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Isotropic Bihemispherical Reflectance (White Sky Albedo)

The bi-hemispherical reflectance is defined as the albedo of a target under isotropic diffuse illumination (i.e., the intensity of the incident radiation is independent on direction). It is also known as white-sky albedo, and can be calculated as $$BHR(2\pi,2\pi)=\int \int BRF(\theta_i,\phi_i,\theta_r,\theta_r)d\Omega_i d\Omega_r$$ where the projected solid angle [sr] is given in terms of zenith ($\theta$) and azimuth ($\phi$) angles by $d\Omega = \sin\theta \cos\theta d\theta d\phi$.
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
The reference plane
The reference plane.

Columns content

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

*: if available, otherwise set to −1.000000.

0.123456	-1.000000