both qc2qi_immersion and nc2ni_immersion are now mutliplied by cld_frac_l. Also added comment on how to compute effective radius

Author: hassanbeydoun

components/eam/src/physics/p3/scream/micro_p3.F90

@@ -2830,7 +2830,7 @@ subroutine back_to_cell_average(cld_frac_l,cld_frac_r,cld_frac_i,
    ! map ice-phase  process rates to cell-avg
    qi2qv_sublim_tend   = qi2qv_sublim_tend*cld_frac_i       ! Sublimation of ice in ice cloud
    nr_ice_shed_tend  = nr_ice_shed_tend*il_cldm    ! Rain # increase due to shedding from rain-ice collisions, occurs when ice and liquid interact
-   qc2qi_hetero_freeze_tend  = qc2qi_hetero_freeze_tend*il_cldm    ! Immersion freezing of cloud drops
+   qc2qi_hetero_freeze_tend  = qc2qi_hetero_freeze_tend*cld_frac_l    ! Immersion freezing of cloud drops
    qrcol   = qrcol*ir_cldm     ! Collection of rain mass by ice
    qc2qr_ice_shed_tend   = qc2qr_ice_shed_tend*il_cldm     ! Rain mass growth due to shedding of fain drops after collisions with ice, occurs when ice and liquid interact
    qi2qr_melt_tend   = qi2qr_melt_tend*cld_frac_i       ! Melting of ice
@@ -2839,7 +2839,7 @@ subroutine back_to_cell_average(cld_frac_l,cld_frac_r,cld_frac_i,
    ni2nr_melt_tend   = ni2nr_melt_tend*cld_frac_i       ! Change in number due to melting
    nc_collect_tend   = nc_collect_tend*il_cldm     ! Cloud # change due to collection of cld water by ice
    ncshdc  = ncshdc*il_cldm    ! Number change due to shedding, occurs when ice and liquid interact
-   nc2ni_immers_freeze_tend  = nc2ni_immers_freeze_tend*il_cldm      ! Number change associated with freexzing of cld drops
+   nc2ni_immers_freeze_tend  = nc2ni_immers_freeze_tend*cld_frac_l      ! Number change associated with freexzing of cld drops
    nr_collect_tend   = nr_collect_tend*ir_cldm     ! Rain number change due to collection from ice
    ni_selfcollect_tend   = ni_selfcollect_tend*cld_frac_i       ! Ice self collection
    qidep   = qidep*cld_frac_i       ! Vapor deposition to ice phase

components/eamxx/src/physics/p3/impl/p3_back_to_cell_average_impl.hpp

@@ -53,7 +53,7 @@ ::back_to_cell_average(
   // map ice-phase  process rates to cell-avg
   qi2qv_sublim_tend.set(context, qi2qv_sublim_tend * cld_frac_i);    // Sublimation of ice in ice cloud
   nr_ice_shed_tend.set(context, nr_ice_shed_tend * il_cldm); // Rain # increase due to shedding from rain-ice collisions, occurs when ice and liquid interact
-  qc2qi_hetero_freeze_tend.set(context, qc2qi_hetero_freeze_tend * il_cldm); // Immersion freezing of cloud drops
+  qc2qi_hetero_freeze_tend.set(context, qc2qi_hetero_freeze_tend * cld_frac_l); // Immersion freezing of cloud drops
   qr2qi_collect_tend.set(context, qr2qi_collect_tend * ir_cldm);  // Collection of rain mass by ice
   qc2qr_ice_shed_tend.set(context, qc2qr_ice_shed_tend * il_cldm);  // Rain mass growth due to shedding of fain drops after collisions with ice, occurs when ice and liquid interact
   qi2qr_melt_tend.set(context, qi2qr_melt_tend * cld_frac_i);    // Melting of ice
@@ -62,7 +62,7 @@ ::back_to_cell_average(
   ni2nr_melt_tend.set(context, ni2nr_melt_tend * cld_frac_i);    // Change in number due to melting
   nc_collect_tend.set(context, nc_collect_tend * il_cldm);  // Cloud # change due to collection of cld water by ice
   ncshdc.set(context, ncshdc * il_cldm); // Number change due to shedding, occurs when ice and liquid interact
-  nc2ni_immers_freeze_tend.set(context, nc2ni_immers_freeze_tend * il_cldm);   // Number change associated with freexzing of cld drops
+  nc2ni_immers_freeze_tend.set(context, nc2ni_immers_freeze_tend * cld_frac_l);   // Number change associated with freexzing of cld drops
   nr_collect_tend.set(context, nr_collect_tend * ir_cldm);  // Rain number change due to collection from ice
   ni_selfcollect_tend.set(context, ni_selfcollect_tend * cld_frac_i);    // Ice self collection
   qv2qi_vapdep_tend.set(context, qv2qi_vapdep_tend * cld_frac_i);    // Vapor deposition to ice phase

components/eamxx/src/physics/p3/impl/p3_main_impl_part3.hpp

@@ -89,6 +89,7 @@ ::p3_main_part3(
 
       if (qc_gt_small.any()) {
         nc(k).set(qc_gt_small,nc_incld*cld_frac_l(k)); //cld_dsd2 might have changed incld nc... need consistency.
+        //diag_eff_radius_qc is obtained by diving the 3rd and 2nd moments of the DSD e.g., eqn 5 of MG2008
         diag_eff_radius_qc(k).set(qc_gt_small, sp(0.5) * (mu_c(k) + 3) / lamc(k));
       }
       if (qc_small.any()) {