Indoor humidity and air-conditioning dehumidification

bld/CLMBuildNamelist.pm

@@ -2375,9 +2375,26 @@ sub setup_logic_urban {
 
   add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'building_temp_method');
   add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'urban_hac');
+  add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'building_humidity_mode');
   add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'urban_explicit_ac');
   add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'urban_traffic');
   add_default($opts, $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'init_interp_fill_missing_urban_with_HD');
+  my $building_humidity_mode = $nl->get_value('building_humidity_mode');
+  if ($building_humidity_mode < 0 || $building_humidity_mode > 2) {
+     $log->fatal_error("building_humidity_mode must be 0, 1, or 2");
+  }
+  if ($building_humidity_mode >= 1 && $nl->get_value('building_temp_method') != 1) {
+     $log->fatal_error("building_humidity_mode=1 or 2 requires building_temp_method=1");
+  }
+  if ($building_humidity_mode == 2) {
+     my $urban_hac = remove_leading_and_trailing_quotes($nl->get_value('urban_hac'));
+     if ($urban_hac ne 'ON' && $urban_hac ne 'ON_WASTEHEAT') {
+        $log->fatal_error("building_humidity_mode=2 requires urban_hac to be ON or ON_WASTEHEAT");
+     }
+     if (! value_is_true($nl->get_value('urban_explicit_ac'))) {
+        $log->fatal_error("building_humidity_mode=2 requires urban_explicit_ac=.true.");
+     }
+  }
 }
 
 #-------------------------------------------------------------------------------

bld/namelist_files/namelist_defaults_ctsm.xml

@@ -235,6 +235,9 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
 <calc_human_stress_indices               >FAST</calc_human_stress_indices>
 <calc_human_stress_indices phys="clm4_5" >NONE</calc_human_stress_indices>
 
+<!-- Urban building humidity and air-conditioning dehumidification -->
+<building_humidity_mode>0</building_humidity_mode>
+
 <!-- Explicit, time-varying urban air conditioning adoption rate scheme -->
 <urban_explicit_ac>.false.</urban_explicit_ac>
 <urban_explicit_ac phys="clm6_0" >.true.</urban_explicit_ac>

bld/namelist_files/namelist_definition_ctsm.xml

@@ -1247,6 +1247,18 @@ Turn urban air conditioning/heating ON or OFF and add wasteheat:
 <entry id="urban_explicit_ac" type="logical" category="clm_physics"
        group="clmu_inparm" valid_values="" >
 If TRUE, use explicit, time-varying AC adoption rate for air-conditioning flux and interior building temperature calculations.
+See Li et al. (2024), doi:10.1029/2023MS004107
+</entry>
+
+<entry id="building_humidity_mode" type="integer" category="clm_physics"
+       group="clmu_inparm" valid_values="0,1,2" >
+Select treatment of indoor building humidity:
+    0 = Existing CLMU formulation without indoor humidity or air-conditioning dehumidification
+    1 = Indoor humidity and latent heat exchange without air-conditioning dehumidification
+    2 = Indoor humidity and latent heat exchange with air-conditioning dehumidification and condensate production
+Modes 1 and 2 require building_temp_method=1 (prognostic calculation of interior building temp (clm5_0)).
+Mode 2 also requires urban_hac to be ON or ON_WASTEHEAT and urban_explicit_ac=.true.
+See Li et al. (2026), doi:10.1038/s44284-026-00474-4
 </entry>
 
 <entry id="urban_traffic" type="logical" category="clm_physics"

bld/unit_testers/build-namelist_test.pl

@@ -165,7 +165,7 @@ sub cat_and_create_namelistinfile {
 #
 # Figure out number of tests that will run
 #
-my $ntests = 3407;
+my $ntests = 3413;
 
 if ( defined($opts{'compare'}) ) {
    $ntests += 2061;
@@ -634,6 +634,36 @@ sub cat_and_create_namelistinfile {
 system( "touch $finidat" );
 
 my %failtest = (
+     "building humidity mode below range"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=-1",
+                                     phys=>"clm6_0",
+                                   },
+     "building humidity mode above range"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=3",
+                                     phys=>"clm6_0",
+                                   },
+     "humidity mode 1 with simple temperature"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=1,building_temp_method=0",
+                                     phys=>"clm6_0",
+                                   },
+     "humidity mode 2 with simple temperature"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=2,building_temp_method=0,urban_hac='ON',urban_explicit_ac=.true.",
+                                     phys=>"clm6_0",
+                                   },
+     "humidity mode 2 with AC off"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=2,building_temp_method=1,urban_hac='OFF',urban_explicit_ac=.true.",
+                                     phys=>"clm6_0",
+                                   },
+     "humidity mode 2 without explicit AC"
+                                  =>{ options=>"-envxml_dir .",
+                                     namelst=>"building_humidity_mode=2,building_temp_method=1,urban_hac='ON',urban_explicit_ac=.false.",
+                                     phys=>"clm6_0",
+                                   },
      "cmip7_w_issp"              =>{ options=>"-envxml_dir . -use_case 1850-2100_SSP2-4.5_transient",
                                      namelst=>"",
                                      CLM_CMIP_ERA=>"cmip7",

src/biogeophys/BalanceCheckMod.F90

@@ -36,6 +36,7 @@ module BalanceCheckMod
   use column_varcon      , only : icol_roof, icol_sunwall, icol_shadewall
   use column_varcon      , only : icol_road_perv, icol_road_imperv
   use clm_varctl         , only : use_hillslope_routing
+  use UrbanParamsType    , only : IsACDehumidificationEnabled
   !
   ! !PUBLIC TYPES:
   implicit none
@@ -499,6 +500,7 @@ subroutine BalanceCheck( bounds, &
      real(r8) :: qflx_glcice_dyn_water_flux_grc(bounds%begg:bounds%endg)  ! grid cell-level water flux needed for balance check due to glc_dyn_runoff_routing [mm H2O/s] (positive means addition of water to the system)
      real(r8) :: qflx_snwcp_discarded_liq_grc(bounds%begg:bounds%endg)  ! grid cell-level excess liquid h2o due to snow capping, which we simply discard in order to reset the snow pack [mm H2O /s]
      real(r8) :: qflx_snwcp_discarded_ice_grc(bounds%begg:bounds%endg)  ! grid cell-level excess solid h2o due to snow capping, which we simply discard in order to reset the snow pack [mm H2O /s]
+     real(r8) :: qflx_condensate_from_ac_grc(bounds%begg:bounds%endg)   ! grid cell-level condensate water flux from air-conditioning [mm H2O /s]
 
      real(r8) :: errh2o_max_val                         ! Maximum value of error in water conservation error  over all columns [mm H2O]
      real(r8) :: errh2osno_max_val                      ! Maximum value of error in h2osno conservation error over all columns [kg m-2]
@@ -558,7 +560,8 @@ subroutine BalanceCheck( bounds, &
 
           qflx_sfc_irrig_col      =>    waterflux_inst%qflx_sfc_irrig_col       , & ! Input:  [real(r8) (:)   ]  column level irrigation flux (mm H2O /s)
           qflx_sfc_irrig_grc      =>    waterlnd2atm_inst%qirrig_grc            , & ! Input:  [real(r8) (:)   ]  grid cell-level irrigation flux (mm H20 /s)
-          qflx_glcice_dyn_water_flux_col => waterflux_inst%qflx_glcice_dyn_water_flux_col  & ! Input: [real(r8) (:)]  column level water flux needed for balance check due to glc_dyn_runoff_routing (mm H2O/s) (positive means addition of water to the system)
+          qflx_glcice_dyn_water_flux_col => waterflux_inst%qflx_glcice_dyn_water_flux_col, & ! Input: [real(r8) (:)]  column level water flux needed for balance check due to glc_dyn_runoff_routing (mm H2O/s) (positive means addition of water to the system)
+          qflx_condensate_from_ac_col => waterflux_inst%qflx_condensate_from_ac_col & ! Input: [real(r8) (:)]  column level condensate water flux from air-conditioning (mm H2O /s)
           )
 
        ! Get step size and time step
@@ -604,6 +607,10 @@ subroutine BalanceCheck( bounds, &
                   - qflx_snwcp_discarded_liq_col(c) &
                   - qflx_snwcp_discarded_ice_col(c)) * dtime
 
+             if (IsACDehumidificationEnabled()) then
+                errh2o_col(c) = errh2o_col(c) - qflx_condensate_from_ac_col(c) * dtime
+             end if
+
           else
 
              errh2o_col(c) = 0.0_r8
@@ -638,6 +645,9 @@ subroutine BalanceCheck( bounds, &
               write(iulog,*)'qflx_surf                 = ',qflx_surf_col(indexc)*dtime
               write(iulog,*)'qflx_qrgwl                = ',qflx_qrgwl_col(indexc)*dtime
               write(iulog,*)'qflx_drain                = ',qflx_drain_col(indexc)*dtime
+              if (IsACDehumidificationEnabled()) then
+                 write(iulog,*)'qflx_condensate_from_ac   = ',qflx_condensate_from_ac_col(indexc)*dtime
+              end if
 
               write(iulog,*)'qflx_ice_runoff           = ',qflx_ice_runoff_col(indexc)*dtime
 
@@ -675,6 +685,12 @@ subroutine BalanceCheck( bounds, &
          qflx_snwcp_discarded_ice_col(bounds%begc:bounds%endc),  &
          qflx_snwcp_discarded_ice_grc(bounds%begg:bounds%endg),  &
          c2l_scale_type= 'urbanf', l2g_scale_type='unity' )
+       if (IsACDehumidificationEnabled()) then
+          call c2g( bounds,  &
+            qflx_condensate_from_ac_col(bounds%begc:bounds%endc),  &
+            qflx_condensate_from_ac_grc(bounds%begg:bounds%endg),  &
+            c2l_scale_type= 'urbanf', l2g_scale_type='unity' )
+       end if
 
        do g = bounds%begg, bounds%endg
           errh2o_grc(g) = endwb_grc(g) - begwb_grc(g)  &
@@ -691,6 +707,10 @@ subroutine BalanceCheck( bounds, &
                - qflx_ice_runoff_grc(g)  &
                - qflx_snwcp_discarded_liq_grc(g)  &
                - qflx_snwcp_discarded_ice_grc(g)) * dtime
+
+          if (IsACDehumidificationEnabled()) then
+             errh2o_grc(g) = errh2o_grc(g) - qflx_condensate_from_ac_grc(g) * dtime
+          end if
        end do
 
        ! add landunit level flux variable, convert from (m3/s) to (kg m-2 s-1)
@@ -738,6 +758,9 @@ subroutine BalanceCheck( bounds, &
              write(iulog,*)'qflx_drain_perched        = ',qflx_drain_perched_grc(indexg)*dtime
              write(iulog,*)'forc_flood                = ',forc_flood_grc(indexg)*dtime
              write(iulog,*)'qflx_glcice_dyn_water_flux = ',qflx_glcice_dyn_water_flux_grc(indexg)*dtime
+             if (IsACDehumidificationEnabled()) then
+                write(iulog,*)'qflx_condensate_from_ac   = ',qflx_condensate_from_ac_grc(indexg)*dtime
+             end if
 
              write(iulog,*)'CTSM is stopping'
              call endrun(subgrid_index=indexg, subgrid_level=subgrid_level_gridcell, msg=errmsg(sourcefile, __LINE__))

src/biogeophys/EnergyFluxType.F90

@@ -14,6 +14,7 @@ module EnergyFluxType
   use ColumnType     , only : col                
   use PatchType      , only : patch                
   use AnnualFluxDribbler, only : annual_flux_dribbler_type, annual_flux_dribbler_gridcell
+  use UrbanParamsType, only : IsACDehumidificationEnabled
   !
   implicit none
   save
@@ -63,14 +64,15 @@ module EnergyFluxType
      real(r8), pointer :: eflx_anthro_patch       (:)   ! patch total anthropogenic heat flux (W/m**2)
      real(r8), pointer :: eflx_traffic_patch      (:)   ! patch traffic sensible heat flux (W/m**2)
      real(r8), pointer :: eflx_wasteheat_patch    (:)   ! patch sensible heat flux from domestic heating/cooling sources of waste heat (W/m**2)
-     real(r8), pointer :: eflx_ventilation_patch  (:)   ! patch sensible heat flux from building ventilation (W/m**2)
+     real(r8), pointer :: eflx_ventilation_patch  (:)   ! patch sensible and latent heat flux from building ventilation (W/m**2)
      real(r8), pointer :: eflx_heat_from_ac_patch (:)   ! patch sensible heat flux put back into canyon due to removal by AC (W/m**2)
      real(r8), pointer :: eflx_traffic_lun        (:)   ! lun traffic sensible heat flux (W/m**2)
      real(r8), pointer :: eflx_wasteheat_lun      (:)   ! lun sensible heat flux from domestic heating/cooling sources of waste heat (W/m**2)
-     real(r8), pointer :: eflx_ventilation_lun    (:)   ! lun sensible heat flux from building ventilation (W/m**2)
+     real(r8), pointer :: eflx_ventilation_lun    (:)   ! lun sensible and latent heat flux from building ventilation (W/m**2)
      real(r8), pointer :: eflx_heat_from_ac_lun   (:)   ! lun sensible heat flux to be put back into canyon due to removal by AC (W/m**2)
-     real(r8), pointer :: eflx_building_lun       (:)   ! lun building heat flux from change in interior building air temperature (W/m**2)
+     real(r8), pointer :: eflx_building_lun       (:)   ! lun building heat flux from change in interior building air temperature (and humidity, if prognosed indoor humidity) (W/m**2)
      real(r8), pointer :: eflx_urban_ac_lun       (:)   ! lun urban air conditioning flux (W/m**2)
+     real(r8), pointer :: eflx_urban_ac_sen_lun   (:)   ! lun sensible heat component of air conditioning flux (W/m**2)
      real(r8), pointer :: eflx_urban_heat_lun     (:)   ! lun urban heating flux (W/m**2)
 
      ! Derivatives of energy fluxes
@@ -234,6 +236,7 @@ subroutine InitAllocate(this, bounds)
     allocate( this%eflx_heat_from_ac_lun   (begl:endl))             ; this%eflx_heat_from_ac_lun   (:)   = nan
     allocate( this%eflx_building_lun       (begl:endl))             ; this%eflx_building_lun       (:)   = nan
     allocate( this%eflx_urban_ac_lun       (begl:endl))             ; this%eflx_urban_ac_lun       (:)   = nan
+    allocate( this%eflx_urban_ac_sen_lun   (begl:endl))             ; this%eflx_urban_ac_sen_lun   (:)   = nan
     allocate( this%eflx_urban_heat_lun     (begl:endl))             ; this%eflx_urban_heat_lun     (:)   = nan
     allocate( this%eflx_traffic_lun        (begl:endl))             ; this%eflx_traffic_lun        (:)   = nan
     allocate( this%eflx_wasteheat_lun      (begl:endl))             ; this%eflx_wasteheat_lun      (:)   = nan
@@ -581,14 +584,21 @@ subroutine InitHistory(this, bounds, is_simple_buildtemp, is_prog_buildtemp)
     else
        this%eflx_building_lun(begl:endl) = spval
        call hist_addfld1d (fname='EFLXBUILD', units='W/m^2',  &
-            avgflag='A', long_name='building heat flux from change in interior building air temperature', &
+            avgflag='A', long_name='building heat flux from change in interior building air temperature (and humidity, if prognosed indoor humidity)', &
             ptr_lunit=this%eflx_building_lun, set_nourb=0._r8, l2g_scale_type='unity')
 
        this%eflx_urban_ac_lun(begl:endl) = spval
        call hist_addfld1d (fname='URBAN_AC', units='W/m^2',  &
             avgflag='A', long_name='urban air conditioning flux', &
             ptr_lunit=this%eflx_urban_ac_lun, set_nourb=0._r8, l2g_scale_type='unity')
 
+       if (IsACDehumidificationEnabled()) then
+          this%eflx_urban_ac_sen_lun(begl:endl) = spval
+          call hist_addfld1d (fname='URBAN_AC_SEN', units='W/m^2',  &
+               avgflag='A', long_name='sensible heat component of urban air conditioning flux', &
+               ptr_lunit=this%eflx_urban_ac_sen_lun, set_nourb=0._r8, l2g_scale_type='unity')
+       end if
+
        this%eflx_urban_heat_lun(begl:endl) = spval
        call hist_addfld1d (fname='URBAN_HEAT', units='W/m^2',  &
             avgflag='A', long_name='urban heating flux', &
@@ -625,7 +635,7 @@ subroutine InitHistory(this, bounds, is_simple_buildtemp, is_prog_buildtemp)
     if ( is_prog_buildtemp )then
        this%eflx_ventilation_patch(begp:endp) = spval
        call hist_addfld1d (fname='VENTILATION', units='W/m^2',  &
-            avgflag='A', long_name='sensible heat flux from building ventilation', &
+            avgflag='A', long_name='sensible (and latent, if prognosed indoor humidity) heat flux from building ventilation', &
             ptr_patch=this%eflx_ventilation_patch, set_nourb=0._r8, c2l_scale_type='urbanf')
     end if
 
@@ -763,6 +773,7 @@ subroutine InitCold(this, bounds, t_grnd_col, is_simple_buildtemp, is_prog_build
           if ( is_prog_buildtemp )then
              this%eflx_building_lun(l)   = 0._r8
              this%eflx_urban_ac_lun(l)   = 0._r8
+             this%eflx_urban_ac_sen_lun(l)= 0._r8
              this%eflx_urban_heat_lun(l) = 0._r8
           end if
 
@@ -776,6 +787,7 @@ subroutine InitCold(this, bounds, t_grnd_col, is_simple_buildtemp, is_prog_build
           if ( is_prog_buildtemp )then
              this%eflx_building_lun(l)   = 0._r8
              this%eflx_urban_ac_lun(l)   = 0._r8
+             this%eflx_urban_ac_sen_lun(l)= 0._r8
              this%eflx_urban_heat_lun(l) = 0._r8
              this%eflx_ventilation_lun(l)= 0._r8
           end if
@@ -874,7 +886,7 @@ subroutine Restart(this, bounds, ncid, flag, is_simple_buildtemp, is_prog_buildt
        end if
        call restartvar(ncid=ncid, flag=flag, varname='EFLX_VENTILATION', xtype=ncd_double, &
            dim1name='landunit', &
-           long_name='sensible heat flux from building ventilation', units='watt/m^2', &
+           long_name='sensible (and latent, if prognosed indoor humidity) heat flux from building ventilation', units='watt/m^2', &
            interpinic_flag='interp', readvar=readvar, data=this%eflx_ventilation_lun)
        if (flag=='read' .and. .not. readvar) then
           if (masterproc) write(iulog,*) "can't find EFLX_VENTILATION in initial file..."

src/biogeophys/HumanIndexMod.F90

@@ -1387,4 +1387,3 @@ end subroutine QSat_2
 !-----------------------------------------------------------------------
 
 end module HumanIndexMod
-

src/biogeophys/SoilFluxesMod.F90

@@ -115,7 +115,7 @@ subroutine SoilFluxes (bounds, num_urbanl, filter_urbanl, &
          htvp                    => energyflux_inst%htvp_col                , & ! Input:  [real(r8) (:)   ]  latent heat of vapor of water (or sublimation) [j/kg]
          eflx_building_heat_errsoi=> energyflux_inst%eflx_building_heat_errsoi_col  , & ! Input: [real(r8) (:)] heat flux to interior surface of walls and roof for errsoi check (W m-2)
          eflx_wasteheat_patch    => energyflux_inst%eflx_wasteheat_patch    , & ! Input:  [real(r8) (:)   ]  sensible heat flux from urban heating/cooling sources of waste heat (W/m**2)
-         eflx_ventilation_patch  => energyflux_inst%eflx_ventilation_patch  , & ! Input:  [real(r8) (:)   ]  sensible heat flux from building ventilation (W/m**2)
+         eflx_ventilation_patch  => energyflux_inst%eflx_ventilation_patch  , & ! Input:  [real(r8) (:)   ]  sensible and latent heat flux from building ventilation (W/m**2)
          eflx_heat_from_ac_patch => energyflux_inst%eflx_heat_from_ac_patch , & ! Input:  [real(r8) (:)   ]  sensible heat flux put back into canyon due to removal by AC (W/m**2)
          eflx_traffic_patch      => energyflux_inst%eflx_traffic_patch      , & ! Input:  [real(r8) (:)   ]  traffic sensible heat flux (W/m**2)     
          dlrad                   => energyflux_inst%dlrad_patch             , & ! Input:  [real(r8) (:)   ]  downward longwave radiation below the canopy [W/m2]