US: Fluorescent optical ranging systems can rapidly assess and map concentrations of marine oil pollution suspended in the top few meters below the water surface, according to an article, Submerged-oil tracking by airborne hyperspectral fluorescent lidar. The article is authored by Sergey M. Babichenko, Doug Beynon and Kevin O’Neill. It was published in SPIE.
The article observes that although numerous remote-sensing systems recently reported on the scope of the BP oil spill in the Gulf of Mexico, there was an obvious lack of detection capability for certain submerged-oil types that occurred after spill weathering and dispersant use. Undetectable movement of ‘hidden oil’ near the surface stymied skimming task forces and caused unpredictable oil sedimentation onshore. Hyperspectral fluorescent-LiDAR-system (FLS)-series light detection and ranging (LiDAR) devices, which are based on laser-induced fluorescence (LIF) combined with spectral-fluorescence-signature (SFS) analysis, are capable of providing such detection, while expert-system advances now support near-real-time map updates for incident responders.
FLS comprises an expert system, a GPS receiver, a rangefinder, and a digital camera. GPS coordinates and metadata accompany every recorded LIF spectrum. Rangefinder information is used to calculate laser-spot positions and correct the intensity of LIF spectra as a function of altitude. Significant oil detections trigger real-time alarms and digital location photography. External devices may include inertial measurement units, parallel data storage, visualization displays, and communication channels.
The ability of airborne FLS LiDAR to detect and map subsurface oil can greatly expand oil mitigation and recovery options available to spill-response teams by directing them in near real-time to identified concentrations not detectable by other means on reasonable timescales. The sensor platform is portable and can be deployed in any number of aircraft types, either alone or in combination with other systems. Further FLS LiDAR development will address enhancement of in-flight data processing and real-time reporting to the ground data centres.