The Use of Ancillary Metocean Data for the Oil Spill Probability Assessment in SAR Images
Accidental pollution at sea can be reduced but never completely eliminated, on the other side, deliberate illegal discharges from ships can indeed be reduced by the strict enforcement of existing regulations and the control, monitoring and surveillance of maritime traffic. Anyhow, operational oil di...
| Main Authors: | , , , |
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| Language: | English |
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PARLAR SCIENTIFIC PUBLICATIONS (P S P)
2008
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| Online Access: | https://publications.jrc.ec.europa.eu/repository/handle/JRC38000 http://www.psp-parlar.de/details_feb_afs_.asp?typ=feb&datum=15.09.2008&jahr=2008 |
| Summary: | Accidental pollution at sea can be reduced but never completely eliminated, on the other side, deliberate illegal discharges from ships can indeed be reduced by the strict enforcement of existing regulations and the control, monitoring and surveillance of maritime traffic. Anyhow, operational oil discharges is a common practice and represents the main source of marine pollution from ships. Because of this situation the demand for efficient detection and mapping of oil pollution in the sea is growing. One of the key instruments to monitor and detect oil spills at sea are Synthetic Aperture Radar (SAR) systems. SAR systems are able to detect spills on the sea surface indirectly, because of the effect on the wind generated short gravity – capillary waves. The oil film damps these waves which are the primary backscatter agents of the radar signals. Unfortunately, oil slicks are not the only phenomena which can appear as a dark feature in a SAR image. The contrast between the spill and its surroundings depends on a number parameters like wind speed, wave height, and the amount and type of oil released. Under certain air/sea boundary layer conditions, other sea surface manifestations of natural origin may result to SAR expressions or false targets, similar to those due to an oil spill. They are usually referred to as look-alikes objects. The largest challenge in detection of oil spills in SAR images remains in the accurate discrimination between oil spills and look-alikes. Dark patches in SAR images can result from different sources like reduced wind speed or from reduced wind stress due to colder sea surface temperatures and other features. The knowledge of environmental conditions like wind, currents, precipitation and other concomitant marine and atmospheric phenomena like internal waves, upwelling, grease ice, algae blooms etc. as well as contextual information about slick position relative to surrounding objects (ships, maritime routes, rigs, platforms, natural seeps) of the past and at the time of the SAR ... |
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