Madronich, S. (2007). Analytic formula for the Clear-sky UV Index. Photochemistry And Photobiology, 83, 1537-1538. doi:10.1111/j.1751-1097.2007.00200.x
An approximate formula for the UV Index (UVI) under cloud-free, unpolluted, low surface albedo conditions is: UVI ~ 12.5µ₀²⁴²(Ω/300)⁻¹²³ where µ₀ is the cosine of the solar zenith angle and Ω is the total vertical ozone column (in Dobson Units, DU). The dependence on µ₀ and Ω is based on a simple... Show moreAn approximate formula for the UV Index (UVI) under cloud-free, unpolluted, low surface albedo conditions is: UVI ~ 12.5µ₀²⁴²(Ω/300)⁻¹²³ where µ₀ is the cosine of the solar zenith angle and Ω is the total vertical ozone column (in Dobson Units, DU). The dependence on µ₀ and Ω is based on a simple physical model of biologically weighted atmospheric transmission in the UV-B and UV-A spectral bands, with coefficients tuned to a detailed radiative transfer model, and is accurate to 10% or better over 060° and 200400 DU. Other factors (clouds, haze, ground, etc.) mostly conserve this dependence and scale simply. Show less
