Laser Sensing of a Subsurface Oceanic Layer. II. Polarization Characteristics of Signals.

In Part I of this paper we calculated depth profiles and polarization characteristics of airborne lidar return signals by the Monte Carlo method. Here we calculate the polarization characteristics of lidar return signals for different types of water. We demonstrate the feasibility of polarization lidar application to the detection of underwater inhomogeneities of different origins.

Laser sensing of a subsurface oceanic layer. I. Effect of the atmosphere and wind-driven sea waves.

Depth profiles and polarization characteristics of airborne lidar return signals have been calculated by the Monte Carlo method. We analyze some peculiarities of depth profiles of lidar return signals for a rough air-water interface. The distorting effect of the atmosphere on the lidar return signal structure is evaluated as a function of the geometry of the observations.

Polarization structure of lidar signals reflected from ice crystal clouds.

Polarization characteristics of signals of a monostatic lidar intended for sensing of homogeneous ice crystal clouds are calculated by the Monte Carlo method. Clouds are modeled as monodisperse ensembles of randomly oriented hexagonal ice crystals. The polarization state of multiply scattered lidar signal components is analyzed for different scattering orders depending on the crystal shapes and sizes as well as on the optical and geometrical conditions of observation.

Numerical evaluation of the possibilities of remote laser sensing of fish schools.

The operation of an airborne lidar intended for the detection of fish schools is numerically simulated by the Monte Carlo method. The calculations are performed for schools located at small depths in order to study the regularities in the shaping of the lidar return accurately. Three models of the phase function of scattering of laser radiation in sea water are used.

Mean characteristics of lidar signals from broken clouds.

The problem of the backscattered laser radiation field formation is solved based on the theory of optical radiation transfer in broken cloudiness as a scattering medium with random geometry. The dependence of the energy characteristics of a lidar return averaged over the ensemble of cloud-field realizations on the type of clouds (cumulus and stratus), cloud fraction, optogeometrical parameters of a cloud field, lidar's geometric parameters, and the distance to a cloudy layer. It has been shown that over long periods the multiple light scattering between the cumulus clouds is the dominating contribution to the lidar signal power.