New article: Measurement and modeling of oil slick transport
The paper “Measurement and modeling of oil slick transport” by Cathleen E. Jones, Knut-Frode Dagestad, Øyvind Breivik, Benjamin Holt, Johannes Röhrs, Kai Håkon Christensen, Martine Espeseth, Camilla Brekke, and Stine Skrunes, made the front page of Journal of Geophysical Research Oceans, in its latest issue in October 2016.
Transport characteristics of oil slicks are reported from a controlled release experiment conducted in the North Sea in June 2015, during which mineral oil emulsions of different volumetric oil fractions and a look-alike biogenic oil were released and allowed to develop naturally. The experiment used the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) to track slick location, size, and shape for ∼8 h following release. Wind conditions during the exercise were at the high end of the range considered suitable for radar-based slick detection, but the slicks were easily detectable in all images acquired by the low noise, L-band imaging radar. The measurements are used to constrain the entrainment length and representative droplet radii for oil elements in simulations generated using the OpenOil advanced oil drift model. Simultaneously released drifters provide near-surface current estimates for the single biogenic release and one emulsion release, and are used to test model sensitivity to upper ocean currents and mixing. Results of the modeling reveal a distinct difference between the transport of the biogenic oil and the mineral oil emulsion, in particular in the vertical direction, with faster and deeper entrainment of significantly smaller droplets of the biogenic oil. The difference in depth profiles for the two types of oils is substantial, with most of the biogenic oil residing below depths of 10 m, compared to the majority of the emulsion remaining above 10 m depth. This difference was key to fitting the observed evolution of the two different types of slicks.
Jones, C.E., Dagestad, K.-F., Breivik, Ø., Holt, B., Röhrs, J., Christensen, K.H., Espeseth, M.M., Brekke, C., Skrunes, S. (2016): Measurement and modeling of oil slick transport. Journal of Geophysical Research – Oceans, Volume 121, Issue 10, October 2016, Pages 7759–7775. DOI: 10.1002/2016JC012113.
Cover text from JGR Oceans: Jones et al. [DOI: 10.1002/2016JC012113] refined an advanced oil drift model based on measurements of the transport and spreading of mineral and plant oil slicks detected with SAR during an oil spill exercise in the North Sea. The experiment used a series of 22 NASA UAVSAR images acquired over an 8-hr period starting shortly after release. Photos show the released mineral oil emulsions with oil-to water ratio of 60:40 (top) and 80:20 (middle) and the general sea state during the experiment (bottom). The study determined that in high wind conditions the plant oil was entrained into the vertical water column a factor of ten more rapidly and mixed more deeply than the mineral oil (proxy for oil spill), providing a reservoir of resurfacing oil. [Photo credit: Øyvind Breivik and the Norwegian Clean Seas Association for Operating Companies]. See pages 7759–7775.
The full journal can be viewed here: http://onlinelibrary.wiley.com/doi/10.1002/jgrc.21410/epdf