| Instrument: AMSU-A : Advanced Microwave Sounding Unit-A |
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Associated Platforms METOP-B NOAA-19 NOAA-18 NOAA-17 NOAA-16 NOAA-15 AQUA Spectral/Frequency Information Wavelength Keyword: Microwave Number Channels: 15 Channels (13 for AMSU-A1, 2 for AMSU-A2) Spectral/Frequency Coverage/Range: 23 - 90 GHz (50-90 GHz for AMSU-A1, 23-32 GHz for AMSU-A2) Related Data Sets View all records related to this instrument Description The objectives of the Advanced Microwave Sounding Unit (AMSU) instrument are to (1) provide atmospheric temperature sounding from the surface up to 40 km, (2) obtain estimates of total column water vapor in the atmosphere, and (3) detect the presence of precipitation. AMSU-A is a 15-channel microwave sounder that obtains temperature profiles in the upper atmosphere and provides a cloud-filtering capability for the AIRS infrared channels for increased accuracy of tropospheric temperature observations. The fifteen AMSU-A channels have a 3.3° beam width, resulting in a nominal horizontal spatial resolution of 40.5 km at nadir. Channels 3 to 14 on AMSU-A are situated on the low-frequency side of the oxygen resonance band (50 ~ 60 GHz) and are used for temperature sounding. Successive channels in this band are situated at frequencies with increasing opacity and therefore respond to radiation from increasing altitudes. Channel 1, located on the first (weak) water vapor resonance line, is used to obtain estimates of total column water vapor in the atmosphere. Channel 2 (at 31 GHz) is used to indicate the presence of rain. Channel 15 on AMSU-A, at 89 GHz, is used as an indicator for precipitation, using the fact that at 89 GHz ice more strongly scatters radiation than it absorbs or emits radiation. The AMSU is currently operational on the NOAA-15 polar orbiting satellite (launched 13 May 1998), the NOAA-16 polar orbiting satellite (launched 21 September 2000), the NASA EOS Aqua (formally PM-1) spacecraft (launched 4 May 2002), the NOAA-17 polar orbiting satellite (launched 21 May 2002), and the NOAA-18 polar orbiting satellite (launched 20 May 2005). The NOAA AMSU configuration consists of the 15-channel AMSU-A and a 5 channel AMSU-B for a total of 20 channels. Key AMSU-A Facts Heritage: Microwave Sounding Unit (MSU) Aperture: 13.2 cm on AMSU-A1 (two apertures); 27.4 cm on AMSU-A2 (one aperture) Swath Width: 1690 km Coverage: Global coverage every 1 - 2 days Spatial Resolution: 40.5 km at nadir Dimensions: 72 cm x 34 cm x 59 cm for AMSU-A1; 73 cm x 61 cm x 86 cm for AMSU-A2 Mass: 91 kg (49 kg for AMSU-A1, 42 kg for AMSU-A2) Power: 101 W (77 W for AMSU-A1, 24 W for AMSU-A2) Duty Cycle: 100% FOV: ± 49.5° cross-track from nadir Instrument IFOV: 3.3° (40.5 km at nadir) for both units Scan Period: 8 s Scan Sampling: 30 x 3.3°, in 6 s Design Life: 3 years Online Resources http://aqua.nasa.gov/about/instrument_amsu.php http://amsu.cira.colostate.edu/ http://www2.ncdc.noaa.gov/docs/klm/html/c3/sec3-3.htm Instrument Logistics Data Rate: 2.0 kbps (1.5 kbps for AMSU-A1, 0.5 kbps for AMSU-A2) Instrument Start Date: 2002-08-31 Instrument Owner: USA/NASA USA/NOAA |
