Presentation
The Evaluation of Remote Sensing Methods to Determine Oil Slick Thickness
DescriptionThe characterization of the degree and extent of surface oil during and after an oil spill is a critical part of emergency response and Natural Resource Damage Assessment (NRDA) activities. More specifically, understanding floating oil thickness in real-time can guide response efforts by directing limited assets to priority cleanup areas; aid in thickness estimates; enhance fate, transport, and effects modeling capabilities; and support natural resource injury determinations. Several types of in situ and remote oil characterization tools are used to assess floating oil thickness. Several sensors were evaluated by the Coastal Response Research Center (CRRC) and National Oceanic and Atmospheric Administration (NOAA) to assess their accuracy and precision and detection capabilities using funding provided by the Canadian Multi-Partner Research Initiative (CAMPRI). The procedure developed by CRRC allowed for production of controlled and repeatable oil slicks on water ranging from 1 – 5,000 µm within a laboratory setting in a stainless steel tank. Materials and water chemical compositions, air movement, the presence of particulate matter, corrosion, and distribution of the oil onto the water’s surface were the main conditions that affected the uniform spreading of the oil. Various light forms were used for illumination. An overhead UV camera produced calibrated images that yielded a nominal average thickness. Multispectral and thermal sensors, a radiometer, sorbent pads, dip plates, an HD visible light camera sensor (ROSV), tube sampler, photometer, and acoustic thickness sensor were evaluated. Operators were not told the thickness of the slicks, but were given a sample of the oil used. The time for operators to process and report thickness was noted and compared to typical operational timeframes during a response. A factor difference (FD) was calculated for each reported thickness. The dip plates and ROSV consistently gave slick thicknesses 4.0 times different than the thickness delivered over the entire range evaluated. At thicknesses of 500 and 1,000 μm, the sorbent pads also had a large negative FD, underestimating the thickness. The remaining sensors (acoustic, multispectral, tube sampler, radiometer, photometer) estimated slick thickness with FDs of |>1.0 to 3.0|, either under- or overestimating the nominal value. The testing protocols that were developed as part of the project are reproducible and can be used for future testing and sensor/sampler validation, to evaluate different oils or other products, and to help train other operators with sensor packages to characterize oil. Evaluations will continue of other sensors and at a newly developed outdoor facility.
Event Type
Paper
TimeTuesday, May 14th1:50pm - 2:10pm CDT
Location278-280
Prevention