Documented 53 enthalpy-related variable units

  Changed comments to use the square bracket notation to document the units of
about 53 variables, most of which relate to enthalpy.  Only comments have been
changed and all answers are bitwise identical.

src/SIS2_ice_thm.F90

@@ -37,8 +37,8 @@ module SIS2_ice_thm
                             !! [degC kg gSalt-1].  (dTf_dS is negative.)
 
   real :: enth_liq_0 = 0.0  !< The value of enthalpy for liquid fresh water at 0 degC [J kg-1].
-  real :: enth_unit = 1.0   !< A conversion factor for enthalpy from Joules kg-1.
-  real :: I_enth_unit = 1.0 !< A conversion factor for enthalpy back to Joules kg-1.
+  real :: enth_unit = 1.0   !< A conversion factor for enthalpy from Joules kg-1 [Enth kg J-1 ~> 1].
+  real :: I_enth_unit = 1.0 !< A conversion factor for enthalpy back to Joules kg-1 [J kg-1 Enth-1 ~> 1].
   logical :: slab_ice = .false. !< If true use the very old slab ice thermodynamics,
                             !! with effectively zero heat capacity of ice and snow.
   logical :: sublimation_bug = .false.  !< If true use an older calculation that omits the
@@ -162,7 +162,7 @@ subroutine ice_temp_SIS2(m_pond, m_snow, m_ice, enthalpy, sice, SF_0, dSF_dT, so
   real, intent(in   ) :: m_ice   !< ice mass per unit area [H ~> kg m-2]
   real, dimension(0:NkIce) , &
         intent(inout) :: enthalpy !< The enthalpy of each layer in a column of
-                                  !! snow and ice, in enth_unit (J kg-1).
+                                  !! snow and ice [Enth ~> J kg-1].
   real, dimension(NkIce), &
         intent(in)    :: Sice  !< ice salinity by layer [gSalt kg-1]
   real, intent(in   ) :: SF_0  !< net upward surface heat flux at ts=0 [W m-2]
@@ -231,7 +231,7 @@ subroutine ice_temp_SIS2(m_pond, m_snow, m_ice, enthalpy, sice, SF_0, dSF_dT, so
   real :: hL_ice_eff
   real :: enth_liq_lim ! The enthalpy at the point where the ice or snow stops
                        ! acting as a solid, and all extra heat goes into
-                       ! melting, in enth_units.
+                       ! melting [Enth ~> J kg-1].
   real :: enth_prev
   real :: rho_ice  ! The nominal density of sea ice [kg m-3].
   real :: rho_snow ! The nominal density of snow [kg m-3].
@@ -543,7 +543,7 @@ subroutine estimate_tsurf(m_pond, m_snow, m_ice, enthalpy, sice, SF_0, dSF_dT, &
   real, intent(in   ) :: m_ice   !< ice mass per unit area [H ~> kg m-2]
   real, dimension(0:NkIce) , &
         intent(in   ) :: enthalpy !< The enthalpy of each layer in a column of
-                                  !! snow and ice, in enth_unit [J kg-1].
+                                  !! snow and ice, in enthalpy units [Enth ~> J kg-1].
   real, dimension(NkIce), &
         intent(in)    :: Sice  !< ice salinity by layer [gSalt kg-1]
   real, intent(in   ) :: SF_0  !< net upward surface heat flux when Tsurf=0 [W m-2]
@@ -861,7 +861,7 @@ subroutine update_lay_enth(m_lay, sice, enth, ftop, ht_body, fbot, dftop_dT, &
                            dfbot_dT, dtt, hf_err_rat, ITV, extra_heat, temp_new, temp_max)
   real, intent(in) :: m_lay    !< This layers mass of ice [kg m-2]
   real, intent(in) :: sice     !< ice salinity [gSalt kg-1]
-  real, intent(inout) :: enth  !< ice enthalpy in enth_units [Enth ~> J kg-1].
+  real, intent(inout) :: enth  !< ice enthalpy in enthaly units [Enth ~> J kg-1].
   real, intent(inout) :: ftop  !< Downward heat flux atop the layer at T = 0 degC, or
                                !! the prescribed heat flux if dftop_dT = 0 [W m-2].
   real, intent(in) :: ht_body  !< Body heating to layer [W m-2]
@@ -1116,7 +1116,7 @@ subroutine ice_check(ms, mi, enthalpy, s_ice, NkIce, msg_part, ITV, &
   real, intent(in) :: ms !< The mass of snow [kg m-2]
   real, intent(in) :: mi !< The mass of ice [kg m-2]
   real, dimension(0:NkIce), &
-        intent(in) :: enthalpy !< The ice enthalpy, in enthalpy units (often J/kg)
+        intent(in) :: enthalpy !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
   real, dimension(NkIce), intent(in) :: s_ice !< The ice bulk salinity [gSalt kg-1]
   integer, intent(in) :: NkIce !< The number of vertical temperature layers in the ice
   character(len=*), intent(in) :: msg_part !< An identifying message
@@ -1176,8 +1176,7 @@ subroutine ice_resize_SIS2(a_ice, m_pond, m_lay, Enthalpy, Sice_therm, Salin, &
   real, dimension(0:NkIce), &
         intent(inout) :: m_lay       !< Snow and ice mass per unit area by layer [kg m-2].
   real, dimension(0:NkIce+1), &
-        intent(inout) :: Enthalpy    !< Snow, ice, and ocean enthalpy by layer in enth_units
-                                     !! (which might be J/kg).
+        intent(inout) :: Enthalpy    !< Snow, ice, and ocean enthalpy by layer [Enth ~> J kg-1].
   real, dimension(NkIce), &
         intent(in)    :: Sice_therm  !< ice salinity by layer, as used for thermodynamics [gSalt kg-1]
   real, dimension(NkIce+1), &
@@ -1210,13 +1209,12 @@ subroutine ice_resize_SIS2(a_ice, m_pond, m_lay, Enthalpy, Sice_therm, Salin, &
 
   real :: top_melt, bot_melt, melt_left ! Heating amounts, all in melt_unit.
   real :: mtot_ice    ! The summed ice mass [kg m-2].
-  real :: enth_freeze ! The enthalpy of newly formed congelation ice, in enth_unit.
+  real :: enth_freeze ! The enthalpy of newly formed congelation ice [Enth ~> J kg-1].
   real, dimension(0:NkIce) :: enth_fr ! The snow and ice layers' freezing point
-                                      ! enthalpy, in units of enth_unit.
-  real :: min_dEnth_freeze    ! The minimum enthalpy change that must occur when
-                              ! freezing water, usually enough to account for
-                              ! the latent heat of fusion in a small fraction of
-                              ! the water, in Enth_unit kg-1 (perhaps J kg-1).
+                                      ! enthalpy [Enth ~> J kg-1].
+  real :: min_dEnth_freeze    ! The minimum enthalpy change that must occur when freezing water,
+                              ! usually enough to account for the latent heat of fusion
+                              ! in a small fraction of the water [Enth ~> J kg-2].
   real :: m_freeze            ! The newly formed ice from freezing [kg m-2].
   real :: M_melt              ! The ice mass lost to melting [kg m-2].
   real :: evap_left           ! The remaining evaporation [kg m-2].
@@ -1488,8 +1486,7 @@ subroutine add_frazil_SIS2(m_lay, Enthalpy, Sice_therm, Salin, npassive, TrLay,
   real, dimension(0:NkIce), &
         intent(inout) :: m_lay       !< Snow and ice mass per unit area by layer [kg m-2].
   real, dimension(0:NkIce+1), &
-        intent(inout) :: Enthalpy    !< Snow, ice, and ocean enthalpy by layer in enth_units
-                                     !! (which might be J/kg).
+        intent(inout) :: Enthalpy    !< Snow, ice, and ocean enthalpy by layer [Enth ~> J kg-1].
   real, dimension(NkIce), &
         intent(in)    :: Sice_therm  !< ice salinity by layer, as used for thermodynamics [gSalt kg-1]
   real, dimension(NkIce+1), &
@@ -1508,20 +1505,19 @@ subroutine add_frazil_SIS2(m_lay, Enthalpy, Sice_therm, Salin, npassive, TrLay,
   real, intent(  out) :: enthalpy_freeze !< The enthalpy gain due to the
                                      !! mass gain by freezing [J m-2].
 
-  real :: enth_frazil ! The enthalpy of newly formed frazil ice, in enth_unit.
+  real :: enth_frazil ! The enthalpy of newly formed frazil ice [Enth ~> J kg-1].
   real :: frazil_per_layer    ! The frazil heat sink from each of the sublayers of
-                              ! of the ice, in units of enth_unit.
+                              ! of the ice [Enth ~> J kg-1].
   real :: t_frazil    ! The temperature which with the frazil-ice is created [degC].
   real :: m_frazil    ! The newly-formed mass per unit area of frazil ice [kg m-2].
-  real :: min_dEnth_freeze    ! The minimum enthalpy change that must occur when
-                              ! freezing water, usually enough to account for
-                              ! the latent heat of fusion in a small fraction of
-                              ! the water, in Enth_unit kg-1 (perhaps J kg-1).
+  real :: min_dEnth_freeze    ! The minimum enthalpy change that must occur when freezing water,
+                              ! usually enough to account for the latent heat of fusion
+                              ! in a small fraction of the water [Enth ~> J kg-2].
   real :: m_freeze            ! The newly formed ice from freezing [kg m-2].
   real :: salin_freeze        ! The salinity of newly frozen ice [gSalt kg-1].
   real :: enthM_freezing      ! The enthalpy gain due to the mass gain by
-                              ! freezing, in enth_unit kg m-2 (often J m-2).
-  real :: enth_unit           ! The units for enthalpy (often J kg-1).
+                              ! freezing [Enth ~> J kg-1].
+  real :: enth_unit           ! Converts from [J kg-1] to units for enthalpy [Enth kg J-1 ~> 1].
   real :: LI          ! The latent heat of fusion [J kg-1].
   ! These variables are used only for debugging.
   real :: mtot_ice    ! The summed ice mass [kg m-2].
@@ -1598,7 +1594,7 @@ end subroutine add_frazil_SIS2
 subroutine rebalance_ice_layers(m_lay, mtot_ice, Enthalpy, Salin, NkIce, npassive, TrLay)
   real, dimension(0:NkIce),   intent(inout) :: m_lay !< The ice mass by layer [kg m-2].
   real,                       intent(out)   :: mtot_ice !< The summed ice mass [kg m-2].
-  real, dimension(0:NkIce+1), intent(inout) :: Enthalpy !< Snow, ice, and ocean enthalpy by layer in enth_units.
+  real, dimension(0:NkIce+1), intent(inout) :: Enthalpy !< Snow, ice, and ocean enthalpy by layer [Enth ~> J kg-1].
   real, dimension(NkIce+1),   intent(inout) :: Salin  !< Conserved ice bulk salinity by layer [gSalt kg-1]
   integer,                    intent(in)    :: NkIce  !< The number of ice layers.
   integer,                    intent(in)    :: npassive !< Number of passive tracers
@@ -1796,7 +1792,7 @@ end subroutine calculate_T_Freeze
 subroutine enthalpy_from_TS(T, S, enthalpy, ITV)
   real, dimension(:), intent(in) :: T  !< The ice temperature [degC]
   real, dimension(:), intent(in) :: S  !< The ice bulk salinity [gSalt kg-1]
-  real, dimension(:), intent(out) :: enthalpy !< The ice enthalpy, in enthalpy units (often J/kg)
+  real, dimension(:), intent(out) :: enthalpy !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
 
   integer :: k, nk_ice
@@ -1811,7 +1807,7 @@ function enth_from_TS(T, S, ITV) result(enthalpy)
   real, intent(in)  :: T  !< The ice temperature [degC]
   real, intent(in)  :: S  !< The ice bulk salinity [gSalt kg-1]
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
-  real :: enthalpy !< The ice enthalpy, in enthalpy units (often J/kg)
+  real :: enthalpy !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
 
   real :: T_fr  ! The freezing temperature [degC].
   real :: Cp_Ice, Enth_liq_0, LI, enth_unit
@@ -1854,7 +1850,7 @@ end function enthalpy_liquid_freeze
 
 !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!
 !> enthalpy_liquid returns the enthalpy of liquid water at the given
-!!     temperature and salinity, in enth_unit.
+!!     temperature and salinity, in enthalpy units [Enth ~> J kg-1]
 function enthalpy_liquid(T, S, ITV)
   real, intent(in)  :: T  !< The ice temperature [degC]
   real, intent(in)  :: S  !< The ice bulk salinity [gSalt kg-1]
@@ -1882,8 +1878,8 @@ end function enth_melt
 !!   for a given ice and snow enthalpy (in enth_units), and a weighting factor
 !!   for the sublimation between the snow and ice.
 function latent_sublimation(enth_snow, enth_ice, wt_snow, ITV) result (latent)
-  real, intent(in) :: enth_snow  !< The enthalpy of the snow in enth_units.
-  real, intent(in) :: enth_ice   !< The enthalpy of the ice surface in enth_units.
+  real, intent(in) :: enth_snow  !< The enthalpy of the snow [Enth ~> J kg-1].
+  real, intent(in) :: enth_ice   !< The enthalpy of the ice surface [Enth ~> J kg-1].
   real, intent(in) :: wt_snow    !< A weighting factor (0-1) for the snow areal
                                  !! coverage; the complement is for the ice.
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
@@ -1912,7 +1908,7 @@ end function latent_sublimation
 !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!
 !> Temp_from_Enth_S sets a column of temperatures from enthalpy and salinity.
 subroutine Temp_from_Enth_S(En, S, Temp, ITV)
-  real, dimension(:), intent(in) :: En !< The ice enthalpy, in enthalpy units (often J/kg)
+  real, dimension(:), intent(in) :: En !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
   real, dimension(:), intent(in) :: S  !< The ice bulk salinity [gSalt kg-1]
   real, dimension(:), intent(out) :: Temp !< The ice temperature [degC]
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
@@ -2014,7 +2010,7 @@ end function dTemp_dEnth_TS
 !> Temp_from_En_S returns the sea ice temperature for ice of a given enthalpy
 !! and salinity.
 function Temp_from_En_S(En, S, ITV) result(Temp)
-  real, intent(in)  :: En !< The ice enthalpy, in enthalpy units [Enth ~> J/kg]
+  real, intent(in)  :: En !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
   real, intent(in)  :: S  !< The ice bulk salinity [gSalt kg-1]
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
   real :: Temp  !< Temperature [degC].
@@ -2155,7 +2151,7 @@ end function e_to_melt_TS
 !> energy_melt_enthS returns the energy needed to melt a given snow/ice
 !!      configuration [J kg-1].
 function energy_melt_enthS(En, S, ITV) result(e_to_melt)
-  real, intent(in) :: En !< The ice enthalpy, in enthalpy units (often J/kg)
+  real, intent(in) :: En !< The ice enthalpy, in enthalpy units [Enth ~> J kg-1]
   real, intent(in) :: S  !< The ice bulk salinity [gSalt kg-1]
   type(ice_thermo_type), intent(in) :: ITV !< The ice thermodynamic parameter structure.
 

src/SIS_fast_thermo.F90

@@ -613,7 +613,7 @@ subroutine do_update_ice_model_fast(Atmos_boundary, IST, sOSS, Rad, FIA, &
                 ! dimension is a combination of angular orientation and frequency.
   real, dimension(0:IG%NkIce) :: T_col ! The temperature of a column of ice and snow [degC].
   real, dimension(IG%NkIce)   :: S_col ! The thermodynamic salinity of a column of ice [gSalt kg-1].
-  real, dimension(0:IG%NkIce) :: enth_col   ! The enthalpy of a column of snow and ice, in enth_unit (J/kg?).
+  real, dimension(0:IG%NkIce) :: enth_col   ! The enthalpy of a column of snow and ice [Enth ~> J kg-1].
   real, dimension(0:IG%NkIce) :: SW_abs_col   ! The shortwave absorption within a column of snow and ice [W m-2].
   real :: dt_fast ! The fast thermodynamic time step [s].
   real :: Tskin   ! The new skin temperature [degC].
@@ -877,9 +877,8 @@ subroutine redo_update_ice_model_fast(IST, sOSS, Rad, FIA, TSF, optics_CSp, &
   real, dimension(0:IG%NkIce) :: &
     T_col, &      ! The temperature of a column of ice and snow [degC].
     SW_abs_col, & ! The shortwave absorption within a column of snow and ice [W m-2].
-    enth_col, &   ! The enthalpy of a column of snow and ice, in enth_unit (J/kg?).
-    enth_col_in   ! The initial enthalpy of a column of snow and ice,
-                  ! in enth_unit (J/kg?).
+    enth_col, &   ! The enthalpy of a column of snow and ice [Enth ~> J kg-1].
+    enth_col_in   ! The initial enthalpy of a column of snow and ice [Enth ~> J kg-1].
 
   real :: dt_here ! The time step here [s].
   real :: Tskin   ! The new skin temperature [degC].

src/SIS_slow_thermo.F90

@@ -104,7 +104,7 @@ module SIS_slow_thermo
   logical :: do_ice_restore !< If true, restore the sea-ice toward climatology
                             !! by applying a restorative heat flux.
   real    :: ice_restore_timescale !< The time scale for restoring ice when
-                            !! do_ice_restore is true, in days.
+                            !! do_ice_restore is true [days].
 
   logical :: do_ice_limit   !< Limit the sea ice thickness to max_ice_limit.
   real    :: max_ice_limit  !< The maximum sea ice thickness [m], when do_ice_limit is true.
@@ -599,11 +599,11 @@ subroutine SIS2_thermodynamics(IST, dt_slow, CS, OSS, FIA, IOF, G, IG)
   real, dimension(0:IG%NkIce) :: Tfr_col0 ! The freezing temperature of a column of ice and snow [degC].
   real, dimension(0:IG%NkIce+1) :: &
     enthalpy              ! The initial enthalpy of a column of ice and snow
-                          ! and the surface ocean, in enth_units (often J/kg).
+                          ! and the surface ocean [Enth ~> J kg-1].
   real, dimension(IG%CatIce) :: frazil_cat  ! The frazil heating applied to each thickness
                           ! category, averaged over the area of that category [J m-2].
-  real :: enthalpy_ocean  ! The enthalpy of the ocean surface waters, in Enth_units.
-  real :: heat_fill_val   ! An enthalpy to use for massless categories, in enth_units.
+  real :: enthalpy_ocean  ! The enthalpy of the ocean surface waters [Enth ~> J kg-1].
+  real :: heat_fill_val   ! An enthalpy to use for massless categories [Enth ~> J kg-1].
 
   real :: I_part        ! The inverse of a part_size, nondim.
   logical :: spec_thermo_sal  ! If true, use the specified salinities of the
@@ -637,14 +637,14 @@ subroutine SIS2_thermodynamics(IST, dt_slow, CS, OSS, FIA, IOF, G, IG)
   real :: frac_keep, frac_melt  ! The fraction of ice and snow to keep or remove, ND.
   real :: ice_melt_lay ! The amount of excess ice removed from each layer [kg m-2].
   real :: snow_melt    ! The amount of excess snow that is melted [kg m-2].
-  real :: enth_freeze  ! The freezing point enthalpy of a layer, in enth_units.
+  real :: enth_freeze  ! The freezing point enthalpy of a layer [Enth ~> J kg-1].
   real :: enth_to_melt ! The enthalpy addition required to melt the excess ice
-                       ! and snow in enth_unit kg/m2.
+                       ! and snow [Enth kg m-2 ~> J m-2].
   real :: I_Nk         ! The inverse of the number of layers in the ice, nondim.
   real :: kg_H_Nk      ! The conversion factor from units of H to kg/m2 over Nk.
   real :: part_sum     ! A running sum of partition sizes.
   real :: part_ocn     ! A slightly modified ocean part size.
-  real :: d_enth       ! The change in enthalpy between categories.
+  real :: d_enth       ! The change in enthalpy between categories [Enth ~> J kg-1].
   real :: fill_frac    ! The fraction of the difference between the thicknesses
                        ! in thin categories that will be removed within a single
                        ! timestep with filling_frazil.

src/SIS_sum_output.F90

@@ -276,7 +276,7 @@ subroutine write_ice_statistics(IST, day, n, G, IG, CS, message, check_column, t
   real :: Extent       ! The total extent of the sea ice [m2].
   real :: heat_imb     ! The column integrated heat imbalance [Enth kg m-2 ~> J m-2].
   real :: mass_imb     ! The column integrated mass imbalance [kg].
-  real :: enth_liq_0   ! The enthalpy of liquid water at the freezing point, in enth_unit.
+  real :: enth_liq_0   ! The enthalpy of liquid water at the freezing point [Enth ~> J kg-1].
   real :: I_nlay, kg_H_nlay, area_pt
   real :: area_h       ! The masked area of a column.
   type(EFP_type) :: &