The SAIL BDRF function
sail_BDRF(w, lai, sumint, tsstoo, rsoil, rdd, tdd, tsd, rsd, tdo, rdo, tss,
too, rsod)
goemeric reflectance parameter
leaf area index
exp int
Bi-directional gap fraction
background reflectance
Bi-hemispherical reflectance over all in & outgoing directions (white-sky albedo).
Bi-hemispherical transmittance (diffuse transmittance in all directions)
Directional hemispherical transmittance for solar flux
Directional hemispherical reflectance for solar flux (diffuse solar angle)
Directional hemispherical transmittance (diffuse in viewing direction)
Directional hemispherical reflectance in viewing direction
Direct transmittance of solar flux
Direct transmittance in viewing direction
Multi scattering contribution
spectra matrixwith 4 reflectance factors and canopy transmission for wavelengths 400 to 2500nm:
[1] = bi-hemispherical reflectance (rddt). White-sky albedo: the reflectance of the canopy under diffuse illumination. The BRDF integrated over all viewing and illumination directions.
[2] = hemispherical directional reflectance (rsdt). Black-sky albedo: reflectance of a surface under direct light without a diffuse component. It is the integral of the BRDF over all viewing directions.
[3] = directional hemispherical reflectance (rdot). Diffuse reflectance in the vieweing direction.
[4] = bi-directional reflectance (rsot). The ratio of reflected radiance in the viewing direction to the incoming radiant flux in the solar direction.
[5] = Canopy transmission of diffuse light through the canopy (taud).
[6] = transmission of direct light through the canopy (taus).