subroutine CloudMarsH2O( xyr_Press, xyz_VirTemp, xyr_Height, xyz_DQH2OSolDtCum, xyz_DQH2OSolDtLSC, xyz_QH2OSol, xy_Rain, xy_Snow )

    ! USE statements
    !

    ! 時刻管理
    ! Time control
    !
    use timeset, only: DelTime            ! $ \Delta t $ [s]

    ! 重力沈降過程
    ! Gravitational sedimentation process
    !
    use grav_sed, only : GravSed


    real(DP), intent(in   ) :: xyr_Press        ( 0:imax-1, 1:jmax, 0:kmax )
    real(DP), intent(in   ) :: xyz_VirTemp      ( 0:imax-1, 1:jmax, 1:kmax )
    real(DP), intent(in   ) :: xyr_Height       ( 0:imax-1, 1:jmax, 0:kmax )
    real(DP), intent(in   ) :: xyz_DQH2OSolDtCum( 0:imax-1, 1:jmax, 1:kmax )
    real(DP), intent(in   ) :: xyz_DQH2OSolDtLSC( 0:imax-1, 1:jmax, 1:kmax )
    real(DP), intent(inout) :: xyz_QH2OSol      ( 0:imax-1, 1:jmax, 1:kmax )
    real(DP), intent(out  ) :: xy_Rain          ( 0:imax-1, 1:jmax )
    real(DP), intent(out  ) :: xy_Snow          ( 0:imax-1, 1:jmax )



    ! 実行文 ; Executable statement
    !

    ! 初期化確認
    ! Initialization check
    !
    if ( .not. cloud_mars_h2o_inited ) then
      call MessageNotify( 'E', module_name, 'This module has not been initialized.' )
    end if


    xyz_QH2OSol = xyz_QH2OSol + ( xyz_DQH2OSolDtCum + xyz_DQH2OSolDtLSC ) * 2.0_DP * DelTime


    xy_Rain = 0.0_DP
    xy_Snow = 0.0_DP

    ! 重力沈降過程
    ! Gravitational sedimentation process
    !
    call GravSed( 'MarsH2OCloud', xyr_Press, xyz_VirTemp, xyr_Height, xyz_QH2OSol, xy_Snow )
    xy_Snow = - xy_Snow


  end subroutine CloudMarsH2O

  subroutine CloudMarsH2OInit

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

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

    ! 重力沈降過程
    ! Gravitational sedimentation process
    !
    use grav_sed, only : GravSedInit

    ! 宣言文 ; Declaration statements
    !

!!$    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 /cloud_simple_nml/ &
!!$      & CloudLifeTime,       &
!!$      & CloudWatLifeTime,    &
!!$      & CloudIceLifeTime,    &
!!$      & CloudCoverMethod,    &
!!$      & RHCrtl,              &
!!$      & CloudCover
          !
          ! デフォルト値については初期化手続 "cloud_mars_h2o#CloudMarsH2OInit"
          ! のソースコードを参照のこと.
          !
          ! Refer to source codes in the initialization procedure
          ! "cloud_mars_h2o#CloudMarsH2OInit" for the default values.
          !

    ! 実行文 ; Executable statement
    !

    if ( cloud_mars_h2o_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 = cloud_mars_h2o_nml,       & ! (out)
!!$        & iostat = iostat_nml )             ! (out)
!!$      close( unit_nml )
!!$
!!$      call NmlutilMsg( iostat_nml, module_name ) ! (in)
!!$    end if



    ! Initialization of modules used in this module
    !

    ! 重力沈降過程
    ! Gravitational sedimentation process
    !
    call GravSedInit


    ! ヒストリデータ出力のためのへの変数登録
    ! Register of variables for history data output
    !
!!$    call HistoryAutoAddVariable( 'EffCloudCover', &
!!$      & (/ 'lon ', 'lat ', 'time' /), &
!!$      & 'effective cloud cover', '1' )



    ! 印字 ; Print
    !
    call MessageNotify( 'M', module_name, '----- Initialization Messages -----' )
    call MessageNotify( 'M', module_name, '-- version = %c', c1 = trim(version) )


    cloud_mars_h2o_inited = .true.

  end subroutine CloudMarsH2OInit