subroutine SurfaceFluxUtilInit
    !
    ! surface_flux_util モジュールの初期化を行います. 
    ! NAMELIST#surface_flux_util_nml の読み込みはこの手続きで行われます. 
    !
    ! "surface_flux_util" module is initialized. 
    ! "NAMELIST#surface_flux_util_nml" is loaded in this procedure. 
    !

    ! モジュール引用 ; USE statements
    !

    ! NAMELIST ファイル入力に関するユーティリティ
    ! Utilities for NAMELIST file input
    !
    use namelist_util, only: namelist_filename, NmlutilMsg, NmlutilAryValid

    ! ファイル入出力補助
    ! File I/O support
    !
    use dc_iounit, only: FileOpen

    ! 種別型パラメタ
    ! Kind type parameter
    !
    use dc_types, only: STDOUT ! 標準出力の装置番号. Unit number of standard output

    ! 文字列操作
    ! Character handling
    !
    use dc_string, only: StoA

    ! ヒストリデータ出力
    ! History data output
    !
    use gtool_historyauto, only: HistoryAutoAddVariable

    ! 座標データ設定
    ! Axes data settings
    !
    use axesset, only: AxnameX, AxnameY, AxnameZ, AxnameR, AxnameT

    ! 宣言文 ; Declaration statements
    !
    implicit none

!!$    integer:: unit_nml        ! NAMELIST ファイルオープン用装置番号. 
!!$                              ! Unit number for NAMELIST file open
!!$    integer:: iostat_nml      ! NAMELIST 読み込み時の IOSTAT. 
!!$                              ! IOSTAT of NAMELIST read

    ! NAMELIST 変数群
    ! NAMELIST group name
    !
!!$    namelist /surface_flux_util_nml/                                  &
!!$      & FlagConstBulkCoef
          !
          ! デフォルト値については初期化手続 "surface_flux_util#SurfaceFluxUtilInit" 
          ! のソースコードを参照のこと. 
          !
          ! Refer to source codes in the initialization procedure
          ! "surface_flux_bulk#SurfaceFluxInit" for the default values. 
          !

    ! 実行文 ; Executable statement
    !

    if ( surface_flux_util_inited ) return


    ! デフォルト値の設定
    ! Default values settings
    !

    ! NAMELIST の読み込み
    ! NAMELIST is input
    !
!!$    if ( trim(namelist_filename) /= '' ) then
!!$      call FileOpen( unit_nml, &          ! (out)
!!$        & namelist_filename, mode = 'r' ) ! (in)
!!$
!!$      rewind( unit_nml )
!!$      read( unit_nml, &                ! (in)
!!$        & nml = surface_flux_util_nml, &  ! (out)
!!$        & iostat = iostat_nml )        ! (out)
!!$      close( unit_nml )
!!$
!!$      call NmlutilMsg( iostat_nml, module_name ) ! (in)
!!$    end if


    ! 印字 ; Print
    !
    call MessageNotify( 'M', module_name, '----- Initialization Messages -----' )

!!$    call MessageNotify( 'M', module_name, '  VelMinForRi       = %f', d = (/ VelMinForRi   /) )
    call MessageNotify( 'M', module_name, '-- version = %c', c1 = trim(version) )

    surface_flux_util_inited = .true.

  end subroutine SurfaceFluxUtilInit

  subroutine SurfaceFluxUtilLimitFlux( DelTime, xyzf_QMix, xyr_Press, xy_SurfH2OVapFlux )
    !
    ! 
    !
    ! Restrict surface flux 
    ! Now, only the H2O vapor flux is restricted.
    !

    ! モジュール引用 ; USE statements
    !

    ! ヒストリデータ出力
    ! History data output
    !
    use gtool_historyauto, only: HistoryAutoPut

    ! 物理定数設定
    ! Physical constants settings
    !
    use constants, only: Grav                  ! $ g $ [m s-2].
                              ! 重力加速度.
                              ! Gravitational acceleration

    ! 時刻管理
    ! Time control
    !
    use timeset, only: TimeN, TimesetClockStart, TimesetClockStop

    ! デバッグ用ユーティリティ
    ! Utilities for debug
    !
    use dc_trace, only: DbgMessage, BeginSub, EndSub

    ! 宣言文 ; Declaration statements
    !
    implicit none

    real(DP), intent(in):: DelTime
                              ! Time step
    real(DP), intent(in):: xyzf_QMix(0:imax-1, 1:jmax, 1:kmax, 1:ncmax)
                              ! $ q $ .     比湿. Specific humidity
    real(DP), intent(in):: xyr_Press (0:imax-1, 1:jmax, 0:kmax)
                              ! $ p_s $ . 地表面気圧 (半整数レベル). 
                              ! Surface pressure (half level)
    real(DP), intent(inout):: xy_SurfH2OVapFlux(0:imax-1, 1:jmax)
                              ! 惑星表面水蒸気フラックス.
                              ! Water vapor flux at the surface
!!$    real(DP), intent(inout):: xyf_QMixFlux(0:imax-1, 1:jmax, 1:ncmax)
!!$                              ! 惑星表面比湿フラックス. 
!!$                              ! Specific humidity flux at surface

    ! 作業変数
    ! Work variables
    !
    real(DP):: xyz_DelMass(0:imax-1, 1:jmax, 1:kmax)
                              ! 
                              ! Mass in each layer
    real(DP):: xy_ConsMass(0:imax-1, 1:jmax)
                              ! 
                              ! Constituent mass in each column
    real(DP):: xy_SurfFlux(0:imax-1, 1:jmax)

    integer:: i               ! 経度方向に回る DO ループ用作業変数
                              ! Work variables for DO loop in longitude
    integer:: j               ! 緯度方向に回る DO ループ用作業変数
                              ! Work variables for DO loop in latitude
    integer:: k               ! 高度方向に回る DO ループ用作業変数
                              ! Work variables for DO loop in altitude
    integer:: n               ! 組成方向に回る DO ループ用作業変数
                              ! Work variables for DO loop in dimension of constituents

    ! 実行文 ; Executable statement
    !

    ! 初期化確認
    ! Initialization check
    !
    if ( .not. surface_flux_util_inited ) then
      call MessageNotify( 'E', module_name, 'This module has not been initialized.' )
    end if


    ! 計算時間計測開始
    ! Start measurement of computation time
    !
    call TimesetClockStart( module_name )

    do k = 1, kmax
      xyz_DelMass(:,:,k) = ( xyr_Press(:,:,k-1) - xyr_Press(:,:,k) ) / Grav
    end do

!!$    do n = 1, ncmax
    do n = IndexH2OVap, IndexH2OVap

      xy_ConsMass = 0.0_DP
      do k = kmax, 1, -1
        xy_ConsMass = xy_ConsMass + xyz_DelMass(:,:,k) * xyzf_QMix(:,:,k,n)
      end do

      if ( n == IndexH2OVap ) then
        xy_SurfFlux = xy_SurfH2OVapFlux
      else
!!$        xy_SurfFlux = xyf_QMixFlux(:,:,n)
      end if

      do j = 1, jmax
        do i = 0, imax-1
          if ( - xy_SurfFlux(i,j) * DelTime > xy_ConsMass(i,j) ) then
            xy_SurfFlux(i,j) = - xy_ConsMass(i,j) / DelTime !&
!!$              & * ( 1.0_DP - 1.0d-15 )
          end if
        end do
      end do

      if ( n == IndexH2OVap ) then
        xy_SurfH2OVapFlux = xy_SurfFlux
      else
!!$        xyf_QMixFlux(:,:,n) = xy_SurfFlux
      end if

    end do


    ! 計算時間計測一時停止
    ! Pause measurement of computation time
    !
    call TimesetClockStop( module_name )

  end subroutine SurfaceFluxUtilLimitFlux