Intermittency of laser scintillation over sea

摘要

The intermittency in optical scintillation was theoretically studied and experimentally observed by laser propagation through the turbulent atmosphere over sea surface. It is found that the intermittent characteristics of the atmospheric turbulence repeat itself in optical irradiance fluctuations, then a method of the singularity measurement analysis was introduced and the intermittency index was presented to quantitatively evaluate the intermittency strength. Experiment results show that the intermittency index in laser scintillation is around 0.1 and varies a little compared with the significant variation of the turbulence strength, which had been approximately estimated at two orders of magnitude in a whole day. The dependence of the intermittency on the wavelength was further studied and the relationship was obtained using a multi-wavelength scintillometer. Generally, the intermittency indices display some differences at the different optical wavelengths, especially in strong turbulence. However, the wavelength dependence is not so notable that the intermittency indices are assumed to be equal within less than 10%, even the maximum error is no more than 20%. Moreover, some statistical results of the intermittency strength are also obtained from a long-term plan of laser propagating in coastal surroundings.