Oil Spill Trajectories: How NOAA Predicts Where Spilled Oil Will Go

When oil spills, the first question is where it will go. The answer decides where responders put containment boom to protect the shore, where they stage cleanup equipment, and which areas they close to fishing and boating. An oil spill trajectory is the map that answers it: where the spilled oil is likely to travel, how soon it may arrive, and which shorelines and environmentally or culturally sensitive places are at risk.

The model behind the map

NOAA oceanographers predict the movement of spilled oil on the water's surface with specialized computer models. Trajectory maps are made with a NOAA-developed model called GNOME (General NOAA Operational Modeling Environment), which forecasts how currents, winds and other physical processes will move oil in the ocean — and how weather, wind, tides and currents affect it.

Updated every day

Nature makes the job hard: wind, weather and currents vary in ways that can change a spill's path unpredictably. So during a spill, the model is updated daily with field observations, aerial surveys and new forecasts of currents and winds. Aircraft and field teams watch the actual course and spread of the oil, and those observations feed back into the model to improve the next forecast.

The uncertainty boundary

Along with the locations of oil, and oil that may reach shore, a trajectory map includes an uncertainty boundary showing other places the oil could be. It accounts for differences between models and for changes in currents and winds. NOAA continues to refine both established and emerging techniques in oil spill science.

Sources

Based on "What is an oil spill trajectory?" from NOAA's National Ocean Service, a work of the United States government in the public domain.