<title>Lidars for oceanological research: criteria for comparison, main limitations, perspectives</title>

Abstract

The paper contains a comparative analysis and discussion of resultant recommendations for the optimization of an airborne lidar's parameters, with application to modern lidar systems as employed in various countries for the Ocean and continental shelf research. As criteria for the systems comparison in different remote sensing conditions ( aircraft altitude, depth, day/night, zenithal sun angle, sea-water attenuation coefficient, receiver optical system's field of view (FOV), laser wavelength, etc.) Sakitt's D-index of discriminability is used. We demonstrate the optical signal, as determined by the following process: reflecting from boundary -backscattering in the atmospheresecondary reflecting from boundary, to be the cause for limiting the distance of underwater measurements. Some estimates for the bottom depth values to be achieved by a "super-lidar" are presented.

Wa-LiD: A New LiDAR Simulator for Waters

“…This model is similar to other Hydrographic LiDAR models (e.g., [5], [6], [7]) except it integrates radiative transfer laws governed by the physical properties of water for any wavelength. This simulation model uses a geometrical representation of the water surface with the geometric model of Cook and Torrance [11] and integrates both the characteristics of detection noise and signal level due to solar radiation.…”

“…Before now, few studies have been published that model LiDAR waveforms on water; these studies include (i) the simulation model of Mclean [10], which generates LiDAR returned waveforms from a wind-roughened ocean, (ii) the work of Feigels [6] on the optimisation of airborne LiDAR's parameters through modelling and analysing waveforms and (iii) work on modelling sea surface return and laser bathymetry from airborne LiDAR [7].…”

Sea floor classification from airborne lidar data

“…The bottom pulse peak power is approximately proportional to 1/H 2 according to basic lidar equations. 10,19,28 Additionally, an increased flight altitude while preserving the lidar FOV-angle, can cause a widening of the bottom pulse due to an increased geometrical pulse path length. 25 The water volume and water surface between the sensor and the sea floor require that accurate corrections are applied for correct sea floor classifications.…”

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

“…With the help of the optical reciprocity theorem 27,28 formula (8) may be rewritten in the form 24 P(t)=fd3rfd2kifdt1 QT(r, -k, t')L(r, k, t-t')= (9) _afd3Jd2k±Jd2ki±JdliL(r k, t-l')L(r, k, () 13_(kk') with Q from (7) and forward-propagating radiance field L, caused by "fictitious" radiation source with the spatial, angular and temporal characteristics just equal to those of lidar receiver. Assuming the receiver FOV to be sufficiently narrow to ensure the applicability of the small-angle approximation for radiance L, the latter may be divided into the two components, L and L,, analogous to Then L is the solution for problem (4) with the boundary condition L(r1, k, t') I Z-Zo = Lo(r1, k, t')I =z, k 1, and L, satisfies equation (5) with L instead of L. So, fmally, we derive Note that due to the approximation used to come to expression (12), the dependence of an optically contrast layer detectability on lidar system FOV is neglected.…”