Heat capacity

Soil heat capacity equals the sum of the heat capacities of soil constituents. Solid soil constituents are given on a volumetric basis. Heat capacity of air is negligible, such that:

                                              (1.16)

where index fs is the volumetric fraction of solid soil material including mineral and organic matter, derived from the porosity of the soil, θm. θ and θi are soil water contents as liquid water and ice, respectively and Cs, Cw and Ci are specific heat capacities for solid material, water and ice, respectively.

Optionally, the heat capacity of solid soil can be described as a function of depth (see switch SolidHeatCapDist):

                                     (1.17)

where cbulk is the heat capacity of solid soil in different layers.

C is never explicitly given for a partly frozen soil since temperature, in this case, is obtained by special calculations (see eqs. (1.29)-(1.31)).