Changeset 15471 for NEMO/trunk/src/OCE/DOM/domvvl.F90

Timestamp:

2021-11-04T17:28:56+01:00 (3 years ago)

Author:

jchanut

Message:

#1791: correct thicknesses at last level with vvl. This ensures total depth is correct (eg matches depth at rest + sea level anomaly) which may otherwise induce unstabilities, and unconsistencies with external mode. The correction is active over steps (no change with purely s-coordinates or in between two adjacent z-levels with partial cells). Contrary to qco formulation, the vvl scheme can lead to negative thicknesses at velocity points, even if total depth at T-points is positive. This is a rare case which is not taken into account in this correction.

File:

• NEMO/trunk/src/OCE/DOM/domvvl.F90 (modified) (4 diffs)

NEMO/trunk/src/OCE/DOM/domvvl.F90

@@ -683 +683 @@
       !
       INTEGER ::   ji, jj, jk                                       ! dummy loop indices
+      INTEGER ::   iku, ikum1, ikv, ikvm1, ikf, ikfm1
       REAL(wp) ::  zlnwd                                            ! =1./0. when ln_wd_il = T/F
       !!----------------------------------------------------------------------
@@ -700 +701 @@
                &                           + e1e2t(ji+1,jj) * ( pe3_in(ji+1,jj,jk) - e3t_0(ji+1,jj,jk) ) )
          END_3D
+         !
+         ! Bottom correction:
+         DO_2D( 1, 0, 1, 0 )
+            iku    = mbku(ji  ,jj)
+            ikum1  = iku - 1
+            pe3_out(ji,jj,iku) = ( umask(ji,jj,iku) * (1.0_wp - zlnwd) + zlnwd )    & 
+               &     * ( 0.5_wp *  r1_e1e2u(ji,jj)                                  &
+               &     * (    e1e2t(ji  ,jj) * ( SUM(tmask(ji  ,jj,:)*(pe3_in(ji  ,jj,:) - e3t_0(ji  ,jj,:))) )   &               
+               &          + e1e2t(ji+1,jj) * ( SUM(tmask(ji+1,jj,:)*(pe3_in(ji+1,jj,:) - e3t_0(ji+1,jj,:))) ) ) &
+               &     - SUM(pe3_out(ji,jj,1:ikum1)))
+         END_2D
+         
          CALL lbc_lnk( 'domvvl', pe3_out(:,:,:), 'U', 1._wp )
          pe3_out(:,:,:) = pe3_out(:,:,:) + e3u_0(:,:,:)
@@ -709 +722 @@
                &                           + e1e2t(ji,jj+1) * ( pe3_in(ji,jj+1,jk) - e3t_0(ji,jj+1,jk) ) )
          END_3D
+         !
+         ! Bottom correction:
+         DO_2D( 1, 0, 1, 0 )
+            ikv    = mbkv(ji  ,jj)
+            ikvm1  = ikv - 1
+            pe3_out(ji,jj,ikv) = ( vmask(ji,jj,ikv) * (1.0_wp - zlnwd) + zlnwd )    & 
+               &     * ( 0.5_wp *  r1_e1e2v(ji,jj)                                  &
+               &     * (    e1e2t(ji,jj  ) * ( SUM(tmask(ji,jj  ,:)*(pe3_in(ji,jj  ,:) - e3t_0(ji,jj  ,:))) )   &               
+               &          + e1e2t(ji,jj+1) * ( SUM(tmask(ji,jj+1,:)*(pe3_in(ji,jj+1,:) - e3t_0(ji,jj+1,:))) ) ) &
+               &     - SUM(pe3_out(ji,jj,1:ikvm1)))
+         END_2D
          CALL lbc_lnk( 'domvvl', pe3_out(:,:,:), 'V', 1._wp )
          pe3_out(:,:,:) = pe3_out(:,:,:) + e3v_0(:,:,:)
@@ -719 +743 @@
                &                           + e1e2u(ji,jj+1) * ( pe3_in(ji,jj+1,jk) - e3u_0(ji,jj+1,jk) ) )
          END_3D
+         !
+         ! Bottom correction:
+         DO_2D( 0, 0, 0, 0 )
+            ikf    = MIN(mbku(ji  ,jj),mbku(ji,jj+1))
+            ikfm1  = ikf - 1
+            pe3_out(ji,jj,ikf) = ( umask(ji,jj,ikf) * umask(ji,jj+1,ikf) * (1.0_wp - zlnwd) + zlnwd )           & 
+               &     * ( 0.5_wp *  r1_e1e2f(ji,jj)                                                              &
+               &     * (    e1e2u(ji,jj  ) * ( SUM(umask(ji,jj  ,:)*(pe3_in(ji,jj  ,:) - e3u_0(ji,jj  ,:))) )   &               
+               &          + e1e2u(ji,jj+1) * ( SUM(umask(ji,jj+1,:)*(pe3_in(ji,jj+1,:) - e3u_0(ji,jj+1,:))) ) ) &
+               &     - SUM(pe3_out(ji,jj,1:ikfm1)))
+         END_2D
          CALL lbc_lnk( 'domvvl', pe3_out(:,:,:), 'F', 1._wp )
          pe3_out(:,:,:) = pe3_out(:,:,:) + e3f_0(:,:,:)