BUG in traadv_tvd.F90 in case of passive tracers and sub-time stepping (trunk & v3.6 stable)

[gm]

Issue: in the routine tra_adv_tvd_zts found in module traadv_tvd.F90 a local array size is hard coded for T-S : the advection scheme can't be used for passive tracers.

This concerns both the trunk and the v3.6_stable.

Solution: replace the following 2 lines:

 328   ||       CALL wrk_alloc( jpi, jpj, jpk, 3, ztrs )

...

566   ||       CALL wrk_dealloc( jpi, jpj, jpk, 3, ztrs )

by

 328   ||       CALL wrk_alloc( jpi, jpj, jpk, kjpt+1, ztrs )

...

 566   ||       CALL wrk_dealloc( jpi, jpj, jpk, kjpt+1, ztrs )

[flavoni]

fix for 3_6_stable in revision 6086.
Not need fix in the trunk.

[mathiot]

At the 3.6 STABLE (r6751) version, NEMO never tries to access or to write to ztrs(:,:,:,jl>=4). NEMO only tries to access or to write to jtb, jtn and jta and these value are between 1 and 3 with a clever technique to swap the indexes. So I am not sure the hard coded allocation was wrong with passive tracers.

[acc]

I agree, the allocation is independent of the number of tracers, This bug fix was unnecessary (albeit benign expect for the temporary waste of space).