A revised study of the validity of the general junge relationship at solar wavelengths: Application to vertical atmospheric aerosol layer studies

The relationship between the Junge aerosol size parameter and the α Ångström turbidity parameter, known as the Junge relationship v = α+2, is commonly applied in aerosol studies. However, this relationship involves some approximations, therefore here the v−α relationship is established generally. A thorough analysis has been carried out taking into account the sensitivity and features of the Junge function on particle radius and wavelengths by means of the volume extinction coefficient and its cumulative values. Hence, the relationship v−α is analysed to (a) extend its validity to solar wavelengths; (b) incorporate new particle radius intervals [r1−r2] and (c) analyse the influence of the particle refractive index. As a consequence the applicability and limitations of the linear Junge relationship v = α+2 become apparent. The results show that the relationship between the v and the α parameters in the visible range can extend its validity in the whole solar range if the volume extinction coefficient shows a linear behaviour throughout this range. Curvatures of the extinction coefficient for particle size distribution functions with an upper limit of 1 μm or lower limit of 0.1 μm have been observed. However, due to these features dependence on the Junge values, these are irrelevant when they are applied to real cases of atmospheric turbidity.