The Light Environment of Plant Canopies
15.4. Using Eq. (15.25) and the coefficient values in the text for VIS and
NIR wavelength bands, plot the B W N and B W v as a function of
view zenith angle for the principal plane of the sun between nadir
and 60". The principal plane occurs when A A Z = 0 or A A Z = ~r .
The horizontal axis of the graph will go from zenith view angles of
-60" to +60° with positive view angles corresponding to A A Z = 0
and negative zenith view angles corresponding to A A Z = n . (with
LA1 = 2.6 and pk = 61"): for VIS a = 1.49, b = 0.32, and
c = 3.44,andNIRa = 9.09, b = 7.62,andc = 46.8(BRFin%
and angles in radians). Considering that A A Z = 0 corresponds to
having the sun behind the sensor and AAZ = TC corresponds to the
viewer looking toward the sun but downward at the canopy, explain
the shape of this curve.
15.4. Using Eq. (15.25) and the coefficient values in the text for VIS and
NIR wavelength bands, plot the B W N and B W v as a function of
view zenith angle for the principal plane of the sun between nadir
and 60". The principal plane occurs when A A Z = 0 or A A Z = ~r .
The horizontal axis of the graph will go from zenith view angles of
-60" to +60° with positive view angles corresponding to A A Z = 0
and negative zenith view angles corresponding to A A Z = n . (with
LA1 = 2.6 and pk = 61"): for VIS a = 1.49, b = 0.32, and
c = 3.44,andNIRa = 9.09, b = 7.62,andc = 46.8(BRFin%
and angles in radians). Considering that A A Z = 0 corresponds to
having the sun behind the sensor and AAZ = TC corresponds to the
viewer looking toward the sun but downward at the canopy, explain
the shape of this curve.