Study of Gulf Coast Deepwater spill site reveals key to tracking pollutants
Results from a new study of ocean circulation patterns at the site of the Deepwater Horizon oil spill have revealed the large role that small-scale ocean currents play in the spread of pollutants, providing new information to help predict movements of oil and other pollutants in the ocean.
MIAMI, FL, Aug. 18, 2014 -- Results from a new study of ocean circulation patterns at the site of the Deepwater Horizon oil spill, which occurred in the Gulf of Mexico in April of 2010, have revealed the significant role that small-scale ocean currents play in the spread of pollutants. Further, these findings provide new information to help predict the movements of oil and other pollutants in the ocean.
Nearly two years after the Deepwater Horizon incident, scientists from the Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE), based at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, conducted a drifter experiment in the northern Gulf of Mexico spill site to study small-scale ocean currents ranging from 100 meters to 100 kilometers.
"Our results conclusively show that ocean flows at small scales (below 10 kilometers) contain significant energy fluctuations to control the initial spread of pollutant clouds," said UM Rosenstiel School Professor and CARTHE Director Tamay Özgökmen. "Now that we have quantified this missing piece of the puzzle, we can improve our real-time predictive capabilities in the event of a future oil spill."
During the 12-day at-sea experiment called GLAD (Grand Lagrangian Deployment), the research team deployed 300 GPS-equipped custom drifters off the UM Rosenstiel School research vessel F.G. Walton Smith in a region where wind-driven continental shelf currents mix with buoyancy-driven Mississippi River outflow currents and deep eddy-driven currents in the Gulf of Mexico.
The drifters flowed along the Gulf of Mexico currents for several months after deployment to capture a multi-dimensional picture of the upper-ocean movements in the presence of wind and waves at DeSoto Canyon, the site of the Deepwater Horizon oil spill. This was the first experiment to deploy so many drifters at once. Data about their whereabouts was retrieved every 5 minutes.
The study, aimed at quantifying the small-scale circulation that cannot be captured by satellite-based altimeter measurements or general circulation models, has immediate practical applications to help better predict the path of catastrophic pollutant events, such as from future oil spills or nuclear disaster events. The results provide new information about the significant dispersion patterns currently unaccounted for in ocean circulation models, according to the authors.