Predicting the Aerial Application of Dispersant Onto an Oil Spill

The release of dispersant from an aircraft onto an oil spill is simulated using the AGDISPpro computer model, to develop a better understanding of how aircraft type, spray systems, and meteorological conditions affect the prediction of surface deposition. This model, originally developed for predicting the aerial release of pesticides for agricultural spray applications, is ideally suited to simulate the effects of aircraft type and flight condition/configuration, spray system arrangement, wind speed and direction, temperature and relative humidity (evaporation), release height, and spray application rate when spraying an oil spill. Predictions of droplet trajectories from the aircraft to the surface, drop size distributions at the release height, and deposition profiles are compared to two historical datasets for the Lockheed C-130, from field studies conducted in 1982 and 1993. This article shows that model accuracy improves from R2 = 0.411 to 0.827 with the earlier data, to R2 = 0.885 to 0.968 with the later data, most probably because of a better understanding of nozzle locations in the 1993 data. Model accuracy also appears improved when the aircraft flies in an in-wind direction, a configuration strongly recommended in the available literature.