Turbidity Factor

turbidity factor [tər′bid·əd·ē ‚fak·tər]

(geophysics)

A measure of the atmospheric transmission of incident solar radiation; ifI₀is the flux density of the solar beam just outside the earth's atmosphere,Ithe flux density measured at the earth's surface with the sun at a zenith distance which implies an optical air massm, andI_m,wthe intensity which would be observed at the earth's surface for a pure atmosphere containing 1 centimeter of precipitable water viewed through the given optical air mass, then turbidity factor θ is given by θ=(lnI₀-lnI)/(lnI₀-lnI_m,w).

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Turbidity Factor 

a quantitative characterization of the transparency of the atmosphere, which indicates the extent to which the transparency of the actual atmosphere under given conditions differs from the transparency of an ideal (ideally clean and absolutely dry) atmosphere. There are a number of turbidity factors. The most widely used is the Linke turbidity factor, T_m ═ in p_m/ln q_m, where p_m and q_m are the transmission coefficients of the actual and ideal atmospheres, respectively, with an atmospheric mass of m (a dimensionless quantity characterizing the atmospheric “mass” through which the beam passes).