The Advanced Along Track Scanning Radiometer (AATSR) (more info here) is one of the instruments aboard the Environmental Satellite ENVISAT (more info here). The prime scientific objective of the AATSR is to establish continuity of the ATSR-1 and ATSR-2 data sets of precise sea surface temperature (SST), thereby ensuring the production of a unique 10 year near-continuous data set at the levels of accuracy required (0.3 K or better) for climate research and for the community of operational as well as scientific users who have been developed through the ERS-1 and ERS-2 missions. More information on specific AATSR applications can be found here.