The Light Environment of Plant Canopies
needed:
1 - exp [-(0.5 + 1.0)2.0]
L*, =
= 0.633
0.5 + 1.0
Term 1 = 0.48 x 310 x 0.633 x 0.5 = 47 W m-2
Term 2 = Pe,h [I - exp(-Kb,(O)Lr) - L*, K ~ ~ ( o ) ]
-
Qst, = E + z = 1 8 + 6 2 = 8 0 ~ m - ~
Term 2 = 0.48 x 80 [l - exp(-0.5 x 2.0) - 0.633 x 0.51
= 12 W mP2
Term 3 = ~s(Qbr + Qd) exp(-Kbe(O)Lt)
Qbt(60) = 230 exp -z/i104 X 1.0 X 2.0 = 230 X 0.67
[
= 154 w mP2
I
Term 3 = 0.15 x (154 + 15) exp(-0.5 x 2.0) = 9 W m-2.
Therefore QView(60) = 47 + 12 + 9 = 68 W m-2 so that BRFN =
- = 0.27. If we had used the more precise Eq. (15.1 1) instead of
Eq. (15.6), then BRFN = 0.32 instead of 0.27.