subroutine SaturateInit
    !
    ! saturate_DennouAGCM モジュールの初期化を行います. 
    !
    !
    ! "saturate_DennouAGCM" module is initialized. 
    !

    ! 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

    ! 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

    ! 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 /saturate_DennouAGCM_nml/ FlagSublimation
          !
          ! デフォルト値については初期化手続 "saturate_DennouAGCM#SaturateInit" 
          ! のソースコードを参照のこと. 
          !
          ! Refer to source codes in the initialization procedure
          ! "saturate_DennouAGCM#SaturateInit" for the default values. 
          !

    ! 実行文 ; Executable statement
    !

    if ( saturate_DennouAGCM_inited ) return


    ! デフォルト値の設定
    ! Default values settings
    !
    FlagSublimation = .false.


    ! NAMELIST の読み込み
    ! NAMELIST is input
    !
    if ( trim(namelist_filename) /= '' ) then
      call FileOpen( unit_nml, namelist_filename, mode = 'r' ) ! (in)

      rewind( unit_nml )
      read( unit_nml, nml = saturate_DennouAGCM_nml, 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, '  FlagSublimation = %b', l = (/ FlagSublimation /) )
    call MessageNotify( 'M', module_name, '-- version = %c', c1 = trim(version) )

    saturate_DennouAGCM_inited = .true.

  end subroutine SaturateInit

  function xyz_CalcDQVapSatDTemp( xyz_Temp, xyz_QVapSat ) result( xyz_DQVapSatDTemp )
    !
    ! 温度 *Temp* と飽和比湿 *QVapSat* を用い, 
    ! 飽和比湿の温度微分 *DQVapSatDTemp* を求めます. 
    !
    ! Calculate temperature derivative of saturation specific humidity 
    ! *DQVapSatDTemp* using
    ! temperature *Temp* and saturation specific humidity *QVapSat*. 
    !

    ! モジュール引用 ; USE statements
    !

    ! 物理定数設定
    ! Physical constants settings
    !
    use constants, only: GasRWet, LatentHeat, LatentHeatFusion, EpsV                  ! $ \epsilon_v $ . 
                              ! 水蒸気分子量比. 
                              ! Molecular weight of water vapor

    ! 宣言文 ; Declaration statements
    !
    implicit none

    real(DP), intent(in):: xyz_Temp   (:,:,:)
                              ! $ T $ . 温度. Temperature
    real(DP), intent(in):: xyz_QVapSat(:,:,:)
                              ! $ q^{*} $ . 飽和比湿. Saturation specific humidity
    real(DP):: xyz_DQVapSatDTemp(size(xyz_Temp,1), size(xyz_Temp,2), size(xyz_Temp,3))
                              ! $ \DP{q^{*}}{T} $ . 飽和比湿の温度微分. 
                              ! Temperature derivative of saturation specific humidity. 

    ! 作業変数
    ! Work variables
    !
    real(DP):: LatentHeatLocal
                              !
                              ! Latent heat used in this routine


    ! 実行文 ; Executable statement
    !

    if ( .not. saturate_DennouAGCM_inited ) then
      call MessageNotify( 'E', module_name, 'This module has not been initialized.' )
    end if

    ! Set a value for latent heat
    if ( FlagSublimation ) then
      LatentHeatLocal = LatentHeat + LatentHeatFusion
    else
      LatentHeatLocal = LatentHeat
    end if

    xyz_DQVapSatDTemp = LatentHeatLocal * xyz_QVapSat / ( GasRWet * xyz_Temp**2 )


  end function xyz_CalcDQVapSatDTemp

  function xyz_CalcQVapSat( xyz_Temp, xyz_Press ) result( xyz_QVapSat )
    !
    ! 温度 *Temp* と気圧 *Press* を用い, 
    ! 飽和比湿 *QVapSat* を求めます. 
    !
    ! Calculate saturation specific humidity *QVapSat* using
    ! temperature *Temp* and air pressure *Press*. 
    !

    ! モジュール引用 ; USE statements
    !

    ! 物理定数設定
    ! Physical constants settings
    !
    use constants, only: GasRWet, LatentHeat, LatentHeatFusion, EpsV                  ! $ \epsilon_v $ . 
                              ! 水蒸気分子量比. 
                              ! Molecular weight of water vapor

    ! 宣言文 ; Declaration statements
    !
    implicit none

    real(DP), intent(in):: xyz_Temp (:,:,:)
                              ! $ T $ . 温度. Temperature
    real(DP), intent(in):: xyz_Press(:,:,:)
                              ! $ p $ . 気圧. Air pressure

    real(DP):: xyz_QVapSat(1:size(xyz_Temp,1), 1:size(xyz_Temp,2), 1:size(xyz_Temp,3))
                              ! $ q^{*} $ . 飽和比湿. Saturation specific humidity

    ! 作業変数
    ! Work variables
    !
    real(DP):: LatentHeatLocal
                              !
                              ! Latent heat used in this routine


    ! 実行文 ; Executable statement
    !

    ! 初期化確認
    ! Initialization check
    !

    if ( .not. saturate_DennouAGCM_inited ) then
      call MessageNotify( 'E', module_name, 'This module has not been initialized.' )
    end if

    ! Set a value for latent heat
    if ( FlagSublimation ) then
      LatentHeatLocal = LatentHeat + LatentHeatFusion
    else
      LatentHeatLocal = LatentHeat
    end if

    xyz_QVapSat = EpsV * Es0 * exp( LatentHeatLocal / GasRWet * ( 1./273. - 1./xyz_Temp ) ) / xyz_Press


  end function xyz_CalcQVapSat