Changeset 12785 for NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/src/ICE/icealb.F90

Timestamp:

2020-04-20T20:48:56+02:00 (4 years ago)

Author:

clem

Message:

debug ice evap for the coupling in sbccpl and implement the possibility to read the cloud cover for a more accurate calculation of ice albedo. This functionality is only implemented in the bulk, I leave the task for the coupling to the people who know better (though I put the first bricks already)

File:

• NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/src/ICE/icealb.F90 (modified) (4 diffs)

NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/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
       !!---------------------------------------------------------------------
       !
@@ -166 +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