Changeset 10276 for branches/UKMO/dev_r5518_obs_oper_update_icethick/NEMOGCM/NEMO/OPA_SRC/OBS

Timestamp:

2018-11-02T18:15:27+01:00 (5 years ago)

Author:

emmafiedler

Message:

Freeboard assimilation updates

Location:

branches/UKMO/dev_r5518_obs_oper_update_icethick/NEMOGCM/NEMO/OPA_SRC/OBS

Files:

• diaobs.F90 (modified) (7 diffs)
• obs_oper.F90 (modified) (2 diffs)
• obs_read_surf.F90 (modified) (2 diffs)
• obs_readsnowdepth.F90 (added)

branches/UKMO/dev_r5518_obs_oper_update_icethick/NEMOGCM/NEMO/OPA_SRC/OBS/diaobs.F90

@@ -22 +22 @@
    USE obs_read_surf            ! Reading and allocation of surface obs
    USE obs_readmdt              ! Reading and allocation of MDT for SLA.
+   USE obs_readsnowdepth        ! Get model snow depth for conversion of freeboard to ice thickness.
    USE obs_prep                 ! Preparation of obs. (grid search etc).
    USE obs_oper                 ! Observation operators
@@ -98 +99 @@
       & surfdata, &          !: Initial surface data
       & surfdataqc           !: Surface data after quality control
+      
    TYPE(obs_prof), PUBLIC, POINTER, DIMENSION(:) :: &
       & profdata, &          !: Initial profile data
@@ -134 +136 @@
       !!        !  15-02  (M. Martin) Simplification of namelist and code
       !!----------------------------------------------------------------------
-
+#if defined key_cice
+      USE sbc_oce, ONLY : &        ! CICE variables
+         & thick_s                 ! snow depth for freeboard conversion       
+#endif         
       IMPLICIT NONE
 
@@ -831 +836 @@
             nextrsurf(jtype) = 0
             IF ( TRIM(cobstypessurf(jtype)) == 'sla' ) nextrsurf(jtype) = 2
+            IF ( TRIM(cobstypessurf(jtype)) == 'sit' ) nextrsurf(jtype) = 2            
 
             !Read in surface obs types
@@ -844 +850 @@
                IF ( ln_altbias ) &
                   & CALL obs_rea_altbias ( surfdataqc(jtype), n2dintsurf(jtype), cn_altbiasfile )
+            ENDIF
+            
+            IF ( TRIM(cobstypessurf(jtype)) == 'sit' ) THEN
+               CALL obs_rea_snowdepth( surfdataqc(jtype), n2dintsurf(jtype), thick_s(:,:) )
             ENDIF
 
@@ -1251 +1261 @@
                ELSE            
 #if defined key_cice
-               ! Will need to convert freeboard to thickness here
                   zsurfvar(:,:) = thick_i(:,:)
 #elif defined key_lim2 || defined key_lim3
@@ -1533 +1542 @@
                &               nit000, idaystp, zsurfvar, zsurfmask,    &
                &               n2dintsurf(jtype), llnightav(jtype),     &
-               &               ravglamscl(jtype), ravgphiscl(jtype),     &
+               &               ravglamscl(jtype), ravgphiscl(jtype),    &
                &               lfpindegs(jtype) )
 
+            ! Change label of data from FBD ("freeboard") to SIT ("Sea Ice Thickness")
+            IF ( TRIM(surfdataqc(jtype)%cvars(1)) == 'FBD' ) THEN
+              surfdata(jtype)%cvars(1) = 'SIT' 
+            ENDIF
+            
          END DO
 

branches/UKMO/dev_r5518_obs_oper_update_icethick/NEMOGCM/NEMO/OPA_SRC/OBS/obs_oper.F90

@@ -37 +37 @@
    USE obs_grid,      ONLY : & 
       & obs_level_search     
-
+#if defined key_cice
+   USE ice_constants, ONLY : &    ! For conversion from sea ice freeboard to thickness
+      & rhos, rhoi, rhow
+#endif 
    IMPLICIT NONE
 
@@ -798 +801 @@
          ENDIF
          
+         IF ( TRIM(surfdataqc%cvars(1)) == 'FBD' ) THEN
+            ! Convert radar freeboard to true freeboard (add 1/4 snow depth; 1/4 based on ratio of speed of light in vacuum compared to snow (3.0e8 vs 2.4e8 m/s))
+            surfdataqc%rext(jobs,1) = surfdataqc%robs(jobs,1)            
+            surfdataqc%robs(jobs,1) = surfdataqc%rext(jobs,1) + 0.25*surfdataqc%rext(jobs,2)
+            ! Convert corrected freeboard to ice thickness following Tilling et al. (2016)
+            surfdataqc%robs(jobs,1) = (surfdataqc%robs(jobs,1)*rhow + surfdataqc%rext(jobs,2)*rhos)/ &
+                                      (rhow - rhoi)            
+         ENDIF
+         
          IF ( zext(1) == obfillflt ) THEN
             ! If the observation value is a fill value, set QC flag to bad

branches/UKMO/dev_r5518_obs_oper_update_icethick/NEMOGCM/NEMO/OPA_SRC/OBS/obs_read_surf.F90

@@ -369 +369 @@
          surfdata%cext(2) = 'MDT'
       ENDIF
+      IF ( ldmod .AND. ( TRIM( surfdata%cvars(1) ) == 'FBD' ) ) THEN
+         surfdata%cext(1) = 'freeboard'
+         surfdata%cext(2) = 'thick_s'
+      ENDIF
       IF ( iextr > kextr ) surfdata%cext(iextr) = 'STD'
 
@@ -450 +454 @@
                ! Observed value
                surfdata%robs(iobs,1) = inpfiles(jj)%pob(1,ji,1)
+               IF ( TRIM(surfdata%cvars(1)) == 'FBD' ) THEN
+                   surfdata%rext(iobs,1) = inpfiles(jj)%pob(1,ji,1)
+                   surfdata%rext(iobs,2) = fbrmdi
+               ENDIF               
 
                ! Model and MDT is set to fbrmdi unless read from file