¹Research Institute for Cargo Transportation, Kobe University of Mercantile Marine Kobe, JAPAN

　

²Department of Navigation, Marine Technical College Kobe, JAPAN

　

³R & D Division, Shibata Industrial Co., Ltd. Akashi, JAPAN

　

Oil pollution caused by tanker casualties is becoming a serious public issue. In the accident of "Exxon Valdez" which occurred at Alaska Bay in March of 1989, the oceanic environment was destroyed owing to about forty thousand kls of spilt oil and four billion dollars were spent for only cleaning up the shorelines. Serious tanker accidents have recently occurred at shorter intervals since the accident, whereas they had done in the cycle of 11 years. In addition, the majority of the causes originate from human errors and there is nothing for it but to rely on a human-wave sweep in the oil spill response. From these situations, the fall of the social reliability to the maritime society is unfathomable. In an oil spill accident, the most important response is prevention of spilt oil diffusion by deploying oil booms at the early stage just after the spill, which is effective to limit the shoreline impact and to recover the oil easily. Although crew on the accident ship is the only people who can achieve the purpose, there is no effective device handled by themselves. As the conservation of an oceanic environment is one of the most important obligations for seafarers, the measures which they can actively take should exist. Therefore, a device to prevent spilt oil diffusion, such as an oil boom, should be treated as one of apparatuses mounted on a ship from the viewpoint of a seafarer. In this research, a device which seafarers can effectively handle is newly proposed and the fundamental characteristics are made clear to investigate the practicality. The various data offered through the research will contribute for the improvement of tanker safety and environmental conservation.

　

　

Seiryo Women's Junior College Kanazawa, Ishikawa Prefecture, JAPAN

sawano@seiryo.ac.jp

　

Shioya to Katano, about 4 km-long sandy beach in Kaga City, was polluted by the oil leaked from the Russian Tanker Nakhodka in January 1997. Over 70 heavy construction machines were introduced for oil recovery works, only to allow 18,000 m³ of oiled sand to remain.

　

Conspicuous regression of the vegetation was revealed as of the autumn of 1997. We tried setting the stakes for gardening as landmarks to observe the environmental changes on the same spots. But all the efforts were in vain because of the drift sand.

　

Since the spring of 1998, we have started making on-site researches based on Geo-informatics. 1) Global Positioning System and traditional land measurement are employed to identify the changing of the heights and vegetation density on the same position. 2) Aeronautical picture is used to acquire the environmental situations before the accident. High-density vegetated area is extracted from the picture geo-corrected by GIS. 3) Since the autumn of 1999, high-density vegetated area is measured by carrying a differential GPS receiver.

　

GIS is used for analyzing the three kinds of time-series data accompanied with absolute position on the same X-Y-Z coordinate. That is, 1) Standard deviation of the heights from the sea level 2) Density of vegetation 3) Distance of the vegetated area in each year.

　

It becomes clear that the vegetation has been regressing and that the denudate area has been enlarging since 1997. These facts strongly suggest all changes are due to the oil spill and the subsequent recovery works.

　

　

¹Research Institute for Applied Mechanics, Kyushu University Fukuoka, JAPAN

vsm@riam.kyushu-u.ac.jp

　

²Office of Marine Prediction Climate and Marine Department Japan Meteorological Agency Tokyo, JAPAN

　

Growing marine oil exploration, production and transportation of hydrocarbon products by sea increase the risk of oil spills in to the seawaters. Numerical modeling and forecast of spilled oil drift and physical properties provide a powerful tool for planning of countermeasures for potential oil spills from possible sources and for organization of spill combating operations in case when it will happen. Example of spill prediction system is demonstrated that is setup for the Sea of Japan and could provide the spill prediction up to 3-5 days based on the numerical meteorological forecasts of the Japan Meteorological Agency (JMA).

　

Combination of surface winds and sea currents is most important factor responsible for the oil slick drift. The model ability to reproduce such drift was verified using results of specialized experiment carried out by JMA in February 2001, when three ARGOS disc-type surface floating buoys were released in to the Sea of Japan and tracked for almost a month. Simulation was done using both the JMA and the ECMWF wind data, different drift presentation algorithms and ocean circulation models. Analysis of results enabled to improve the oil spill simulation and prediction system and are discussed.