Estimation of fog drop size distribution based on meteorological measurement

Exact modelling of free space optical link attenuation require information about current drop size distribution (DSD) of fog. Modified gamma distribution with three parameters is widely used to express the shape of fog DSD. ITU-R recommendation specifies two sets of the parameters according to two typical fog cases, heavy advection and moderate radiation fog. Some studies also estimate two parameters of the gamma distribution when the value of the third parameter is fixed. This study shows method for estimation of all the three parameters which are determined on basis of liquid water content, particle surface area and visibility. Method is implemented on real data measured at a mountain observatory.