Keep GLACIER_REGION=1 unused

We realized that the renumbering of regions could cause silent wrong
behavior if a user was using an old user_nl_clm file that specified
behaviors for the old 4 regions. So instead, we're keeping the old
numbering for the Greenland and Antarctica regions and keeping
GLACIER_REGION=1 unused for now.

bld/namelist_files/namelist_defaults_ctsm.xml

@@ -466,27 +466,30 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
 
 <!-- Default glacier behavior is:
      Mountain glaciers: single_at_atm_topo
+     Currently-unused region 1: UNSET
      Greenland: virtual
      Antarctica: multiple
 
      If CISM is running over Antarctica, then we change the Antarctica
      behavior to virtual. Note that the Greenland behavior is always
      virtual, even if Greenland isn't included in this run.
 -->
-<glacier_region_behavior glc_use_antarctica="0">'single_at_atm_topo','virtual','multiple'</glacier_region_behavior>
-<glacier_region_behavior glc_use_antarctica="1">'single_at_atm_topo','virtual','virtual' </glacier_region_behavior>
+<glacier_region_behavior glc_use_antarctica="0">'single_at_atm_topo','UNSET','virtual','multiple'</glacier_region_behavior>
+<glacier_region_behavior glc_use_antarctica="1">'single_at_atm_topo','UNSET','virtual','virtual' </glacier_region_behavior>
 
 <!-- Default glacier melt behavior is:
      Mountain glaciers: remains_in_place
+     Currently-unused region 1: UNSET
      Greenland: replaced_by_ice
      Antarctica: replaced_by_ice -->
-<glacier_region_melt_behavior>'remains_in_place','replaced_by_ice','replaced_by_ice'</glacier_region_melt_behavior>
+<glacier_region_melt_behavior>'remains_in_place','UNSET','replaced_by_ice','replaced_by_ice'</glacier_region_melt_behavior>
 
 <!-- Default glacier ice runoff behavior is:
      Mountain glaciers: melted
+     Currently-unused region 1: UNSET
      Greenland: remains_ice
      Antarctica: remains_ice -->
-<glacier_region_ice_runoff_behavior>'melted','remains_ice','remains_ice'</glacier_region_ice_runoff_behavior>
+<glacier_region_ice_runoff_behavior>'melted','UNSET','remains_ice','remains_ice'</glacier_region_ice_runoff_behavior>
 
 <!-- This parameter is tied (in a scientific sense) to h2osno_max: For large
      values of h2osno_max, glc_snow_persistence_max_days should be 0; for small

bld/namelist_files/namelist_definition_ctsm.xml

@@ -550,7 +550,7 @@ Only works when running with a non-stub glacier model.
 
 <entry id="glacier_region_behavior" type="char*32(10)" category="clm_physics"
        group="clm_glacier_behavior"
-       valid_values="multiple,virtual,single_at_atm_topo" >
+       valid_values="multiple,virtual,single_at_atm_topo,UNSET" >
 Behavior of each glacier region (GLACIER_REGION in surface dataset).
 First item corresponds to GLACIER_REGION with ID 0 in the surface dataset,
 second to GLACIER_REGION with ID 1, etc.
@@ -563,12 +563,13 @@ Allowed values are:
 'single_at_atm_topo': glacier landunits in these grid cells have a single column,
    whose elevation matches the atmosphere's topographic height (so that there is no
    adjustment due to downscaling)
-Behavior of 'virtual' is required in the region where we have an ice sheet model
+'UNSET': place-holder for non-existent regions
+Behavior of 'virtual' is required in the region(s) where SMB is being sent to an ice sheet model
 </entry>
 
 <entry id="glacier_region_melt_behavior" type="char*32(10)" category="clm_physics"
        group="clm_glacier_behavior"
-       valid_values="replaced_by_ice,remains_in_place" >
+       valid_values="replaced_by_ice,remains_in_place,UNSET" >
 Treatment of ice melt for each glacier region (GLACIER_REGION in surface dataset).
 First item corresponds to GLACIER_REGION with ID 0 in the surface dataset,
 second to GLACIER_REGION with ID 1, etc.
@@ -577,17 +578,17 @@ Allowed values are:
    this results in positive liquid runoff and negative ice runoff
 'remains_in_place': any melted ice remains in place as liquid until it refreezes;
    thus, ice melt does not result in any runoff
+'UNSET': place-holder for non-existent regions
 IMPORTANT NOTE: Regions with the 'remains_in_place' behavior also do not
 compute SMB (because negative SMB would be pretty much meaningless in
-those regions). Thus, you cannot use this behavior where GLC is
-operating.
+those regions). Thus, you cannot use this behavior where SMB is being sent to an ice sheet model.
 Regions with the 'replaced_by_ice' behavior also compute SMB for the
 vegetated column.
 </entry>
 
 <entry id="glacier_region_ice_runoff_behavior" type="char*32(10)" category="clm_physics"
        group="clm_glacier_behavior"
-       valid_values="remains_ice,melted" >
+       valid_values="remains_ice,melted,UNSET" >
 Treatment of ice runoff for each glacier region (GLACIER_REGION in surface dataset).
 First item corresponds to GLACIER_REGION with ID 0 in the surface dataset,
 second to GLACIER_REGION with ID 1, etc.
@@ -599,6 +600,7 @@ Allowed values are:
    (generating a negative sensible heat flux) and runs off as liquid; this is appropriate in
    regions that have little iceberg calving in reality. This can be important to avoid unrealistic
    cooling of the ocean and consequent runaway sea ice growth.
+'UNSET': place-holder for non-existent regions
 Only applies when melt_non_icesheet_ice_runoff is .true.
 </entry>
 

cime_config/SystemTests/lvg.py

@@ -32,12 +32,12 @@ def _case_one_setup(self):
         append_to_user_nl_files(
             caseroot=self._get_caseroot(),
             component="clm",
-            contents="glacier_region_behavior = 'single_at_atm_topo', 'virtual', 'multiple'",
+            contents="glacier_region_behavior = 'single_at_atm_topo', 'UNSET', 'virtual', 'multiple'",
         )
 
     def _case_two_setup(self):
         append_to_user_nl_files(
             caseroot=self._get_caseroot(),
             component="clm",
-            contents="glacier_region_behavior = 'single_at_atm_topo', 'virtual', 'virtual'",
+            contents="glacier_region_behavior = 'single_at_atm_topo', 'UNSET', 'virtual', 'virtual'",
         )

cime_config/usermods_dirs/_includes/cmip6_glaciers_virtual_antarctica/user_nl_clm

@@ -5,5 +5,5 @@
 ! This differs from the default in that it turns on virtual columns over Antarctica
 ! This is desired so that we have the output needed to drive a later offline CISM Antarctica simulation
 ! However, this increases the cost of CLM by about 10%
-glacier_region_behavior = 'single_at_atm_topo', 'virtual', 'virtual'
+glacier_region_behavior = 'single_at_atm_topo', 'UNSET', 'virtual', 'virtual'
 

src/main/glcBehaviorMod.F90

@@ -405,7 +405,8 @@ subroutine translate_glacier_region_behavior
                glacier_region_behavior(i) = BEHAVIOR_SINGLE_AT_ATM_TOPO
             case (behavior_str_unset)
                write(iulog,*) ' ERROR: glacier_region_behavior not specified for ID ', i
-               write(iulog,*) 'You probably need to extend the glacier_region_behavior namelist array'
+               write(iulog,*) 'You may need to extend the glacier_region_behavior namelist array,'
+               write(iulog,*) 'or you may be running with an old/incompatible surface dataset.'
                call endrun(msg=' ERROR: glacier_region_behavior not specified for ID '// &
                     errMsg(sourcefile, __LINE__))
             case default
@@ -436,7 +437,8 @@ subroutine translate_glacier_region_melt_behavior
                glacier_region_melt_behavior(i) = MELT_BEHAVIOR_REMAINS_IN_PLACE
             case (behavior_str_unset)
                write(iulog,*) ' ERROR: glacier_region_melt_behavior not specified for ID ', i
-               write(iulog,*) 'You probably need to extend the glacier_region_melt_behavior namelist array'
+               write(iulog,*) 'You may need to extend the glacier_region_melt_behavior namelist array,'
+               write(iulog,*) 'or you may be running with an old/incompatible surface dataset.'
                call endrun(msg=' ERROR: glacier_region_melt_behavior not specified for ID '// &
                     errMsg(sourcefile, __LINE__))
             case default
@@ -467,7 +469,8 @@ subroutine translate_glacier_region_ice_runoff_behavior
                glacier_region_ice_runoff_behavior(i) = ICE_RUNOFF_BEHAVIOR_MELTED
             case (behavior_str_unset)
                write(iulog,*) ' ERROR: glacier_region_ice_runoff_behavior not specified for ID ', i
-               write(iulog,*) 'You probably need to extend the glacier_region_ice_runoff_behavior namelist array'
+               write(iulog,*) 'You may need to extend the glacier_region_ice_runoff_behavior namelist array,'
+               write(iulog,*) 'or you may be running with an old/incompatible surface dataset.'
                call endrun(msg=' ERROR: glacier_region_ice_runoff_behavior not specified for ID '// &
                     errMsg(sourcefile, __LINE__))
             case default

tools/mksurfdata_esmf/gen_mksurfdata_namelist.xml

@@ -140,7 +140,7 @@ version of the raw dataset will probably go away.
 
   <mksrf_fglacierregion>
     <entry>
-      <data_filename>lnd/clm2/rawdata/mksrf_GlacierRegion_10x10min_nomask_cd5_c240815.nc</data_filename>
+      <data_filename>lnd/clm2/rawdata/mksrf_GlacierRegion_10x10min_nomask_cd5_c240822.nc</data_filename>
       <mesh_filename>lnd/clm2/mappingdata/grids/UNSTRUCTgrid_10x10min_nomask_cdf5_c200129.nc</mesh_filename>
     </entry>
   </mksrf_fglacierregion>