Supplément 1.2: Les instruments de télédétection utilisés pour surveiller la pollution marine (en anglais)
Remote Sensing Instruments Used in Marine Pollution Monitoring
Platform / Sensor |
Abbr. | Wavelength range in which the sensor is operating | Method | What does it ‘see’? | Limitations | Application |
---|---|---|---|---|---|---|
Satellite | ||||||
Synthetic Aperture Radar | SAR | Microwaves: 1 mm - 1 m |
active | reflectance properties of the sea surface at microwave frequencies | not applicable in heavy rain conditions and in wind <2 Bft and >6 Bft | presence and extent of slicks at the sea surface |
Aircraft | ||||||
Side-Looking Airborne Radar | SLAR | Microwaves: 1 mm - 1 m |
active | reflectance properties of the sea surface at microwave frequencies | not applicable in heavy rain conditions and in wind <2 Bft and >6 Bft | long-range detection of slicks at the sea surface |
Laser Fluorosensor | LFS / LIDAR | UV-VIS: 300-700 nm |
active | fluorescence spectra specific to oil class, water Raman scatter dependent on film thickness | not applicable with clouds between aircraft and sea surface | advanced analysis of pollutants, e.g. identification of oil species and film thickness in the range 0.1 - 10 μm |
Downward-looking Thermal Infrared | IR Scanner | Infrared (IR): 8 - 14 μm |
passive | brightness temperature in the thermal infrared | not applicable with clouds between aircraft and sea surface | temperature differences on the sea surface; e.g. relative film thickness of oil of approx. 10 - 100 μm |
Downward-looking Ultraviolet | UV Scanner | Ultraviolet (UV): 280 - 400 nm |
passive | reflected UV solar radiation | in daylight only, not applicable with clouds between aircraft and sea surface | e.g. relative film thickness of oil of up to 10 μm |
Forward-looking Infrared | FLIR | Infrared (IR): 8 - 14 μm |
passive | brightness temperature in the thermal infrared | not applicable with clouds between aircraft and sea surface | temperature differences on the sea surface |
Microwave Radiometer | MWR | Microwaves: 1 mm - 1 m |
passive | brightness temperature at microwave wavelengths | not applicable in heavy rain conditions | analysis of oil film thickness >100 μm |
Multispectral Imager | VIS/NIR Scanner | VIS-NIR: 400 - 1100 nm |
passive | reflectance of daylight at various visible and near-infrared wavelengths | not applicable with clouds between aircraft and sea surface | presence, extent and relative thickness of oil spills in the range 0.1 - 100 μm |
Wavelengths and frequencies of electromagnetic waves on logarithmic scales, and spectral range of remote sensing instruments
used for marine pollution detection and analysis. Passive instruments detect signals which are naturally available, e.g., sunlight reflected
or thermal radiation emitted from a target. Active instruments provide their own source of radiation for target illumination and signal detection. See module Understanding Spectra from the Earth for more details on electromagnetic waves. |