Presentation
Aerial Quantification of Oil – Comparing Oil Categories with BAOAC Using National Aerial Surveillance Program (NASP) Data
DescriptionThe primary mandate of the National Aerial Surveillance Program (NASP) is to monitor Canadian waters for marine pollution. The NASP aircraft are equipped with a suite of remote sensors optimized to detect, document, and report oil spills, including an estimated volume for each incident observed. As there are currently no sensors operationally deployed in Canada that measure the actual thickness of oil on water, oil volume estimates are determined using the thickness appearance relationship. NASP surveillance officers are trained to assess the visual appearance of the oil and assign thickness values according to the Canadian Coast Guard (CCG) Oil Categories. This six-category system, which has a maximum thickness value of 3µm, provides a single, conservative estimate of oil volume. Many other countries use a different coding system: the Bonn Agreement Oil Appearance Code (BAOAC), a five-code system, with minimum and maximum thickness values for each code except the thickest code assigned a value of 200µm yielding a range of oil volumes. This paper uses historic NASP data to compare spill volumes calculated using both the Oil Categories and BAOAC. It also highlights the use of the NASP infrared (IR) sensor to support the visual identification of the thicker parts of spills that currently contradicts the assigned thickness value from the Oil Categories. This analysis found that most spills (82%) observed by the NASP contain only light sheen and rainbow (i.e., Categories A-D), and for those spills the volumes from both Oil Categories and BAOAC minimal volumes are well aligned. For the remaining spills when thicker oil is present, the factor differences of the volumes can be large, which is expected when assigning a greater thickness value. From this analysis and much discussion, on April 1, 2024 the NASP will switch to quantifying oil volumes using the common international standard Bonn Agreement Oil Appearance Code thereby aligning aerial quantifications with the on-board remote sensors.
Event Type
Paper
TimeThursday, May 16th10:00am - 10:20am CDT
Location298-299
Remediation