Changeset 12854 for NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/src/ICE/icevar.F90

Timestamp:

2020-05-01T19:06:23+02:00 (4 years ago)

Author:

clem

Message:

1st implementation of snow fraction (impact on albedo). Light transmission is still not ok since we need a non-zero penetration of solar flux when snow thickness is > 0

File:

• NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/src/ICE/icevar.F90 (modified) (5 diffs)

NEMO/branches/2020/r4.0-HEAD_r12713_clem_dan_fixcpl/src/ICE/icevar.F90

@@ -51 +51 @@
    !!   ice_var_sshdyn    : compute equivalent ssh in lead
    !!   ice_var_itd       : convert N-cat to M-cat
+   !!   ice_var_snwfra    : fraction of ice covered by snow
    !!----------------------------------------------------------------------
    USE dom_oce        ! ocean space and time domain
@@ -77 +78 @@
    PUBLIC   ice_var_sshdyn
    PUBLIC   ice_var_itd
+   PUBLIC   ice_var_snwfra
 
    INTERFACE ice_var_itd
       MODULE PROCEDURE ice_var_itd_1c1c, ice_var_itd_Nc1c, ice_var_itd_1cMc, ice_var_itd_NcMc
+   END INTERFACE
+
+   INTERFACE ice_var_snwfra
+      MODULE PROCEDURE ice_var_snwfra_1d, ice_var_snwfra_2d, ice_var_snwfra_3d
    END INTERFACE
 
@@ -187 +193 @@
       REAL(wp), PARAMETER ::   zhl_max =  0.015_wp  ! pond lid thickness above which the ponds disappear from the albedo calculation
       REAL(wp), PARAMETER ::   zhl_min =  0.005_wp  ! pond lid thickness below which the full pond area is used in the albedo calculation
-      REAL(wp), DIMENSION(jpi,jpj,jpl) ::   z1_a_i, z1_v_i, z1_a_ip
+      REAL(wp), DIMENSION(jpi,jpj,jpl) ::   z1_a_i, z1_v_i, z1_a_ip, za_s_fra
       !!-------------------------------------------------------------------
 
@@ -234 +240 @@
          &                                                       ( h_il(:,:,:) - zhl_min ) / ( zhl_max - zhl_min )
       END WHERE
+      !
+      CALL ice_var_snwfra( h_s, za_s_fra )           ! calculate ice fraction covered by snow
+      a_ip_eff = MIN( a_ip_eff, 1._wp - za_s_fra )   ! make sure (a_ip_eff + a_s_fra) <= 1
+      !
       !                                           !---  salinity (with a minimum value imposed everywhere)     
       IF( nn_icesal == 2 ) THEN
@@ -1268 +1278 @@
    END SUBROUTINE ice_var_itd_NcMc
 
+   !!-------------------------------------------------------------------
+   !! INTERFACE ice_var_snwfra
+   !!
+   !! ** Purpose :  fraction of ice covered by snow
+   !!
+   !! ** Method  :  In absence of proper snow model on top of sea ice,
+   !!               we argue that snow does not cover the whole ice because
+   !!               of wind blowing...
+   !!                
+   !! ** Arguments : ph_s: snow thickness
+   !!                
+   !! ** Output    : pa_s_fra: fraction of ice covered by snow
+   !!
+   !!-------------------------------------------------------------------
+   SUBROUTINE ice_var_snwfra_3d( ph_s, pa_s_fra )
+      !!-------------------------------------------------------------------
+      REAL(wp), DIMENSION(:,:,:), INTENT(in   ) ::   ph_s        ! snow thickness
+      REAL(wp), DIMENSION(:,:,:), INTENT(  out) ::   pa_s_fra    ! ice fraction covered by snow
+      !!-------------------------------------------------------------------
+      pa_s_fra(:,:,:) = 1._wp - EXP( -0.2_wp * rhos * ph_s(:,:,:) )
+   END SUBROUTINE ice_var_snwfra_3d
+
+   SUBROUTINE ice_var_snwfra_2d( ph_s, pa_s_fra )
+      !!-------------------------------------------------------------------
+      REAL(wp), DIMENSION(:,:), INTENT(in   ) ::   ph_s        ! snow thickness
+      REAL(wp), DIMENSION(:,:), INTENT(  out) ::   pa_s_fra    ! ice fraction covered by snow
+      !!-------------------------------------------------------------------
+      pa_s_fra(:,:) = 1._wp - EXP( -0.2_wp * rhos * ph_s(:,:) )
+   END SUBROUTINE ice_var_snwfra_2d
+
+   SUBROUTINE ice_var_snwfra_1d( ph_s, pa_s_fra )
+      !!-------------------------------------------------------------------
+      REAL(wp), DIMENSION(:), INTENT(in   ) ::   ph_s        ! snow thickness
+      REAL(wp), DIMENSION(:), INTENT(  out) ::   pa_s_fra    ! ice fraction covered by snow
+      !!-------------------------------------------------------------------
+      pa_s_fra(:) = 1._wp - EXP( -0.2_wp * rhos * ph_s(:) )
+   END SUBROUTINE ice_var_snwfra_1d
+   
+
 #else
    !!----------------------------------------------------------------------