Increased dispersion of oil from a deep water seabed release by energetic mesoscale eddies. (July 2020)

• Record Type: Journal Article
• Authors: Gilchrist, Ryan M.; Hall, Rob A.; Bacon, John C.; Rees, Jon M.; Graham, Jennifer A.
• Is Part Of: Marine pollution bulletin. Volume 156(2020)
• Publication Date: 2020-07
• Subjects: Deep water oil spills -- Oil dispersion -- Mesoscale eddies -- Model resolution -- Faroe-Shetland Channel -- North Atlantic; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2020.111258
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Hydrodynamics play a critical role in determining the trajectory of an oil spill. Currents, stratification and mesoscale processes all contribute to how a spill behaves. Using an industry‑leading oil spill model, we compare forecasts of oil dispersion when forced with two different hydrodynamic models of the North-West European Shelf (7 km and 1.5 km horizontal resolution). This demonstrates how the trajectory of a deep water (>1000 m) release in the central Faroe-Shetland Channel is influenced by explicitly resolving mesoscale processes. The finer resolution hydrodynamic model dramatically enhances the horizontal dispersion of oil and transports pollutant further afield. This is a consequence of higher mesoscale variability. Stratification influences the depth of subsurface plume trapping and subsequently the far-field transport of oil. These results demonstrate that the choice of hydrodynamic model resolution is crucial when designing particle tracking or tracer release experiments. Graphical abstract: Unlabelled Image Highlights: An oil spill is simulated in the deep Faroe-Shetland Channel, forced by hydrodynamic models with different resolutions. Explicitly resolving mesoscale eddies leads to dramatically increased pollutant dispersion at and below the surface. A change in stratification leads to differences in subsurface plume trapping depth and subsequent far-field transport.