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The Environment Agency has a duty under the Water Resources Act 1991 to monitor the extent of pollution in controlled waters and, under the Environment Act 1995, to form an opinion on the general state of pollution of the environment.
Environment Agency surveillance aeroplane To help in these duties a thermal scanner with both video and digital output is mounted in the aircraft used by the Agency for aerial surveillance operations.
The thermal scanner measures thermal infrared radiation in the 8-13 Ám part of the electromagnetic spectrum. Relative signal intensity is digitised and recorded at 8 bit resolution. The instrument is sensitive to sub degree changes in surface temperature resulting in a detailed image which maps relative temperature changes.
The onboard GPS and attitude information collected simultaneously with the image data are used to georectify and orientate the images to the British National Grid. Digital image processing techniques are used to enhance features of interest and add quantitative colour scales where necessary.
Applications of the thermal sensor include:
* Detection of discharge plumes in water;
Discharge into Southampton water
Thermal image of discharge
* Monitoring of discharges over tidal cycles;
Warm discharge plumes from Sizewell Power Station
* Detection of "hot spots" in landfill sites;
* Heat loss surveys.