Changeset 8046

Timestamp:

2017-05-19T12:07:10+02:00 (8 years ago)

Author:

davestorkey

Message:

UKMO/dev_r5518_GO6_package branch: Add extra option for freshwater input from ice shelves in coupled models.

Location:

branches/UKMO/dev_r5518_GO6_package/NEMOGCM

Files:

• CONFIG/SHARED/namelist_ref (modified) (1 diff)
• NEMO/OPA_SRC/ICB/icbclv.F90 (modified) (1 diff)
• NEMO/OPA_SRC/IOM/restart.F90 (modified) (1 diff)
• NEMO/OPA_SRC/SBC/sbc_oce.F90 (modified) (1 diff)
• NEMO/OPA_SRC/SBC/sbccpl.F90 (modified) (6 diffs)
• NEMO/OPA_SRC/SBC/sbcisf.F90 (modified) (2 diffs)

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/CONFIG/SHARED/namelist_ref

@@ -378 +378 @@
    ln_usecplmask = .false.   !  use a coupling mask file to merge data received from several models
                              !   -> file cplmask.nc with the float variable called cplmask (jpi,jpj,nn_cplmodel)
-   ln_coupled_iceshelf_fluxes = .false. ! If true use rate of change of mass of Greenland and Antarctic icesheets to set the 
-                                        ! combined magnitude of the iceberg calving and iceshelf melting freshwater fluxes.
+   nn_coupled_iceshelf_fluxes = 0 ! =0 : total freshwater input from iceberg calving and ice shelf basal melting 
+                                  ! taken from climatologies used (no action in coupling routines).
+                                  ! =1 :  use rate of change of mass of Greenland and Antarctic icesheets to set the 
+                                  ! combined magnitude of the iceberg calving and iceshelf melting freshwater fluxes.
+                                  ! =2 :  specify constant freshwater inputs in this namelist to set the combined
+                                  ! magnitude of iceberg calving and iceshelf melting freshwater fluxes.
    ln_iceshelf_init_atmos     = .true.  ! If true force ocean to initialise icesheet masses from atmospheric values rather than
                                         ! from values in ocean restart file. 
+   rn_greenland_total_fw_flux   = 0.0  ! Constant total rate of freshwater input (kg/s) for Greenland (if nn_coupled_iceshelf_fluxes=2) 
    rn_greenland_calving_fraction = 0.5  ! Set fraction of total freshwater flux for iceberg calving - remainder goes to iceshelf melting.
+   rn_antarctica_total_fw_flux  = 0.0  ! Constant total rate of freshwater input (kg/s) for Antarctica (if nn_coupled_iceshelf_fluxes=2)
    rn_antarctica_calving_fraction = 0.5 ! Set fraction of total freshwater flux for iceberg calving - remainder goes to iceshelf melting.
    rn_iceshelf_fluxes_tolerance = 1e-6  ! Fractional threshold for detecting differences in icesheet masses (must be positive definite).

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/NEMO/OPA_SRC/ICB/icbclv.F90

@@ -66 +66 @@
 
       IF( lk_oasis) THEN
-      ! ln_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
-      IF( ln_coupled_iceshelf_fluxes ) THEN
+      ! nn_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
+      IF( nn_coupled_iceshelf_fluxes .gt. 0 ) THEN
 
         ! Adjust total calving rates so that sum of iceberg calving and iceshelf melting in the northern

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/NEMO/OPA_SRC/IOM/restart.F90

@@ -158 +158 @@
 #endif
                      IF( lk_oasis) THEN
-                     ! ln_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
-                     IF( ln_coupled_iceshelf_fluxes ) THEN
+                     ! nn_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
+                     IF( nn_coupled_iceshelf_fluxes .eq. 1 ) THEN
                         CALL iom_rstput( kt, nitrst, numrow, 'greenland_icesheet_mass', greenland_icesheet_mass )
                         CALL iom_rstput( kt, nitrst, numrow, 'greenland_icesheet_timelapsed', greenland_icesheet_timelapsed )

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/NEMO/OPA_SRC/SBC/sbc_oce.F90

@@ -153 +153 @@
    ! sbccpl namelist parameters associated with icesheet freshwater input code. Included here rather than in sbccpl.F90 to 
    ! avoid circular dependencies.
-   LOGICAL, PUBLIC     ::   ln_coupled_iceshelf_fluxes     ! If true use rate of change of mass of Greenland and Antarctic icesheets to set the 
+   INTEGER, PUBLIC     ::   nn_coupled_iceshelf_fluxes     ! =0 : total freshwater input from iceberg calving and ice shelf basal melting 
+                                                           ! taken from climatologies used (no action in coupling routines).
+                                                           ! =1 :  use rate of change of mass of Greenland and Antarctic icesheets to set the 
                                                            ! combined magnitude of the iceberg calving and iceshelf melting freshwater fluxes.
+                                                           ! =2 :  specify constant freshwater inputs in this namelist to set the combined
+                                                           ! magnitude of iceberg calving and iceshelf melting freshwater fluxes.
    LOGICAL, PUBLIC     ::   ln_iceshelf_init_atmos         ! If true force ocean to initialise iceshelf masses from atmospheric values rather
-                                                           ! than values in ocean restart.
+                                                           ! than values in ocean restart (applicable if nn_coupled_iceshelf_fluxes=1).
+   REAL(wp), PUBLIC    ::   rn_greenland_total_fw_flux    ! Constant total rate of freshwater input (kg/s) for Greenland (if nn_coupled_iceshelf_fluxes=2) 
    REAL(wp), PUBLIC    ::   rn_greenland_calving_fraction  ! Set fraction of total freshwater flux for iceberg calving - remainder goes to iceshelf melting.
+   REAL(wp), PUBLIC    ::   rn_antarctica_total_fw_flux   ! Constant total rate of freshwater input (kg/s) for Antarctica (if nn_coupled_iceshelf_fluxes=2) 
    REAL(wp), PUBLIC    ::   rn_antarctica_calving_fraction ! Set fraction of total freshwater flux for iceberg calving - remainder goes to iceshelf melting.
    REAL(wp), PUBLIC    ::   rn_iceshelf_fluxes_tolerance   ! Absolute tolerance for detecting differences in icesheet masses. 

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/NEMO/OPA_SRC/SBC/sbccpl.F90

@@ -240 +240 @@
          &                  sn_rcv_qns , sn_rcv_emp   , sn_rcv_rnf   , sn_rcv_cal   , sn_rcv_iceflx,  &
          &                  sn_rcv_co2 , sn_rcv_grnm  , sn_rcv_antm  , sn_rcv_ts_ice, nn_cplmodel  ,  &
-         &                  ln_usecplmask, ln_coupled_iceshelf_fluxes, ln_iceshelf_init_atmos,        &
-         &                  rn_greenland_calving_fraction, &
-         &                  rn_antarctica_calving_fraction, rn_iceshelf_fluxes_tolerance
+         &                  ln_usecplmask, nn_coupled_iceshelf_fluxes, ln_iceshelf_init_atmos,        &
+         &                  rn_greenland_total_fw_flux, rn_greenland_calving_fraction, &
+         &                  rn_antarctica_total_fw_flux, rn_antarctica_calving_fraction, rn_iceshelf_fluxes_tolerance
       !!---------------------------------------------------------------------
 
@@ -311 +311 @@
          WRITE(numout,*)'  nn_cplmodel                         = ', nn_cplmodel
          WRITE(numout,*)'  ln_usecplmask                       = ', ln_usecplmask
-         WRITE(numout,*)'  ln_coupled_iceshelf_fluxes          = ', ln_coupled_iceshelf_fluxes
+         WRITE(numout,*)'  nn_coupled_iceshelf_fluxes          = ', nn_coupled_iceshelf_fluxes
          WRITE(numout,*)'  ln_iceshelf_init_atmos              = ', ln_iceshelf_init_atmos
+         WRITE(numout,*)'  rn_greenland_total_fw_flux         = ', rn_greenland_total_fw_flux
+         WRITE(numout,*)'  rn_antarctica_total_fw_flux        = ', rn_antarctica_total_fw_flux
          WRITE(numout,*)'  rn_greenland_calving_fraction       = ', rn_greenland_calving_fraction
          WRITE(numout,*)'  rn_antarctica_calving_fraction      = ', rn_antarctica_calving_fraction
@@ -950 +952 @@
       ncpl_qsr_freq = 86400 / ncpl_qsr_freq
 
-      IF( ln_coupled_iceshelf_fluxes ) THEN
+      IF( nn_coupled_iceshelf_fluxes .gt. 0 ) THEN
           ! Crude masks to separate the Antarctic and Greenland icesheets. Obviously something
           ! more complicated could be done if required.
@@ -1343 +1345 @@
       ENDIF
 
-      IF( srcv(jpr_grnm)%laction ) THEN
+      IF( srcv(jpr_grnm)%laction .AND. nn_coupled_iceshelf_fluxes == 1 ) THEN
          greenland_icesheet_mass_array(:,:) = frcv(jpr_grnm)%z3(:,:,1)
          ! take average over ocean points of input array to avoid cumulative error over time
@@ -1375 +1377 @@
          IF(lwp) WRITE(numout,*) 'Greenland icesheet mass rate of change (kg/s) is ', greenland_icesheet_mass_rate_of_change
          IF(lwp) WRITE(numout,*) 'Greenland icesheet seconds lapsed since last change is ', greenland_icesheet_timelapsed
+      ELSE IF ( nn_coupled_iceshelf_fluxes == 2 ) THEN
+         greenland_icesheet_mass_rate_of_change = rn_greenland_total_fw_flux
       ENDIF
 
       !                                                        ! land ice masses : Antarctica
-      IF( srcv(jpr_antm)%laction ) THEN
+      IF( srcv(jpr_antm)%laction .AND. nn_coupled_iceshelf_fluxes == 1 ) THEN
          antarctica_icesheet_mass_array(:,:) = frcv(jpr_antm)%z3(:,:,1)
          ! take average over ocean points of input array to avoid cumulative error from rounding errors over time
@@ -1410 +1414 @@
          IF(lwp) WRITE(numout,*) 'Antarctica icesheet mass rate of change (kg/s) is ', antarctica_icesheet_mass_rate_of_change
          IF(lwp) WRITE(numout,*) 'Antarctica icesheet seconds lapsed since last change is ', antarctica_icesheet_timelapsed
+      ELSE IF ( nn_coupled_iceshelf_fluxes == 2 ) THEN
+         antarctica_icesheet_mass_rate_of_change = rn_antarctica_total_fw_flux
       ENDIF
 

branches/UKMO/dev_r5518_GO6_package/NEMOGCM/NEMO/OPA_SRC/SBC/sbcisf.F90

@@ -255 +255 @@
 
             IF( lk_oasis) THEN
-            ! ln_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
-            IF( ln_coupled_iceshelf_fluxes ) THEN
+            ! nn_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
+            IF( nn_coupled_iceshelf_fluxes .gt. 0 ) THEN
 
               ! Adjust total iceshelf melt rates so that sum of iceberg calving and iceshelf melting in the northern
@@ -304 +304 @@
 
             IF( lk_oasis) THEN
-            ! ln_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
-            IF( ln_coupled_iceshelf_fluxes ) THEN
+            ! nn_coupled_iceshelf_fluxes uninitialised unless lk_oasis=true
+            IF( nn_coupled_iceshelf_fluxes .gt. 0 ) THEN
 
               ! Adjust total iceshelf melt rates so that sum of iceberg calving and iceshelf melting in the northern