parameters.f90

集合卡尔曼滤波(EnKF) 数据同化方法可以避免了EKF 中协方差演变方程预报过程中出现的计算不准确和关于协方差矩阵的大量数据的存储问题,最主要的是可以有效的控制估计误差方差的增长,改善预报的效果。

!! Copyright (C) 2008 Pavel Sakov
!! 
!! This file is part of EnKF-Matlab. EnKF-Matlab is a free software. See 
!! LICENSE for details.

! File:           parameters.f90
!
! Created:        31/08/2007
!
! Last modified:  08/02/2008
!
! Author:         Pavel Sakov
!                 CSIRO Marine and Atmospheric Research
!                 NERSC
!
! Purpose:        Fortran code for QG model. Reads and stores the model
!                 parameters.
!
! Description:    
!
! Revisions:

module parameters_mod

  use utils_mod
  implicit none

  save

  public parameters_read

  integer, parameter, private :: FID_PRM = 111

  ! This is the place to change the resolution of the model, by
  ! changing the parameter MREFIN:
  ! To make the ocean a rectangular (at your own risk!) change nx1,
  ! ny1 to (2,4), and adjust domain size (Lx, Ly)...
  !
  integer, parameter, public :: MREFIN = 7
  integer, parameter, public :: NX1 = 2
  integer, parameter, public :: NY1 = 2
  integer, parameter, public :: M = NX1 * 2 ** (MREFIN - 1) + 1
  integer, parameter, public :: N = NY1 * 2 ** (MREFIN - 1) + 1

  real(8), parameter, public :: PI = 3.14159265358979323d0

  real(8), parameter, public :: rf_coeff = 0.1 ! Roberts filter coefficient
                                               ! for the leap-frog scheme

  real(8), public :: dt            ! time step
  real(8), public :: rkb           ! bottom friction
  real(8), public :: rkh           ! horizontal friction
  real(8), public :: rkh2          ! biharmonic friction
  real(8), public :: F             ! Froud number, (L / Rd)^2
  real(8), public :: r             ! factor in front of nonlinear
                                   ! advection term
  integer, public :: rstart = 0
  real(8), public :: tend
  real(8), public :: dtout
  integer, public :: verbose = VERBOSE_DEF
  character(STRLEN), public :: scheme
  character(STRLEN), public :: restartfname
  character(STRLEN), public :: outfname

  ! secondary parameters

  real(8), dimension(N, M), public :: CURLT

  real(8), public :: dx
  real(8), public :: dy

contains

  subroutine parameters_read(prmfname)
    character(STRLEN) :: prmfname
    integer :: j
    integer :: m1 = M - 1

    namelist /parameters/ &
         tend, &
         dtout, &
         dt, &
         rkb, &
         rkh, &
         rkh2, &
         F, &
         r, &
         verbose, &
         scheme, &
         rstart, &
         restartfname, &
         outfname

    call wopen(trim(prmfname), FID_PRM, 'old')
    read(FID_PRM, parameters)

    if (verbose > 0) then
       write(stdout, *) 'parameters:'
       write(stdout, *) '  tend =', tend
       write(stdout, *) '  dtout =', dtout
       write(stdout, *) '  dt =', dt
       write(stdout, *) '  RKB =', rkb
       write(stdout, *) '  RKH =', rkh
       write(stdout, *) '  RKH2 =', rkh2
       write(stdout, *) '  F =', F
       write(stdout, *) '  r =', r
       write(stdout, *) '  verbose =', verbose
       write(stdout, *) '  scheme = "', trim(scheme), '"'
       write(stdout, *) '  rstart =', rstart
       write(stdout, *) '  restart file = "', trim(restartfname), '"'
       write(stdout, *) '  output file = "', trim(outfname), '"'
    end if

    dx = 1.0d0 / dble(N - 1)
    dy = 1.0d0 / dble(M - 1)

    do j = 1, M
       CURLT(:, j) = - 2.0d0 * PI * sin(2.0d0 * PI * (j - 1) / m1)
    end do

    close(FID_PRM)
  end subroutine parameters_read

  subroutine parameters_get(N_out, M_out, tend_out, dtout_out, dt_out, &
       rkb_out, rkh_out, rkh2_out, F_out, r_out, verbose_out, &
       scheme_out, rstart_out, restartfname_out, outfname_out)

    integer, intent(out) :: N_out, M_out
    real(8), intent(out) :: dt_out
    real(8), intent(out) :: rkb_out
    real(8), intent(out) :: rkh_out
    real(8), intent(out) :: rkh2_out
    real(8), intent(out) :: F_out
    real(8), intent(out) :: r_out
    real(8), intent(out) :: tend_out
    real(8), intent(out) :: dtout_out
    integer, intent(out) :: verbose_out
    character(STRLEN), intent(out) :: scheme_out
    integer, intent(out) :: rstart_out
    character(STRLEN), intent(out) :: restartfname_out
    character(STRLEN), intent(out) :: outfname_out
    
    N_out = N
    M_out = M
    tend_out = tend
    dtout_out = dtout
    dt_out = dt
    rkb_out = rkb
    rkh_out = rkh
    rkh2_out = rkh2
    F_out = F
    r_out = r
    verbose_out = verbose
    scheme_out = scheme
    rstart_out = rstart
    restartfname_out = restartfname
    outfname_out = outfname
  end subroutine parameters_get
       
end module parameters_mod