compatibility between isf and tramle

[mathiot]

Context

After testing eORCA1 with tramle activated and , I found it more instable. By looking at the code, I am not convinced at all, tramle.F90 is compatible with ice shelf cavities.

Analysis

• nlb10 is computed like this:

  !                                ! deepest/shallowest W level Above/Below ~10m
  !!gm BUG in s-coordinate this does not work!
        zrefdep = 10._wp - 0.1_wp * MINVAL( e3w_1d )                   ! ref. depth with tolerance (10% of minimum layer thickness)
        nlb10 = MINLOC( gdepw_1d, mask = gdepw_1d > zrefdep, dim = 1 ) ! shallowest W level Below ~10m
        nla10 = nlb10 - 1                                              ! deepest    W level Above ~10m
  !!gm end bug
  

• With this definition of nla10, this definition of mld used for MLE under an ice shelf does not make sense to me (because rhop(ji,jj,nla10) is on land):

        !                                      !==  MLD used for MLE  ==!
        !                                                ! compute from the 10m density to deal with the diurnal cycle
        inml_mle(:,:) = mbkt(:,:) + 1                    ! init. to number of ocean w-level (T-level + 1)
        IF ( nla10 > 0 ) THEN                            ! avoid case where first level is thicker than 10m
           DO jk = jpkm1, nlb10, -1                      ! from the bottom to nlb10 (10m)
              DO jj = 1, jpj
                 DO ji = 1, jpi                          ! index of the w-level at the ML based
                    IF( rhop(ji,jj,jk) > rhop(ji,jj,nla10) + rn_rho_c_mle )   inml_mle(ji,jj) = jk      ! Mixed layer
                 END DO
              END DO
           END DO
        ENDIF
        ikmax = MIN( MAXVAL( inml_mle(:,:) ), jpkm1 )                  ! max level of the computation
  

• Based on the name of the variables, I am not sure if the masking is right, should it be uwmask instead of umask ?

                 zpsi_uw(ji,jj,jk) = zpsim_u(ji,jj) * zmuw * umask(ji,jj,jk)
                 zpsi_vw(ji,jj,jk) = zpsim_v(ji,jj) * zmvw * vmask(ji,jj,jk)
  

• There is also some gdepw here and there in tramle, are they adapted under an isf (with respect to the definition of the mld under an isf) ?.

• it affects NEMO4 and trunk

Recommendation

• advices are needed from someone who know this part of code.
• as a temporary fix before it is fixed, probably this should do the job: multiply zpsi_u/vw by u/vmask(:,:,1) should do the trick to set it to 0 inside a cavity.

[mathiot]

In 14210:

Error: Failed to load processor CommitTicketReference

No macro or processor named 'CommitTicketReference' found

[mathiot]

In 14211:

Error: Failed to load processor CommitTicketReference

No macro or processor named 'CommitTicketReference' found