= Land surface model =

== Overview ==
Since r1551 a full land surface model (LSM) is available in PALM. It consists of a four layer soil model, predicting soil temperature and moisture content, and a solver for the energy balance of the skin surface layer. Moreover, a liquid water reservoir accounts for the presence of liquid water on plants and soil due to precipitation. The implementation is based on the ECMWF-IFS land surface parametrization (H-TESSEL) and its adaptation in the DALES model (Heus et al. 2010).

Note that the use of the LSM requires using a [wiki:doc/tec/radiation radiation model] to provide radiative fluxes at the surface.

== Energy balance solver ==
The energy balance of the Earth's surface reads
\begin{equation}
   C_0 \dfrac{dT_0}{dt} = R_\mathrm{n} - H - LE - G
  \label{eq:energybalance}
\end{equation}
where
{{{#!Latex $C_0$, $T_0$}}} 
are the heat capacity and radiative temperature of the surface skin layer, respectively. $R_\mathrm{n}$, $H$, $LE$, and $G$ are the net radiation, sensible heat flux, latent heat flux, and ground (soil) heat flux at the surface, respectively. $H$ is calculated as
\begin{equation}
  H = - \rho\ c_\mathrm{p}\ \dfrac{1}{r_\mathrm{a}} ( \theta_1 - \theta_0 )
\end{equation}
where $\rho$ is the density of the air, $c_\mathrm{p} = \unit[1005]{J\ kg^{-1} K^{-1}}$ is the specific heat at constant pressure, $r_\mathrm{a}$ is the aerodynamic resistance, and $\theta_0$ and $\theta_1$ are the potential temperature at the surface and at the first grid level above the surface, respectively. $r_\mathrm{a}$ is calculated via Monin-Obukhov similarity theory, based on roughness lengths for heat and momentum and the assumption of a constant flux layer between the surface and the first grid level.


== Soil model ==

== Usage ==

== References ==