Land Surface Parameters

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 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 vegetation types and 7 different 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, and veg_type. Setting of initial vertical profiles of soil_temperature and soil_moisture are recommened.

Note that the use of the LSM requires using a radiation model.

NAMELIST group name: lsm_par

Parameter Name	FORTRAN Type	Default Value	Explanation
alpha_vangenuchten	R	depending on soil_type	Value of the coefficient alpha for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
c_surface	R	20000.0	Heat capacity of the surface (skin layer) per unit of area (in J/m²/K).
canopy_resistance_coefficient	R	depending on veg_type	A coefficient (in 1/hPa) for the dependence of the canopy resistance on water vapor pressure deficit.
conserve_water_content	L	.T.	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.
dewfall	L	.T.	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 and the filling level of the liquid water reservoir). Alternatively, dewfall = .F. will switch off this parametrization (yet to be tested).
f_shortwave_incoming	R	depending on veg_type	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.
hydraulic_conductivity	R	depending on soil_type	Hydraulic conductivity of the soil at saturation (in m/s).
lambda_surface_stable	R	depending on veg_type	Aerodynamic coupling between canopy and soil (in W/m²/K) in case of stable stratification.
lambda_surface_unstable	R	depending on veg_type	Aerodynamic coupling between canopy and soil (in W/m²/K) in case of unstable stratification.
leaf_area_index	R	depending on veg_type	Leaf area index of the canopy (in m²/m²).
l_vangenuchten	R	depending on soil_type	Value of the coefficient l for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
min_canopy_resistance	R	depending on veg_type	Minimum canopy (i.e., stomatal) resistance (in s/m).
min_soil_resistance	R	50.0	Minimum soil resistance (in s/m).
field_capacity	R	depending on soil_type	Soil moisture at field capacity (in m³/m³).
residual_moisture	R	depending on soil_type	Residual soil moisture content (in m³/m³).
saturation_moisture	R	depending on soil_type	Soil moisture at saturation (in m³/m³).
wilting_point	R	depending on soil_type	Soil moisture at permanent wilting point (in m³/m³).
n_vangenuchten	R	depending on soil_type	Value of the coefficient n for the calculation of the hydraulic conductivity of soil in the parametrization after Van Genuchten (1980).
root_fraction	R(4)	depending on veg_type	Root distribution over the four soil layers (with index k). It must hold that TracMath macro processor has detected an error. Please fix the problem before continuing. The command: '/usr/bin/pdflatex -interaction=nonstopmode d49f6bd132e77a76b186811acd3a169dbf1c45cb.tex' failed with the following output: "This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)\n restricted \\write18 enabled.\nentering extended mode\n(./d49f6bd132e77a76b186811acd3a169dbf1c45cb.tex\nLaTeX2e <2011/06/27>\nBabel <3.9h> and hyphenation patterns for 78 languages loaded.\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/article.cls\nDocument Class: article 2007/10/19 v1.4h Standard LaTeX document class\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/size10.clo))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/inputenc.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/utf8.def\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/t1enc.dfu)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/ot1enc.dfu)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/omsenc.dfu)))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/cmap/cmap.sty)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/cm-super/type1ec.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/t1cmr.fd))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/fontenc.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/base/t1enc.def)<<t1.cmap\n>>) (/localdata/software/texlive/2013/texmf-dist/tex/latex/amsmath/amsmath.sty\nFor additional information on amsmath, use the `?' option.\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsmath/amstext.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsmath/amsgen.sty))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsmath/amsbsy.sty)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsmath/amsopn.sty))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amscls/amsthm.sty)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsfonts/amssymb.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsfonts/amsfonts.sty))\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/tools/bm.sty)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/preview/preview.sty\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/preview/prtightpage.def)\n) (./d49f6bd132e77a76b186811acd3a169dbf1c45cb.aux)\nPreview: Fontsize 10pt\nPreview: PDFoutput 1\n<<ot1.cmap>><<oml.cmap>><<oms.cmap>><<omx.cmap>>\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsfonts/umsa.fd)\n(/localdata/software/texlive/2013/texmf-dist/tex/latex/amsfonts/umsb.fd)\n! Missing { inserted.\n<to be read again> \n \\limits \nl.14 \\[ \\sum_\\limits\n _{k=1}^4 R_k = 1. \\]\n! Limit controls must follow a math operator.\n<recently read> \\limits \n \nl.14 \\[ \\sum_\\limits\n _{k=1}^4 R_k = 1. \\]\n! Missing } inserted.\n<inserted text> \n }\nl.14 \\[ \\sum_\\limits_{k=1}^4 R_k = 1. \\]\n \nPreview: Tightpage -32891 -32891 32891 32891\n[1{/localdata/software/texlive/2013/texmf-var/fonts/map/pdftex/updmap/pdftex.ma\np}] (./d49f6bd132e77a76b186811acd3a169dbf1c45cb.aux) )\n(see the transcript file for additional information)</localdata/software/texliv\ne/2013/texmf-dist/fonts/type1/public/amsfonts/cm/cmex10.pfb></localdata/softwar\ne/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm/cmmi5.pfb></localdata/\nsoftware/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm/cmmi7.pfb></loc\naldata/software/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm/cmr5.pfb\n></localdata/software/texlive/2013/texmf-dist/fonts/type1/public/amsfonts/cm/cm\nr7.pfb>\nOutput written on d49f6bd132e77a76b186811acd3a169dbf1c45cb.pdf (1 page, 42440 b\nytes).\nTranscript written on d49f6bd132e77a76b186811acd3a169dbf1c45cb.log.\n"
soil_moisture	R(4)	4*0.0	Soil moisture distribution over the four soil layers (given by zs in K.. Soil moisture is only predicted when 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 at model start.
soil_temperature	R(5)	see Description	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. The last (fifth) value represents the deep soil temperature, which is fixed (boundary condition).
soil_type	I	3	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_vg), l_vengenuchten (l_vg), n_vangenuchten (n_vg), hydraulic_conductivity (gamma_w_sat), saturation_moisture (m_sat), field_capacity (m_fc), wilting_point (m_wilt), 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 -
vegetation_coverage	R	depending on veg_type	Vegetation coverage of the surface (values of 0-1). The residual fraction is considered to be bare soil.
veg_type	I	2	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 (r_c_min), leaf_area_index (LAI), vegetation_coverage (c_veg), canopy_resistance_coefficient (gD), z0_eb, z0h_eb, lambda_surface_stable (lambda_s), lambda_surface_unstable (lambda_u), f_shortwave_incoming (f_sw_in), 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)
zs	R(4)	see description	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
z0_eb	R	depending on veg_type	Roughness length for momentum (in m). The setting of z0_eb overwrites roughness_length, unless z0_eb is not set.
z0h_eb	R	depending on veg_type	Roughness length for heat and moisture (in m). The setting of z0h_eb overwrites z0h_factor, unless z0h_eb is not set. In this case, the roughness length for heat is calculated from z0h_factor and z0h_eb (or #roughness_length).