MODELING THE WATER BALANCE COMPONENTS OF THE SOYBEAN CANOPY BY SOIL-VEGETATIONATMOSPHERE TRANSFER MODEL - Soybean and Wheat Crops: Growth, Fertilization, and Yield - page 44

Figure 2. Schematic diagram of the Land-Air Parameterization Scheme (LAPS). The transfer pathways
for latent and sensible heat fluxes are shown on the left- and right-hand sides of the diagram,
respectively.

( )

= 2

T − T

H

f a

ρ c

(5)

f p

r

b

( )

T − T

g a

, (6) H = ρ c

g p

r

d

where T a is canopy air space temperature (K).
The latent and sensible heat fluxes from the soil and canopy combine to give the total
surface fluxes, which are transferred from the canopy air space to the reference height, z r and
are given by

( )

ρ c

e − e

p

(7) λ E + λ E =

a r

f g

r γ

a

( )

T − T

H + H = ρ c

, (8)

a r

f g p

r

a

where e r is vapor pressure at the reference height (mb), r a is aerodynamic resistance (s m -1 ),
and T r is air temperature at the reference height, z r (K). Substituting (3) through (8) into (1)
and (2) yields two differential equations for T f and T g . These are solved simultaneously using
a backwards implicit method.