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Read Leith parameters in MOM_lateral_coeffs.F90
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- Now reading parameters for Leith in MOM_lateral_coeffs.F90 (in
  additional to MOM_hor_visc.F90 which we'll remove later).
- Removed parameters from dummy argument list.
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@adcroft
adcroft committed Dec 5, 2017
1 parent 7dc2510 commit c59f87e
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Showing 2 changed files with 56 additions and 20 deletions.
12 changes: 1 addition & 11 deletions src/parameterizations/lateral/MOM_hor_visc.F90
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Original file line number Diff line number Diff line change
Expand Up @@ -306,9 +306,6 @@ subroutine horizontal_viscosity(u, v, h, diffu, diffv, MEKE, VarMix, G, GV, CS,
real :: KhSm ! Smagorinsky Laplacian viscosity (m2/s)
real :: AhLth ! 2D Leith biharmonic viscosity (m4/s)
real :: KhLth ! 2D Leith Laplacian viscosity (m2/s)
real :: mod_Leith ! nondimensional coefficient for divergence part of modified Leith
! viscosity. Here set equal to nondimensional Laplacian Leith constant.
! This is set equal to zero if modified Leith is not used.
real :: Shear_mag ! magnitude of the shear (1/s)
! real :: Vort_mag ! magnitude of the vorticity (1/s)
real :: h2uq, h2vq ! temporary variables in units of H^2 (i.e. m2 or kg2 m-4).
Expand Down Expand Up @@ -521,13 +518,6 @@ subroutine horizontal_viscosity(u, v, h, diffu, diffv, MEKE, VarMix, G, GV, CS,
enddo ; enddo
endif

! Coefficient for modified Leith
if (CS%Modified_Leith) then
mod_Leith = 1.0
else
mod_Leith = 0.0
endif

! Evaluate u0 = x.Div(Grad u) and v0 = y.Div( Grad u)
if (CS%biharmonic) then
do j=js-1,Jeq+1 ; do I=Isq-1,Ieq+1
Expand Down Expand Up @@ -555,7 +545,7 @@ subroutine horizontal_viscosity(u, v, h, diffu, diffv, MEKE, VarMix, G, GV, CS,
endif

if ((CS%Leith_Kh) .or. (CS%Leith_Ah)) then
call calc_vert_vort_mag(G, GV, u, v, h, k, CS%no_slip, mod_Leith, .false., vert_vort_mag_h, vert_vort_mag_q)
call calc_vert_vort_mag(VarMix, G, GV, u, v, h, k, vert_vort_mag_h, vert_vort_mag_q)
endif

do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
Expand Down
64 changes: 55 additions & 9 deletions src/parameterizations/lateral/MOM_lateral_mixing_coeffs.F90
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Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,21 @@ module MOM_lateral_mixing_coeffs
!! and especially 2 are coded to be more efficient.
real :: Visbeck_S_max !< Upper bound on slope used in Eady growth rate (nondim).

! Leith parameters
logical :: use_QG_Leith !< If true, enables the QG Leith scheme
logical :: Leith_Kh !< If true, enables the Leith scheme
logical :: modified_Leith !< if true, include the divergence contribution to Leith viscosity
real :: Leith_Lap_const !< The non-dimensional coefficient in the Leith viscosity
logical :: Leith_Ah !< If true, enables the bi-harmonic Leith scheme
real :: Leith_bi_const !< The non-dimensional coefficient in the bi-harmonic Leith viscosity
logical :: no_slip !< If true, no slip boundary conditions are used.
!! Otherwise free slip boundary conditions are assumed.
!! The implementation of the free slip boundary
!! conditions on a C-grid is much cleaner than the
!! no slip boundary conditions. The use of free slip
!! b.c.s is strongly encouraged. The no slip b.c.s
!! are not implemented with the biharmonic viscosity.

! Diagnostics
!>@{
!! Diagnostic identifier
Expand Down Expand Up @@ -721,18 +736,14 @@ subroutine calc_slope_functions_using_just_e(h, G, GV, CS, e, calculate_slopes)
end subroutine calc_slope_functions_using_just_e

!> Calculates the magnitude of the vertical component of vorticity for use in the Leith-like schemes
subroutine calc_vert_vort_mag(G, GV, u, v, h, k, no_slip, mod_Leith, QG_Leith, vert_vort_mag_h, vert_vort_mag_q)
subroutine calc_vert_vort_mag(CS, G, GV, u, v, h, k, vert_vort_mag_h, vert_vort_mag_q)
type(VarMix_CS), pointer :: CS !< Variable mixing coefficients
type(ocean_grid_type), intent(in) :: G !< Ocean grid structure
type(verticalGrid_type), intent(in) :: GV !< The ocean's vertical grid structure.
real, dimension(SZIB_(G),SZJ_(G),SZK_(G)), intent(in) :: u !< Zonal flow (m s-1)
real, dimension(SZI_(G),SZJB_(G),SZK_(G)), intent(in) :: v !< Meridional flow (m s-1)
real, dimension(SZI_(G),SZJB_(G),SZK_(G)), intent(in) :: h !< Layer thickness (m or kg m-2)
integer, intent(in) :: k !< Layer for which to calculate vorticity magnitude
logical, intent(in) :: no_slip !< True if vorticity should have no-slip BCs
real, intent(in) :: mod_Leith !< Non-dimensional coefficient multiplying the
!! divergence contribution to the Leith viscosity.
!! Set to zero for conventional Leith.
logical, intent(in) :: QG_Leith !< True if using QG Leith scheme
real, dimension(SZI_(G),SZJ_(G)), intent(out) :: vert_vort_mag_h !< Magnitude of vertical component
!! of vorticity at h-ponts (s-1)
real, dimension(SZIB_(G),SZJB_(G)), intent(out) :: vert_vort_mag_q !< Magnitude of vertical component
Expand All @@ -749,7 +760,7 @@ subroutine calc_vert_vort_mag(G, GV, u, v, h, k, no_slip, mod_Leith, QG_Leith, v
vort_xy_dy, & ! y-derivative of vertical vorticity (d/dy(dv/dx - du/dy)) (m-1 s-1)
div_xx_dx ! x-derivative of horizontal divergence (d/dx(du/dx + dv/dy)) (m-1 s-1)
real, dimension(SZI_(G),SZJ_(G)) :: div_xx ! Estimate of horizontal divergence at h-points (s-1)
real :: DY_dxBu, DX_dyBu
real :: mod_Leith, DY_dxBu, DX_dyBu
integer :: i, j, is, ie, js, je, Isq, Ieq, Jsq, Jeq
is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
Isq = G%IscB ; Ieq = G%IecB ; Jsq = G%JscB ; Jeq = G%JecB
Expand Down Expand Up @@ -784,7 +795,7 @@ subroutine calc_vert_vort_mag(G, GV, u, v, h, k, no_slip, mod_Leith, QG_Leith, v
enddo ; enddo

! Vorticity
if (no_slip) then
if (CS%no_slip) then
do J=js-2,Jeq+1 ; do I=is-2,Ieq+1
vort_xy(I,J) = (2.0-G%mask2dBu(I,J)) * ( dvdx(I,J) - dudy(I,J) )
enddo ; enddo
Expand All @@ -806,7 +817,7 @@ subroutine calc_vert_vort_mag(G, GV, u, v, h, k, no_slip, mod_Leith, QG_Leith, v
enddo ; enddo

! Add in beta for QG Leith
if (QG_Leith) then
if (CS%use_QG_Leith) then
do J=js-2,Jeq+1 ; do I=is-1,Ieq+1
vort_xy_dx(i,J) = vort_xy_dx(i,J) + 0.5 * ( G%dF_dx(i,j) + G%dF_dx(i,j+1) )
enddo ; enddo
Expand All @@ -815,6 +826,8 @@ subroutine calc_vert_vort_mag(G, GV, u, v, h, k, no_slip, mod_Leith, QG_Leith, v
enddo ; enddo
endif

mod_Leith = 0.; if (CS%modified_Leith) mod_Leith = 1.0

! Magnitude of vorticity at h-points
do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
vert_vort_mag_h(i,j) = sqrt( &
Expand Down Expand Up @@ -1131,6 +1144,39 @@ subroutine VarMix_init(Time, G, param_file, diag, CS)
call wave_speed_init(CS%wave_speed_CSp, use_ebt_mode=CS%Resoln_use_ebt, mono_N2_depth=N2_filter_depth)
endif

! Leith parameters
call get_param(param_file, mdl, "LEITH_KH", CS%Leith_Kh, &
"If true, use a Leith nonlinear eddy viscosity.", &
default=CS%use_QG_Leith)
call get_param(param_file, mdl, "LEITH_AH", CS%Leith_Ah, &
"If true, use a biharmonic Leith nonlinear eddy \n"//&
"viscosity.", default=.false.)
call get_param(param_file, mdl, "USE_QG_LEITH", CS%use_QG_Leith, &
"If true, use the QG Leith nonlinear eddy viscosity.", &
default=.false.)
call get_param(param_file, mdl, "MODIFIED_LEITH", CS%modified_Leith, &
"If true, add a term to Leith viscosity which is \n"//&
"proportional to the gradient of divergence.", &
default=.false.)
call get_param(param_file, mdl, "LEITH_LAP_CONST", CS%Leith_Lap_const, &
"The nondimensional Laplacian Leith constant, \n"//&
"often set to 1.0", units="nondim", default=0.0, &
fail_if_missing = CS%Leith_Kh)
call get_param(param_file, mdl, "LEITH_BI_CONST", CS%Leith_bi_const, &
"The nondimensional biharmonic Leith constant, \n"//&
"typical values are thus far undetermined.", units="nondim", default=0.0, &
fail_if_missing = CS%Leith_Ah)
if (CS%Leith_Kh .or. CS%Leith_Ah) then
in_use = .true.
call get_param(param_file, mdl, "NOSLIP", CS%no_slip, &
"If true, no slip boundary conditions are used; otherwise \n"//&
"free slip boundary conditions are assumed. The \n"//&
"implementation of the free slip BCs on a C-grid is much \n"//&
"cleaner than the no slip BCs. The use of free slip BCs \n"//&
"is strongly encouraged, and no slip BCs are not used with \n"//&
"the biharmonic viscosity.", default=.false.)
endif

! If nothing is being stored in this class then deallocate
if (in_use) then
CS%use_variable_mixing = .true.
Expand Down

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