AMSU-A

AMSU-A (Advanced Microwave Sounding Unit-A) is a cross-track passive microwave radiometer designed for atmospheric temperature profiling using oxygen absorption bands near 50-58 GHz and a window channel at 23.8 GHz. The instrument operates 15 channels and scans cross-track at 30 positions per scan line.^[1] IFOV at nadir is reported as 48 km^[1] and 45 km^[2] in different sources. Swath width is reported as 2250 km^[1] and 1650 km^[2] in different sources.

AMSU-A was built by Northrop Grumman and flew on five NOAA Polar Operational Environmental Satellites (NOAA-15 through NOAA-19) beginning in 1998, on NASA's Aqua satellite, and on EUMETSAT's MetOp-A, MetOp-B, and MetOp-C.^[3][4] It provides radiance data used operationally for numerical weather prediction temperature soundings from the surface to the upper stratosphere.^[1] The Advanced Technology Microwave Sounder (ATMS) succeeds AMSU-A on the Joint Polar Satellite System, consolidating the temperature-profiling role of AMSU-A with the humidity-profiling role of AMSU-B into a single instrument.