sloshing_initialization.F90

!> Initialization for the "sloshing" internal waves configuration.
module sloshing_initialization

! This file is part of MOM6. See LICENSE.md for the license.

use mom_domains, only : sum_across_pes
use mom_dyn_horgrid, only : dyn_horgrid_type
use mom_error_handler, only : mom_mesg, mom_error, fatal, is_root_pe
use mom_file_parser, only : get_param, log_version, param_file_type
use mom_get_input, only : directories
use mom_grid, only : ocean_grid_type
use mom_sponge, only : set_up_sponge_field, initialize_sponge, sponge_cs
use mom_tracer_registry, only : tracer_registry_type
use mom_unit_scaling, only : unit_scale_type
use mom_variables, only : thermo_var_ptrs
use mom_verticalgrid, only : verticalgrid_type
use mom_eos, only : calculate_density, calculate_density_derivs, eos_type

implicit none ; private

#include <MOM_memory.h>

! The following routines are visible to the outside world
public sloshing_initialize_topography
public sloshing_initialize_thickness
public sloshing_initialize_temperature_salinity

contains

!> Initialization of topography.
subroutine sloshing_initialize_topography( D, G, param_file, max_depth )
  type(dyn_horgrid_type),  intent(in)  :: g !< The dynamic horizontal grid type
  real, dimension(G%isd:G%ied,G%jsd:G%jed), &
                           intent(out) :: d !< Ocean bottom depth in the units of depth_max
  type(param_file_type),   intent(in)  :: param_file !< Parameter file structure
  real,                    intent(in)  :: max_depth !< Maximum ocean depth in arbitrary units

  ! Local variables
  integer   :: i, j

  do i=g%isc,g%iec ; do j=g%jsc,g%jec
    d(i,j) = max_depth
  enddo ; enddo

end subroutine sloshing_initialize_topography


!> Initialization of thicknesses
!! This routine is called when THICKNESS_CONFIG is set to 'sloshing'
!!
!! This routine initializes layer positions to set off a sloshing motion in
!! the zonal direction in a rectangular basin. All layers have initially the
!! same thickness but all interfaces (except bottom and sea surface) are
!! displaced according to a half-period cosine, with maximum value on the
!! left and minimum value on the right. This sets off a regular sloshing motion.
subroutine sloshing_initialize_thickness ( h, G, GV, US, param_file, just_read_params)
  type(ocean_grid_type),   intent(in)  :: g           !< The ocean's grid structure.
  type(verticalgrid_type), intent(in)  :: gv          !< The ocean's vertical grid structure.
  type(unit_scale_type),   intent(in)  :: us          !< A dimensional unit scaling type
  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
                           intent(out) :: h           !< The thickness that is being initialized [H ~> m or kg m-2].
  type(param_file_type),   intent(in)  :: param_file  !< A structure indicating the open file
                                                      !! to parse for model parameter values.
  logical,       optional, intent(in)  :: just_read_params !< If present and true, this call will
                                                      !! only read parameters without changing h.

  real    :: displ(szk_(g)+1)   ! The interface displacement in depth units.
  real    :: z_unif(szk_(g)+1)  ! Fractional uniform interface heights [nondim].
  real    :: z_inter(szk_(g)+1) ! Interface heights, in depth units.
  real    :: a0                 ! The displacement amplitude in depth units.
  real    :: weight_z           ! A (misused?) depth-space weighting, in inconsistent units.
  real    :: x1, y1, x2, y2     ! Dimensonless parameters.
  real    :: x, t               ! Dimensionless depth coordinates?
  logical :: use_ic_bug         ! If true, set the initial conditions retaining an old bug.
  logical :: just_read          ! If true, just read parameters but set nothing.
  ! This include declares and sets the variable "version".
# include "version_variable.h"
  character(len=40)  :: mdl = "sloshing_initialization" !< This module's name.

  integer :: i, j, k, is, ie, js, je, nx, nz

  is = g%isc ; ie = g%iec ; js = g%jsc ; je = g%jec ; nz = g%ke

  just_read = .false. ; if (present(just_read_params)) just_read = just_read_params
  if (.not.just_read) call log_version(param_file, mdl, version, "")
  call get_param(param_file, mdl, "SLOSHING_IC_AMPLITUDE", a0, &
                 "Initial amplitude of sloshing internal interface height "//&
                 "displacements it the sloshing test case.", &
                 units='m', default=75.0, scale=us%m_to_Z, do_not_log=just_read)
  call get_param(param_file, mdl, "SLOSHING_IC_BUG", use_ic_bug, &
                 "If true, use code with a bug to set the sloshing initial conditions.", &
                 default=.false., do_not_log=just_read)

  if (just_read) return ! All run-time parameters have been read, so return.

  ! Define thicknesses
  do j=g%jsc,g%jec ; do i=g%isc,g%iec

    ! Define uniform interfaces
    do k = 0,nz
      z_unif(k+1) = -real(k)/real(nz)
    enddo

    ! 1. Define stratification
    do k = 1,nz+1

      ! Thin pycnocline in the middle
      !z_inter(k) = (2.0**(n-1)) * (z_unif(k) + 0.5)**n - 0.5

      ! Thin pycnocline in the middle (piecewise linear profile)
      x1 = 0.30; y1 = 0.48; x2 = 0.70; y2 = 0.52

      x = -z_unif(k)

      if ( x <= x1 ) then
        t = y1*x/x1
      elseif ( (x > x1 ) .and. ( x < x2 )) then
        t = y1 + (y2-y1) * (x-x1) / (x2-x1)
      else
        t = y2 + (1.0-y2) * (x-x2) / (1.0-x2)
      endif

      t = - z_unif(k)

      z_inter(k) = -t * g%max_depth

    enddo

    ! 2. Define displacement
    ! a0 is set via get_param; by default a0 is a 75m Displacement amplitude in depth units.
    do k = 1,nz+1

      weight_z = - 4.0 * ( z_unif(k) + 0.5 )**2 + 1.0

      x = g%geoLonT(i,j) / g%len_lon
      if (use_ic_bug) then
        displ(k) = a0 * cos(acos(-1.0)*x) + weight_z * us%m_to_Z
      else
        displ(k) = a0 * cos(acos(-1.0)*x) * weight_z
      endif

      if ( k == 1 ) then
        displ(k) = 0.0
      endif

      if ( k == nz+1 ) then
        displ(k) = 0.0
      endif

      z_inter(k) = z_inter(k) + displ(k)

    enddo

    ! 3. The last interface must coincide with the seabed
    z_inter(nz+1) = -g%bathyT(i,j)
    ! Modify interface heights to make sure all thicknesses are strictly positive
    do k = nz,1,-1
      if ( z_inter(k) < (z_inter(k+1) + gv%Angstrom_Z) ) then
        z_inter(k) = z_inter(k+1) + gv%Angstrom_Z
      endif
    enddo

    ! 4. Define layers
    do k = 1,nz
      h(i,j,k) = gv%Z_to_H * (z_inter(k) - z_inter(k+1))
    enddo

  enddo ; enddo

end subroutine sloshing_initialize_thickness


!> Initialization of temperature and salinity
!!
!! This subroutine initializes linear profiles for T and S according to
!! reference surface layer salinity and temperature and a specified range.
!! Note that the linear distribution is set up with respect to the layer
!! number, not the physical position).
subroutine sloshing_initialize_temperature_salinity ( T, S, h, G, GV, param_file, &
                                                      eqn_of_state, just_read_params)
  type(ocean_grid_type),                     intent(in)  :: g !< Ocean grid structure.
  type(verticalgrid_type),                   intent(in)  :: gv !< The ocean's vertical grid structure.
  real, dimension(SZI_(G),SZJ_(G), SZK_(G)), intent(out) :: t !< Potential temperature [degC].
  real, dimension(SZI_(G),SZJ_(G), SZK_(G)), intent(out) :: s !< Salinity [ppt].
  real, dimension(SZI_(G),SZJ_(G), SZK_(G)), intent(in)  :: h !< Layer thickness [H ~> m or kg m-2].
  type(param_file_type),                     intent(in)  :: param_file !< A structure indicating the
                                                            !! open file to parse for model
                                                            !! parameter values.
  type(eos_type),                            pointer     :: eqn_of_state !< Equation of state structure.
  logical,       optional, intent(in)  :: just_read_params !< If present and true, this call will
                                                      !! only read parameters without changing h.

  integer :: i, j, k, is, ie, js, je, nz
  real    :: delta_s, delta_t
  real    :: s_ref, t_ref;      ! Reference salinity and temerature within
                                ! surface layer
  real    :: s_range, t_range;  ! Range of salinities and temperatures over the
                                ! vertical
  integer :: kdelta
  real    :: deltah
  real    :: xi0, xi1
  logical :: just_read    ! If true, just read parameters but set nothing.
  character(len=40)  :: mdl = "initialize_temp_salt_linear" ! This subroutine's
                                                            ! name.

  is = g%isc ; ie = g%iec ; js = g%jsc ; je = g%jec ; nz = g%ke

  just_read = .false. ; if (present(just_read_params)) just_read = just_read_params

  call get_param(param_file, mdl, "S_REF", s_ref, 'Reference value for salinity', &
                 default=35.0, units='1e-3', do_not_log=just_read)
  call get_param(param_file, mdl, "T_REF", t_ref, 'Reference value for temperature', &
                 units='degC', fail_if_missing=.not.just_read, do_not_log=just_read)

  ! The default is to assume an increase by 2 ppt for the salinity and a uniform temperature.
  call get_param(param_file, mdl,"S_RANGE",s_range,'Initial salinity range.', &
                 units='1e-3', default=2.0, do_not_log=just_read)
  call get_param(param_file, mdl,"T_RANGE",t_range,'Initial temperature range', &
                 units='degC', default=0.0, do_not_log=just_read)

  if (just_read) return ! All run-time parameters have been read, so return.

  ! Prescribe salinity
  !delta_S = S_range / ( G%ke - 1.0 )

  !S(:,:,1) = S_ref
  !do k = 2,G%ke
  !  S(:,:,k) = S(:,:,k-1) + delta_S
  !enddo

  deltah = g%max_depth / nz
  do j=js,je ; do i=is,ie
    xi0 = 0.0
    do k = 1,nz
      xi1 = xi0 + deltah / g%max_depth ! =  xi0 + 1.0 / real(nz)
      s(i,j,k) = 34.0 + 0.5 * s_range * (xi0 + xi1)
      xi0 = xi1
    enddo
  enddo ; enddo

  ! Prescribe temperature
  delta_t = t_range / ( g%ke - 1.0 )

  t(:,:,1) = t_ref
  do k = 2,g%ke
    t(:,:,k) = t(:,:,k-1) + delta_t
  enddo
  kdelta = 2
  t(:,:,g%ke/2 - (kdelta-1):g%ke/2 + kdelta) = 1.0

end subroutine sloshing_initialize_temperature_salinity

!> \namespace sloshing_initialization
!!
!! The module configures the model for the non-rotating sloshing test case.
end module sloshing_initialization