Impact of atmosphere on attenuation of free space optical links - Long term results from Milesovka observatory

The Institute of Atmospheric Physics Prague of the Czech Academy of Sciences operates an experimental dual-wavelength free space optical (FSO) link at the meteorological observatory Milesovka being 70 km north to Prague (837 m.a.s.l.). Relevant meteorological quantities attenuating the signal (meteorological visibility, rain rate, air temperature, air humidity and wind velocity vector) are also measured and sampled. In this paper there is the statistical behavior of atmospheric attenuation described. Some event analysis is added. Particular physical influences of fog, rain, atmospheric turbulences and sonic temperature on FSO attenuation are discussed.