晴天散射辐照度D是大气质量m和大气透明度×的函数,即D(m,x)=φ(m)ψ(x)。函数φ(m)的数学表达式见文献^[1],本文旨在建立函数ψ(x)的数学表达式。

The fine scattered irradiance D is the function of air mass m and atmospheric transparency x, its general formula is D(m,x)=φ(m)ψ(x).We have established the mathematical formula of φ(m)before, the mathematical formula of ψ(x)will be established in this paper.Using two components of Linke turbidity factor T, i.e.wet turbidity factor W, and the rest turbidity factor R as the characteristics of transparency, the mathematical formula ψ(x)=a +bW₂ +cR₂ has been obtained (W₂ and R₂ are the values of W and R when m=2, respectively).The values of empirical constants a, b and c are different with the places.