Changeset 15356 for branches/UKMO/dev_r5518_obs_oper_update_DepthBug/NEMOGCM/NEMO/OPA_SRC/OBS/obsinter_z1d.h90

Timestamp:

2021-10-12T15:52:10+02:00 (2 years ago)

Author:

kingr

Message:

Chnages to fix test in obs_level_search to ensure index of level below obdepth is returned, and to obs_prep to remove code which altered obdepths, and to vertical interpolation routine to deal with obs in top half of top box or bottom half of bottom box.

File:

• branches/UKMO/dev_r5518_obs_oper_update_DepthBug/NEMOGCM/NEMO/OPA_SRC/OBS/obsinter_z1d.h90 (modified) (1 diff)

branches/UKMO/dev_r5518_obs_oper_update_DepthBug/NEMOGCM/NEMO/OPA_SRC/OBS/obsinter_z1d.h90

@@ -62 +62 @@
          z1dm = ( pdep(kkco(jdep)) - pobsdep(jdep)      )
          z1dp = ( pobsdep(jdep)    - pdep(kkco(jdep)-1) )
+         
+         ! Where ob is at or above top model T-point, use model top rather than extrapolate
+         IF ( pobsdep(jdep) <= pdep(kkco(jdep)-1) ) z1dp = 0.0_wp
+         
+         ! Where ob is at or below bottom model T-point, use model bottom rather than extrapolate
+         IF ( pobsdep(jdep) >= pdep(kkco(jdep)) ) z1dm = 0.0_wp
+
+         ! Where deeper level is masked, only use higher level
          IF ( pobsmask(kkco(jdep)) == 0.0_wp ) z1dp = 0.0_wp
 
          zsum = z1dm + z1dp
          
-         IF ( k1dint == 0 ) THEN
-
-            !-----------------------------------------------------------------
-            !  Linear interpolation
-            !-----------------------------------------------------------------
-            pobs(jdep) = (   z1dm * pobsk(kkco(jdep)-1) &
-               &           + z1dp * pobsk(kkco(jdep)  ) ) / zsum
-
-         ELSEIF ( k1dint == 1 ) THEN
-
-            !-----------------------------------------------------------------
-            ! Cubic spline interpolation
-            !-----------------------------------------------------------------
-            zsum2 = zsum * zsum
-            pobs(jdep)  = (  z1dm                             * pobsk (kkco(jdep)-1) &
-               &           + z1dp                             * pobsk (kkco(jdep)  ) &
-               &           + ( z1dm * ( z1dm * z1dm - zsum2 ) * pobs2k(kkco(jdep)-1) &
-               &           +   z1dp * ( z1dp * z1dp - zsum2 ) * pobs2k(kkco(jdep)  ) &
-               &             ) / 6.0_wp                                              &
-               &          ) / zsum
-
+         IF ( zsum > 0.0_wp ) THEN
+            IF ( k1dint == 0 ) THEN
+
+               !-----------------------------------------------------------------
+               !  Linear interpolation
+               !-----------------------------------------------------------------
+               pobs(jdep) = (   z1dm * pobsk(kkco(jdep)-1) &
+                  &           + z1dp * pobsk(kkco(jdep)  ) ) / zsum
+
+            ELSEIF ( k1dint == 1 ) THEN
+
+               !-----------------------------------------------------------------
+               ! Cubic spline interpolation
+               !-----------------------------------------------------------------
+               zsum2 = zsum * zsum
+               pobs(jdep)  = (  z1dm                             * pobsk (kkco(jdep)-1) &
+                  &           + z1dp                             * pobsk (kkco(jdep)  ) &
+                  &           + ( z1dm * ( z1dm * z1dm - zsum2 ) * pobs2k(kkco(jdep)-1) &
+                  &           +   z1dp * ( z1dp * z1dp - zsum2 ) * pobs2k(kkco(jdep)  ) &
+                  &             ) / 6.0_wp                                              &
+                  &          ) / zsum
+
+            ENDIF
+         ELSE ! take value directly from the higher model level
+            pobs(jdep)  = pobsk(kkco(jdep)-1)
          ENDIF
       END DO