Laser remote sensing of aquatic environment: first- and second-order scattering model.

Transport of a small divergent (of several millirads) laser beam in shallow waters has been investigated. A simple model was developed to describe and calculate the first- and second-order power and energy flux. From evaluation of the truncation error the applicability of the second-order approach for clear waters is concluded. On the other hand, turbid waters can be treated by introducing an effective beam attenuation coefficient. The computations were performed for different geometrical configurations of a lidar system and for diverse aquatic conditions. Finally, an alternative method for remote sensing of the concentration of particulate material by an airborne lidar instrument is proposed by using off-axis detection.