Long-term near-ground optical scintillation measurements

A long-term measurement of the received-power fluctuations caused by atmospheric index-of-refraction turbulence in a near-ground optical free-space laser transmission experiment has been carried out over a eight-months period. Atmospheric index-of-refraction turbulence causes intensity variations in time and space (so called scintillations). These are recorded with differently sized receiver-telescopes, allowing for the calculation of diurnal, seasonal, and meteorological dependences in the received-power statistics. The purpose of this experiment was to gather data for the evaluation of atmospheric optical free-space transmission scenarios. This paper presents statistical evaluations of received-power fluctuations (scintillation-index, fades) over time-of-day and the season. Comparisons with the meteorological circumstances e.g. windspeed and temperature are made.