On December 12, 1999, the Erika tanker broke in two sections at about 30 miles from the Brittany coast in the Bay of Biscay, France. The two parts of the wreck sank a few hours after the break. Some 15,000 tons of heavy fuel were released into the manne environment. It is the most serious discharge that has occurred in France since 1980 (Tanio, 6,000 tons). The nature of the incident, the kind and quantity of oil spilled, and the prevailing weather conditions posed considerable response problems. The spilled oil drifted for 2 weeks before reaching the coast. Three different models were implemented by CEntre de Documentation de Recherche et d'Experimentations sur les pollutions accidentelles des eaux (CEDRE) within a couple of hours of the Erika sinking. On December 14, it appeared that the forecast of the MOTHY model was closer to reality.The MOTHY model was developed by Meteo-France (the French national weather service) to simulate the movement of pollutants in three dimensions. MOTHY is an integrated system that includes hydrodynamic coastal ocean modeling and realtime atmospheric forcing from a global model. Pollutants can be oil or floating objects. CEDRE contributes to the improvement and validation of the model using both experiments and interventions during actual pollution events. New developments, exercises, and training are jointly conducted. In the event of marine pollution, Meteo-France sends meteorological forecasts and pollutant drift forecasts to CEDRE. This response system has been operational since February 1994.The MOTHY model was used routinely for several weeks after the ship broke up. The model predicted that the coastline was at risk and that the beaching of the main slick would occur after 2 weeks. Diffuse pollution reached the coastline 1 or 2 days before the main slicks, about 200 km west of the main beaching. Hindcast runs and backward integration of the model explained this unexpected arrival of oil. Some pollution was still arriving onshore several weeks after the initial release. This longer-term pollution came from the wrecks, but also of older pollution by the coastal detachment and deposit tides. Using the model in conjunction with remote sensing information allowed operators to develop and then execute a response strategy rather than react only to observed information.
Abstract. A mesoscale non-hydrostatic atmospheric model has been coupled with a mesoscale oceanic model. The case study is a four-day simulation of a strong storm event observed during the SEMAPHORE experiment over a 500 × 500 km2 domain. This domain encompasses a thermohaline front associated with the Azores current. In order to analyze the effect of mesoscale coupling, three simulations are compared: the first one with the atmospheric model forced by realistic sea surface temperature analyses; the second one with the ocean model forced by atmospheric fields, derived from weather forecast re-analyses; the third one with the models being coupled. For these three simulations the surface fluxes were computed with the same bulk parametrization. All three simulations succeed well in representing the main oceanic or atmospheric features observed during the storm. Comparison of surface fields with in situ observations reveals that the winds of the fine mesh atmospheric model are more realistic than those of the weather forecast re-analyses. The low-level winds simulated with the atmospheric model in the forced and coupled simulations are appreciably stronger than the re-analyzed winds. They also generate stronger fluxes. The coupled simulation has the strongest surface heat fluxes: the difference in the net heat budget with the oceanic forced simulation reaches on average 50 Wm-2 over the simulation period. Sea surface-temperature cooling is too weak in both simulations, but is improved in the coupled run and matches better the cooling observed with drifters. The spatial distributions of sea surface-temperature cooling and surface fluxes are strongly inhomogeneous over the simulation domain. The amplitude of the flux variation is maximum in the coupled run. Moreover the weak correlation between the cooling and heat flux patterns indicates that the surface fluxes are not responsible for the whole cooling and suggests that the response of the ocean mixed layer to the atmosphere is highly non-local and enhanced in the coupled simulation.Key words. Oceanography: physical (air · sea interac- tion; eddies and mesoscale processes). Meteorology and atmospheric dynamics (ocean · atmosphere interactions)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.