Simulation of Oil Spills Near a Tropical Island in the Equatorial Southwest Atlantic

Abstract

In this work we coupled the Ocean Modelling System - ROMS Regional Oceanic Circulation model with the MEDSLIK-II hydrocarbon dispersion model to simulate the evolution of accidental oil spills from tankers that travel near the Fernando de Noronha Archipelago in the tropical Southwest Atlantic. Six scenarios were evaluated, consisting of three spill positions on the eastern side of the Archipelago and two months (March and July). The results show that the predominance of advective forcings would tend to counteract the oil degradation processes and shorten the time window for possible mitigation actions. The worst scenario occurred in March with the plume reaching the island within 48 hours with 2.3% of the initial volume (1350 tonnes) adhering to the shore. The affected region is part of the Fernando de Noronha Marine National Park area. We propose the delimitation of a region between 3°41.9'S and 03°57'S and ~62 km perpendicular from the eastern limit of the FNA, restrictive to tanker traffic to increase the time window response in case of an oil spill.Keywords: Semi-lagrangian model, ROMS, MEDSLIK-II, Fernando de Noronha Archipelago, Oil wheathering.

Avaliação do impacto da hidrodinâmica associada a um derramamento de óleo na Bacia de Cumuruxatiba (BA) com base no modelo MEDSLIK-II

“…Our results show that, in the winter months, the meridional BC transport are lower, enabling the spills that occurred to west of the EEZ, are transported by wind and ocean zonal component to the coast, with speeds greater than 0,5 m.s -1 . According to Queiroz et al (2019), the weathering of oil in the ocean tends to reduce the risk in the tropical region, but the high speed of oil transport reduces the time window for possible mitigation actions.…”

“…ROMS coupling with MEDSLIK-II is performed by Python routines. These new routines are necessary to recognize the ROMS output files (in netCDF format), as input of the forces of sea surface temperature, currents and winds, as described by Queiroz et al (2019). The MEDSLIK-II parameterization is done through source code files and secondary codes (medslik_II.sh, Extract_II.for e medslik_II.for).…”