|Oil spill modelling for the Antarctic seas|
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Reference no: A3/58/001
Period: August 1992 till September 1996
Thesaurus terms: Coastal waters; Hydrocarbons; Modelling; Ocean circulation; Oil pollution; Sea ice
Geographical terms: PSE, Antarctic Ocean [Marine Regions]; PSW, Weddell Sea [Marine Regions]
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- Koninklijk Belgisch Instituut voor Natuurwetenschappen; Operationele Directie Natuurlijk Milieu; Beheerseenheid Mathematisch Model Noordzee en Schelde-estuarium (BMM), more
- Belgian Science Policy (BELSPO), more, sponsor
|The risk of oil pollution in the Antarctic has grown considerably due to human presence and activities and to shipping in this region. The nature of the coastline, the presence of the ice pack and the sensitivity of the biomass explain the high vulnerability of the Antarctic ecosystem to oil pollution. Although adequate models exist to simulate the behaviour of oil spilled at sea, no reliable model is available to predict the interaction of oil with sea ice in Antarctic conditions. Observations made in the Arctic by Canadian and Scandinavian authors suggest a complex behaviour of oil spills in the presence of sea ice. The MUMM proposes to construct a model capable of describing the behaviour of an oil spill and the evolution of the sea ice when the two interact.
The aim of the project is to develop a deterministic model capable of predicting the behaviour of an oil spill in the Antarctic coastal area in the presence of ice over a seasonal cycle. The evolution of the spill on the surface, in the water column and in the ice will be simulated and represented graphically so as to assess the impact of the spill. The following objectives have been defined in order to achieve this goal:
- study of the processes affecting hydrocarbons in a cold sea;
- study of sea/ice interactions;
- study of the processes affecting the ice following a possible oil spill in the Southern Ocean;
- development of models describing these different phenomena;
- examination of the possibilities of collaboration with the atmospheric model developed separately by the UCL;
- application to the Weddell Sea area over a seasonal cycle.
Means and methodology:
Three models developed at the MUMM will serve as the basis for the study:
- a deterministic oil dispersion model (MU-SLICK);
- a composite deterministic/probabilistic oil dispersion model (PARCEL);
- a sea ice evolution model developed during Phase II of the Belgian Research Programme on the Antarctic (SEAICE).
The useful components of these models will be selected and adapted with a view to coupling within a single system. Contacts will be established to examine the possibilities of access to the atmospheric model of the UCL. A statistical law will be developed to determine the position of the ice in each mesh of the discrete application grid.
Products and results:
The project will synthesize current knowledge on the behaviour of hydrocarbons in a cold sea, the ice/oil interactions, the oceanic circulation in the Antarctic and the seasonal evolution of the ice in the Antarctic in a coherent whole allowing the behaviour of an oil spill in the Weddell Sea over a seasonal cycle to be studied.
The model developed in this way will be a three-dimensional oil model using the results of an ocean-circulation model, calculating wind pressure from atmospheric predictions and simulating the important weathering and ageing processes. The ice model will include a thermodynamic component (melting/freezing) and a dynamic component (ice movement). The complete model will be applied to the Weddell Sea and several simulations will be carried out modifying the time and place of the oil spill. The results will provide us with an initial idea of the impact of a major oil spill on the Antarctic environment.
The following information will be available at the end of a simulation:
- trajectory of the oil slick;
- trajectories of dispersed oil fractions;
- trajectories of oil fractions trapped by the ice;
- final position of the different fractions;
- inventory of the impacted targets.
The model created in this way is not intended to constitute a marketable product but will essentially remain a research tool. In the event of a real oil spill, the MUMM would be able to apply the model to obtain a quick assessment of the foreseeable environmental consequences.