Changeset 12937 for NEMO/branches/UKMO/NEMO_4.0.1_fix_cpl_v2/src/ICE/icealb.F90

Timestamp:

2020-05-15T18:15:25+02:00 (4 years ago)

Author:

dancopsey

Message:

Merge in Clem's branch. It was originally here:

​svn+ssh://forge.ipsl.jussieu.fr/ipsl/forge/projets/nemo/svn/NEMO/branches/UKMO/NEMO_4.0.1_dan_test_clems_branch

File:

• NEMO/branches/UKMO/NEMO_4.0.1_fix_cpl_v2/src/ICE/icealb.F90 (modified) (6 diffs)

NEMO/branches/UKMO/NEMO_4.0.1_fix_cpl_v2/src/ICE/icealb.F90

@@ -45 +45 @@
 CONTAINS
 
-   SUBROUTINE ice_alb( pt_su, ph_ice, ph_snw, ld_pnd_alb, pafrac_pnd, ph_pnd, palb_cs, palb_os )
+   SUBROUTINE ice_alb( pt_su, ph_ice, ph_snw, ld_pnd_alb, pafrac_pnd, ph_pnd, pcloud_fra, palb_ice )
       !!----------------------------------------------------------------------
       !!               ***  ROUTINE ice_alb  ***
@@ -97 +97 @@
       REAL(wp), INTENT(in   ), DIMENSION(:,:,:) ::   pafrac_pnd   !  melt pond relative fraction (per unit ice area)
       REAL(wp), INTENT(in   ), DIMENSION(:,:,:) ::   ph_pnd       !  melt pond depth
-      REAL(wp), INTENT(  out), DIMENSION(:,:,:) ::   palb_cs      !  albedo of ice under clear    sky
-      REAL(wp), INTENT(  out), DIMENSION(:,:,:) ::   palb_os      !  albedo of ice under overcast sky
+      REAL(wp), INTENT(in   ), DIMENSION(:,:)   ::   pcloud_fra   !  cloud fraction
+      REAL(wp), INTENT(  out), DIMENSION(:,:,:) ::   palb_ice     !  albedo of ice
       !
       INTEGER  ::   ji, jj, jl                ! dummy loop indices
@@ -106 +106 @@
       REAL(wp) ::   zalb_ice, zafrac_ice      ! bare sea ice albedo & relative ice fraction
       REAL(wp) ::   zalb_snw, zafrac_snw      ! snow-covered sea ice albedo & relative snow fraction
+      REAL(wp) ::   zalb_cs, zalb_os          ! albedo of ice under clear/overcast sky
       !!---------------------------------------------------------------------
       !
@@ -119 +120 @@
          DO jj = 1, jpj
             DO ji = 1, jpi
-               !                       !--- Specific snow, ice and pond fractions (for now, we prevent melt ponds and snow at the same time)
-               IF( ph_snw(ji,jj,jl) == 0._wp ) THEN
+               !---------------------------------------------!
+               !--- Specific snow, ice and pond fractions ---!
+               !---------------------------------------------!               
+               IF( ph_snw(ji,jj,jl) == 0._wp ) THEN   !--- no snow : we prevent melt ponds and snow at the same time (for now)
                   zafrac_snw = 0._wp
                   IF( ld_pnd_alb ) THEN
@@ -129 +132 @@
                   zafrac_ice = 1._wp - zafrac_pnd
                ELSE
-                  zafrac_snw = 1._wp      ! Snow fully "shades" melt ponds and ice
+                  zafrac_snw = 1._wp                  !--- snow : fully "shades" melt ponds and ice
                   zafrac_pnd = 0._wp
                   zafrac_ice = 0._wp
                ENDIF
                !
+               !---------------!
+               !--- Albedos ---!
+               !---------------!               
                !                       !--- Bare ice albedo (for hi > 150cm)
                IF( ld_pnd_alb ) THEN
@@ -161 +167 @@
                ENDIF
                !                       !--- Surface albedo is weighted mean of snow, ponds and bare ice contributions
-               palb_os(ji,jj,jl) = ( zafrac_snw * zalb_snw + zafrac_pnd * zalb_pnd + zafrac_ice * zalb_ice ) * tmask(ji,jj,1)
-               !
-               palb_cs(ji,jj,jl) = palb_os(ji,jj,jl)  &
-                  &                - ( - 0.1010 * palb_os(ji,jj,jl) * palb_os(ji,jj,jl)  &
-                  &                    + 0.1933 * palb_os(ji,jj,jl) - 0.0148 ) * tmask(ji,jj,1)
-               !
+               zalb_os = ( zafrac_snw * zalb_snw + zafrac_pnd * zalb_pnd + zafrac_ice * zalb_ice ) * tmask(ji,jj,1)
+               !
+               zalb_cs = zalb_os - ( - 0.1010 * zalb_os * zalb_os  &
+                  &                  + 0.1933 * zalb_os - 0.0148 ) * tmask(ji,jj,1)
+               !
+               ! albedo depends on cloud fraction because of non-linear spectral effects
+               palb_ice(ji,jj,jl) = ( 1._wp - pcloud_fra(ji,jj) ) * zalb_cs + pcloud_fra(ji,jj) * zalb_os
+
             END DO
          END DO