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Isotropic Bihemispherical Reflectance (White Sky Albedo)

The isotropic bi-hemispherical reflectance is defined as the albedo of a target that is illuminated in a spatially-uniform manner at the top-of-canopy level by an isotropic diffuse light source, i.e., the intensity of the incident radiation is independent of direction. Based on these illumination conditions, the bhr_iso can then be said to be equal to:

where the projected solid angle [sr] is given in terms of zenith (θ) and azimuth (ϕ) angle by:

Notice that within RAMI all incident and exiting radiation has to pass through a (virtual) planar reference surface of specified lateral dimension and elevation above the target, and oriented perpendicular to the underlying surface normal.

Isotropic diffuse
Isotropic diffuse

Columns content

Content Format
isotropic bihemispherical reflectance %.6f
standard deviation of bhr_iso estimate* %.6f

*: if available, otherwise set to −1.000000.

0.123456	-1.000000