2.3 Soil module

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2.3 Soil module

The heat capacity of the soil surface and the vegetation is assumed to be zero. On both levels the total sum of energy fluxes therefore has to be zero:

(1 - $\displaystyle\sigma_{f}^{}$ ) $\displaystyle\cdot$ (I + D_R + $\displaystyle\overline{R}$ $\displaystyle\downarrow$ ) - ( $\displaystyle\overline{R_s}$ $\displaystyle\uparrow$ )(T_s) - Q_H,s(T_s,z/L) - Q_E,s(T_s,z/L) - Q_G(T_s,z/L) = 0			(29)
$\displaystyle\sigma_{f}^{}$ $\displaystyle\cdot$ (I + D_R + $\displaystyle\overline{R}$ $\displaystyle\downarrow$ ) - ( $\displaystyle\overline{R_f}$ $\displaystyle\uparrow$ )(T_f) - Q_H,f(T_f,z/L) - Q_E,f(T_f,z/L) = 0			(30)

The definitions of the mathematical symbols are listed in table 1.

To calculate the ground heat flux, a five layer soil module was implemented. Deardorff's (1978) big-leaf concept, where vegetation is approximated with one big homogeneous leaf per model column was used to represent the influence of vegetation.

The soil parameterizations were arranged into a closed system of three equations:

E_s(T_s,T_f,z/L)	=
E_f(T_s,T_f,z/L)	=		(31)
f_zL(T_s,T_f,z/L)	=	z/L,

which is solved for T_s , T_f , and z/L iteratively, using the Newton-Raphson iteration method. The parameterization for the determination of the fluxes are discussed in Perego (1996) in full detail.

Next: 2.4 Emissions and deposition Up: 2 Model description Previous: 2.2 Radiation

Silvan Perego
1/21/1999