A Satellite-Based Sky Luminance Model for the Tropics

Figure 4

The partition of the sky in concentric zones around the zenith or concentric zones of 𝑍 indicated by 𝑍_𝑖(𝑖=1,…,17) and concentric zones around the sun or concentric zones of 𝜒 indicated by 𝜒_𝑗(𝑗=1,…,30).