+Add 2 runtime params for ice shelf temperatures

  Added the new runtime parameters INFLOW_SHELF_TEMPERATURE and
MISSING_SHELF_TEMPERATURE to the ice_shelf_dynamics module to replace hard coded
ice shelf temperatures.  By default, all answers are bitwise identical, but
there are new entries in some MOM_parameter_doc files for cases that use the
ice shelf code with DYNAMIC_SHELF_MASS.

src/ice_shelf/MOM_ice_shelf_dynamics.F90

@@ -147,7 +147,7 @@ module MOM_ice_shelf_dynamics
   logical :: moving_shelf_front  !< Specify whether to advance shelf front (and calve).
   logical :: calve_to_mask       !< If true, calve off the ice shelf when it passes the edge of a mask.
   real :: min_thickness_simple_calve !< min. ice shelf thickness criteria for calving [Z ~> m].
-
+  real :: T_shelf_missing   !< An ice shelf temperature to use where there is no ice shelf [degC ~> C]
   real :: cg_tolerance !< The tolerance in the CG solver, relative to initial residual, that
                        !! determines when to stop the conjugate gradient iterations [nondim].
   real :: nonlinear_tolerance !< The fractional nonlinear tolerance, relative to the initial error,
@@ -234,6 +234,8 @@ subroutine register_ice_shelf_dyn_restarts(G, US, param_file, CS, restart_CS)
   type(ice_shelf_dyn_CS), pointer       :: CS !< A pointer to the ice shelf dynamics control structure
   type(MOM_restart_CS),   intent(inout) :: restart_CS !< MOM restart control struct
 
+  ! Local variables
+  real :: T_shelf_missing ! An ice shelf temperature to use where there is no ice shelf [degC ~> C]
   logical :: shelf_mass_is_dynamic, override_shelf_movement, active_shelf_dynamics
   character(len=40)  :: mdl = "MOM_ice_shelf_dyn"  ! This module's name.
   integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB
@@ -260,9 +262,12 @@ subroutine register_ice_shelf_dyn_restarts(G, US, param_file, CS, restart_CS)
   endif
 
   if (active_shelf_dynamics) then
+    call get_param(param_file, mdl, "MISSING_SHELF_TEMPERATURE", T_shelf_missing, &
+                 "An ice shelf temperature to use where there is no ice shelf.",&
+                 units="degC", default=-10.0, scale=US%degC_to_C, do_not_log=.true.)
     allocate( CS%u_shelf(IsdB:IedB,JsdB:JedB), source=0.0 )
     allocate( CS%v_shelf(IsdB:IedB,JsdB:JedB), source=0.0 )
-    allocate( CS%t_shelf(isd:ied,jsd:jed), source=-10.0*US%degC_to_C ) ! [C ~> degC]
+    allocate( CS%t_shelf(isd:ied,jsd:jed), source=T_shelf_missing ) ! [C ~> degC]
     allocate( CS%ice_visc(isd:ied,jsd:jed), source=0.0 )
     allocate( CS%AGlen_visc(isd:ied,jsd:jed), source=2.261e-25 ) ! [Pa-3 s-1]
     allocate( CS%basal_traction(isd:ied,jsd:jed), source=0.0 )   ! [R L2 T-2 ~> Pa]
@@ -329,6 +334,8 @@ subroutine initialize_ice_shelf_dyn(param_file, Time, ISS, CS, G, US, diag, new_
                         ! a restart file to the internal representation in this run.
   real    :: vel_rescale ! A rescaling factor for horizontal velocities from the representation
                         ! in a restart file to the internal representation in this run.
+  real    :: T_shelf_bdry ! A default ice shelf temperature to use for ice flowing
+                          ! in through open boundaries [C ~> degC]
   !This include declares and sets the variable "version".
 # include "version_variable.h"
   character(len=200) :: IC_file,filename,inputdir
@@ -438,7 +445,13 @@ subroutine initialize_ice_shelf_dyn(param_file, Time, ISS, CS, G, US, diag, new_
                  "if CONSTANT a constant value (for debugging).", &
                  default="MODEL")
 
+    call get_param(param_file, mdl, "INFLOW_SHELF_TEMPERATURE", T_shelf_bdry, &
+                 "A default ice shelf temperature to use for ice flowing in through "//&
+                 "open boundaries.", units="degC", default=-15.0, scale=US%degC_to_C)
   endif
+  call get_param(param_file, mdl, "MISSING_SHELF_TEMPERATURE", CS%T_shelf_missing, &
+                 "An ice shelf temperature to use where there is no ice shelf.",&
+                 units="degC", default=-10.0, scale=US%degC_to_C)
   call get_param(param_file, mdl, "MIN_THICKNESS_SIMPLE_CALVE", CS%min_thickness_simple_calve, &
                  "Min thickness rule for the VERY simple calving law",&
                  units="m", default=0.0, scale=US%m_to_Z)
@@ -447,7 +460,7 @@ subroutine initialize_ice_shelf_dyn(param_file, Time, ISS, CS, G, US, diag, new_
   ! previously allocated for registration for restarts.
 
   if (active_shelf_dynamics) then
-    allocate( CS%t_bdry_val(isd:ied,jsd:jed), source=-15.0*US%degC_to_C) ! [C ~> degC]
+    allocate( CS%t_bdry_val(isd:ied,jsd:jed), source=T_shelf_bdry) ! [C ~> degC]
     allocate( CS%thickness_bdry_val(isd:ied,jsd:jed), source=0.0)
     allocate( CS%u_face_mask(Isdq:Iedq,Jsdq:Jedq), source=0.0)
     allocate( CS%v_face_mask(Isdq:Iedq,Jsdq:Jedq), source=0.0)
@@ -3223,7 +3236,7 @@ subroutine ice_shelf_temp(CS, ISS, G, US, time_step, melt_rate, Time)
     if (ISS%h_shelf(i,j) > 0.0) then
       CS%t_shelf(i,j) = th_after_vflux(i,j) / ISS%h_shelf(i,j)
     else
-      CS%t_shelf(i,j) = -10.0*US%degC_to_C
+      CS%t_shelf(i,j) = CS%T_shelf_missing
     endif
 !   endif
 
@@ -3234,11 +3247,11 @@ subroutine ice_shelf_temp(CS, ISS, G, US, time_step, melt_rate, Time)
       else
         ! the ice is about to melt away in this case set thickness, area, and mask to zero
         ! NOTE: not mass conservative, should maybe scale salt & heat flux for this cell
-        CS%t_shelf(i,j) = -10.0*US%degC_to_C
+        CS%t_shelf(i,j) = CS%T_shelf_missing
         CS%tmask(i,j) = 0.0
       endif
     elseif (ISS%hmask(i,j) == 0) then
-      CS%t_shelf(i,j) = -10.0*US%degC_to_C
+      CS%t_shelf(i,j) = CS%T_shelf_missing
     elseif ((ISS%hmask(i,j) == 3) .or. (ISS%hmask(i,j) == -2)) then
       CS%t_shelf(i,j) = CS%t_bdry_val(i,j)
     endif