Lidar Measurements of Ocean Optical Properties in Tank Tests and Coastal Water With Model Simulation Closure

Christopher Michael Strait, Harbor Branch Oceanographic Institute, Fort Pierce, United States, Michael S Twardowski, Harbor Branch Oceanographic Institute, Ft. Pierce, United States, Fraser Dalgleish, Florida Atlantic University, Harbor Branch Oceanographic Institute, Fort Pierce, FL, United States, Alberto Tonizzo, Sunstone Scientific LLC, Fort Pierce, FL, United States and Anni KAISA Vuorenkoski, Florida Atlantic University-HBOI, United States
The optical properties of seawater are directly related to its biogeochemical constituents and can thus be used to study the productivity and health of marine ecosystems. Range-gated lidar systems have strong potential as a tool for remotely profiling water column optical properties rapidly, while underway, without disturbing particle fields. Moving the system from above water to underwater has the advantages of finer spatial resolution and not having signal losses from large scattered returns at the air-sea interface. Such a system can be deployed on vessels and underwater platforms.

A dual wavelength, monostatic underwater profiling lidar system has been developed at Harbor Branch that has now been rigorously characterized in laboratory tank tests and the field. Lidar performance has additionally been simulated through Monte-Carlo modeling. Tank tests were conducted to demonstrate closure between measurements and modeling for two carefully characterized particle fields with significantly different scattering properties. Measurements were also made off the coast of Florida along with water column optical property measurements to assess closure with simulations. Relationships between lidar data and in water optical properties is assessed for all measurements and for simulated optical property data for a wide range of water types. Results show good closure and the potential of lidar as a next generation tool in oceanography.