# AMSU-A
*sensor . products*

AMSU-A is a cross-track passive microwave temperature sounder using oxygen absorption bands.

## Specifications
- **manufacturer**: northrop-grumman
- **deployment context**: orbital
- **sensor**: {"instrument_family":"radiometer","measurement_principle":"passive","frequency_bands_ghz":[23.8,31.4,50.3,52.8,53.596,54.4,54.94,55.5,57.29,89],"scan_type":"cross-track","swath_km":2250}
- **entity type**: sensor
- **last verified date**: 2026-06-11
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: northrop-grumman
- **attributes**: {"kind":"sensor","manufacturer":"northrop-grumman","description":"AMSU-A is a cross-track passive microwave temperature sounder using oxygen absorption bands.","deployment_context":"orbital","sensor":"{\"instrument_family\":\"radiometer\",\"measurement_principle\":\"passive\",\"frequency_bands_ghz\":[23.8,31.4,50.3,52.8,53.596,54.4,54.94,55.5,57.29,89],\"scan_type\":\"cross-track\",\"swath_km\":2250}"}
- **technology**: microwave-radiometry

## Editorial
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.[^oscar-amsu-a] IFOV at nadir is reported as 48 km[^oscar-amsu-a] and 45 km[^wikipedia-amsu] in different sources. Swath width is reported as 2250 km[^oscar-amsu-a] and 1650 km[^wikipedia-amsu] 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.[^esa-amsu-a1-metop][^noaa-mirs-amsu-a] It provides radiance data used operationally for numerical weather prediction temperature soundings from the surface to the upper stratosphere.[^oscar-amsu-a] 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.

## Compositional position
- metop-a (missions) --[mission_payloads]--> AMSU-A
- metop-b (missions) --[mission_payloads]--> AMSU-A
- metop-c (missions) --[mission_payloads]--> AMSU-A

## Sources
- [oscar-amsu-a] | WMO OSCAR - Details for Instrument AMSU-A | https://space.oscar.wmo.int/instruments/view/amsu_a | tier=agency-doc | accessed=2026-06-11
- [esa-amsu-a1-metop] | ESA MetOp - About AMSU-A1 | https://www.esa.int/Applications/Observing_the_Earth/Meteorological_missions/MetOp/About_AMSU-A1 | tier=agency-doc | accessed=2026-06-11
- [noaa-mirs-amsu-a] | NOAA MIRS - AMSU-A Overview | https://www.star.nesdis.noaa.gov/mirs/amsua.php | tier=operator-engineering | accessed=2026-06-11
- [wikipedia-amsu] | Advanced Microwave Sounding Unit - Wikipedia | https://en.wikipedia.org/wiki/Advanced_microwave_sounding_unit | tier=community | accessed=2026-06-11

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Source: https://eo-atlas.org/products/sensor/amsu-a
Maintainer: SpectraWorks B.V. (CC-BY 4.0)