An oil slick was spotted on Friday noon off Corsica.
Presumably the result of a wild degassing, it approached the Corsican coast on Saturday before moving away due to the climatic conditions.
The authorities have deployed significant resources to try to recover these hydrocarbons and contain this pollution.
The race against the clock is on as the oil slick is breaking up, now located in the south-east of Corsica. Mobilizing significant resources, the authorities have already succeeded in recovering three to four tonnes of this marine pollution, originally divided into two slicks with a length of approximately 35 kilometers. A part, on the other hand, will continue to drift with the winds and currents, but in which direction? Can residues reach Marseille, as happened in 2018, after a collision between two ships off Cap Corse?
“From a strictly theoretical point of view, notes Isabelle Taupier-Letage, researcher at the Mediterranean Institute of Oceanology (MIO) and specialist in marine and atmospheric circulation of the Mediterranean, the water located along the east coast of Corsica goes north.
It joins the Gulf of Genoa, then the Provençal coasts and forms the northern current, which passes in front of Marseille, ”she explains.
“Finally, it is on average, because otherwise it would be too easy, she adds, there are vortices that can delay or deviate this average trajectory”.
A very improbable hypothesis
Between theoretical average and practical reality, such forecasts actually seem quite hazardous, especially since hydrocarbons do not behave like the rest of the body of water.
A "slick of hydrocarbons, which is on the surface, will drift more with the wind than with the currents", adds the oceanologist, known in particular for having led in 2011 an expedition on the scientific sailboat Tara. "The system for forecasting the evolution of oil slicks is made up of two parts: on the one hand a dynamic part which simulates the drift of the slick and on the other hand a physical part which takes into account the modifications of the characteristics. of the aquifer in the marine environment ”, specifies in a scientific publication Pierre Daniel, of Météo-France, an organization which assists the authorities in the event of marine pollution by hydrocarbons with modeling.
From the point of view of meteorological conditions, within two weeks "an episode of Sirocco, pushing the water table towards the north is expected, followed by Mistral, a wind which pushes in the South-East", details Andrea Doglioli, physicist oceanographer at the MIO.
"I do not want to risk making forecasts, but it seems to me very unlikely that these hydrocarbons will eventually touch the Provençal coasts," he concludes.
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