Closed jdha closed 8 months ago
@jdha, it is part of the Southern Ocean package that went into GOSI9:
" Tuning of the e-folding length scale nn_htau associated with the parameterisation of near-inertial wave breaking resulted in the choice of a larger length scale in the Southern Ocean \citep[Fig. 2]{Storkey2018} where summertime climatological \citep{DeBoyerMontegut2004} mixed layers are on average deeper than in the northern latitudes. Revisiting this work we found that reducing the mixing depth between 10$^{\circ}$ and 40$^{\circ}$ S improved the warm subsurface bias in the Indian Ocean. The changes were tested in the forced eORCA025 GOSI9 configuration before being implemented as standard in the three GOSI9 configurations. "
All references to it are (I believe) in zdftke.F90:
zdftke.F90: REAL(wp) :: rn_htau_scaling ! a acaling factor to apply to the penetration of TKE zdftke.F90: & rn_htau_scaling , & zdftke.F90: WRITE(numout,) ' scaling factor for tke penetration depth rn_htau_scaling = ', rn_htau_scaling zdftke.F90: htau(:,:) = rn_htau_scaling10._wp zdftke.F90: htau(ji,jj) = MAX( 0.5_wp, MIN( 30._wp, 45._wp rn_htau_scalingABS( SIN( rpi/180._wp gphit(ji,jj) ) ) ) ) zdftke.F90: htau(ji,jj) = MAX( 0.5_wp, MIN( 10._wp, 45._wp rn_htau_scalingABS( SIN( rpi/180._wp gphit(ji,jj) ) ) ) ) zdftke.F90: htau(ji,jj) = MAX( 0.5_wp, MIN( 10._wp, 45._wp rn_htau_scalingABS( SIN( rpi/180._wp * gphit(ji,jj) ) ) ) )
@atb299 - yes I realise its purpose ... this was just a ticket to workout how I manage to include it into the namelist_ref
for 4.2.1 and it not being in the code. I thought I'd just merged the NEMO 4.2.1 tag with SE-NEMO at 4.0.4 ... so I'm a little puzzled how it got into the namelist!
Is is because you use(d) GLS instead of TKE? If the code was there, you wanted to activate it you'd need to set nn_htau = 4 or 5 in the namelist. Looking at a GO6 namelist, I think a variant of the spatially varying TKE was present even at v3.6. As far as I can tell it is always set to rn_htau_scaling=1.0.
No we've used both - and when we've run with TKE we've run with nn_htau =4
... In the 4.0.4 GO8 code we have there is no scaling applied using option 4
Ha! Just figured out what's happened (will confirm when ARCHER2 is back online). When I merged tag 4.2.1 and SE-NEMO 4.0.4 I also had an eye on the NPD 4.2.1. I think the fact you've edited SHARED/namelist_ref
has probably thrown me - and that's where rn_htau_scaling
has crept in. I tend to leave my SHARED
directory untouched and any namelist mods based on MY_SRC
go into an updated namelist_ref
in the EXP
dir. Will have to look again at the NPD and see if we can align SE-NEMO with NPD going forward!
Interesting, I use nn_htau = 5. I've just tracked that down to the change from GO8p7 to GOSI9p8 (see https://code.metoffice.gov.uk/trac/GO/wiki/GODocumentation/GO8.0/GO8Releases )
"4. The TKE mixing depth has been reduced. This change results in the deepening of the MLD in a band around 40S associated with a SST warming in winter and cooling in summer."
Closing for now. I've left rn_htau_scaling
in the 4.2.2 namelist_ref but commented out. I will raise a further ticket addressing the streamlining of the code towards NPD after I've had a chat with @atb299 about the best way forward.
in 4.2.1 there is a namelist variable
htau_scaling
that doesn't appear in the code. It isn't present in 4.0.4 and it also doesn't appear in 4.2.2. Not sure where it's come from.