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Merge pull request #200 from ESMG/obs_henyey_new
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Obsolete the HENYEY_IGW_BACKGROUND_NEW option.
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marshallward authored Sep 13, 2022
2 parents de3f260 + 13b40a3 commit 6f05649
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Showing 3 changed files with 3 additions and 41 deletions.
1 change: 1 addition & 0 deletions src/diagnostics/MOM_obsolete_params.F90
Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,7 @@ subroutine find_obsolete_params(param_file)

call obsolete_real(param_file, "VSTAR_SCALE_COEF")
call obsolete_real(param_file, "ZSTAR_RIGID_SURFACE_THRESHOLD")
call obsolete_logical(param_file, "HENYEY_IGW_BACKGROUND_NEW")

! Test for inconsistent parameter settings.
split = .true. ; test_logic = .false.
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23 changes: 2 additions & 21 deletions src/parameterizations/vertical/MOM_bkgnd_mixing.F90
Original file line number Diff line number Diff line change
Expand Up @@ -280,7 +280,7 @@ subroutine bkgnd_mixing_init(Time, G, GV, US, param_file, diag, CS, physical_OBL
call get_param(param_file, mdl, "HENYEY_IGW_BACKGROUND_NEW", CS%Henyey_IGW_background_new, &
"If true, use a better latitude-dependent scaling for the "//&
"background diffusivity, as described in "//&
"Harrison & Hallberg, JPO 2008.", default=.false.)
"Harrison & Hallberg, JPO 2008. This option is obsolete.", default=.false.)
if (CS%Henyey_IGW_background_new) call check_bkgnd_scheme(CS, "HENYEY_IGW_BACKGROUND_NEW")

if (CS%Kd>0.0 .and. (trim(CS%bkgnd_scheme_str)=="BRYAN_LEWIS_DIFFUSIVITY" .or.&
Expand Down Expand Up @@ -316,7 +316,7 @@ subroutine bkgnd_mixing_init(Time, G, GV, US, param_file, diag, CS, physical_OBL

CS%Kd_via_Kdml_bug = .false.
if ((CS%Kd /= CS%Kd_tot_ml) .and. .not.(CS%Kd_tanh_lat_fn .or. CS%physical_OBL_scheme .or. &
CS%Henyey_IGW_background .or. CS%Henyey_IGW_background_new .or. &
CS%Henyey_IGW_background .or. &
CS%horiz_varying_background .or. CS%Bryan_Lewis_diffusivity)) then
call get_param(param_file, mdl, "KD_BACKGROUND_VIA_KDML_BUG", CS%Kd_via_Kdml_bug, &
"If true and KDML /= KD and several other conditions apply, the background "//&
Expand Down Expand Up @@ -453,25 +453,6 @@ subroutine calculate_bkgnd_mixing(h, tv, N2_lay, Kd_lay, Kd_int, Kv_bkgnd, j, G,
Kd_lay(i,k) = Kd_int(i,1)
enddo ; enddo

elseif (CS%Henyey_IGW_background_new) then
I_x30 = 2.0 / invcosh(CS%N0_2Omega*2.0) ! This is evaluated at 30 deg.
I_2Omega = 0.5 / CS%omega
do k=1,nz ; do i=is,ie
abs_sinlat = max(min_sinlat, abs(sin(G%geoLatT(i,j)*deg_to_rad)))
N_2Omega = max(abs_sinlat, sqrt(N2_lay(i,k))*I_2Omega)
N02_N2 = (CS%N0_2Omega/N_2Omega)**2
Kd_lay(i,k) = max(CS%Kd_min, CS%Kd * &
((abs_sinlat * invcosh(N_2Omega/abs_sinlat)) * I_x30)*N02_N2)
enddo ; enddo
! Update Kd_int and Kv_bkgnd, based on Kd_lay. These might be just used for diagnostic purposes.
do i=is,ie
Kd_int(i,1) = 0.0; Kv_bkgnd(i,1) = 0.0
Kd_int(i,nz+1) = 0.0; Kv_bkgnd(i,nz+1) = 0.0
enddo
do K=2,nz ; do i=is,ie
Kd_int(i,K) = 0.5*(Kd_lay(i,k-1) + Kd_lay(i,k))
Kv_bkgnd(i,K) = Kd_int(i,K) * CS%prandtl_bkgnd
enddo ; enddo
else
! Set a potentially spatially varying surface value of diffusivity.
if (CS%Henyey_IGW_background) then
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20 changes: 0 additions & 20 deletions src/parameterizations/vertical/_V_diffusivity.dox
Original file line number Diff line number Diff line change
Expand Up @@ -253,26 +253,6 @@ in \cite harrison2008, but that isn't what is in the MOM6 code. Instead, the sur
value is propagated down, with the assumption that the tidal mixing parameterization
will provide the deep mixing: \ref section_Internal_Tidal_Mixing.

There is also a "new" Henyey version, taking into account the effect of stratification on
TKE dissipation,

\todo Harrison (personal communication) recommends that this option be made obsolete and
eventually removed.

\f[
\epsilon = \epsilon_0 \frac{f}{f_0} \frac{\mbox{acosh} (N/f)}{\mbox{acosh} (N_0 / f_0)}
\f]

where \f$N_0\f$ and \f$f_0\f$ are the reference buoyancy frequency and inertial frequencies, respectively
and \f$\epsilon_0\f$ is the reference dissipation at \f$(N_0, f_0)\f$. In the previous version, \f$N =
N_0\f$. Additionally, the relationship between diapycnal diffusivities and stratification is included:

\f[
\kappa = \frac{\epsilon}{N^2}
\f]
This approach assumes that work done against gravity is uniformly distributed throughout the water column.
The original version concentrates buoyancy work in regions of strong stratification.

\subsection subsection_danabasoglu_back Danabasoglu background mixing

The shape of the \cite danabasoglu2012 background mixing has a uniform background value, with a dip
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