Envisat's instruments

Instrument

Main purpose

Global Ozone Monitoring by Occultation of Stars  (GOMOS) 

To observe the concentration of ozone in the stratosphere.

Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY)

To measure trace gases and aerosol concentrations in the atmosphere.

Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) 

To collect information about chemical and physical processes in the stratosphere, such as those that will affect ozone concentration in future.

Medium Resolution Imaging Spectrometer (MERIS)

Measures radiation in 15 frequency bands that give information about ocean biology, marine water quality, vegetation on land, cloud and water vapour.

Advanced Synthetic Aperture Radar (ASAR)

All weather, day or night radar imaging.

Advanced along track scanning radiometer (AATSR)

To measure sea-surface temperature, a key parameter in determining the existence and/or extent of global warming.

Radar Altimeter (RA-2) 

Measures distance from satellite to Earth. So can measure sea-surface height, an important measurement for monitoring El Nino, for example.

Microwave Radiometer (MWR) 

Allows corrections to be made to radar altimeter data.

Doppler Orbitography and Radio positioning Integrated by Satellite (DORIS)

Gives the position of Envisat in its orbit to within a few centimetres. This is crucial to understanding the measurements all the instruments make.

Laser Retro-Reflector (LRR)

Reflects pulsed laser to ground stations to help determine the satellite’s exact position in its orbit.