The Advanced Microwave Scanning Radiometer (AMSR) instrument was launched on board the Advanced Earth Observation Satellite II (ADEOS-II), also known as Midori-II, on 14 December 2002. AMSR was an eight-frequency, passive-microwave radiometer system with the ability to observe from day to night, under any weather conditions with less cloud effects. It measured horizontally polarized radiances at 6.9, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz, and vertically polarized radiances at 50.3 and 52.8 GHz. Spatial resolution of the individual measurements varies from 5 km at 89 GHz to approximately 50 km at 6.9 and 10.65 GHz.

The AMSR instrument on ADEOS-II measured geophysical variables such as atmospheric water vapor, precipitation, sea surface wind speed, sea surface temperature, soil moisture, sea ice extent, and snow water equivalent.

NSIDC archives and distributes daily Level-1A data from AMSR. Please see the AMSR/ADEOS-II Data at NSIDC Web site for tools to order and work with the data, information regarding the availability of data products, how to obtain guide documentation, FAQs, and other related AMSR information.