Meteorologisk institutt met.no

LEOLong-term effects of oil accidents on the pelagic ecosystem of the Norwegian and

Barents Seas

Yvonne Gusdal

Meteorologisk institutt met.no

• Future oil production accident can be very harmful on the fish stocks– Barents Sea Cod – egg / larvae (passive particles)

• Egg, larvae and oil trajectories can be simulated by using an advection model forced by currents– Egg an larvae drift is computed based

on a semi-Lagrange advection model (Arne Melsom).

– Oil drift is simulated based on the oil drift model at the Meteorological Institute

Meteorologisk institutt met.no

• The impact of the oil accident on the fish eggs/ fish larvae are dependent on:– Sea conditions– Spawning location– Spawning period– Oil spill location/ spill period

Meteorologisk institutt met.no

LEO - area

Meteorologisk institutt met.no

Sea conditions

• Currents and hydrography are obtained from a coupled model system consisting of the ocean model MI-POM and the ice model MI-IM.– Area: The Barents Sea and the

Norwegian Sea – Simulation period: 1986 - 1995– Resolution: 4km– Interpolated to a mesh size of 8km

Meteorologisk institutt met.no

• To provide the best possible description of drift pathways of oil and fish eggs, we have to include the non-deterministic variability in the ocean

• A ten-member ocean circulation ensemble has been constructed– Each ensemble only differ in the

atmospheric forcing

• Eddy permitting model – However, finer scale processes are not

resolved

Meteorologisk institutt met.no

• Gaussian noise is added to the model results with a velocity:

uuu mdladv ),0(~ 20uNu,

• Have only been used in the semi-Lagrange advection model for the egg and larvae drift.

Meteorologisk institutt met.no

Spawning period: Cod eggs1. April

15. April15. March

• Particle release of 5 days

• The particles are advected until September 1th

• Release depth: 10m and 20m

Meteorologisk institutt met.no

Spawning sites: Cod eggs

nordyttersid

a

vestfjorden

Meteorologisk institutt met.no

Meteorologisk institutt met.no

Meteorologisk institutt met.no

Particle release: larvae

• June - September

• Depth: 20m and 30m

Meteorologisk institutt met.no

OIL - drift• For the oil release, the operational Oil

Drift Model at the Norwegian Meteorological Institute is applied.

• The oil drift is computed on the basis of currents from the ten ensemble members, supplemented by wave induced Stokes drift– Temperature, salinity, significant wave

height, wave period and wind are also included

– The wind is obtained from HIRLAM, while the operational wave model WAM supplies the oil model with significant wave height, mean wave period and stokes drift.

Meteorologisk institutt met.no

OIL - concentration

• Oil chemestry - toxic– Not included

• Vertical mixing– Included

• Toxic – oil concentration– Adding up all submerged oil particles

over a volume of 8km x 8km x 10m– Three layers: 0m-10m, 10m – 20m and

20m – 30m.

Meteorologisk institutt met.no

OIL drift

Meteorologisk institutt met.no

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