthalpy formulas in [31]

  164. enthalpy_converter.relaxed_is_temperate_tolerance (number)

    Value

    0.001000 (Kelvin)

    Description

    Tolerance within which ice is treated as temperate (cold-ice mode and diagnostics).

  165. flow_law.Hooke.A (number)

    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 [73]

  166. flow_law.Hooke.C (number)

    Value

    0.166120 (Kelvin^{flow_law.Hooke.k})

    Description

    See [73]

  167. flow_law.Hooke.Q (number)

    Value

    78800 (Joule / mol)

    Description

    Activation energy, see [73]

  168. flow_law.Hooke.Tr (number)

    Value

    273.390000 (Kelvin)

    Description

    See [73]

  169. flow_law.Hooke.k (number)

    Value

    1.170000 (pure number)

    Description

    See [73]

  170. flow_law.Paterson_Budd.A_cold (number)

    Value

    3.610000e-13 (Pascal-3 / second)

    Description

    Paterson-Budd A_cold, see [69]

  171. flow_law.Paterson_Budd.A_warm (number)

    Value

    1730 (Pascal-3 / second)

    Description

    Paterson-Budd A_warm, see [69]

  172. flow_law.Paterson_Budd.Q_cold (number)

    Value

    60000 (Joule / mol)

    Description

    Paterson-Budd Q_cold, see [69]

  173. flow_law.Paterson_Budd.Q_warm (number)

    Value

    139000 (Joule / mol)

    Description

    Paterson-Budd Q_warm, see [69]

  174. flow_law.Paterson_Budd.T_critical (number)

    Value

    263.150000 (Kelvin)

    Description

    Paterson-Budd critical temperature, see [69]

  175. flow_law.Schoof_regularizing_length (number)

    Value

    1000 (km)

    Description

    Regularizing length (Schoof definition)

  176. flow_law.Schoof_regularizing_velocity (number)

    Value

    1 (meter / year)

    Description

    Regularizing velocity (Schoof definition)

  177. flow_law.gpbld.water_frac_coeff (number)

    Value

    181.250000 (pure number)

    Description

    coefficient in Glen-Paterson-Budd flow law for extra dependence of softness on liquid water fraction (omega) [52], [71]

  178. flow_law.gpbld.water_frac_observed_limit (number)

    Value

    0.010000 (1)

    Description

    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]

  179. flow_law.isothermal_Glen.ice_softness (number)

    Value

    3.168900e-24 (Pascal-3 second-1)

    Description

    ice softness used by IsothermalGlenIce [30]

  180. fracture_density.constant_fd (flag)

    Value

    no

    Option

    -constant_fd

    Description

    FIXME

  181. fracture_density.constant_healing (flag)

    Value

    no

    Option

    -constant_healing

    Description

    Constant healing

  182. fracture_density.enabled (flag)

    Value

    no

    Option

    -fractures

    Description

    Calculation of fracture density according to stresses and strain rate field.

  183. fracture_density.fd2d_scheme (flag)

    Value

    no

    Option

    -scheme_fd2d

    Description

    FIXME

  184. fracture_density.fracture_weighted_healing (flag)

    Value

    no

    Option

    -fracture_weighted_healing

    Description

    Fracture weighted healing

  185. fracture_density.include_grounded_ice (flag)

    Value

    no

    Option

    -do_frac_on_grounded

    Description

    model fracture density in grounded areas

  186. fracture_density.lefm (flag)

    Value

    no

    Option

    -lefm

    Description

    FIXME

  187. fracture_density.max_shear_stress (flag)

    Value

    no

    Option

    -max_shear

    Description

    Use the max. shear stress criterion.

  188. fracture_density.phi0 (number)

    Value

    0 (1)

    Option

    -phi0

    Description

    FIXME

  189. fracture_density.softening_lower_limit (number)

    Value

    1 (1)

    Option

    -fracture_softening

    Description

    epsilon in equation (6) in Albrecht and Levermann, ‘Fracture-induced softening for large-scale ice dynamics’

  190. frontal_melt.constant.melt_rate (number)

    Value

    1 (m / day)

    Option

    -frontal_melt_rate

    Description

    default melt rate used by the ‘constant’ frontal_melt model

  191. frontal_melt.discharge_given.file (string)

    Value

    no default

    Option

    -frontal_melt_discharge_given_file

    Description

    Name of the file containing climate forcing fields.

  192. frontal_melt.discharge_given.period (integer)

    Value

    0

    Option

    -frontal_melt_discharge_given_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  193. frontal_melt.discharge_given.reference_year (integer)

    Value

    0

    Option

    -frontal_melt_discharge_given_reference_year

    Description

    Reference year to use when frontal_melt.discharge_given.period is active.

  194. frontal_melt.given.file (string)

    Value

    no default

    Option

    -frontal_melt_given_file

    Description

    Name of the file containing climate forcing fields.

  195. frontal_melt.given.period (integer)

    Value

    0

    Option

    -frontal_melt_given_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  196. frontal_melt.given.reference_year (integer)

    Value

    0

    Option

    -frontal_melt_given_reference_year

    Description

    Reference year to use when frontal_melt.given.period is active.

  197. frontal_melt.include_floating_ice (flag)

    Value

    no

    Description

    Apply frontal melt to all grid icy cells next to ocean cells

  198. frontal_melt.models (string)

    Value

    no default

    Option

    -frontal_melt

    Description

    Comma-separated list of frontal melt models and modifiers. (Leave empty to disable.)

  199. frontal_melt.routing.file (string)

    Value

    no default

    Option

    -frontal_melt_routing_file

    Description

    Name of the file containing climate forcing fields.

  200. frontal_melt.routing.parameter_a (number)

    Value

    0.000300 (m-alpha day^(alpha-1) Celsius-beta)

    Description

    parameter A in eqn. 1 in [101]

  201. frontal_melt.routing.parameter_b (number)

    Value

    0.150000 (m day^(alpha-1) Celsius-beta)

    Description

    parameter B in eqn. 1 in [101]

  202. frontal_melt.routing.period (integer)

    Value

    0

    Option

    -frontal_melt_routing_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  203. frontal_melt.routing.power_alpha (number)

    Value

    0.390000 (1)

    Description

    exponent \(\alpha\) in eqn. 1 in [101]

  204. frontal_melt.routing.power_beta (number)

    Value

    1.180000 (1)

    Description

    exponent \(\beta\) in eqn. 1 in [101]

  205. frontal_melt.routing.reference_year (integer)

    Value

    0

    Option

    -frontal_melt_routing_reference_year

    Description

    Reference year to use when frontal_melt.routing.period is active.

  206. geometry.front_retreat.prescribed.file (string)

    Value

    no default

    Option

    -front_retreat_file

    Description

    Name of the file containing the maximum ice extent mask \(land_ice_area_fraction_retreat\)

  207. geometry.front_retreat.prescribed.period (integer)

    Value

    0

    Description

    Length of the period of the front retreat data. Set to zero to disable.

  208. geometry.front_retreat.prescribed.reference_year (integer)

    Value

    0

    Description

    Reference year to use when \(geometry.front_retreat.prescribed.period\) is active.

  209. geometry.front_retreat.use_cfl (flag)

    Value

    false

    Option

    -front_retreat_cfl

    Description

    apply CFL criterion for eigen-calving rate front retreat

  210. geometry.front_retreat.wrap_around (flag)

    Value

    false

    Option

    -front_retreat_wrap_around

    Description

    If true, wrap around domain boundaries. This may be needed in some regional synthetic geometry setups.

  211. geometry.grounded_cell_fraction (flag)

    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.

  212. geometry.ice_free_thickness_standard (number)

    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.

  213. geometry.part_grid.enabled (flag)

    Value

    no

    Option

    -part_grid

    Description

    apply partially filled grid cell scheme

  214. geometry.part_grid.max_iterations (integer)

    Value

    10

    Description

    maximum number of residual redistribution iterations

  215. geometry.remove_icebergs (flag)

    Value

    no

    Option

    -kill_icebergs

    Description

    identify and kill detached ice-shelf areas

  216. geometry.update.enabled (flag)

    Value

    yes

    Option

    -mass

    Description

    Solve the mass conservation equation

  217. geometry.update.use_basal_melt_rate (flag)

    Value

    yes

    Option

    -bmr_in_cont

    Description

    Include basal melt rate in the continuity equation

  218. grid.Lbz (number)

    Value

    1000 (meters)

    Option

    -Lbz

    Description

    Thickness of the thermal bedrock layer. (Inactive if grid.Mbz < 2)

  219. grid.Lx (number)

    Value

    1500000 (meters)

    Description

    Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.

  220. grid.Ly (number)

    Value

    1500000 (meters)

    Description

    Default computational box is 3000 km x 3000 km (= 2 Lx x 2 Ly) in horizontal.

  221. grid.Lz (number)

    Value

    4000 (meters)

    Option

    -Lz

    Description

    Height of the computational domain.

  222. grid.Mbz (integer)

    Value

    1

    Option

    -Mbz

    Description

    Number of thermal bedrock layers; 1 level corresponds to no bedrock.

  223. grid.Mx (integer)

    Value

    61

    Option

    -Mx

    Description

    Number of grid points in the x direction.

  224. grid.My (integer)

    Value

    61

    Option

    -My

    Description

    Number of grid points in the y direction.

  225. grid.Mz (integer)

    Value

    31

    Option

    -Mz

    Description

    Number of vertical grid levels in the ice.

  226. grid.allow_extrapolation (flag)

    Value

    no

    Option

    -allow_extrapolation

    Description

    Allow extrapolation during regridding.

  227. grid.ice_vertical_spacing (keyword)

    Value

    quadratic

    Choices

    quadratic, equal

    Option

    -z_spacing

    Description

    vertical spacing in the ice

  228. grid.lambda (number)

    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.

  229. grid.max_stencil_width (integer)

    Value

    2

    Description

    Maximum width of the finite-difference stencil used in PISM.

  230. grid.periodicity (keyword)

    Value

    xy

    Choices

    none, x, y, xy

    Option

    -periodicity

    Description

    horizontal grid periodicity

  231. grid.recompute_longitude_and_latitude (flag)

    Value

    yes

    Description

    Re-compute longitude and latitude using grid information and provided projection parameters. Requires PROJ.

  232. grid.registration (keyword)

    Value

    center

    Choices

    center, corner

    Description

    horizontal grid registration

  233. hydrology.add_water_input_to_till_storage (flag)

    Value

    yes

    Description

    Add surface input to water stored in till. If no it will be added to the transportable water.

  234. hydrology.cavitation_opening_coefficient (number)

    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

  235. hydrology.creep_closure_coefficient (number)

    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

  236. hydrology.distributed.init_p_from_steady (flag)

    Value

    no

    Option

    -hydrology_init_p_form_steady

    Description

    if ‘yes’, initialize subglacial water pressure from P(W) formula that applies in steady state

  237. 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

  238. hydrology.gradient_power_in_flux (number)

    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

  239. hydrology.hydraulic_conductivity (number)

    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

  240. hydrology.maximum_time_step (number)

    Value

    1 (years)

    Description

    maximum allowed time step length used by hydrology::Routing and hydrology::Distributed

  241. hydrology.model (keyword)

    Value

    null

    Choices

    null, routing, steady, distributed

    Option

    -hydrology

    Description

    Basal hydrology sub-model.

  242. hydrology.null_diffuse_till_water (flag)

    Value

    no

    Description

    Diffuse stored till water laterally. See equation (11) of [25]

  243. hydrology.null_diffusion_distance (number)

    Value

    20000 (meters)

    Description

    diffusion distance for till water thickness; see equation (11) in [25]; only active if hydrology.null_diffuse_till_water is set

  244. hydrology.null_diffusion_time (number)

    Value

    1000 (years)

    Description

    diffusion time for till water thickness; see equation (11) in [25]; only active if hydrology.null_diffuse_till_water is set

  245. hydrology.null_strip_width (number)

    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

  246. hydrology.regularizing_porosity (number)

    Value

    0.010000 (pure number)

    Option

    -hydrology_regularizing_porosity

    Description

    phi_0 in notes; regularizes pressure equation by multiplying time derivative term

  247. hydrology.roughness_scale (number)

    Value

    0.100000 (meters)

    Option

    -hydrology_roughness_scale

    Description

    W_r in notes; roughness scale determining maximum amount of cavitation opening in hydrology::Distributed

  248. hydrology.routing.include_floating_ice (flag)

    Value

    no

    Description

    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.

  249. hydrology.steady.flux_update_interval (number)

    Value

    1 (years)

    Description

    interval between updates of the steady state flux

  250. hydrology.steady.input_rate_scaling (number)

    Value

    1.000000e+07 (seconds)

    Description

    input rate scaling

  251. hydrology.steady.n_iterations (integer)

    Value

    7500

    Description

    maxinum number of iterations to use in while estimating steady-state water flux

  252. hydrology.steady.potential_delta (number)

    Value

    10000 (Pa)

    Description

    potential adjustment used to fill sinks (smaller values require more iterations but produce fewer artifacts)

  253. hydrology.steady.potential_n_iterations (integer)

    Value

    1000

    Description

    maxinum number of iterations to take while pre-processing hydraulic potential

  254. hydrology.steady.volume_ratio (number)

    Value

    0.100000 (1)

    Description

    water volume ratio used as the stopping criterion

  255. hydrology.surface_input.file (string)

    Value

    no default

    Description

    Name of the file containing water_input_rate, the rate at which water from the ice surface is added to the subglacial hydrology system

  256. hydrology.surface_input.period (integer)

    Value

    0

    Description

    Length of the period of the water input rate. Set to zero to disable.

  257. hydrology.surface_input.reference_year (integer)

    Value

    0

    Description

    Reference year to use when hydrology.surface_input.period is active.

  258. hydrology.surface_input_from_runoff (flag)

    Value

    no

    Description

    Use surface runoff as surface input.

  259. hydrology.thickness_power_in_flux (number)

    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

  260. hydrology.tillwat_decay_rate (number)

    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

  261. hydrology.tillwat_max (number)

    Value

    2 (meters)

    Option

    -hydrology_tillwat_max

    Description

    maximum effective thickness of the water stored in till

  262. hydrology.use_const_bmelt (flag)

    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

  263. input.bootstrap (flag)

    Value

    no

    Option

    -bootstrap

    Description

    It true, use bootstrapping heuristics when initializing PISM.

  264. input.file (string)

    Value

    no default

    Option

    -i

    Description

    Input file name

  265. input.forcing.buffer_size (integer)

    Value

    60

    Description

    number of 2D climate forcing records to keep in memory; = 5 years of monthly records

  266. input.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)

  267. input.regrid.file (string)

    Value

    no default

    Option

    -regrid_file

    Description

    Regridding (input) file name

  268. 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.

  269. inverse.design.cH1 (number)

    Value

    0 (1)

    Option

    -inv_design_cH1

    Description

    weight of derivative part of an H1 norm for inversion design variables

  270. inverse.design.cL2 (number)

    Value

    1 (1)

    Option

    -inv_design_cL2

    Description

    weight of derivative-free part of an H1 norm for inversion design variables

  271. inverse.design.func (keyword)

    Value

    sobolevH1

    Choices

    sobolevH1, tv

    Option

    -inv_design_func

    Description

    functional used for inversion design variables

  272. inverse.design.param (keyword)

    Value

    exp

    Choices

    ident, trunc, square, exp

    Option

    -inv_design_param

    Description

    parameterization of design variables used during inversion

  273. inverse.design.param_hardav_eps (number)

    Value

    10000 (Pascal second^(1/3))

    Description

    tiny vertically-averaged hardness used as a substitute for 0 in some tauc parameterizations

  274. inverse.design.param_hardav_scale (number)

    Value

    1.000000e+08 (Pascal second^(1/3))

    Description

    typical size of ice hardness

  275. inverse.design.param_tauc_eps (number)

    Value

    100 (Pascal)

    Description

    tiny yield stress used as a substitute for 0 in some tauc parameterizations

  276. inverse.design.param_tauc_scale (number)

    Value

    100000 (Pascal)

    Description

    typical size of yield stresses

  277. inverse.design.param_trunc_hardav0 (number)

    Value

    1000000 (Pascal second^(1/3))

    Description

    transition point of change to linear behaviour for design variable parameterization type ‘trunc’

  278. inverse.design.param_trunc_tauc0 (number)

    Value

    1000 (Pascal)

    Description

    transition point of change to linear behaviour for design variable parameterization type ‘trunc’

  279. inverse.log_ratio_scale (number)

    Value

    10 (pure number)

    Option

    -inv_log_ratio_scale

    Description

    Reference scale for log-ratio functionals

  280. inverse.max_iterations (integer)

    Value

    1000

    Option

    -inv_max_it

    Description

    maximum iteration count

  281. inverse.ssa.hardav_max (number)

    Value

    1.000000e+10 (Pascal second^(1/3))

    Description

    Maximum allowed value of hardav for inversions with bound constraints

  282. inverse.ssa.hardav_min (number)

    Value

    0 (Pascal second^(1/3))

    Description

    Minimum allowed value of hardav for inversions with bound constraints

  283. inverse.ssa.length_scale (number)

    Value

    50000 (meters)

    Description

    typical length scale for rescaling derivative norms

  284. 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

  285. inverse.ssa.tauc_max (number)

    Value

    5.000000e+07 (Pascal)

    Description

    Maximum allowed value of tauc for inversions with bound constraints

  286. inverse.ssa.tauc_min (number)

    Value

    0 (Pascal)

    Description

    Minimum allowed value of tauc for inversions with bound constraints

  287. inverse.ssa.tv_exponent (number)

    Value

    1.200000 (pure number)

    Option

    -inv_ssa_tv_exponent

    Description

    Lebesgue exponent for pseudo-TV norm

  288. inverse.ssa.velocity_eps (number)

    Value

    0.100000 (meter / year)

    Description

    tiny size of ice velocities during inversion

  289. inverse.ssa.velocity_scale (number)

    Value

    100 (meter / year)

    Description

    typical size of ice velocities expected during inversion

  290. inverse.state_func (keyword)

    Value

    meansquare

    Choices

    meansquare, log_ratio, log_relative

    Option

    -inv_state_func

    Description

    functional used for inversion design variables

  291. inverse.target_misfit (number)

    Value

    100 (meter / year)

    Option

    -inv_target_misfit

    Description

    desired root misfit for SSA inversions

  292. inverse.tikhonov.atol (number)

    Value

    1.000000e-10 (meter / year)

    Option

    -tikhonov_atol

    Description

    absolute threshold for Tikhonov stopping criterion

  293. inverse.tikhonov.penalty_weight (number)

    Value

    1 (1)

    Option

    -tikhonov_penalty

    Description

    penalty parameter for Tikhonov inversion

  294. inverse.tikhonov.ptol (number)

    Value

    0.100000 (pure number)

    Option

    -tikhonov_ptol

    Description

    threshold for reaching desired misfit for adaptive Tikhonov algorithms

  295. inverse.tikhonov.rtol (number)

    Value

    0.050000 (1)

    Option

    -tikhonov_rtol

    Description

    relative threshold for Tikhonov stopping criterion

  296. inverse.use_design_prior (flag)

    Value

    yes

    Option

    -inv_use_design_prior

    Description

    Use prior from inverse data file as initial guess.

  297. inverse.use_zeta_fixed_mask (flag)

    Value

    yes

    Option

    -inv_use_zeta_fixed_mask

    Description

    Enforce locations where the parameterized design variable should be fixed. (Automatically determined if not provided)

  298. ocean.always_grounded (flag)

    Value

    no

    Option

    -dry

    Description

    Dry (ocean-less) simulation; ice is considered grounded regardless of ice thickness, bed elevation, and sea level.

  299. ocean.anomaly.file (string)

    Value

    no default

    Option

    -ocean_anomaly_file

    Description

    Name of the file containing shelf basal mass flux offset fields.

  300. 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.

  301. ocean.anomaly.reference_year (integer)

    Value

    0

    Option

    -ocean_anomaly_reference_year

    Description

    Reference year to use when ocean.anomaly.period is active.

  302. ocean.cache.update_interval (integer)

    Value

    10

    Option

    -ocean_cache_update_interval

    Description

    update interval of the ‘cache’ ocean modifier

  303. ocean.constant.melange_back_pressure_fraction (number)

    Value

    0 (1)

    Description

    default melange back pressure fraction in the ‘contant’ ocean model

  304. ocean.constant.melt_rate (number)

    Value

    0.051914 (m / year)

    Option

    -shelf_base_melt_rate

    Description

    default melt rate used by the ‘constant’ ocean model (computed as \(Q / (L \rho_i)\))

  305. ocean.delta_T.file (string)

    Value

    no default

    Option

    -ocean_delta_T_file

    Description

    Name of the file containing temperature offsets.

  306. ocean.delta_T.period (integer)

    Value

    0

    Option

    -ocean_delta_T_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  307. ocean.delta_T.reference_year (integer)

    Value

    0

    Option

    -ocean_delta_T_reference_year

    Description

    Reference year to use when ocean.delta_T.period is active.

  308. ocean.delta_mass_flux.file (string)

    Value

    no default

    Option

    -ocean_delta_mass_flux_file

    Description

    Name of the file containing sub-shelf mass flux offsets.

  309. ocean.delta_mass_flux.period (integer)

    Value

    0

    Option

    -ocean_delta_mass_flux_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  310. ocean.delta_mass_flux.reference_year (integer)

    Value

    0

    Option

    -ocean_delta_mass_flux_reference_year

    Description

    Reference year to use when ocean.delta_mass_flux.period is active.

  311. ocean.delta_sl.file (string)

    Value

    no default

    Option

    -ocean_delta_sl_file

    Description

    Name of the file containing sea level offsets.

  312. ocean.delta_sl.period (integer)

    Value

    0

    Option

    -ocean_delta_sl_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  313. ocean.delta_sl.reference_year (integer)

    Value

    0

    Option

    -ocean_delta_sl_reference_year

    Description

    Reference year to use when ocean.delta_sl.period is active.

  314. ocean.delta_sl_2d.file (string)

    Value

    no default

    Description

    Name of the file containing climate forcing fields.

  315. ocean.delta_sl_2d.period (integer)

    Value

    0

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  316. ocean.delta_sl_2d.reference_year (integer)

    Value

    0

    Description

    Reference year to use when ocean.delta_sl_2d.period is active.

  317. ocean.frac_MBP.file (string)

    Value

    no default

    Option

    -ocean_frac_MBP_file

    Description

    Name of the file containing melange back-pressure scaling.

  318. ocean.frac_MBP.period (integer)

    Value

    0

    Option

    -ocean_frac_MBP_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  319. ocean.frac_MBP.reference_year (integer)

    Value

    0

    Option

    -ocean_frac_MBP_reference_year

    Description

    Reference year to use when ocean.frac_MBP.period is active.

  320. ocean.frac_mass_flux.file (string)

    Value

    no default

    Option

    -ocean_frac_mass_flux_file

    Description

    Name of the file containing sub-shelf mass flux scaling.

  321. ocean.frac_mass_flux.period (integer)

    Value

    0

    Option

    -ocean_frac_mass_flux_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  322. ocean.frac_mass_flux.reference_year (integer)

    Value

    0

    Option

    -ocean_frac_mass_flux_reference_year

    Description

    Reference year to use when ocean.frac_mass_flux.period is active.

  323. ocean.given.file (string)

    Value

    no default

    Option

    -ocean_given_file

    Description

    Name of the file containing climate forcing fields.

  324. 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.

  325. ocean.given.reference_year (integer)

    Value

    0

    Option

    -ocean_given_reference_year

    Description

    Reference year to use when ocean.given.period is active.

  326. ocean.melange_back_pressure_fraction (number)

    Value

    0 (1)

    Description

    default melange back pressure fraction

  327. ocean.models (string)

    Value

    constant

    Option

    -ocean

    Description

    Comma-separated list of ocean models and modifiers.

  328. ocean.pico.continental_shelf_depth (number)

    Value

    -800 (meters)

    Option

    -continental_shelf_depth

    Description

    Determines the edge of the continental shelf to calculate mean ocean properties

  329. ocean.pico.exclude_ice_rises (flag)

    Value

    yes

    Option

    -exclude_icerises

    Description

    Exclude ice rises for box calculation in PICO

  330. ocean.pico.file (string)

    Value

    no default

    Option

    -ocean_pico_file

    Description

    Name of the file containing climate forcing fields.

  331. ocean.pico.heat_exchange_coefficent (number)

    Value

    0.000020 (meters second-1)

    Option

    -gamma_T

    Description

    Turbulent heat exchange coefficient

  332. ocean.pico.maximum_ice_rise_area (number)

    Value

    100000 (km2)

    Description

    Maximum ice rise area. Patches of grounded ice that are bugger than this are treated as continental ice sheets.

  333. ocean.pico.number_of_boxes (integer)

    Value

    5

    Option

    -number_of_boxes

    Description

    Default maximum number of boxes (for the largest ice shelves)

  334. ocean.pico.overturning_coefficent (number)

    Value

    1000000 (meters6 seconds-1 kg-1)

    Option

    -overturning_coeff

    Description

    Overturning stregth coefficient

  335. 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.

  336. ocean.pico.reference_year (integer)

    Value

    0

    Option

    -ocean_pico_reference_year

    Description

    Reference year to use when ocean.pico.period is active.

  337. ocean.pik_melt_factor (number)

    Value

    0.005000 (1)

    Option

    -meltfactor_pik

    Description

    dimensionless tuning parameter in the ‘-ocean pik’ ocean heat flux parameterization; see [3]

  338. ocean.sub_shelf_heat_flux_into_ice (number)

    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().

  339. ocean.th.file (string)

    Value

    no default

    Option

    -ocean_th_file

    Description

    Name of the file containing climate forcing fields.

  340. 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.

  341. ocean.th.reference_year (integer)

    Value

    0

    Option

    -ocean_th_reference_year

    Description

    Reference year to use when ocean.th.period is active.

  342. ocean.three_equation_model_clip_salinity (flag)

    Value

    yes

    Option

    -clip_shelf_base_salinity

    Description

    Clip shelf base salinity so that it is in the range [4, 40] k/kg. See [11].

  343. output.ISMIP6 (flag)

    Value

    false

    Description

    Follow ISMIP6 conventions (units, variable names, “standard names”) when writing output variables.

  344. output.ISMIP6_extra_variables (string)

    Value

    lithk, orog, topg, hfgeoubed, acabf, libmassbfgr, libmassbffl, dlithkdt, velsurf, zvelsurf, velbase, zvelbase, velmean, litemptop, litempbotgr, litempbotfl, strbasemag, licalvf, lifmassbf, sftgif, sftgrf, sftflf

    Description

    Comma-separated list of fields reported by models participating in ISMIP6 simulations.

  345. output.ISMIP6_ts_variables (string)

    Value

    lim, limnsw, iareagr, iareafl, tendacabf, tendlibmassbf, tendlibmassbffl, tendlicalvf, tendlifmassbf

    Description

    Comma-separated list of scalar variables (time series) reported by models participating in ISMIP6 simulations.

  346. output.backup_interval (number)

    Value

    1 (hours)

    Option

    -backup_interval

    Description

    wall-clock time between automatic backups

  347. 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

  348. output.extra.append (flag)

    Value

    no

    Option

    -extra_append

    Description

    Append to an existing output file.

  349. output.extra.file (string)

    Value

    no default

    Option

    -extra_file

    Description

    Name of the output file containing spatially-variable diagnostics.

  350. output.extra.split (flag)

    Value

    no

    Option

    -extra_split

    Description

    Save spatially-variable diagnostics to separate files (one per time record).

  351. output.extra.stop_missing (flag)

    Value

    yes

    Option

    -extra_stop_missing

    Description

    Stop if requested variable is not available instead of warning.

  352. output.extra.times (string)

    Value

    no default

    Option

    -extra_times

    Description

    List or a range of times defining reporting intervals for spatially-variable diagnostics.

  353. output.extra.vars (string)

    Value

    no default

    Option

    -extra_vars

    Description

    Comma-separated list of spatially-variable diagnostics.

  354. output.file_name (string)

    Value

    unnamed.nc

    Option

    -o

    Description

    The file to save final model results to.

  355. output.fill_value (number)

    Value

    -2.000000e+09 (none)

    Description

    _FillValue used when saving diagnostic quantities

  356. output.format (keyword)

    Value

    netcdf3

    Choices

    netcdf3, netcdf4_parallel, pnetcdf, pio_pnetcdf, pio_netcdf4p, pio_netcdf4c, pio_netcdf

    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.

  357. output.ice_free_thickness_standard (number)

    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.

  358. output.pio.base (integer)

    Value

    0

    Description

    Rank of the first I/O task

  359. output.pio.n_writers (integer)

    Value

    1

    Description

    Number of I/O tasks to use

  360. output.pio.stride (integer)

    Value

    1

    Description

    Offset between I/O tasks

  361. 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

  362. 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.)

  363. output.runtime.time_use_calendar (flag)

    Value

    yes

    Description

    Whether to use the current calendar when printing model time in summary to stdout.

  364. output.runtime.viewer.size (integer)

    Value

    320

    Option

    -view_size

    Description

    default diagnostic viewer size (number of pixels of the longer side)

  365. output.runtime.viewer.variables (string)

    Value

    no default

    Option

    -view

    Description

    comma-separated list of map-plane diagnostic quantities to view at runtime

  366. 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

  367. 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

  368. 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.

  369. 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, 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.

  370. 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.

  371. output.snapshot.file (string)

    Value

    no default

    Option

    -save_file

    Description

    Snapshot (output) file name (or prefix, if saving to individual files).

  372. 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

  373. output.snapshot.split (flag)

    Value

    no

    Option

    -save_split

    Description

    Save model state snapshots to separate files (one per time record).

  374. output.snapshot.times (string)

    Value

    no default

    Option

    -save_times

    Description

    List or a range of times to save model state snapshots at.

  375. output.timeseries.append (flag)

    Value

    false

    Option

    -ts_append

    Description

    If true, append to the scalar time series output file.

  376. 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.

  377. 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.

  378. output.timeseries.times (string)

    Value

    no default

    Option

    -ts_times

    Description

    List or range of times defining reporting time intervals.

  379. output.timeseries.variables (string)

    Value

    no default

    Option

    -ts_vars

    Description

    Requested scalar (time-series) diagnostics. Leave empty to save all available diagnostics.

  380. output.use_MKS (flag)

    Value

    false

    Description

    Use MKS units in output files.

  381. regional.no_model_strip (number)

    Value

    5 (km)

    Option

    -no_model_strip

    Description

    Default width of the ‘no model strip’ in regional setups.

  382. regional.no_model_yield_stress (number)

    Value

    1000 (kPa)

    Description

    High yield stress used in the ‘no_model_mask’ area in the regional mode.

  383. regional.zero_gradient (flag)

    Value

    false

    Option

    -zero_grad_where_no_model

    Description

    Use zero ice thickness and ice surface gradient in the no_model_mask area.

  384. run_info.institution (string)

    Value

    no default

    Option

    -institution

    Description

    Institution name. This string is written to output files as the ‘institution’ global attribute.

  385. 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.

  386. sea_level.models (string)

    Value

    constant

    Option

    -sea_level

    Description

    Comma-separated list of sea level models and modifiers.

  387. stress_balance.calving_front_stress_bc (flag)

    Value

    no

    Option

    -cfbc

    Description

    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].

  388. stress_balance.ice_free_thickness_standard (number)

    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.

  389. 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

  390. stress_balance.prescribed_sliding.file (string)

    Value

    no default

    Description

    The name of the file containing prescribed sliding velocity (variable names: \(ubar\), \(vbar\)).

  391. stress_balance.sia.Glen_exponent (number)

    Value

    3 (pure number)

    Option

    -sia_n

    Description

    Glen exponent in ice flow law for SIA

  392. stress_balance.sia.bed_smoother.range (number)

    Value

    5000 (meters)

    Option

    -bed_smoother_range

    Description

    half-width of smoothing domain for stressbalance::BedSmoother, in implementing [93] bed roughness parameterization for SIA; set value to zero to turn off mechanism

  393. stress_balance.sia.bed_smoother.theta_min (number)

    Value

    0 (1)

    Description

    minimum value of \(\theta\) in [93] bed roughness parameterization for SIA

  394. stress_balance.sia.e_age_coupling (flag)

    Value

    no

    Option

    -e_age_coupling

    Description

    Couple the SIA enhancement factor to age as in [32].

  395. stress_balance.sia.enhancement_factor (number)

    Value

    1 (1)

    Option

    -sia_e

    Description

    Flow enhancement factor for SIA

  396. stress_balance.sia.enhancement_factor_interglacial (number)

    Value

    1 (1)

    Option

    -sia_e_interglacial

    Description

    Flow enhancement factor for SIA; used for ice accumulated during interglacial periods.

  397. 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.

  398. stress_balance.sia.grain_size_age_coupling (flag)

    Value

    no

    Option

    -grain_size_age_coupling

    Description

    Use age of the ice to compute grain size to use with the Goldsby-Kohlstedt [70] flow law

  399. stress_balance.sia.limit_diffusivity (flag)

    Value

    no

    Option

    -limit_sia_diffusivity

    Description

    Limit SIA diffusivity by \(stress_balance.sia.max_diffusivity\).

  400. stress_balance.sia.max_diffusivity (number)

    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.

  401. 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

  402. stress_balance.ssa.Glen_exponent (number)

    Value

    3 (pure number)

    Option

    -ssa_n

    Description

    Glen exponent in ice flow law for SSA

  403. stress_balance.ssa.compute_surface_gradient_inward (flag)

    Value

    no

    Description

    If yes then use inward first-order differencing in computing surface gradient in the SSA objects.

  404. stress_balance.ssa.dirichlet_bc (flag)

    Value

    no

    Option

    -ssa_dirichlet_bc

    Description

    apply SSA velocity Dirichlet boundary condition

  405. stress_balance.ssa.enhancement_factor (number)

    Value

    1 (1)

    Option

    -ssa_e

    Description

    Flow enhancement factor for SSA

  406. stress_balance.ssa.enhancement_factor_interglacial (number)

    Value

    1 (1)

    Option

    -ssa_e_interglacial

    Description

    Flow enhancement factor for SSA; used for ice accumulated during interglacial periods.

  407. stress_balance.ssa.epsilon (number)

    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 \(s^{1/3}\) [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 [102], but with a tiny thickness \(H\) of about 1 cm.

  408. stress_balance.ssa.fd.brutal_sliding (flag)

    Value

    false

    Option

    -brutal_sliding

    Description

    Enhance sliding speed brutally.

  409. stress_balance.ssa.fd.brutal_sliding_scale (number)

    Value

    1 (1)

    Option

    -brutal_sliding_scale

    Description

    Brutal SSA Sliding Scale

  410. stress_balance.ssa.fd.lateral_drag.enabled (flag)

    Value

    false

    Description

    set viscosity at ice shelf margin next to ice free bedrock as friction parameterization

  411. stress_balance.ssa.fd.lateral_drag.viscosity (number)

    Value

    5.000000e+15 (Pascal second)

    Option

    -nu_bedrock

    Description

    Staggered Viscosity used as side friction parameterization.

  412. stress_balance.ssa.fd.max_iterations (integer)

    Value

    300

    Option

    -ssafd_picard_maxi

    Description

    Maximum number of Picard iterations for the ice viscosity computation, in the SSAFD object

  413. stress_balance.ssa.fd.max_speed (number)

    Value

    300000 (km s-1)

    Option

    -ssafd_max_speed

    Description

    Upper bound for the ice speed computed by the SSAFD solver.

  414. stress_balance.ssa.fd.nuH_iter_failure_underrelaxation (number)

    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.

  415. stress_balance.ssa.fd.relative_convergence (number)

    Value

    0.000100 (1)

    Option

    -ssafd_picard_rtol

    Description

    Relative change tolerance for the effective viscosity in the SSAFD object

  416. stress_balance.ssa.fd.replace_zero_diagonal_entries (flag)

    Value

    yes

    Description

    Replace zero diagonal entries in the SSAFD matrix with basal_resistance.beta_ice_free_bedrock to avoid solver failures.

  417. 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.

  418. stress_balance.ssa.method (keyword)

    Value

    fd

    Choices

    fd, fem

    Option

    -ssa_method

    Description

    Algorithm for computing the SSA solution.

  419. stress_balance.ssa.read_initial_guess (flag)

    Value

    yes

    Option

    -ssa_read_initial_guess

    Description

    Read the initial guess from the input file when re-starting.

  420. stress_balance.ssa.strength_extension.constant_nu (number)

    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 \(Pa s^{1/3}\) [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 [102].

  421. stress_balance.ssa.strength_extension.min_thickness (number)

    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.

  422. 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.

  423. stress_balance.weertman_sliding.A (number)

    Value

    1.800000e-16 (Pa-3 year-1 m-2)

    Description

    Sliding parameter in the Weertman-style sliding parameterization [75]

  424. stress_balance.weertman_sliding.k (number)

    Value

    0.200000 (1)

    Description

    The ratio of the basal water pressure and the ice overburden pressure in the Weertman-style sliding parameterization.

  425. surface.anomaly.file (string)

    Value

    no default

    Option

    -surface_anomaly_file

    Description

    Name of the file containing climate forcing fields.

  426. 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.

  427. surface.anomaly.reference_year (integer)

    Value

    0

    Option

    -surface_anomaly_reference_year

    Description

    Reference year to use when surface.anomaly.period is active.

  428. surface.cache.update_interval (integer)

    Value

    10

    Description

    Update interval (in years) for the \(-surface cache\) modifier.

  429. surface.delta_T.file (string)

    Value

    no default

    Option

    -surface_delta_T_file

    Description

    Name of the file containing temperature offsets.

  430. surface.delta_T.period (integer)

    Value

    0

    Option

    -surface_delta_T_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  431. surface.delta_T.reference_year (integer)

    Value

    0

    Option

    -surface_delta_T_reference_year

    Description

    Reference year to use when surface.delta_T.period is active.

  432. surface.elevation_change.file (string)

    Value

    no default

    Option

    -surface_elevation_change_file

    Description

    Name of the file containing the reference surface elevation field (variable usurf).

  433. surface.elevation_change.period (integer)

    Value

    0

    Option

    -surface_elevation_change_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  434. surface.elevation_change.reference_year (integer)

    Value

    0

    Option

    -surface_elevation_change_reference_year

    Description

    Reference year to use when surface.elevation_change.period is active.

  435. surface.elevation_change.smb.exp_factor (number)

    Value

    0 (Kelvin-1)

    Option

    -smb_exp_factor

    Description

    Exponential for the surface mass balance.

  436. surface.elevation_change.smb.lapse_rate (number)

    Value

    0 ((m / year) / km)

    Option

    -smb_lapse_rate

    Description

    Lapse rate for the surface mass balance.

  437. surface.elevation_change.smb.method (keyword)

    Value

    shift

    Choices

    scale, shift

    Option

    -smb_adjustment

    Description

    Choose the SMB adjustment method. scale: use temperature-change-dependent scaling factor. shift: use the SMB lapse rate.

  438. surface.elevation_change.temperature_lapse_rate (number)

    Value

    0 (K / km)

    Option

    -temp_lapse_rate

    Description

    Lapse rate for the temperature at the top of the ice.

  439. surface.force_to_thickness.alpha (number)

    Value

    0.010000 (year-1)

    Option

    -force_to_thickness_alpha

    Description

    exponential coefficient in force-to-thickness mechanism

  440. surface.force_to_thickness.ice_free_alpha_factor (number)

    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

  441. surface.force_to_thickness.ice_free_thickness_threshold (number)

    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.

  442. surface.force_to_thickness.start_time (number)

    Value

    -4.540000e+09 (years)

    Description

    Starting time for the “force to thickness” modifier; the default is “start from the creation of the Earth.”

  443. 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.

  444. surface.given.file (string)

    Value

    no default

    Option

    -surface_given_file

    Description

    Name of the file containing climate forcing fields.

  445. 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.

  446. surface.given.reference_year (integer)

    Value

    0

    Option

    -surface_given_reference_year

    Description

    Reference year to use when surface.given.period is active.

  447. surface.given.smb_max (number)

    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.

  448. surface.ismip6.file (string)

    Value

    no default

    Option

    -surface_ismip6_file

    Description

    Name of the file containing climate forcing anomaly fields.

  449. surface.ismip6.period (integer)

    Value

    0

    Option

    -surface_ismip6_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  450. surface.ismip6.reference_file (string)

    Value

    no default

    Option

    -surface_ismip6_reference_file

    Description

    Name of the file containing reference climate forcing fields.

  451. surface.ismip6.reference_year (integer)

    Value

    0

    Description

    Reference year to use when surface.ismip6.period is active.

  452. surface.models (string)

    Value

    given

    Option

    -surface

    Description

    Comma-separated list of surface models and modifiers.

  453. surface.pdd.air_temp_all_precip_as_rain (number)

    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

  454. surface.pdd.air_temp_all_precip_as_snow (number)

    Value

    273.150000 (Kelvin)

    Description

    threshold temperature below which all precipitation is snow

  455. surface.pdd.balance_year_start_day (integer)

    Value

    274

    Description

    day of year for October 1st, beginning of the balance year in northern latitudes.

  456. surface.pdd.factor_ice (number)

    Value

    0.008791 (meter / (Kelvin day))

    Description

    EISMINT-Greenland value [7]; = (8 mm liquid-water-equivalent) / (pos degree day)

  457. surface.pdd.factor_snow (number)

    Value

    0.003297 (meter / (Kelvin day))

    Description

    EISMINT-Greenland value [7]; = (3 mm liquid-water-equivalent) / (pos degree day)

  458. surface.pdd.fausto.T_c (number)

    Value

    272.150000 (Kelvin)

    Description

    = -1 + 273.15; for formula (6) in [1]

  459. surface.pdd.fausto.T_w (number)

    Value

    283.150000 (Kelvin)

    Description

    = 10 + 273.15; for formula (6) in [1]

  460. surface.pdd.fausto.beta_ice_c (number)

    Value

    0.015000 (meter / (Kelvin day))

    Description

    water-equivalent thickness; for formula (6) in [1]

  461. surface.pdd.fausto.beta_ice_w (number)

    Value

    0.007000 (meter / (Kelvin day))

    Description

    water-equivalent thickness; for formula (6) in [1]

  462. surface.pdd.fausto.beta_snow_c (number)

    Value

    0.003000 (meter / (Kelvin day))

    Description

    water-equivalent thickness; for formula (6) in [1]

  463. surface.pdd.fausto.beta_snow_w (number)

    Value

    0.003000 (meter / (Kelvin day))

    Description

    water-equivalent thickness; for formula (6) in [1]

  464. surface.pdd.fausto.enabled (flag)

    Value

    false

    Option

    -pdd_fausto

    Description

    Set PDD parameters using formulas (6) and (7) in [1]

  465. surface.pdd.fausto.latitude_beta_w (number)

    Value

    72 (degree_north)

    Description

    latitude below which to use warm case, in formula (6) in [1]

  466. surface.pdd.firn_compaction_to_accumulation_ratio (number)

    Value

    0.750000 (1)

    Description

    How much firn as a fraction of accumulation is turned into ice

  467. 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.

  468. surface.pdd.interpret_precip_as_snow (flag)

    Value

    no

    Description

    Interpret precipitation as snow fall.

  469. 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

  470. surface.pdd.method (keyword)

    Value

    expectation_integral

    Choices

    expectation_integral, repeatable_random_process, random_process

    Option

    -pdd_method

    Description

    PDD implementation method

  471. surface.pdd.positive_threshold_temp (number)

    Value

    273.150000 (Kelvin)

    Description

    temperature used to determine meaning of ‘positive’ degree day

  472. surface.pdd.refreeze (number)

    Value

    0.600000 (1)

    Description

    EISMINT-Greenland value [7]

  473. surface.pdd.refreeze_ice_melt (flag)

    Value

    yes

    Description

    If set to ‘yes’, refreeze surface.pdd.refreeze fraction of melted ice, otherwise all of the melted ice runs off.

  474. surface.pdd.std_dev (number)

    Value

    5 (Kelvin)

    Description

    std dev of daily temp variation; = EISMINT-Greenland value [7]

  475. surface.pdd.std_dev.file (string)

    Value

    no default

    Option

    -pdd_sd_file

    Description

    The name of the file to read \(air_temp_sd\) (standard deviation of air temperature) from.

  476. surface.pdd.std_dev.period (integer)

    Value

    0

    Option

    -pdd_sd_period

    Description

    Length of the period of the climate forcing data. Set to zero to disable.

  477. surface.pdd.std_dev.reference_year (integer)

    Value

    0

    Option

    -pdd_sd_reference_year

    Description

    Reference year to use when surface.pdd.std_dev.period is active.

  478. surface.pdd.std_dev_lapse_lat_base (number)

    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

  479. surface.pdd.std_dev_lapse_lat_rate (number)

    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

  480. surface.pdd.std_dev_param_a (number)

    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.

  481. surface.pdd.std_dev_param_b (number)

    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.

  482. surface.pdd.std_dev_use_param (flag)

    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.

  483. surface.pressure (number)

    Value

    0 (Pascal)

    Description

    atmospheric pressure; = pressure at ice surface

  484. 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.

  485. time.dimension_name (string)

    Value

    time

    Description

    The name of the time dimension in PISM output files.

  486. time.eemian_end (number)

    Value

    -114500 (years)

    Description

    End of the Eemian interglacial period. See [67].

  487. time.eemian_start (number)

    Value

    -132000 (years)

    Description

    Start of the Eemian interglacial period. See [67].

  488. time.holocene_start (number)

    Value

    -11000 (years)

    Description

    Start of the Holocene interglacial period. See [67].

  489. time.reference_date (string)

    Value

    1-1-1

    Description

    year-month-day; reference date used for calendar computations and in PISM output files

  490. time.run_length (number)

    Value

    1000 (years)

    Description

    Default run length

  491. time.start_year (number)

    Value

    0 (years)

    Description

    Start year.

  492. time_stepping.adaptive_ratio (number)

    Value

    0.120000 (1)

    Option

    -adapt_ratio

    Description

    Adaptive time stepping ratio for the explicit scheme for the mass balance equation; [26], inequality (25)

  493. time_stepping.count_steps (flag)

    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.

  494. time_stepping.hit_extra_times (flag)

    Value

    yes

    Option

    -extra_force_output_times

    Description

    Modify the time-stepping mechanism to hit times requested using -extra_times.

  495. time_stepping.hit_multiples (number)

    Value

    0 (years)

    Option

    -timestep_hit_multiples

    Description

    Hit every X years, where X is specified using this parameter. Use 0 to disable

  496. time_stepping.hit_save_times (flag)

    Value

    no

    Option

    -save_force_output_times

    Description

    Modify the time-stepping mechanism to hit times requested using -save_times.

  497. time_stepping.hit_ts_times (flag)

    Value

    no

    Description

    Modify the time-stepping mechanism to hit times requested using -ts_times.

  498. time_stepping.maximum_time_step (number)

    Value

    60 (years)

    Option

    -max_dt

    Description

    Maximum allowed time step length

  499. time_stepping.skip.enabled (flag)

    Value

    no

    Option

    -skip

    Description

    Use the temperature, age, and SSA stress balance computation skipping mechanism.

  500. 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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