Functions soil_thermalConductivity
and soil_thermalCapacity
calculate thermal conductivity and thermal capacity
for each soil layer, given its texture and water content. Functions soil_temperatureGradient
and soil_temperatureChange
are used to calculate soil temperature gradients (in ºC/m) and temporal temperature change (in ºC/s)
given soil layer texture and water content (and possibly including heat flux from above).
Usage
soil_thermalCapacity(soil, model = "SX")
soil_thermalConductivity(soil, model = "SX")
soil_temperatureGradient(widths, Temp)
soil_temperatureChange(
widths,
Temp,
sand,
clay,
W,
Theta_SAT,
Theta_FC,
Gdown,
tstep
)
Arguments
- soil
Soil object (returned by function
soil
).- model
Either 'SX' or 'VG' for Saxton's or Van Genuchten's pedotransfer models.
- widths
Width of soil layers (in mm).
- Temp
Temperature (in ºC) for each soil layer.
- sand
Percentage of sand (in percent weight) for each layer.
- clay
Percentage of clay (in percent weight) for each layer.
- W
Soil moisture (in percent of field capacity) for each layer.
- Theta_SAT
Relative water content (in percent volume) at saturation for each layer.
- Theta_FC
Relative water content (in percent volume) at field capacity for each layer.
- Gdown
Downward heat flux from canopy to soil (in W·m-2).
- tstep
Time step (interval) in seconds.
Value
Function soil_thermalConductivity
returns a vector with values of thermal conductivity (W/m/ºK) for each soil layer.
Function soil_thermalCapacity
returns a vector with values of heat storage capacity (J/m3/ºK) for each soil layer.
Function soil_temperatureGradient
returns a vector with values of temperature gradient between consecutive soil layers.
Function soil_temperatureChange
returns a vector with values of instantaneous temperature change (ºC/s) for each soil layer.
References
Cox, P.M., Betts, R.A., Bunton, C.B., Essery, R.L.H., Rowntree, P.R., and Smith, J. 1999. The impact of new land surface physics on the GCM simulation of climate and climate sensitivity. Climate Dynamics 15: 183–203.
Dharssi, I., Vidale, P.L., Verhoef, A., MacPherson, B., Jones, C., and Best, M. 2009. New soil physical properties implemented in the Unified Model at PS18. 9–12.
Examples
#Define soil and complete parameters
examplesoil = soil(defaultSoilParams(4))
soil_thermalConductivity(examplesoil)
#> [1] 2.2 2.2 2.2 2.2
soil_thermalCapacity(examplesoil)
#> [1] 2486214 2486214 2486214 2486214
#Values change when altering water content (drier layers have lower conductivity and capacity)
examplesoil$W = c(0.1, 0.4, 0.7, 1.0)
soil_thermalConductivity(examplesoil)
#> [1] 0.4266171 1.4943000 1.9252995 2.2000000
soil_thermalCapacity(examplesoil)
#> [1] 1342121 1723486 2104850 2486214