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. 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_temperature soil_type, and veg_type.

NAMELIST group name: lsm_par

Parameter Name	FORTRAN Type	Default Value	Explanation
alpha_vangenuchten	R	9999999.9	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	9999999.9	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	9999999.9	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	9999999.9	Hydraulic conductivity of the soil at saturation (in m/s).
lambda_surface_stable	R	9999999.9	Aerodynamic coupling between canopy and soil (in W/m²/K) in case of stable stratification.
lambda_surface_unstable	R	9999999.9	Aerodynamic coupling between canopy and soil (in W/m²/K) in case of unstable stratification.
leaf_area_index	R	9999999.9	Leaf area index of the canopy (in m²/m²).
l_vangenuchten	R	9999999.9	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	9999999.9	Minimum canopy resistance (in s/m).
min_soil_resistance	R	50.0	Minimum soil resistance (in s/m).
field_capacity	R	9999999.9	Soil moisture at field capacity (in m³/m³).
residual_moisture	R	9999999.9	Residual soil moisture content (in m³/m³).
saturation_moisture	R	9999999.9	Soil moisture at saturation (in m³/m³).
wilting_point	R	9999999.9	Soil moisture at permanent wilting point (in m³/m³).
n_vangenuchten	R	9999999.9	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)	4*9999999.9	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 (in m³/m³).
soil_temperature	R(4)	4*9999999.9	Soil temperature distribution over the four soil layers (in K).
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, l_vengenuchten, n_vangenuchten, hydraulic_conductivity, saturation_moisture, field_capacity, wilting_point, residual_moisture.
vegetation_coverage	R	9999999.9	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 Notes 0 user defined All vegetation-related parameters must be explicitly set by the user. 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 Not implemented yet. 13 bogs and marshes 14 inland water Not implemented yet. 15 ocean Not implemented yet. 16 evergreen shrubs 17 deciduous shrubs 18 mixed forest/woodland 19 interrupted forest The following parameters will then be automatically set: min_canopy_resistance, leaf_area_index, vegetation_coverage, canopy_resistance_coefficient, z0_eb, z0h_eb, lambda_surface_stable, lambda_surface_unstable, f_shortwave_incoming, root_fraction.
zs	R(4)	0.07, 0.28, 1.0, 2.89	Depths of the four soil layers (in m).
z0_eb	R	9999999.9	Roughness length for momentum (in m). The setting of z0_eb overwrites roughness_length, unless z0_eb is not set.
z0h_eb	R	9999999.9	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).