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A.e. Ground and surface layer
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Ground temperature is calculated by the 1D thermal conduction equation.
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(A.55) |
Where  is the ground temperature (K),  is soil density
(kgm-3),  is specific heat (Jkg-1K-1)
and
is thermal conductivity (Wm-1K-1).
Surface temperature  is given as
 .
The boundary condition at the surface is given as follows.
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(A.56) |
where 
is the solar radiative flux at the surface (the sign of a downward flux is positive),
 is surface albedo,  is the net infrared radiative flux emitted from the surface
and
 is the sensible heat flux.
The sign of an upward flux is positive for
the net infrared radiative flux and the sensible heat flux.
The lower boundary of the ground is given as an insulation boundary.
The values of soil density, thermal conductivity and specific heat are
the same as those of the standard model of
Kieffer et al. (1977),
where
= 0.25,
= 1650 kgm-3,
= 588 JK-1kg-1,
= 7.63×10-2
JK-1m-1sec-1.
By using these values, the thermal inertia
 is 272
Wm-2sec1/2K-1 and the diurnal skin depth
 is about 8.2 cm, where
 is the length of day.
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