<title>Theoretical model for backscattered pulse kinetics and interpretation of some anomalies in lidar remote sensing data</title>

Abstract

A new theoretical approach is suggested for the problem of backscattered light signal kinetics under the pulsed illumination of sea water column. The developed model uses the small-angle-scattering approximation for the sounding and backscattered light beams and takes into account the angular anisotropy of volume scattering function (VSF) in the back hemisphere. The predictions of the theory are supported by the results oflaboratory experiments with model scattering media.On the base of the model, an interpretation is proposed for some anomalies in the shape of lidar signals registered in airborne sounding experiments. The interpretation of the effect of "enhanced backscattering" from separate sea water layers is shown to be consistent with the recent unique measurements of VSF in the vicinity of 1800 and revealed fine structure of vertical profiles of the backscattering coefficient.The physical nature of the effect is discussed. The recently obtained theoretical results allows to suppose that, along with high concentration oflarge biological particles, coherent light backscattering by refractive turbulence in the corresponding water layers may be the cause of enhanced echo-signals from isolated depth levels.