Transmission and absorption of diffuse radiation is modelled using the method of Norman ([1979]), while the non-intercepted radiation reaching a canopy point is calculated in the sun direction for direct beam according to the hourly zenith and azimuth angles of the sun and of various azimuth and zenith directions for the diffuse sky radiation.
Gueymard, C. A. Parameterized transmittance model for direct beam and circumsolar spectral irradiance.
The models have the pseudo-spherical treatment of the direct beam attenuation.
The pattern we saw, if we had only every other one, was here the direct beam, first reflection, second reflection, third reflection, fourth reflection.
As the ratio of diffuse sunlight to direct beam sunlight increases, the rate of photosynthesis rises, and greater levels of biological productivity are favoured in the biosphere below.
These solar collectors thus captured the direct beam component of the solar radiation that predominates on sunny days.
Ray tracing diagrams are presented to study the direct beam propagation, refracted rays and total reflection rays.
This simulator will be a virtual beam diagnostic tool which is especially useful when direct beam measurements are not available.
For the proposed configuration (Fig. 1c), the direct-solar irradiation, including the direct beam and circumsolar components, is rejected by the reflector and never reaches the emitter, that is Psolar-direct = 0.
The incident solar irradiation comprises direct beam and circumsolar radiation emanating from the solar disk, equivalent to a solid angle of 6.87 × 10−5 steradians (about 0.5° planar angle), and isotropic diffuse-solar radiation36.
Holographic optical elements (HOE) can be used to reflect the direct (beam) sunlight incident on a window whilst allowing the diffuse light to pass through.
