Coherent light backscattering by refractive turbulence in lidar sounding of the atmosphere and the ocean

Theoretical analysis of light waves backscattering by a layer of random medium with weak refractive index fluctuations is presented, and some estimates for the effect contribution to lidar signals in atmospheric and ocean remote sounding are given. It is shown that coherent light backscattering by a thin turbulent layer may be strong enough compared with incoherent component caused by dispersed matter in the medium. For echo-signals registered in turbulent media, the effect in question is found to depend critically on lidar instrument function shape, in particular, on sounding pulse duration. That is why backscattering by turbulence does not affect noticeably the lidar systems employed in atmospheric and oceanographic investigations