introduce linear scaling parameter for reactivity

cime_config/namelist_definition_blom.xml

@@ -4760,6 +4760,26 @@
     <desc>Sediment: CaCO3 dissolution rate (1/(kmol CO3--/m3 s))</desc>
   </entry>
 
+  <entry id="sed_alpha_poc">
+    <type>real</type>
+    <category>bgcparams</category>
+    <group>bgcparams</group>
+    <values>
+      <value>None</value>
+    </values>
+    <desc>Sediment: moving-average prcorca decay rate for sed. qualiy-based remin (1/d)</desc>
+  </entry>
+
+  <entry id="sed_qual_sc">
+    <type>real</type>
+    <category>bgcparams</category>
+    <group>bgcparams</group>
+    <values>
+      <value>None</value>
+    </values>
+    <desc>Sediment: scaling factor for sed. qualiy-based remin. rate (-)</desc>
+  </entry>
+
   <entry id="rano3denit_sed">
     <type>real</type>
     <category>bgcparams</category>

hamocc/mo_param_bgc.F90

@@ -100,7 +100,7 @@ module mo_param_bgc
   public :: POM_remin_q10,opal_remin_q10,POM_remin_Tref,opal_remin_Tref
   public :: O2thresh_aerob,O2thresh_hypoxic,NO3thresh_sulf
   public :: shelfbreak_depth
-  public :: sed_alpha_poc
+  public :: sed_alpha_poc,sed_qual_sc
 
   ! extended nitrogen cycle
   public :: q10ano3denit,sc_ano3denit,Trefano3denit,rano3denit,bkano3denit,      &
@@ -488,8 +488,8 @@ module mo_param_bgc
   real, protected :: disso_sil   = 3.e-8          ! 1/(kmol Si(OH)4/m3 s) Dissolution rate constant of opal
   real, protected :: disso_caco3 = 1.e-7          ! 1/(kmol CO3--/m3 s) Dissolution rate constant of CaCO3
   real, protected :: sed_denit   = 0.01/86400.    ! 1/s Denitrification rate constant of POP
-  real, protected :: sed_alpha_poc = 1./90.       ! 1/d 1/decay time for sediment moving average
-
+  real, protected :: sed_alpha_poc = 1./90.       ! 1/d 1/decay time for sediment moving average - assuming ~3 month memory here
+  real, protected :: sed_qual_sc = 1.             ! scaling factor for sediment quality-based remineralization
   !********************************************************************
   ! Densities etc. for SEDIMENT SHIFTING
   !********************************************************************
@@ -629,7 +629,7 @@ subroutine read_bgcnamelist()
                          bkoxan2odenit_sed,bkan2odenit_sed,q10dnra_sed,          &
                          bkoxdnra_sed,bkdnra_sed,q10anh4nitr_sed,                &
                          bkoxamox_sed,bkanh4nitr_sed,q10ano2nitr_sed,            &
-                         bkoxnitr_sed,bkano2nitr_sed
+                         bkoxnitr_sed,bkano2nitr_sed,sed_alpha_poc,sed_qual_sc
 
     if (mnproc.eq.1) then
       write(io_stdo_bgc,*)
@@ -1013,6 +1013,7 @@ subroutine write_parambgc()
       call pinfo_add_entry('claydens',    claydens)
       if (use_sediment_quality) then
         call pinfo_add_entry('sed_alpha_poc',    sed_alpha_poc)
+        call pinfo_add_entry('sed_qual_sc',      sed_qual_sc)
       endif
     endif
     if (use_extNcycle) then

hamocc/mo_powach.F90

@@ -40,7 +40,7 @@ subroutine powach(kpie,kpje,kpke,kbnd,prho,omask,psao,ptho,lspin)
     use mo_chemcon,     only: calcon
     use mo_param_bgc,   only: rnit,rcar,rdnit1,rdnit2,ro2ut,disso_sil,silsat,disso_poc,sed_denit,  &
                             & disso_caco3,ro2utammo,sed_alpha_poc,                                 &
-                            & POM_remin_q10_sed,POM_remin_Tref_sed,bkox_drempoc_sed
+                            & POM_remin_q10_sed,POM_remin_Tref_sed,bkox_drempoc_sed,sed_qual_sc
     use mo_sedmnt,      only: porwat,porsol,powtra,produs,prcaca,prorca,seddw,sedhpl,sedlay,       &
                               silpro,pror13,pror14,prca13,prca14,prorca_mavg,sed_reactivity_a,     &
                               sed_reactivity_k,sed_applied_reminrate
@@ -213,17 +213,22 @@ subroutine powach(kpie,kpje,kpke,kbnd,prho,omask,psao,ptho,lspin)
           if (omask(i,j) > 0.5 ) then
             ! update moving average TOC flux to bottom - units of prorca: kmol P/m2/dt
             ! prorca_mvg in mmol P/m2/d
-            prorca_mavg(i,j) = sed_alpha_poc * prorca(i,j)*1e6*dtbgc/86400. + (1.-sed_alpha_poc)*prorca_mavg(i,j)
+            prorca_mavg(i,j) = sed_alpha_poc*prorca(i,j)*1e6*dtbgc/86400.                          &
+                             & + (1.-sed_alpha_poc)*prorca_mavg(i,j)
 
             ! update surface age due to fresh POC sedimentation flux
             sedlay(i,j,1,issso12_age) = sedlay(i,j,1,issso12) * sedlay(i,j,1,issso12_age)          &
                           & / ((prorca(i,j)/(porsol(i,j,1)*seddw(1))) + sedlay(i,j,1,issso12) + eps)
             do k = 1, ks
               sedlay(i,j,k,issso12_age) = sedlay(i,j,k,issso12_age) + dtbgc/31104000. ! [years]
-              avgDOU                    = prorca_mavg(i,j)*ro2ut                      ! mean DOU flux [mmol/m2/d] (NOTE: thus far oxidation to NO3 assumed)
-              sed_reactivity_a(i,j,k)   = 2.48 * 10**(1.293 - 0.9822*log10(avgDOU))   ! Eq.(12) in Pika et al. 2023 * correction factor 2.48 = a (sed reactivity)
-              ! Calculating overall reactivity k [1/year] -> [1/(kmol O2/m3 dt)] using 1mumol O2/m3 as reference for now
-              sed_reactivity_k(i,j,k)   = 0.151/(sed_reactivity_a(i,j,k) + sedlay(i,j,k,issso12_age))*dtbgc/31104000./1e-6
+              ! mean DOU flux [mmol/m2/d] (NOTE: thus far oxidation to NO3 assumed)
+              avgDOU                    = max(eps,prorca_mavg(i,j)*ro2ut)
+              ! Eq.(12) in Pika et al. 2023 * correction factor 2.48 = a (sed reactivity)
+              sed_reactivity_a(i,j,k)   = 2.48 * 10**(1.293 - 0.9822*log10(avgDOU))
+              ! Calculating overall (scaled) reactivity k [1/year] -> [1/(kmol O2/m3 dt)]
+              ! using 1mumol O2/m3 as reference
+              sed_reactivity_k(i,j,k)   = sed_qual_sc*0.151*dtbgc/(31104000.*1e-6)                 &
+                                        & /(sed_reactivity_a(i,j,k) + sedlay(i,j,k,issso12_age)+eps)
             enddo
           endif
         enddo