This commit (re)adds the ability to turn off 5 heterogeneous reaction…

…s via the Input_Opt%TurnOffHetRates toggle. This is the preferred solution for GEOS runs. The 5 heterogenous reactions are:

ClNO3 + HBr --> BrCl + HNO3
ClNO3 + BrSALA --> BrCl + HNO3
ClNO3 + BrSALC --> BrCl + HNO3
BrNO3 + HCl --> BrCl + HNO3
HOCl + HBr --> BrCl + H2O

This toggle was added to a previous version of GEOS-Chem (v12) but its functionality did not get transferred to the updated heterogeneous chemistry reaction rate code.

This is a zero-diff change unless one enables the Input_Opt%TurnOffHetRates toggle.

KPP/fullchem/commonIncludeVars.H

@@ -194,6 +194,11 @@
      LOGICAL  :: cloudBox       ! Are we in a box with cloud?
      REAL(dp) :: fracOrgAer     ! Fraction of organic aerosol [1]
      REAL(dp) :: fracInorgAer   ! Fraction of organic aerosol [1]
+     !
+     ! Additional fields for GEOS runs
+     !    
+     LOGICAL  :: TurnOffHetRates ! Turn off heterogeneous reactions in stratosphere?
+
   END TYPE HetState
   TYPE(HetState), TARGET, PUBLIC :: State_Het
   !$OMP THREADPRIVATE( State_Het )

KPP/fullchem/fullchem_HetStateFuncs.F90

@@ -221,6 +221,9 @@ SUBROUTINE FullChem_SetStateHet( I,         J,         L,                  &
     ! ... check if there is surface NAT at this grid box
     H%natSurface = ( H%pscBox .and. ( C(ind_NIT) > 0.0_dp )                 )
 
+    ! Flag to turn off heterogeneous reactions in stratosphere
+    H%TurnOffHetRates = Input_Opt%TurnOffHetRates
+
   END SUBROUTINE FullChem_SetStateHet
 !EOC
 !------------------------------------------------------------------------------

KPP/fullchem/fullchem_RateLawFuncs.F90

@@ -898,6 +898,10 @@ FUNCTION BrNO3uptkByHCl( H ) RESULT( k )
 
     ! Assume BrNO3 is limiting, so update the removal rate accordingly
     k = kIIR1Ltd( C(ind_BrNO3), C(ind_HCl), k )
+
+    ! Force to zero if HetRate flag is turned on
+    IF ( H%TurnOffHetRates ) k = 0.0_dp
+
   END FUNCTION BrNO3uptkByHCl
 
   !=========================================================================
@@ -1328,6 +1332,10 @@ FUNCTION ClNO3uptkByHBr( H ) RESULT( k )
     !
     ! Assume ClNO3 is limiting, so recompute reaction rate accordingly
     k = kIIR1Ltd( C(ind_ClNO3), C(ind_HBr), k )
+
+    ! Force to zero if HetRate flag is turned on
+    IF ( H%TurnOffHetRates ) k = 0.0_dp
+
   END FUNCTION ClNO3uptkByHBr
 
   FUNCTION ClNO3uptkByBrSALA( H ) RESULT( k )
@@ -1360,6 +1368,10 @@ FUNCTION ClNO3uptkByBrSALA( H ) RESULT( k )
     !
     ! Assume ClNO3 is limiting, so recompute reaction rate accordingly
     k = kIIR1Ltd( C(ind_ClNO3), C(ind_BrSALA), k )
+
+    ! Force to zero if HetRate flag is turned on
+    IF ( H%TurnOffHetRates ) k = 0.0_dp
+
   END FUNCTION ClNO3uptkByBrSALA
 
   FUNCTION ClNO3uptkByBrSALC( H ) RESULT( k )
@@ -1392,6 +1404,10 @@ FUNCTION ClNO3uptkByBrSALC( H ) RESULT( k )
     !
     ! Assume ClNO3 is limiting, so recompute reaction rate accordingly
     k = kIIR1Ltd( C(ind_ClNO3), C(ind_BrSALC), k )
+
+    ! Force to zero if HetRate flag is turned on
+    IF ( H%TurnOffHetRates ) k = 0.0_dp
+
   END FUNCTION ClNO3uptkByBrSALC
 
   FUNCTION ClNO3uptkBySALACL( H ) RESULT( k )
@@ -1414,6 +1430,7 @@ FUNCTION ClNO3uptkBySALACL( H ) RESULT( k )
     !
     ! Assume ClNO3 is limiting, so recompute reaction rate accordingly
     k = kIIR1Ltd( C(ind_ClNO3), C(ind_SALACL), k )
+
   END FUNCTION ClNO3uptkBySALACL
 
   FUNCTION ClNO3uptkBySALCCL( H ) RESULT( k )
@@ -2241,6 +2258,10 @@ FUNCTION HOClUptkByHBr( H ) RESULT( k )
     !
     ! Assume HOCl is limiting, so recompute reaction rate accordingly
     k = kIIR1Ltd( C(ind_HOCl), C(ind_HBr), k )
+
+    ! Force to zero if HetRate flag is turned on
+    IF ( H%TurnOffHetRates ) k = 0.0_dp
+
   END FUNCTION HOClUptkByHBr
 
   FUNCTION HOClUptkBySALACL( H ) RESULT( k )