AMSU is derived from the Microwave Sounding Unit (MSU) which began service in 1978 on TIROS-N and continued on the NOAA 6 through 14 satellites. AMSU flies on the NOAA KLM satellites: NOAA 15, launched 13 May 1998; NOAA 16, launched 21 September 2000; and NOAA 17, launched 24 June 2002.

The AMSU system is implemented in two separate modules: the AMSU-A and AMSU-B. The AMSU is a multi-channel microwave radiometer that is used for measuring global atmospheric temperature profiles and provides information on atmospheric water in all of its forms (with the exception of small ice particles, which are transparent at microwave frequencies)

AMSU-A is on board of AQUA, launched on May 4, 2002 and also on MetOp-A, launched on July 21, 2006. The AMSU-A is a 15-channel microwave sounder designed primarily to obtain temperature profiles in the upper atmosphere (especially the stratosphere) and to provide a cloud-filtering capability for tropospheric temperature observations.
The AMSU-B is designed to allow the calculation of the vertical water vapor profiles from the Earth’s surface to about a 200-millibar pressure altitude (12 km or 7.5 mi). The AMSU-B is a crosstrack, continuous line scanning, total power radiometer and provides measurements of scene radiance in five channels.

Objectives

The AMSU-A1 measures scene radiance in the microwave spectrum. The data from this instrument is used in conjunction with the High-resolution Infrared Sounder (HIRS) instrument to calculate the global atmospheric temperature and humidity profiles from the Earth's surface to the upper stratosphere, at approximately 2-millibar pressure altitude (48 km). The data is used to provide precipitation and surface measurements including snow cover, sea-ice concentration and soil moisture.

The AMSU-A2 measures scene radiance in the microwave spectrum. The data from this instrument is used in conjunction with the High-resolution Infrared Sounder (HIRS) instrument to calculate the global atmospheric temperature and humidity profiles from the Earth's surface to the upper stratosphere, at approximately 2-millibar pressure altitude (48 km). The data is used to provide precipitation and surface measurements including snow cover, sea-ice concentration and soil moisture.  

Instrument

The AMSU-A is a crosstrack scanning total power radiometer. It is divided into two physically separate modules, each of which operates and interfaces with the spacecraft independently. Module A-1 contains 13 channels (23.8 GHz - 57.3 GHz) and Module A-2 contains two additional channels (57.3 GHz & 89.0 GHz).

The instrument has an IFOV of 3.3° at the half-power points (Swath Width 2343 km) providing a nominal spatial resolution at nadir of 48 km (29.8 mi). The antenna provides a cross-track scan, scanning ± 48.3° from nadir with a total of 30 Earth fields-of view per scan line. The instrument completes one scan every 8 seconds.

The AMSU-B is a crosstrack, continuous line scanning, total power radiometer and provides measurements of scene radiance in five channels. The instrument has an IFOV of 1.1° (at the halfpower points). Spatial resolution at nadir is nominally 16 km (9.94 mi).The antenna provides a crosstrack scan, scanning ±48.95° from nadir with a total of 90 Earth fields-of-view per scan line. The instrument completes one scan every 2.66 seconds.

Characteristics:

Data Access

General Data Product Level Definition

Data is avaiaible in HDF-EOS format by NOAA/NESDIS's Microwave Sensing Group

If you have McIDAS, you can get two types of AMSU data:

• Single-orbit ("swath") data
• Mapped data

The MetOp programme and Aqua Plaform

The Meteorological Operational satellite programme (MetOp) is a new European undertaking providing weather data services that will be used to monitor climate and improve weather forecasts. The MetOp programme’s series of three satellites has been jointly established by ESA and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), forming the space segment of EUMETSAT's Polar System (EPS).
MetOp-A has been designed to work in conjunction with the NOAA satellite system whereby the two satellites fly in complementary orbits. MetOp-A’s polar orbit is Sun synchronous, so that the satellite track along the Earth is always at the same local time, in this case in the mid-morning. NOAA will continue to operate its mid-afternoon orbit satellite service as part of the Polar Orbit Enviromental Satellites (POES) system.

The MetOp satellites, have been designed to embark instruments provided by NOAA, EUMETSAT, ESA and other European partners. MetOp will have different performances than the actual NOAA system due to a platform designed with high pointing accuracy, full on board recording capacity, digital high rate and low rate communication system, encryption capability and an increased payload.

Other Instruments on the Metop-A platform include the Advanced Scatterometer ASCAT, the Global Ozone Monitoring Experiment GOME-2, the Global positioning system Receiver for Atmospheric Sounding GRAS, the High Resolution Infrared Sounder IASI, the Microwave Humidity Sounder MHS, the Advanced Microwave Temperature Sounder AMSU, the Advanced Very High Resolution Radiometer AVHRR.

MetOp’s main objectives are to furnish data for operational meteorology and climate monitoring. Many of the above instruments will give detailed information on the atmospheric temperature/humidity profiles, essential for weather forecasting.

Aqua carries six state-of-the-art instruments in a near-polar low-Earth orbit. The six instruments are the Atmospheric Infrared Sounder (AIRS), the Humidity Sounder for Brazil (HSB), the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), the Moderate-Resolution Imaging Spectroradiometer (MODIS), and Clouds and the Earth's Radiant Energy System (CERES). Each has unique characteristics and capabilities, and all six serve together to form a powerful package for Earth observations.

Links

• Microwave Tutorial for Forecasters
• MetOp instrument overview

Contact

If you would like to have more information about the AMSU data, please contact wdc@dlr.de.