Predicting Surface Oil Transport in California Using a High-Resolution Regional Ocean Modeling System (ROMS) and the National Oceanic and Atmospheric Administration's (NOAA's) Trajectory Analysis Planner (TAP)

Abstract

The Bureau of Ocean Energy Management (BOEM) and Bureau of Safety and Environmental Enforcement (BSEE) Pacific Region conduct oil spill risk analyses to determine potential impacts to environmental resources. Oil spill trajectory modeling is conducted to predict the movement and fate of spilled oil, if a spill occurred, from existing offshore oil and gas operations in southern California. To improve BOEM and BSEE Pacific Region's ability to conduct oil spill risk analyses for southern California, BOEM partnered with the University of California, Los Angeles (UCLA) to run a multi-year hind cast (re-analysis) of winds, waves, and currents along the coast of California. UCLA created a high-resolution (1 km) ROMS hind cast for the 10 year period 2004–2013 from Morro Bay, California to the border with Mexico. The project was conducted in three phases: (1) Surface winds were calculated at high horizontal and temporal resolution and validated using existing datasets; (2) A wave model was forced by the wind model results and validated through in situ measurements; and (3) The ocean model was run at high resolution and includes temperature, salinity, and currents; it assimilated in situ data and was forced by the hind cast atmospheric model results. BOEM is subsequently partnering with NOAA, to utilize the surface currents and winds from the ROMS hind cast analysis with NOAA's General NOAA Operational Modeling Environment (GNOME) to produce multiple trajectories for NOAA's TAP. Using realistic oil spill scenarios over a range of different regional oceanographic regimes (such as upwelling, relaxation, and eddy-driven flow), TAP will calculate the probabilities of oil contacting parcels of water and shoreline were any oil to spill from southern California oil platforms. This will enable analysts to understand where an oil spill may travel, how long it could take to get there, and the likelihood of spilled oil contacting their resource area. An online TAP viewer with the GNOME-generated data from this study will be publicly available along with the ROMS hind cast data for oil spill response planning along with other oceanographic modeling needs.