soil thermodynamics: Soil thermodynamic functions

Description

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 <U+00BA>C/m) and temporal temperature change (in <U+00BA>C/s) given soil layer texture and water content (and possibly including heat flux from above).

Usage

soil.thermalconductivity(soil, model = "SX")
soil.thermalcapacity(soil, model = "SX")
soil.temperaturechange(dVec, Temp, sand, clay, W, Theta_FC, Gdown)
soil.temperaturegradient(dVec, Temp)

Arguments

soil

Soil object (returned by function soil).

model

Either 'SX' or 'VG' for Saxton's or Van Genuchten's pedotransfer models.

dVec

Width of soil layers (in mm).

Temp

Temperature (in <U+00BA>C) for each soil layer.

clay

Percentage of clay (in percent weight) for each layer.

sand

Percentage of sand (in percent weight) for each layer.

Soil moisture (in percent of field capacity) 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<U+00B7>m-2).

Value

Function soil.thermalconductivity returns a vector with values of thermal conductivity (W/m/<U+00BA>K) for each soil layer. Function soil.thermalcapacity returns a vector with values of heat storage capacity (J/m3/<U+00BA>K) 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 (<U+00BA>C/s) for each soil layer.

References

Cox, P.M., Betts, R.A., Bunton, C.B., Essery, R.L.H., Rowntree, P.R., & Smith, J. 1999. The impact of new land surface physics on the GCM simulation of climate and climate sensitivity. Climate Dynamics 15: 183<U+2013>203.

Dharssi, I., Vidale, P.L., Verhoef, A., MacPherson, B., Jones, C., & Best, M. 2009. New soil physical properties implemented in the Unified Model at PS18. 9<U+2013>12.

Examples

Run this code

# NOT RUN {
examplesoil = soil(defaultSoilParams())
soil.thermalconductivity(examplesoil)
soil.thermalcapacity(examplesoil)

#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)
soil.thermalcapacity(examplesoil)
# }