Changeset 5756

Timestamp:

2015-09-23T15:26:27+02:00 (9 years ago)

Author:

dancopsey

Message:

Using absolute tolerance for land ice mass change. Also do not allow negative numbers. If it goes negative remember the previous mass and wait for it to increase above that (passing zero as iceberg flux in the mean time).

Location:

branches/UKMO/dev_r5518_coupling_GSI7_GSI8_landice/NEMOGCM/NEMO/OPA_SRC/SBC

Files:

• sbc_oce.F90 (modified) (1 diff)
• sbccpl.F90 (modified) (2 diffs)

branches/UKMO/dev_r5518_coupling_GSI7_GSI8_landice/NEMOGCM/NEMO/OPA_SRC/SBC/sbc_oce.F90

@@ -157 +157 @@
    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_calving_fraction ! Set fraction of total freshwater flux for iceberg calving - remainder goes to iceshelf melting.
-   REAL(wp), PUBLIC    ::   rn_iceshelf_fluxes_tolerance   ! Fractional threshold for detecting differences in icesheet masses. 
+   REAL(wp), PUBLIC    ::   rn_iceshelf_fluxes_tolerance   ! Absolute tolerance for detecting differences in icesheet masses. 
 
    !! * Substitutions

branches/UKMO/dev_r5518_coupling_GSI7_GSI8_landice/NEMOGCM/NEMO/OPA_SRC/SBC/sbccpl.F90

@@ -1280 +1280 @@
          zgreenland_icesheet_mass_in = zgreenland_icesheet_mass_in / zmask_sum
          greenland_icesheet_timelapsed = greenland_icesheet_timelapsed + rdt         
-         IF( ABS( zgreenland_icesheet_mass_in - greenland_icesheet_mass )/( greenland_icesheet_mass + zepsilon ) > zepsilon ) THEN
+         IF( ABS( zgreenland_icesheet_mass_in - greenland_icesheet_mass ) > zepsilon ) THEN
             zgreenland_icesheet_mass_b = greenland_icesheet_mass
-            greenland_icesheet_mass = zgreenland_icesheet_mass_in
+            
+            ! Only update the mass if it has increased
+            IF ( (zgreenland_icesheet_mass_in - greenland_icesheet_mass) > 0.0 ) THEN
+               greenland_icesheet_mass = zgreenland_icesheet_mass_in
+            ENDIF
+            
             IF( zgreenland_icesheet_mass_b /= 0.0 ) &
            &     greenland_icesheet_mass_rate_of_change = ( greenland_icesheet_mass - zgreenland_icesheet_mass_b ) / greenland_icesheet_timelapsed 
             greenland_icesheet_timelapsed = 0.0_wp       
          ENDIF
-         IF(lwp) WRITE(numout,*) 'Greenland icesheet mass (kg) is ', greenland_icesheet_mass
+         IF(lwp) WRITE(numout,*) 'Greenland icesheet mass (kg) read in is ', zgreenland_icesheet_mass_in
+         IF(lwp) WRITE(numout,*) 'Greenland icesheet mass (kg) used is    ', greenland_icesheet_mass
          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
@@ -1302 +1308 @@
          zantarctica_icesheet_mass_in = zantarctica_icesheet_mass_in / zmask_sum
          antarctica_icesheet_timelapsed = antarctica_icesheet_timelapsed + rdt         
-         IF( ABS( zantarctica_icesheet_mass_in - antarctica_icesheet_mass )/( antarctica_icesheet_mass + zepsilon ) > zepsilon ) THEN
+         IF( ABS( zantarctica_icesheet_mass_in - antarctica_icesheet_mass ) > zepsilon ) THEN
             zantarctica_icesheet_mass_b = antarctica_icesheet_mass
-            antarctica_icesheet_mass = zantarctica_icesheet_mass_in
+            
+            ! Only update the mass if it has increased
+            IF ( (zantarctica_icesheet_mass_in - antarctica_icesheet_mass) > 0.0 ) THEN
+               antarctica_icesheet_mass = zantarctica_icesheet_mass_in
+            END IF
+            
             IF( zantarctica_icesheet_mass_b /= 0.0 ) &
           &      antarctica_icesheet_mass_rate_of_change = ( antarctica_icesheet_mass - zantarctica_icesheet_mass_b ) / antarctica_icesheet_timelapsed 
             antarctica_icesheet_timelapsed = 0.0_wp       
          ENDIF
-         IF(lwp) WRITE(numout,*) 'Antarctica icesheet mass (kg) is ', antarctica_icesheet_mass
+         IF(lwp) WRITE(numout,*) 'Antarctica icesheet mass (kg) read in is ', zantarctica_icesheet_mass_in
+         IF(lwp) WRITE(numout,*) 'Antarctica icesheet mass (kg) used is    ', antarctica_icesheet_mass
          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