== Land Surface Parameters ==
[[TracNav(doc/app/partoc|nocollapse)]]

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 at the surface. Moreover, a liquid water reservoid accounts for the presence of liquid water on plants due to dew/fog. The implementation is based on the ECMWF-IFS land surface parametrization (TESSEL) and its adaption in the DALES model.

All parts of the LSM code are modularized in module [/browser/palm/trunk/SOURCE/land_surface_model.f90 land_surface_model_mod]. In this context, a new Fortran NAMELIST {{{lsm_par}}} was added, containing all LSM-related steering parameters. The LSM is automatically activated when a {{{lsm_par}}} is set in the parameter file ({{{_p3d}}}). The user can easily set all relevant LSM parameters by choosing between 19 pre-defined [#veg_type vegetation types] and 7 different [#soil_type soil types]. The default setting of the LSM is a soil of medium porosity covered to 85% with short grass. It is also possible to modify the pre-defined vegetation/soil types by overwriting some of the parameters. Moreover it is possible to create user-defined vegetation and soil types from scratch.

A minimum configuration of the LSM requires setting of the parameters [#soil_type soil_type], and [#veg_type veg_type]. Setting of initial vertical profiles of [#soil_temperature soil_temperature] and [#soil_moisture soil_moisture] are recommened. 

Note that the use of the LSM requires using a [wiki:doc/tec/radiation radiation model].


\\\\\\\\\\\\
'''NAMELIST group name: lsm_par''' \\\\

||='''Parameter Name'''  =||='''[../fortrantypes FORTRAN Type]'''  =||='''Default Value'''  =||='''Explanation'''  =||
|----------------
{{{#!td style="vertical-align:top"
[=#alpha_vengenuchten '''alpha_vangenuchten''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Value of the coefficient alpha for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#c_surface '''c_surface''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
20000.0
}}}
{{{#!td
Heat capacity of the surface (skin layer) per unit of area (in J/m²/K).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#canopy_resistance_coefficient '''canopy_resistance_coefficient''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
A coefficient (in 1/hPa) for the dependence of the canopy resistance on water vapor pressure deficit.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#conserve_water_content '''conserve_water_content''']
}}}
{{{#!td style="vertical-align:top"
L
}}}
{{{#!td style="vertical-align:top"
.T.
}}}
{{{#!td
Flag parameter for the bottom boundary condition of the soil model.

The usee can choose between the following two options:

'' '.T.' ''

Closed bottom (bedrock, no drainage). Conservation of water in the soil and atmosphere is guaranteed.


'' '.F.' ''

Open bottom (free drainage). Water can leave the soil model and conservation of water is not guaranteed.

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#dewfall '''dewfall''']
}}}
{{{#!td style="vertical-align:top"
L
}}}
{{{#!td style="vertical-align:top"
.T.
}}}
{{{#!td
In case dewfall = .T., all supersatured water at the lowest grid level is immediately removed and transferred to the liquid water reservoir (or soil, depending on the [#vegetation_coverage vegetation coverage] and the filling level of the liquid water reservoir). Alternatively, dewfall = .F. will switch off this parametrization (yet to be tested).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#f_shortwave_incoming '''f_shortwave_incoming''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Fraction of the net shortwave radiation that is transmitted directly to the top soil layer. The remaining fraction of the shortwave radiation is absorbed by the surface (skin layer). This parameter has not been fully implemented yet and is fixed to 0.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#hydraulic_conductivity '''hydraulic_conductivity''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Hydraulic conductivity of the soil at saturation (in m/s).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#lambda_surface_stable '''lambda_surface_stable''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Aerodynamic coupling between canopy and soil (in W/m²/K) in case of stable stratification.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#lambda_surface_unstable '''lambda_surface_unstable''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Aerodynamic coupling between canopy and soil (in W/m²/K) in case of unstable stratification.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#leaf_area_index '''leaf_area_index''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Leaf area index of the canopy (in m²/m²).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#l_vangenuchten '''l_vangenuchten''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Value of the coefficient {{{l}}} for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#min_canopy_resistance '''min_canopy_resistance''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Minimum canopy (i.e., stomatal) resistance (in s/m).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#min_soil_resistance '''min_soil_resistance''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
50.0
}}}
{{{#!td
Minimum soil resistance (in s/m).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#field_capacity '''field_capacity''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Soil moisture at field capacity (in m³/m³).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#residual_moisture '''residual_moisture''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Residual soil moisture content (in m³/m³).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#saturation_moisture '''saturation_moisture''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Soil moisture at saturation (in m³/m³).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#wilting_point '''wilting_point''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Soil moisture at permanent wilting point (in m³/m³).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#n_vangenuchten '''n_vangenuchten''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#soil_type soil_type]
}}}
{{{#!td
Value of the coefficient {{{n}}} for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#root_fraction '''root_fraction''']
}}}
{{{#!td style="vertical-align:top"
R(4)
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Root distribution 
{{{
#!Latex
\[ R_k \]
}}}
over the four soil layers (with index {{{k}}}).

It must hold that
{{{
#!Latex
\[ \sum_\limits_{k=1}^4 R_k = 1. \]
}}}

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#soil_moisture '''soil_moisture''']
}}}
{{{#!td style="vertical-align:top"
R(4)
}}}
{{{#!td style="vertical-align:top"
4*0.0
}}}
{{{#!td
Soil moisture distribution over the four soil layers (given by [#zs zs] in K.. Soil moisture is only predicted when [wiki:doc/app/inipar#humidity humidity]{{{ = .T.}}}.

'''Default (dry):'''
{{{
soil_moisture = 0.0, 0.0, 0.0, 0.0
}}}
Note that the soil moisture is internally set to a minimum value according to [#wilting_point wilting_point] at model start.

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#soil_temperature '''soil_temperature''']
}}}
{{{#!td style="vertical-align:top"
R(5)
}}}
{{{#!td style="vertical-align:top"
see Description
}}}
{{{#!td
Soil temperature distribution over the four soil layers in K.

'''Default:'''
{{{
soil_temperature = 290.0, 287.0, 285.0, 283.0, 283.0
}}}
The first four values represent the temperature of the soil layers (defined at the center of the layers of depth [#zs zs]. The last (fifth) value represents the deep soil temperature, which is fixed (boundary condition).

}}}
|----------------
{{{#!td style="vertical-align:top"
[=#soil_type '''soil_type''']
}}}
{{{#!td style="vertical-align:top"
I
}}}
{{{#!td style="vertical-align:top"
3
}}}
{{{#!td
Soil type to be used in the soil model.


The user can choose from 7 soil types according to the ECMWF-IFS classification (parametrization after Van Genuchten (1980):
||= '''soil_type'''=||='''Description''' =||='''Notes''' =||
|| 0||user defined ||All soil-related parameters must be explicitly set by the user. ||
|| 1||coarse ||||
|| 2||medium ||||
|| 3||medium-fine ||||
|| 4||fine ||||
|| 5||very fine ||||
|| 6||organic ||||
|| 7||loamy (CH) ||Parametrization after Clapp & Hornberger (1978)||

The following parameters will then be automatically set: [#alpha_vangenuchten alpha_vangenuchten] (alpha_vg), [#l_vengenuchten l_vengenuchten] (l_vg), [#n_vangenuchten n_vangenuchten] (n_vg), [#hydraulic_conductivity hydraulic_conductivity] (gamma_w_sat), [#saturation_moisture saturation_moisture] (m_sat), [#field_capacity field_capacity] (m_fc), [#wilting_point wilting_point] (m_wilt), [#residual_moisture residual_moisture] (m_res).

||= '''soil_type'''=||='''alpha_vg''' =||='''l_vg''' =||='''n_vg''' =||='''gamma_w_sat (m/s)''' =||='''m_sat (m³/m³)''' =||='''m_fc (m³/m³)''' =||='''m_wilt (m³/m³)''' =||='''m_res (m³/m³)''' =||
||  1|| 3.83||  1.150|| 1.38|| 6.94E-6|| 0.403|| 0.244|| 0.059|| 0.025||
||  2|| 3.14|| -2.342|| 1.28|| 1.16E-6|| 0.439|| 0.347|| 0.151|| 0.010||
||  3|| 0.83|| -0.588|| 1.25|| 0.26E-6|| 0.430|| 0.383|| 0.133|| 0.010||
||  4|| 3.67|| -1.977|| 1.10|| 2.87E-6|| 0.520|| 0.448|| 0.279|| 0.010||
||  5|| 2.65||  2.500|| 1.10|| 1.74E-6|| 0.614|| 0.541|| 0.335|| 0.010||
||  6|| 1.30||  0.400|| 1.20|| 1.20E-6|| 0.766|| 0.663|| 0.267|| 0.010||
||  7||    -||      -||    -||       -|| 0.472|| 0.323|| 0.171||     -||
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#vegetation_coverage '''vegetation_coverage''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Vegetation coverage of the surface (values of 0-1). The residual fraction is considered to be bare soil.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#veg_type '''veg_type''']
}}}
{{{#!td style="vertical-align:top"
I
}}}
{{{#!td style="vertical-align:top"
2
}}}
{{{#!td
Vegetation type to be used in the land surface model.

The user can choose from 19 different pre-defined vegetation classes accoring to the ECMWF-IFS classification:
||= '''veg_type'''=||='''Description''' =||
|| 0||user defined ||
|| 1||crops, mixed farming ||
|| 2||short grass ||
|| 3||evergreen needleleaf trees ||
|| 4||deciduous needleleaf trees ||
|| 5||evergreen broadleaf trees ||
|| 6||deciduous broadleaf trees ||
|| 7||tall grass ||
|| 8||desert ||
|| 9||tundra ||
|| 10||irrigated crops ||
|| 11||semidesert ||
|| 12*||ice caps and glaciers ||
|| 13||bogs and marshes ||
|| 14*||inland water ||
|| 15*||ocean ||
|| 16||evergreen shrubs ||
|| 17||deciduous shrubs ||
|| 18||mixed forest/woodland ||
|| 19||interrupted forest ||
(* not yet implemented)


The following parameters will then be automatically set: [#min_canopy_resistance min_canopy_resistance] (r_c_min), [#leaf_area_index leaf_area_index] (LAI), [#vegetation_coverage vegetation_coverage] (c_veg), [#canopy_resistance_coefficient canopy_resistance_coefficient] (gD), [#z0_eb z0_eb], [#z0h_eb z0h_eb], [#lambda_surface_stable lambda_surface_stable] (lambda_s), [#lambda_surface_unstable lambda_surface_unstable] (lambda_u), [#f_shortwave_incoming f_shortwave_incoming] (f_sw_in), [#root_fraction root_fraction]. The following tables provide an overview of the parameter values.

||= '''veg_type'''=||='''r_c_min (s/m)''' =||='''LAI (m²/m²)''' =||='''c_veg''' =||='''gD (1/hPa)''' =||='''z0_eb (m)''' =||='''z0h_eb (m)''' =||='''lambda_s (W/m²/K)''' =||='''lambda_u (W/m²/K)''' =||='''f_sw_in''' =||
||  1|| 180.0|| 3.00|| 0.90|| 0.00||   0.25||  0.25E-2||   10.0||   10.0|| 0.05||
||  2|| 110.0|| 2.00|| 0.85|| 0.00||   0.20||  0.20E-2||   10.0||   10.0|| 0.05||
||  3|| 500.0|| 5.00|| 0.90|| 0.03||   2.00||     2.00||   20.0||   15.0|| 0.03||
||  4|| 500.0|| 5.00|| 0.90|| 0.03||   2.00||     2.00||   20.0||   15.0|| 0.03||
||  5|| 175.0|| 5.00|| 0.90|| 0.03||   2.00||     2.00||   20.0||   15.0|| 0.03||
||  6|| 240.0|| 6.00|| 0.99|| 0.13||   2.00||     2.00||   20.0||   15.0|| 0.03||
||  7|| 100.0|| 2.00|| 0.70|| 0.00||   0.47||  0.47E-2||   10.0||   10.0|| 0.05||
||  8|| 250.0|| 0.05|| 0.00|| 0.00||  0.013|| 0.013E-2||   15.0||   15.0|| 0.00||
||  9||  80.0|| 1.00|| 0.50|| 0.00||  0.034|| 0.034E-2||   10.0||   10.0|| 0.05||
|| 10|| 180.0|| 3.00|| 0.90|| 0.00||    0.5||  0.50E-2||   10.0||   10.0|| 0.05||
|| 11|| 150.0|| 0.50|| 0.10|| 0.00||   0.17||  0.17E-2||   10.0||   10.0|| 0.05||
|| 12*||   0.0|| 0.00|| 0.00|| 0.00|| 1.3E-3||   1.3E-4||   58.0||   58.0|| 0.00||
|| 13|| 240.0|| 4.00|| 0.60|| 0.00||   0.83||  0.83E-2||   10.0||   10.0|| 0.05||
|| 14*||   0.0|| 0.00|| 0.00|| 0.00||   0.00||     0.00|| 1.0E20|| 1.0E20|| 0.00||
|| 15*||   0.0|| 0.00|| 0.00|| 0.00||   0.00||     0.00|| 1.0E20|| 1.0E20|| 0.00||
|| 16|| 225.0|| 3.00|| 0.50|| 0.00||   0.10||  0.10E-2||   10.0||   10.0|| 0.05||
|| 17|| 225.0|| 1.50|| 0.50|| 0.00||   0.25||  0.25E-2||   10.0||   10.0|| 0.05||
|| 18|| 250.0|| 5.00|| 0.90|| 0.03||   2.00||  2.00E-2||   20.0||   15.0|| 0.03||
|| 19|| 175.0|| 2.50|| 0.90|| 0.03||   1.10||  1.10E-2||   20.0||   15.0|| 0.03||
(* not yet implemented)
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#zs '''zs''']
}}}
{{{#!td style="vertical-align:top"
R(4)
}}}
{{{#!td style="vertical-align:top"
see description
}}}
{{{#!td
Depths of the four soil layers (in m). Note that the model operates with negative values below the surface, data output will thus be at located at {{{-zs}}}.

'''Default:'''
{{{
zs = 0.07, 0.28, 1.0, 2.89
}}}


}}}
|----------------
{{{#!td style="vertical-align:top"
[=#z0_eb '''z0_eb''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Roughness length for momentum (in m). The setting of {{{z0_eb}}} overwrites [wiki:doc/app/inipar#roughness_length roughness_length], unless {{{z0_eb}}} is not set.
}}}
|----------------
{{{#!td style="vertical-align:top"
[=#z0h_eb '''z0h_eb''']
}}}
{{{#!td style="vertical-align:top"
R
}}}
{{{#!td style="vertical-align:top"
depending on [#veg_type veg_type]
}}}
{{{#!td
Roughness length for heat and moisture (in m). The setting of {{{z0h_eb}}} overwrites [wiki:doc/app/inipar#z0h_factor z0h_factor], unless {{{z0h_eb}}} is not set. In this case, the roughness length for heat is calculated from [wiki:doc/app/inipar#z0h_factor z0h_factor] and {{{z0h_eb}}} (or [wiki:doc/app/inipar#roughness_length #roughness_length]).
}}}