Simulating oil droplet dispersal from the Deepwater Horizon spill with a Lagrangian approach

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Abstract

An analytical multiphase plume model, combined with time-varying flow and hydrographic fields generated by the 3-D South Atlantic Bight and Gulf of Mexico model (SABGOM) hydrodynamic model, were used as input to a Lagrangian transport model (LTRANS), to simulate transport of oil droplets dispersed at depth from the recent Deepwater Horizon MC 252 oil spill. The plume model predicts a stratification-dominated near field, in which small oil droplets detrain from the central plume containing faster rising large oil droplets and gas bubbles and become trapped by density stratification. Simulated intrusion (trap) heights of ∼ 310–370 m agree well with the midrange of conductivity-temperature-depth observations, though the simulated variation in trap height was lower than observed, presumably in part due to unresolved variability in source composition (percentage oil versus gas) and location (multiple leaks during first half of spill). Simulated droplet trajectories by the SABGOM-LTRANS modeling system showed that droplets with diameters between 10 and 50 μm formed a distinct subsurface plume, which was transported horizontally and remained in the subsurface for >1 month. In contrast, droplets with diameters ≥90 μm rose rapidly to the surface. Simulated trajectories of droplets ≤50 μm in diameter were found to be consistent with field observations of a southwest-tending subsurface plume in late June 2010 reported by Camilli et al. [2010]. Model results suggest that the subsurface plume looped around to the east, with potential subsurface oil transport to the northeast and southeast. Ongoing work is focusing on adding degradation processes to the model to constrain droplet dispersal.

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Publication type Book chapter
Publication Subtype Book Chapter
Title Simulating oil droplet dispersal from the Deepwater Horizon spill with a Lagrangian approach
DOI 10.1029/2011GM001102
Volume 195
Year Published 2011
Language English
Publisher American Geophysical Union
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 10 p.
Larger Work Type Book
Larger Work Subtype Other Government Series
Larger Work Title Monitoring and modeling the Deepwater Horizon oil spill: A record-breaking enterprise
First page 217
Last page 226
Country United States
Other Geospatial Gulf Of Mexico
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