Sedimentation of tracers in the generic PCM
IMPORTANT: This page concerns the newsedim routine in the Generic physics package (by the way the latest version may be checked here on the trac: https://trac.lmd.jussieu.fr/Planeto/browser/trunk/LMDZ.GENERIC/libf/phystd/newsedim.F
Overview of the newsedim routine
This routine handles the sedimentation of non-gaseous tracers by computing the sedimentation velocity of particles. This requires handling each particle of a given type (fixed radius and density, but also shape) at a time.
Detailed description of assumptions and computations
TODO: By Benjamin?
Some references
- Stokes law corrected for low pressure by the Cunnigham slip-flow correction according to Rossow (1978, https://doi.org/10.1016/0019-1035(78)90072-6 )
- Estimation of the viscosity and the mean molecular radius of the gas mixture composing the atmosphere: ... Kunze et al. 2022, Ackerman & Marley 2001, etc.
THIS IS A TEST (MARTIN):
$r_2 = 611.14$ \\
$r_3 = 17.269$ (liquide), 21.875 (solide) \\
$r_4 = 35.86$ (liquide), 7.66 (solide)
L'humidit\'e sp\'ecifique ($q_s$) est d\'efinie comme le rapport entre la masse de vapeur $m_v$ et la masse de l'air m\'elang\'e ($m_d + m_v$):
\begin{equation} q_s = \frac{e_s/(R_vT)}{(p-e_s)/(R_dT) + e_s/(R_vT)} \end{equation} o\`u $p$ est la pression totale, $R_d$ est la constante de gaz pour l'air sec, $R_v$ est la constante de gaz pour la vapeur d'eau. Avec la notation \begin{equation} \epsilon = \frac{R_d}{R_v} \end{equation} \begin{equation} q_s = \frac{\epsilon e_s}{p - (1-\epsilon) e_s} \end{equation}
La d\'eriv\'e de $q_s$ par rapport \`a la temp\'erature est donn\'ee par la formule suivante:
\begin{equation} \frac{dq_s}{dT} = \frac{d}{dT}(q_s) = \frac{r_3(t_0-r_4)q_s(T,p)} {(T-r_4)^2 (1-(1-\epsilon) e_s(T)/p)} \end{equation}
