Inverse problems of lidar sensing of the ocean

We consider the inverse problems in the retrieval of the water's inherent optical properties (IOP) and the properties of the hydro-physical processes taking place in a water body using the returned signal of an oceanic lidar. An algorithm for the retrieval of the depth distributions of IOPs from a lidar signal was developed using correlations between IOPs in the middle of the visual spectrum. Our algorithm gives simple equations for the attenuation coefficient's depth profile using narrow and wide lidar receiving angles. We also show how to find this profile for an arbitrary lidar receiving angle. Analysis of the algorithm's accuracy demonstrated that the probabilistic nature of the correlations between IOPs produces large errors in the retrieved lOPs. These errors increase with the optical depth of the sensed layer. The suggested adaptive algorithm improves retrieval accuracy by processing the lidar signal itself. It is shown how a two-channel lidar with specific directivity diagrams can be used to well-determine one water optical property, and then find the other TOPs with correlations. We also consider the possibility of detecting hydro-physical processes in water by the example of lidar images of internal waves.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.