Changes between Version 44 and Version 45 of doc/tec/lsm

Timestamp:

Jun 13, 2017 10:24:50 AM (8 years ago)

Author:

maronga

Comment:

--

doc/tec/lsm

@@ -2 +2 @@
 
 == Overview ==
-Since r1551 a full land surface model (LSM) is available in PALM (see [source:palm/trunk/SOURCE/land_surface_model_mod.f90 land_surface_model_mod.f90]). It consists of a four layer soil model, predicting soil temperature and moisture content, and a solver for the energy balance, predicting the temperature of the skin 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 Heus et al. 2010]).
+Since r1551 a full land surface model (LSM) is available in PALM (see [source:palm/trunk/SOURCE/land_surface_model_mod.f90 land_surface_model_mod.f90]). It consists of a multi layer soil model, predicting soil temperature and moisture content, and a solver for the energy balance, predicting the temperature of the surface or the skin layer (depending on land use classification). Moreover, a liquid water reservoir accounts for the presence of liquid water on plants, pavement, and bare 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 Heus et al. 2010]).
 
 Note that the use of the LSM requires using some kind of [wiki:doc/tec/radiation radiation model] to provide radiative fluxes at the surface.
@@ -41 +41 @@
 \end{equation*}
 }}}
-with ''Λ'' being the heat conductivity between skin layer and the soil, and ''T'',,soil,1,, being the temperature of the uppermost soil layer. 
+with ''Λ'' being the heat conductivity between skin layer and the soil, and ''T'',,soil,1,, being the temperature of the uppermost soil layer. When no skin layer is used, ''Λ'' is replaced by the heat conductivity of the uppermost soil layer (divided by the layer depth).
 
 === Parameterization of ''LE'' ===
@@ -53 +53 @@
 Here, ''l'',,v,, = 2.5 * 10^6^ J kg^-1^ is the latent heat of vaporisation, ''r'',,s,, is the surface resistance, ''q'',,v,1,, is the specific humidity at first grid level, and ''q'',,v,sat,, is the saturation specific humidity at temperature ''T'',,0,,. 
 
-All equations above are solved locally for each surface element of the LES grid. Each element can consist of both patches of bare soil, vegetation, and a liquid water reservoir, which is the interception water stored on plants and soil from precipitation. Therefore, an additional equation is solved for the liquid water reservoir. ''LE'' is then calculated for each of the three components (bare soil, vegetation, liquid water). The resistances are calculated separately for bare soil and vegetation following Jarvis (1976). The canopy resistance is calculated as
+All equations above are solved locally for each surface element of the LES grid. Each element for the surface type 'vegetation' can consist of patches of bare soil, vegetation, and a liquid water reservoir, which is the interception water stored on plants and soil from precipitation. Therefore, an additional equation is solved for the liquid water reservoir. A liquid water reservoir is also available when the surface type is set to 'pavement'. ''LE'' is then calculated for each of the three components (bare soil, vegetation, liquid water). The resistances are calculated separately for bare soil and vegetation following Jarvis (1976). The canopy resistance is calculated as
 {{{
 #!Latex