Redundant logical keys in lateral diffusion for passive tracers

[lovato]

Context

In NEMO 4.0, the revised lateral diffusion for passive tracers (namtrc_ldf) can be turned off and on, with the latter case using the same parameterizations of the active tracers (namtra_ldf)
It seems very redundant to have in namtrc_ldf two options, one to control on/off ln_trcldf_OFF and one to force use of active tracers setting ln_trcldf_tra

Proposal

I suggest to simply have a single logical to control the lateral diffusion for passive tracers ln_trcldf that turns off and on (this using ln_trcldf_tra settings) and
possibly output a log warning to check ldf parameters in namtra_ldf only when using offline transport.

[gm]

Hi Tomas,

Thanks for you suggestion.
I agree that ln_trcldf_OFF and ln_trcldf_tra seem to be a duplication, and ln_trcldf_OFF is sufficient to make the choice.
Nevertheless, keeping the two is better.
Indeed, having two logicals, both set to .false. by default (namlist_top_ref), forces a user to make a choice (If he does nothing, the model will stop).
He therefore have to think about it and make a voluntary choice.

This change in the philosophy of mamlist_ref/_cfg is for me an improvement in the v4.0.
A short description is the revised philosophy is given here: ​New namelist framework

If you agree, please close this ticket.

Gurvan

[cetlod]

I agree Gurvan