Development and improvement of an operational oil drift model

MeteoGalicia

Oil spill history

Galicia has the record of oil spill disasters in last 25 years: • Urquiola (May 13th,

1976 )

• Andros Patria (1978 )

• Cason (December 5th, 1987 ) (Toxic waste?)

• Mar Egeo (December 3th, 1992 )

• Prestige (November 13th-19th, 2002)

Prestige case• November 13th, 2002,14

UTC: Prestige suffered an accident, 30 miles away from coast.

• Between 13th and 14th: it was practically adrift approaching 4 miles to the coast.

• Next days: Prestige was moved to the NW and then to the SW.

• November 19th 08 UTC: Prestige collapsed, about 140 miles from Cape Silleiro (42°15N 12°08W)

Oil main features• Different density fuels should

appear.• Very spread polluted area,

including open sea areas.• Heavy fuel: Very high density

near 0.993 • In near coast areas, can

appear mixed with sand, changing density

• Low evaporation ratio. Tends to remain in the water column for a long time. Emulsification: 45 % water content after 5-7 days

Actions by MeteoGalicia

• Developing an oil drift forecast system based on available tools at MeteoGalicia:

• MeteoMohid: Based on ARPS forecast plus hydrodynamic model MOHID

• Deriva: Based on ARPS forecast only.

• Identification of main physical processes causing oil drift:

• Direct wind drift• Wind generated currents• Slope currents• River run-off

Prestige Oil Spills

• Initial (First) Oil Spill.-– Slick of fuel oil during the ship's track between 13th and 18th.– Total fuel oil spilled: 10000 Tm– Reached the coast: November 16th

• Main (Second) Oil Spill.- – Fuel oil spilled in the vessel sunk place. 19th at 07 UTC.– Total fuel oil spilled: more than 10000 Tm– Reached the coast: November 30th at night

• Third Oil Spill.- – Oil into the tanks leaks out through several breaches on the hull.– A flow of about 125 Tm/day was estimated during 2 months.

FirstFirst spillspill

Simulation ARPS+MOHID November 25th 2002 (CCMM)

Forcement:

•Wind: SW, F6•Currents: River runoff, slope current

Main oil spill

Comparison between MOHID+ARPS results day by day (coloured spots)

and the observed maximum fuel concentration (number inside black

circle).

Main Oil Spill. Forecast made on 27th

Subsurface oil spill hypothesis

Movement of the Oil Spill

Scheme of the subsurface slick hypothesis

Subsurface path simulation

November 17th, 2002 – ASAR-ENVISAT ESA satellite image showing two branches of fuel.

November 17th 19UTC, 2002 model simulation results using different depth for tracers origin.

ToDo List…

• Waves impact on drift at open sea (Stokes drift)

• Importance of seasonal current (polewar current)

• River run-off roll in Rias

Thanks!!!