Evaluation of met-ocean forecast data effectiveness for tracking drifters deployed during operational oil spill response in Australian waters

Pollution of the marine environment from hydrocarbon spills is a potential environmental issue with many incidents being reported in recent times. The need for a better understanding of the ocean circulation for spill predictions is essential so that correct response actions can be implemented to minimise environmental damage. There are currently several ocean current models available in the Australian region. This study was aimed at investigating which forecast currents work best when tracking surface drifters deployed during operational oil spill response. The track of a drifter deployed during the Montara well release in the Timor Sea (October 2009) was modelled using six different current models including BLUElink, FOAM, GSLA, HYCOM, NCOM and NLOM. Wind forcing was also required to simulate the track of the drifter and was provided by two wind forecast models, GFS and NOGAPS. Therefore, an ensemble of 12 different model forcing combinations were possible. The NCOM current model with NOGAPS winds produced the best result with an absolute error of 7.19 km after 120 hours (5 days); however NCOM currents with GFS winds tended to more closely predict the track throughout the entire simulation, although the error at the end of the simulation was slightly higher at 11.51 km.