Training Resource Description
Satellite data are used to provide decision support for oil spill response during accidents that release large volumes of oil into the sea.
The data are used in two ways: optical and SAR data from satellites and aircrafts provide information on; the location, extent and thickness of surface oil. While other sensors provide wind, wave and current measurements that can be used as input into numerical models to predict how the spill will evolve. This is used, for example, by the European Maritime Safety Agency (EMSA), to provide an oil spill monitoring service that alerts the authorities when an oil slick indicates a breach of regulations to prevent oil pollution.
Oil spill detection
The main satellite sensor for oil spill detection is Synthetic Aperture Radar (SAR). It has a sufficiently high resolution to reveal relatively small areas of surface oil, and can ‘see’ through clouds.
How does it work?
- Oil spill detection works at wind speeds between 3 and 10-12 m/s.
- Oil appears darker than water in SAR images because it calms the wind-ripples that make the sea surface appear bright in SAR images when wind speeds exceed 3 m/s.
- Above 10-12 m/s the oil is increasing mixed into the water and disappears.
Satellite data for oil spill detection are used in different ways:
- In support of oil spill response during major accidents (e.g. Deepwater Horizon oil spill)
- Routine monitoring of shipping lanes, ports and off-shore installations to check on compliance with discharge limits (e.g. EMSA Clean Sea Net)
- In environmental impact assessments: either to assess the impact of new infrastructure (ports, oil refineries, off-shore installations) or to assess the impact of large scale accidents.