Diagnostic quantities

The availability of a diagnostic depends on modeling choices. For example, the bed uplift rate dbdt is available only if a bed deformation model is selected.

Some scalar diagnostics come in two versions: the one with the suffix _glacierized and the one without. Here the former account for the ice output.ice_free_thickness_standard meters or thicker (10 meters by default) and the latter include all ice regardless of the thickness. “Glacierized” versions were added to make it easier to analyze changes in glacier volumes and areas and exclude changes in the seasonal snow cover.

Spatially-variable fields

  1. air_temp_mean_summer
    Units:Kelvin
    Description:mean summer near-surface air temperature used in the cosine yearly cycle
  2. air_temp_sd
    Units:Kelvin
    Description:standard deviation of near-surface air temperature
  3. air_temp_snapshot
    Units:Kelvin
    Description:instantaneous value of the near-surface air temperature
  4. basal_mass_flux_floating
    Units:kg m-2 year-1
    Description:average basal mass flux over the reporting interval (floating areas)
    Comment:positive flux corresponds to ice gain
  5. basal_mass_flux_grounded
    Units:kg m-2 year-1
    Description:average basal mass flux over the reporting interval (grounded areas)
    Comment:positive flux corresponds to ice gain
  6. basal_melt_rate_grounded
    Units:m year-1
    Description:ice basal melt rate from energy conservation, in ice thickness per time (valid in grounded areas)
    Comment:positive basal melt rate corresponds to ice loss
  7. bedtoptemp
    Units:Kelvin
    Description:temperature at the top surface of the bedrock thermal layer
  8. beta
    Units:Pa s / m
    Description:basal drag coefficient
  9. bfrict
    Units:W m-2
    Description:basal frictional heating
  10. bheatflx
    Units:mW m-2
    Description:upward geothermal flux at the bottom bedrock surface
    Comment:positive values correspond to an upward flux
  11. bmelt
    Units:m year-1
    Description:ice basal melt rate from energy conservation and subshelf melt, in ice thickness per time
    Standard name:land_ice_basal_melt_rate
    Comment:positive basal melt rate corresponds to ice loss
  12. bwat
    Units:m
    Description:thickness of transportable subglacial water layer
  13. bwatvel
    • bwatvel[0]
      Units:m year-1
      Description:velocity of water in subglacial layer, i-offset
    • bwatvel[1]
      Units:m year-1
      Description:velocity of water in subglacial layer, j-offset
  14. bwp
    Units:Pa
    Description:pressure of transportable water in subglacial layer
  15. bwprel
    Units:
    Description:pressure of transportable water in subglacial layer as fraction of the overburden pressure
  16. calving_threshold
    Units:m
    Description:threshold used by the ‘calving at threshold’ calving method
  17. cell_grounded_fraction
    Units:
    Description:fractional grounded/floating mask (floating=0, grounded=1)
  18. climatic_mass_balance
    Units:kg m-2 year-1
    Description:surface mass balance (accumulation/ablation) rate
    Standard name:land_ice_surface_specific_mass_balance_flux
  19. cts
    Units:1
    Description:cts = E/E_s(p), so cold-temperate transition surface is at cts = 1
  20. dHdt
    Units:m year-1
    Description:ice thickness rate of change
    Standard name:tendency_of_land_ice_thickness
  21. dbdt
    Units:mm year-1
    Description:bedrock uplift rate
    Standard name:tendency_of_bedrock_altitude
  22. deviatoric_stresses
    • sigma_xx
      Units:Pa
      Description:deviatoric stress in X direction
    • sigma_yy
      Units:Pa
      Description:deviatoric stress in Y direction
    • sigma_xy
      Units:Pa
      Description:deviatoric shear stress
  23. diffusivity
    Units:m2 s-1
    Description:diffusivity of SIA mass continuity equation
  24. diffusivity_staggered
    • diffusivity_i
      Units:m2 s-1
      Description:diffusivity of SIA mass continuity equation on the staggered grid (i-offset)
    • diffusivity_j
      Units:m2 s-1
      Description:diffusivity of SIA mass continuity equation on the staggered grid (j-offset)
  25. effbwp
    Units:Pa
    Description:effective pressure of transportable water in subglacial layer (overburden pressure minus water pressure)
  26. effective_air_temp
    Units:Kelvin
    Description:effective mean-annual near-surface air temperature
  27. effective_precipitation
    Units:kg m-2 year-1
    Description:effective precipitation rate
    Standard name:precipitation_flux
  28. effective_viscosity
    Units:kPascal second
    Description:effective viscosity of ice
  29. eigen_calving_rate
    Units:m year-1
    Description:horizontal calving rate due to eigen-calving
  30. enthalpy
    Units:J kg-1
    Description:ice enthalpy (includes sensible heat, latent heat, pressure)
  31. enthalpybase
    Units:J kg-1
    Description:ice enthalpy at the base of ice
  32. enthalpysurf
    Units:J kg-1
    Description:ice enthalpy at 1m below the ice surface
  33. firn_depth
    Units:m
    Description:firn cover depth
  34. flux
    • uflux
      Units:m2 year-1
      Description:Vertically integrated horizontal flux of ice in the X direction
    • vflux
      Units:m2 year-1
      Description:Vertically integrated horizontal flux of ice in the Y direction
  35. flux_divergence
    Units:m year-1
    Description:flux divergence
  36. flux_mag
    Units:m2 year-1
    Description:magnitude of vertically-integrated horizontal flux of ice
  37. flux_staggered
    Units:m2 year-1
    Description:fluxes through cell interfaces (sides) on the staggered grid
  38. frontal_melt_rate
    Units:m year-1
    Description:horizontal front retreat rate due to melt
  39. h_x
    • h_x_i
      Units:
      Description:the x-component of the surface gradient, i-offset
    • h_x_j
      Units:
      Description:the x-component of the surface gradient, j-offset
  40. h_y
    • h_y_i
      Units:
      Description:the y-component of the surface gradient, i-offset
    • h_y_j
      Units:
      Description:the y-component of the surface gradient, j-offset
  41. hardav
    Units:Pa s0.333333
    Description:vertical average of ice hardness
  42. hardness
    Units:Pa s0.333333
    Description:ice hardness computed using the SIA flow law
  43. height_above_flotation
    Units:m
    Description:ice thickness in excess of the maximum floating ice thickness
    Comment:shows how close to floatation the ice is at a given location
  44. hfgeoubed
    Units:mW m-2
    Description:upward geothermal flux at the top bedrock surface
    Standard name:upward_geothermal_heat_flux_at_ground_level
    Comment:positive values correspond to an upward flux
  45. ice_area_specific_volume
    Units:m3/m2
    Description:ice-volume-per-area in partially-filled grid cells
    Comment:this variable represents the amount of ice in a partially-filled cell and not the corresponding geometry, so thinking about it as ‘thickness’ is not helpful
  46. ice_mass
    Units:kg
    Description:mass per cell
  47. ice_surface_liquid_water_fraction
    Units:1
    Description:ice liquid water fraction at the ice surface
  48. ice_surface_temp
    Units:Kelvin
    Description:ice temperature at the ice surface
  49. lat
    Units:degree_north
    Description:latitude
    Standard name:latitude
  50. liqfrac
    Units:1
    Description:liquid water fraction in ice (between 0 and 1)
  51. lon
    Units:degree_east
    Description:longitude
    Standard name:longitude
  52. mask
    Units:
    Description:ice-type (ice-free/grounded/floating/ocean) integer mask
  53. melange_back_pressure_fraction
    Units:1
    Description:dimensionless pressure fraction at calving fronts due to presence of melange
  54. nuH
    • nuH[0]
      Units:kPa s m
      Description:ice thickness times effective viscosity, i-offset
    • nuH[1]
      Units:kPa s m
      Description:ice thickness times effective viscosity, j-offset
  55. ocean_kill_mask
    Units:
    Description:mask specifying fixed calving front locations
  56. ocean_pressure_difference
    Units:
    Description:ocean pressure difference at calving fronts
  57. pressure
    Units:Pa
    Description:pressure in ice (hydrostatic)
  58. rank
    Units:1
    Description:processor rank
  59. schoofs_theta
    Units:1
    Description:multiplier ‘theta’ in Schoof’s (2003) theory of bed roughness in SIA
  60. sea_level
    Units:meters
    Description:sea level elevation, relative to the geoid
  61. sftflf
    Units:1
    Description:fraction of a grid cell covered by floating ice
    Standard name:floating_ice_sheet_area_fraction
  62. sftgif
    Units:1
    Description:fraction of a grid cell covered by ice (grounded or floating)
    Standard name:land_ice_area_fraction
  63. sftgrf
    Units:1
    Description:fraction of a grid cell covered by grounded ice
    Standard name:grounded_ice_sheet_area_fraction
  64. shelfbmassflux
    Units:kg m-2 s-1
    Description:mass flux at the basal surface of ice shelves
  65. shelfbtemp
    Units:Kelvin
    Description:ice temperature at the basal surface of ice shelves
  66. snow_depth
    Units:m
    Description:snow cover depth (set to zero once a year)
  67. ssa_bc_mask
    Units:
    Description:Dirichlet boundary mask
  68. ssa_bc_vel
    • u_ssa_bc
      Units:m year-1
      Description:X-component of the SSA velocity boundary conditions
    • v_ssa_bc
      Units:m year-1
      Description:Y-component of the SSA velocity boundary conditions
  69. strain_rates
    • eigen1
      Units:s-1
      Description:first eigenvalue of the horizontal, vertically-integrated strain rate tensor
    • eigen2
      Units:s-1
      Description:second eigenvalue of the horizontal, vertically-integrated strain rate tensor
  70. strainheat
    Units:mW m-3
    Description:rate of strain heating in ice (dissipation heating)
  71. subglacial_water_input_rate
    Units:m year-1
    Description:total input rate of subglacial water (basal melt rate plus input from the surface)
    Comment:positive flux corresponds to water gain
  72. surface_accumulation_flux
    Units:kg m-2 year-1
    Description:accumulation (precipitation minus rain), averaged over the reporting interval
  73. surface_accumulation_rate
    Units:Gt year-1
    Description:accumulation (precipitation minus rain), averaged over the reporting interval
  74. surface_layer_mass
    Units:kg
    Description:mass of the surface layer (snow and firn)
  75. surface_layer_thickness
    Units:meters
    Description:thickness of the surface layer (snow and firn)
  76. surface_melt_flux
    Units:kg m-2 year-1
    Description:surface melt, averaged over the reporting interval
    Standard name:surface_snow_and_ice_melt_flux
  77. surface_melt_rate
    Units:Gt year-1
    Description:surface melt, averaged over the reporting interval
  78. surface_runoff_flux
    Units:kg m-2 year-1
    Description:surface runoff, averaged over the reporting interval
    Standard name:surface_runoff_flux
  79. surface_runoff_rate
    Units:Gt year-1
    Description:surface runoff, averaged over the reporting interval
  80. taub
    • taub_x
      Units:Pa
      Description:X-component of the shear stress at the base of ice
      Comment:this field is purely diagnostic (not used by the model)
    • taub_y
      Units:Pa
      Description:Y-component of the shear stress at the base of ice
      Comment:this field is purely diagnostic (not used by the model)
  81. taub_mag
    Units:Pa
    Description:magnitude of the basal shear stress at the base of ice
    Standard name:magnitude_of_land_ice_basal_drag
    Comment:this field is purely diagnostic (not used by the model)
  82. tauc
    Units:Pa
    Description:yield stress for basal till (plastic or pseudo-plastic model)
  83. taud
    • taud_x
      Units:Pa
      Description:X-component of the driving shear stress at the base of ice
      Comment:this is the driving stress used by the SSA solver
    • taud_y
      Units:Pa
      Description:Y-component of the driving shear stress at the base of ice
      Comment:this is the driving stress used by the SSA solver
  84. taud_mag
    Units:Pa
    Description:magnitude of the driving shear stress at the base of ice
    Comment:this is the magnitude of the driving stress used by the SSA solver
  85. tauxz
    Units:Pa
    Description:shear stress xz component (in shallow ice approximation SIA)
  86. tauyz
    Units:Pa
    Description:shear stress yz component (in shallow ice approximation SIA)
  87. temp
    Units:K
    Description:ice temperature
    Standard name:land_ice_temperature
  88. temp_pa
    Units:deg_C
    Description:pressure-adjusted ice temperature (degrees above pressure-melting point)
  89. tempbase
    Units:K
    Description:ice temperature at the base of ice
    Standard name:land_ice_basal_temperature
  90. tempicethk
    Units:m
    Description:temperate ice thickness (total column content)
  91. tempicethk_basal
    Units:m
    Description:thickness of the basal layer of temperate ice
  92. temppabase
    Units:Celsius
    Description:pressure-adjusted ice temperature at the base of ice
  93. tempsurf
    Units:K
    Description:ice temperature at 1m below the ice surface
    Standard name:temperature_at_ground_level_in_snow_or_firn
  94. tendency_of_ice_amount
    Units:kg m-2 year-1
    Description:rate of change of the ice amount
  95. tendency_of_ice_amount_due_to_basal_mass_flux
    Units:kg m-2 year-1
    Description:average basal mass flux over reporting interval
    Comment:positive flux corresponds to ice gain
  96. tendency_of_ice_amount_due_to_conservation_error
    Units:kg m-2 year-1
    Description:average mass conservation error flux over reporting interval
    Comment:positive flux corresponds to ice gain
  97. tendency_of_ice_amount_due_to_discharge
    Units:kg m-2 year-1
    Description:discharge (calving and frontal melt) flux
    Standard name:land_ice_specific_mass_flux_due_to_calving_and_ice_front_melting
    Comment:positive flux corresponds to ice gain
  98. tendency_of_ice_amount_due_to_flow
    Units:kg m-2 year-1
    Description:rate of change of ice amount due to flow
    Comment:positive flux corresponds to ice gain
  99. tendency_of_ice_amount_due_to_surface_mass_flux
    Units:kg m-2 year-1
    Description:average surface mass flux over reporting interval
    Comment:positive flux corresponds to ice gain
  100. tendency_of_ice_mass
    Units:Gt year-1
    Description:rate of change of the ice mass
  101. tendency_of_ice_mass_due_to_basal_mass_flux
    Units:Gt year-1
    Description:average basal mass flux over reporting interval
    Standard name:tendency_of_land_ice_mass_due_to_basal_mass_balance
    Comment:positive flux corresponds to ice gain
  102. tendency_of_ice_mass_due_to_conservation_error
    Units:Gt year-1
    Description:average mass conservation error flux over reporting interval
    Comment:positive flux corresponds to ice gain
  103. tendency_of_ice_mass_due_to_discharge
    Units:Gt year-1
    Description:discharge (calving and frontal melt) flux
    Comment:positive flux corresponds to ice gain
  104. tendency_of_ice_mass_due_to_flow
    Units:Gt year-1
    Description:rate of change of ice mass due to flow
    Comment:positive flux corresponds to ice gain
  105. tendency_of_ice_mass_due_to_surface_mass_flux
    Units:Gt year-1
    Description:average surface mass flux over reporting interval
    Comment:positive flux corresponds to ice gain
  106. tendency_of_subglacial_water_mass
    Units:Gt year-1
    Description:rate of change of the total mass of subglacial water
    Comment:positive flux corresponds to water gain
  107. tendency_of_subglacial_water_mass_at_domain_boundary
    Units:Gt year-1
    Description:subglacial water flux at domain boundary (in regional model configurations)
    Comment:positive flux corresponds to water gain
  108. tendency_of_subglacial_water_mass_at_grounded_margins
    Units:Gt year-1
    Description:subglacial water flux at grounded ice margins
    Comment:positive flux corresponds to water gain
  109. tendency_of_subglacial_water_mass_at_grounding_line
    Units:Gt year-1
    Description:subglacial water flux at grounding lines
    Comment:positive flux corresponds to water gain
  110. tendency_of_subglacial_water_mass_due_to_conservation_error
    Units:Gt year-1
    Description:subglacial water flux due to conservation error (mass added to preserve non-negativity)
    Comment:positive flux corresponds to water gain
  111. tendency_of_subglacial_water_mass_due_to_flow
    Units:Gt year-1
    Description:rate of change subglacial water mass due to lateral flow
    Comment:positive flux corresponds to water gain
  112. tendency_of_subglacial_water_mass_due_to_input
    Units:Gt year-1
    Description:subglacial water flux due to input
    Comment:positive flux corresponds to water gain
  113. thk
    Units:m
    Description:land ice thickness
    Standard name:land_ice_thickness
  114. thksmooth
    Units:m
    Description:thickness relative to smoothed bed elevation in Schoof’s (2003) theory of bed roughness in SIA
  115. tillphi
    Units:degrees
    Description:friction angle for till under grounded ice sheet
  116. tillwat
    Units:m
    Description:effective thickness of subglacial water stored in till
  117. topg
    Units:m
    Description:bedrock surface elevation
    Standard name:bedrock_altitude
  118. topg_sl_adjusted
    Units:meters
    Description:sea-level adjusted bed topography (zero is at sea level)
  119. topgsmooth
    Units:m
    Description:smoothed bed elevation in Schoof’s (2003) theory of bed roughness in SIA
  120. usurf
    Units:m
    Description:ice upper surface elevation
    Standard name:surface_altitude
  121. uvel
    Units:m year-1
    Description:horizontal velocity of ice in the X direction
    Standard name:land_ice_x_velocity
  122. velbar
    • ubar
      Units:m year-1
      Description:vertical mean of horizontal ice velocity in the X direction
      Standard name:land_ice_vertical_mean_x_velocity
    • vbar
      Units:m year-1
      Description:vertical mean of horizontal ice velocity in the Y direction
      Standard name:land_ice_vertical_mean_y_velocity
  123. velbar_mag
    Units:m year-1
    Description:magnitude of vertically-integrated horizontal velocity of ice
  124. velbase
    • uvelbase
      Units:m year-1
      Description:x-component of the horizontal velocity of ice at the base of ice
      Standard name:land_ice_basal_x_velocity
    • vvelbase
      Units:m year-1
      Description:y-component of the horizontal velocity of ice at the base of ice
      Standard name:land_ice_basal_y_velocity
  125. velbase_mag
    Units:m year-1
    Description:magnitude of horizontal velocity of ice at base of ice
  126. velsurf
    • uvelsurf
      Units:m year-1
      Description:x-component of the horizontal velocity of ice at ice surface
      Standard name:land_ice_surface_x_velocity
    • vvelsurf
      Units:m year-1
      Description:y-component of the horizontal velocity of ice at ice surface
      Standard name:land_ice_surface_y_velocity
  127. velsurf_mag
    Units:m year-1
    Description:magnitude of horizontal velocity of ice at ice surface
  128. vonmises_calving_rate
    Units:m year-1
    Description:horizontal calving rate due to von Mises calving
  129. vonmises_stress
    Units:Pascal
    Description:tensile von Mises stress
  130. vvel
    Units:m year-1
    Description:horizontal velocity of ice in the Y direction
    Standard name:land_ice_y_velocity
  131. wallmelt
    Units:m year-1
    Description:wall melt into subglacial hydrology layer from (turbulent) dissipation of energy in transportable water
  132. wvel
    Units:m year-1
    Description:vertical velocity of ice, relative to geoid
  133. wvel_rel
    Units:m year-1
    Description:vertical velocity of ice, relative to base of ice directly below
  134. wvelbase
    Units:m year-1
    Description:vertical velocity of ice at the base of ice, relative to the geoid
    Standard name:land_ice_basal_upward_velocity
  135. wvelsurf
    Units:m year-1
    Description:vertical velocity of ice at ice surface, relative to the geoid
    Standard name:land_ice_surface_upward_velocity

Scalar time-series

  1. basal_mass_flux_floating
    Units:Gt year-1
    Description:total sub-shelf ice flux
    Comment:positive means ice gain
  2. basal_mass_flux_grounded
    Units:Gt year-1
    Description:total over grounded ice domain of basal mass flux
    Comment:positive means ice gain
  3. dt
    Units:year
    Description:mass continuity time step
  4. ice_area_glacierized
    Units:m2
    Description:glacierized area
  5. ice_area_glacierized_cold_base
    Units:m2
    Description:glacierized area where basal ice is cold
  6. ice_area_glacierized_floating
    Units:m2
    Description:area of ice shelves in glacierized areas
  7. ice_area_glacierized_grounded
    Units:m2
    Description:area of grounded ice in glacierized areas
  8. ice_area_glacierized_temperate_base
    Units:m2
    Description:glacierized area where basal ice is temperate
  9. ice_enthalpy
    Units:J
    Description:enthalpy of the ice, including seasonal cover
  10. ice_enthalpy_glacierized
    Units:J
    Description:enthalpy of the ice in glacierized areas
  11. ice_mass
    Units:kg
    Description:mass of the ice, including seasonal cover
  12. ice_mass_glacierized
    Units:kg
    Description:mass of the ice in glacierized areas
  13. ice_volume
    Units:m3
    Description:volume of the ice, including seasonal cover
  14. ice_volume_cold
    Units:m3
    Description:volume of cold ice, including seasonal cover
  15. ice_volume_glacierized
    Units:m3
    Description:volume of the ice in glacierized areas
  16. ice_volume_glacierized_cold
    Units:m3
    Description:volume of cold ice in glacierized areas
  17. ice_volume_glacierized_floating
    Units:m3
    Description:volume of ice shelves in glacierized areas
  18. ice_volume_glacierized_grounded
    Units:m3
    Description:volume of grounded ice in glacierized areas
  19. ice_volume_glacierized_temperate
    Units:m3
    Description:volume of temperate ice in glacierized areas
  20. ice_volume_temperate
    Units:m3
    Description:volume of temperate ice, including seasonal cover
  21. limnsw
    Units:kg
    Description:mass of the ice not displacing sea water
  22. liquified_ice_flux
    Units:m3 / year
    Description:rate of ice loss due to liquefaction, averaged over the reporting interval
    Comment:positive means ice loss
  23. max_diffusivity
    Units:m2 s-1
    Description:maximum diffusivity
  24. max_hor_vel
    Units:m year-1
    Description:maximum abs component of horizontal ice velocity over grid in last time step during time-series reporting interval
  25. sea_level_rise_potential
    Units:m
    Description:the sea level rise that would result if all the ice were melted
  26. surface_accumulation_rate
    Units:kg year-1
    Description:surface accumulation rate (PDD model)
  27. surface_melt_rate
    Units:kg year-1
    Description:surface melt rate (PDD model)
  28. surface_runoff_rate
    Units:kg year-1
    Description:surface runoff rate (PDD model)
  29. tendency_of_ice_mass
    Units:Gt year-1
    Description:rate of change of the mass of ice, including seasonal cover
  30. tendency_of_ice_mass_due_to_basal_mass_flux
    Units:Gt year-1
    Description:total over ice domain of bottom surface ice mass flux
    Comment:positive means ice gain
  31. tendency_of_ice_mass_due_to_conservation_error
    Units:Gt year-1
    Description:total numerical flux needed to preserve non-negativity of ice thickness
    Comment:positive means ice gain
  32. tendency_of_ice_mass_due_to_discharge
    Units:Gt year-1
    Description:discharge (calving & icebergs) flux
    Comment:positive means ice gain
  33. tendency_of_ice_mass_due_to_flow
    Units:Gt year-1
    Description:rate of change of the mass of ice due to flow (i.e. prescribed ice thickness)
  34. tendency_of_ice_mass_due_to_surface_mass_flux
    Units:Gt year-1
    Description:total over ice domain of top surface ice mass flux
    Comment:positive means ice gain
  35. tendency_of_ice_mass_glacierized
    Units:Gt year-1
    Description:rate of change of the ice mass in glacierized areas
  36. tendency_of_ice_volume
    Units:m3 year-1
    Description:rate of change of the ice volume, including seasonal cover
  37. tendency_of_ice_volume_glacierized
    Units:m3 year-1
    Description:rate of change of the ice volume in glacierized areas

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