Changeset 12449 for NEMO/branches/UKMO/NEMO_4.0_add_pond_lids_prints/src/ICE/icethd_dh.F90

Timestamp:

2020-02-24T18:04:40+01:00 (4 years ago)

Author:

dancopsey

Message:

• Snow into meltponds contributes to snow to ice diagnostics affecting thickness and salinity of the ice.
• Avoid divide by zero errors by:
  • Removing meltponds from small ice areas.
  • Removing divide by pond fractions apart from lid shrinking there a minimum pond fraction is imnposed
• Ponds leaking into the ocean have a salinity flux to the ocean (also a new diagnostic).
• Add vertical fluxing of pond water.

File:

• NEMO/branches/UKMO/NEMO_4.0_add_pond_lids_prints/src/ICE/icethd_dh.F90 (modified) (4 diffs)

NEMO/branches/UKMO/NEMO_4.0_add_pond_lids_prints/src/ICE/icethd_dh.F90

@@ -99 +99 @@
       REAL(wp), DIMENSION(jpij,nlay_i) ::   zh_i      ! ice layer thickness
       REAL(wp), DIMENSION(jpij,nlay_i) ::   zdeltah
+      REAL(wp), DIMENSION(jpij,nlay_i) ::   zdeltah_pnd  ! Change in thickness due to melting into ponds
       INTEGER , DIMENSION(jpij,nlay_i) ::   icount    ! number of layers vanished by melting 
 
@@ -281 +282 @@
                zdeltah  (ji,jk) = MAX( zdeltah(ji,jk) , - zh_s(ji,jk) )                   ! bound melting
                zdh_s_mel(ji)    = zdh_s_mel(ji) + zdeltah(ji,jk)
+               zdeltah_pnd(ji,jk) = zdeltah  (ji,jk) * a_pnd_avail_1d(ji)
                
                hfx_snw_1d(ji)     = hfx_snw_1d(ji)     - zdeltah(ji,jk) * a_i_1d(ji) * e_s_1d (ji,jk) * r1_rdtice   ! heat used to melt snow(W.m-2, >0)
-               wfx_snw_sum_1d(ji) = wfx_snw_sum_1d(ji) - rhos           * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice   ! snow melting only = water into the ocean (then without snow precip)
+               wfx_snw_sum_1d(ji) = wfx_snw_sum_1d(ji) - rhos           * a_i_1d(ji) * (zdeltah(ji,jk) - zdeltah_pnd(ji,jk)) * r1_rdtice   ! snow melting only = water into the ocean (then without snow precip)
                
                ! updates available heat + thickness
                dh_s_mlt(ji)    = dh_s_mlt(ji) + zdeltah(ji,jk)
-               dh_s_pnd(ji)    = dh_s_pnd(ji) + zdeltah(ji,jk) * a_pnd_avail_1d(ji)                   ! Cumulate surface melt on areas contributing to melt ponds
+               dh_s_pnd(ji)    = dh_s_pnd(ji) + zdeltah_pnd(ji,jk)                ! Cumulate surface melt on areas contributing to melt ponds
                zq_top  (ji)    = MAX( 0._wp , zq_top(ji) + zdeltah(ji,jk) * e_s_1d(ji,jk) )
                h_s_1d  (ji)    = MAX( 0._wp , h_s_1d(ji) + zdeltah(ji,jk) )
-               h_i_1d  (ji)    = MAX( 0._wp , h_i_1d(ji) - zdeltah(ji,jk) * a_pnd_avail_1d(ji) * rhos * r1_rhoi )   ! Snow melt trapped in ponds contrbutes to ice thickness
                zh_s    (ji,jk) = MAX( 0._wp , zh_s(ji,jk) + zdeltah(ji,jk) )
+
+               ! Snow melt trapped in ponds contrbutes to ice thickness and snow to ice conversion
+               h_i_1d  (ji)    = MAX( 0._wp , h_i_1d(ji) - zdeltah_pnd(ji,jk) * rhos * r1_rhoi ) 
+               wfx_sni_1d(ji)     = wfx_sni_1d(ji)     - a_i_1d(ji) * zdeltah_pnd(ji,jk) * rhos * r1_rdtice
+               wfx_snw_sni_1d(ji) = wfx_snw_sni_1d(ji) + a_i_1d(ji) * zdeltah_pnd(ji,jk) * rhos * r1_rdtice
                !
             ENDIF
@@ -400 +406 @@
                zdE            =    zEi - zEw                          ! Specific enthalpy difference < 0
                
-               zfmdt          = - zq_top(ji) / zdE                    ! Mass flux to the ocean [kg/m2, >0]
-               
-               zdeltah(ji,jk) = - zfmdt * r1_rhoi                     ! Melt of layer jk [m, <0]
+               zfmdt          = - zq_top(ji) / zdE                    ! Mass flux to the ocean or meltponds [kg/m2, >0]
+               
+               zdeltah(ji,jk) = - zfmdt * r1_rhoi * (1._wp - a_pnd_avail_1d(ji))                    ! Melt of layer jk [m, <0] into the ocean
+               zdeltah_pnd(ji,jk) = - zfmdt * r1_rhoi * a_pnd_avail_1d(ji)                          ! Melt of layer jk [m, <0] into meltponds
                
                zdeltah(ji,jk) = MIN( 0._wp , MAX( zdeltah(ji,jk) , - zh_i(ji,jk) ) )    ! Melt of layer jk cannot exceed the layer thickness [m, <0]
@@ -408 +415 @@
                zq_top(ji)      = MAX( 0._wp , zq_top(ji) - zdeltah(ji,jk) * rhoi * zdE ) ! update available heat
                
-               dh_i_sum(ji)   = dh_i_sum(ji) + zdeltah(ji,jk) * (1._wp - a_pnd_avail_1d(ji))         ! Cumulate surface melt on areas not contributing to melt ponds
-               dh_i_pnd(ji)   = dh_i_pnd(ji) + zdeltah(ji,jk) * a_pnd_avail_1d(ji)                   ! Cumulate surface melt on areas contributing to melt ponds
+               dh_i_sum(ji)   = dh_i_sum(ji) + zdeltah(ji,jk)          ! Cumulate surface melt on areas not contributing to melt ponds
+               dh_i_pnd(ji)   = dh_i_pnd(ji) + zdeltah_pnd(ji,jk)      ! Cumulate surface melt on areas contributing to melt ponds
                
                zfmdt          = - rhoi * zdeltah(ji,jk)               ! Recompute mass flux [kg/m2, >0]