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 f_s is the volumetric fraction of solid soil material including mineral and organic matter, derived from the porosity of the soil, θ_m. θ and θ_i are soil water contents as liquid water and ice, respectively and C_s, C_w and C_i 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 c_bulk 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)).