% 表題  2 次元非弾性流体モデル deepconv-mars 解説: 数理モデル編
%       第 1 節 モデルの概要
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% 履歴  1998/06/29  小高正嗣
%       1999/06/15  小高正嗣
%       2001/11/01  小高正嗣
%       2007/04/24  小高正嗣: 英語版の作成
%
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\section{\DselJ{deepconv-mars の概要}{Outline of the model}}

\DselJ{
deepconv-mars は地球大気の積雲対流をシミュレートするために Nakajima
(1994) において開発された 2 次元非弾性流体モデル deepconv を火星大気対流
へ応用したものである. ただし数値モデル内に考慮されている物理過程は 
deepconv から変更, もしくは新たに追加されている. 

モデルの概要を簡単に以下に示す. deepconv から変更したのは地表フラックス
モデル, 新たに追加したのはダストの移流, 大気とダストの放射過程, 地表面熱
収支の取り扱いである. deepconv で考慮されていた水蒸気過程は取り外してあ
る. 
}
{
    The 2D model system consists of the atmosphere and the grand surface. 
    The model atmosphere is composed of ideal gas. 
    The atmospheric constituent is assumed to
        CO${}_{2}$ only and its condensation and
        sublimation are not considered.
    The values of soil density, thermal conductivity and specific
       heat are constant each other. 
    The surface topography is not considered.
}


\begin{description}
 \item [\DselJ{大気モデル}{Atmospheric model}] 
        \DselJ{回転系の 2 次元非弾性方程式系(Ogura and Phllips, 1962)
              である. }
              {
        The governing equation of model atmospheric dynamics is the 2D
           anelastic system (Ogura and Phillips, 1962). }

 \item [\DselJ{乱流モデル}
              {Turbulent parametarization}] 
        \DselJ{Klemp and Wilhelmson (1978) の 2 次クロージャーモデ
	     ル. ただし運動量の混合係数とスカラー量の混合係数とを等しい
	     とした.}
      {The subgrid turbulent mixingis
          evaluated by the formula of Klemp and Wilhelmson (1978).
       The value of turbulent diffusion coefficient for heat is equal
          to that for momentum.}

 \item [\DselJ{地表フラックス}{Surface flux}] 
       \DselJ{Louis (1979) によるバルク法. ただし運動量のバル
	     ク係数とスカラー量のバルク係数とを等しいとした.}
       {
       The surface momentum and heat fluxes
          are given by the bulk formulae, where the bulk coefficients
          depend on static stability and vertical wind shear (
          Louis, 1979).
       The bulk coefficient for heat transport has same value of that
          for momentum.
       The roughness length for the bulk coefficients is 1 cm (
         Sutton {\it et al.}, 1978).}

 \item [\DselJ{ダスト}{Dust transport}] 
       \DselJ{重力沈降を考慮した移流方拡散程式. 沈降速度は Conrath
	     (1975) の方法で計算. ダストの地表からの巻き上げは地表摩擦が
	     ある値を超える生じるとする. 巻き上げフラックスの値は一定と
	     する. }
       {
    The spatial distribution of dust is calculated by advection
       diffusion equation which considers gravitational settling of
       dust. 
    The representation of dust terminal velocity follows 
       Conrath (1975). 
    The radius of dust particle is constant value (0.4 $\mu$ m).
    The value of dust flux from the surface is constant.}

 \item [\DselJ{放射}{Radiation}] 

 \DselJ{
 \begin{itemize}
   \item CO${}_{2}$ 放射は Goody のバンドモデル. 考慮する波長帯は赤外 1
	 バンドと近赤外 3 バンド(15, 4.3, 2.7, 2.0 $\mu$m バンド). 

   \item ダスト放射は $\delta$-Eddington 近似で計算. 考慮する波長帯は赤
	 外と可視で合計 3 バンドとする. 
 \end{itemize}	     
 }
 {
       The radiative transfer of
         CO${}_{2}$ atmosphere is calculated by a
       Goody narrow band model which considers 15 $\mu$m band in
       infrared wavelength and 4.3, 2.7, 2.0 $\mu$m band in near
       infrared wavelength.
    The values of absorption line intensities and widths in each band
       are same as those of Houghton (1986).

    The radiative transfer of dust is
       calculated by $\delta$-Eddington approximation model which
       considers two bands in infrared wavelength region (5-11.6,
       20-200 $\mu$m) and one band in solar wavelength region (0.1-5
       $\mu$m). 
    The values of band width and optical parameters of dust
       (extinction efficiency, single scattering albedo, asymmetry
       factor) in each band are same as those of 
       Forget {\it et al.} (1999)
       except in 11.6-20 $\mu$m band which is not considered in our
       model.
 }

 \item [\DselJ{地表面モデル}{Ground surface}] 
       \DselJ{地面の温度は鉛直 1 次元熱伝導方程式で計算する. 物性パラメータは 
    Kieffer {\it et al.} (1977) の標準モデルの値を用いる.}
      {
    The ground temperature is calculated by 1D thermal conduction
       equation. The values of soil density, thermal conductivity and
       specific heat are same as those of 
       Kieffer {\it et al.} (1977) standard model.}

	     
\end{description}

