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Glossary P-S

Term Symbol Unit
photometric observer CIE standard    
photopic vision    
pixel    
radiance Le W/(m² sr)
radiant flux Φe W
Rayleigh atmosphere    
reflectance ρ 1
relative optical air mass m 1
root mean square deviation RMSD %
sky, CIE standard clear    
sky, CIE standard overcast    
sky, cloudy    
sky, intermediate    
sky, sunny    
skylight    
slope β degree
solar azimuth αs degree
solar constant 1367 W/m²
solar declination δs degree
solar elevation γs degree
solar hour angle ωs degree
solar hour angle at sunrise and sunset ωso degree
solar radiation    
solar zenith angle ξs degree
solid angle Ω steradian
spectral luminous efficiency v(λ) 1
steradian sr  
sun-earth distance correction factor r 1
sunlight    
sunshine duration S hour
sunshine duration, astronomical So hour
sunshine duration, possible Sor hour
sunshine duration, relative S/So 1