https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf 24.4 2026-07-22T11:07:16.739Z https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/instruments/39ac1813-238f-4fa3-b0cb-fe08a7dcadc4 ATSR The Along Track Scanning Radiometer and Microwave Sounder (ATSR) isone of the instruments carried on-board of the European Remote SensingSatellites (ERS-1 and ERS-2) launched by the European Space Agency on17 July 1991 and 20 April 1995.The ATSR incorporates two separate instruments: an advanced four-channel infrared radiometer (the ATSR-IRR, commonly called the ATSR)used for measuring sea surface temperature and cloud top temperatures,and a two-channel Microwave Sounder (the ATSR-MWR, commonly called theMWR) designed to measure total precipitable water vapour and the totalliquid water content of the atmosphere.The ATSR-IRR images are in four co-registered infra-red channels in a500 km wide swath. The viewing geometry involves a unique scanningtechnique where the surface is viewed at two angles, one close to thenadir (0 degree, nadir swath) and the other at 47 degrees (forwardswath), within the space of two minutes (the time it takes thesub-satellite point to reach the along track point which is separatedby approximately 800 km). These two swaths are produced by a scanningmirror with a rotation axis inclined 23.45 degrees from the vertical,resulting in a near-elliptical path on the Earth's surface.On-board calibration is carried out by incorporating two 'blackbodies' into the instrument scan pattern. The IR sensors are kept to80 K by an active cooling system to minimize the thermal noisecomponent in the sensor signals.ATSR-IRR characteristics:------------------------------------------------------------Spectral channels: 1.6, 3.7, 11 and 12 micronsSpatial resolution: 1 km x 1 km (nadir); 1.5 km x 2 km(forward)Swath width: 500 kmDetector: single element InSb and HgCdTeCooler: Stirling Cycle CoolerRadiometric precision: 0.1 KSST predicted accuracy: 0.5 K over a 50 kmx 50 km squarewith 80% cloud cover------------------------------------------------------------The ATSR was designed to provide the following:- global sea surface temperature, accurate to better than0.5K (absolute) with a spatial resolution of 50 Km inconditions of up to 80% cloud cover- images of surface temperature, accurate to 0.1K(relative) with 1 km resolution and 500 km swath width- total water vapour content of the atmosphere- observations of clouds, aerosols, haze, land-ice andsea-ice surface emissivity- tropospheric range correction of the Radar Altimetermeasurements to better than 5 cmThe ATSR provides important information in scientific disciplines suchas oceanography, climatology and meteorology. When combined withobservations of cloud top temperatures, cloud cover, haze, aerosol andtotal water vapour content of the atmosphere, significant improvementsmay be expected in the accuracy of medium range weatherforecasting. Also accurate sea surface temperatures can be of use to anumber of commercial users, particularly those involved in fishing andthe management of fishing areas. In the field of research, potentialapplications of the ATSR include distinguishing thin new ice from openwater, identifying surface type, and the accumulation rate of landice.Related URL: 'http://earth.esa.int/atsr/'Reference online documentation:'http://earth.esa.int/services/esa_doc/doc_ats.html'For any query, please refer to:ESA/ESRIN Earth Observation Help Desk'http://earth.esa.int'E-mail: eohelp@esa.intPhone: +39 06 94180777Fax: +39 06 94180292Address:ESA/ESRINVia G.Galilei00044 FrascatiItaly