Advanced Along-Track Scanning Radiometer (AATSR) is one of the Announcement of Opportunity (AO) instruments on board the European Space Agency (ESA) satellite ENVISAT. It is the most recent in a series of instruments designed primarily to measure Sea Surface Temperature (SST), following on from ATSR-1 and ATSR-2 on board ERS-1 and ERS-2. AATSR data have a resolution of 1 km at nadir, and are derived from measurements of reflected and emitted radiation taken at the following wavelengths:
0.55 µm, 0.66 µm, 0.87 µm, 1.6 µm,
3.7 µm, 11 µm and 12 µm.
Special features of the AATSR instrument include its use of a conical scan to give a dual-view of the Earth's surface, on-board calibration targets and use of mechanical coolers to maintain the thermal environment necessary for optimal operation of the infrared detectors.
The scheduled maintenance affecting the (A)ATSR MERCI service on Monday 25 January 2010 has been completed and the service is now back to nominal operations.