@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix ns0: <http://gcmd.gsfc.nasa.gov/kms#> .

<https://gcmd.earthdata.nasa.gov/kms/concept/2a393a42-ecf9-4137-b1ea-1c25692384b4>
  skos:changeNote """2019-02-22 13:14:25.0 [mmorahan]  
insert WeightedRelation (id: null
related concept uuid: 6120cea0-c943-4c7c-bddd-8d8648d58022
relationship type: null
relationship value: null
generated by: null); 
""", """2020-10-05 13:58:49.0 [sritz]  
update Definition (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&#176; 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), the NOAA-18 polar orbiting satellite (launched 20 May 2005), the NOAA-19 polar orbiting satellite (launched 06 February 2009), and the METOP-B satellite (launched 17 September 2012). 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: &#177; 49.5&#176; cross-track from nadir
Instrument IFOV: 3.3&#176; (40.5 km at nadir) for both units
Scan Period: 8 s
Scan Sampling: 30 x 3.3&#176;, in 6 s
Design Life: 3 years


Group: Instrument_Details
   Entry_ID: AMSU-A
   Group: Instrument_Identification
      Instrument_Category: Earth Remote Sensing Instruments
      Instrument_Class: Passive Remote Sensing
      Instrument_Type: Profilers/Sounders
      Short_Name: AMSU-A
      Long_Name: Advanced Microwave Sounding Unit-A
   End_Group
   Group: Associated_Platforms
      Short_Name: METOP-B
      Short_Name: NOAA-19
      Short_Name: NOAA-18
      Short_Name: NOAA-17
      Short_Name: NOAA-16
      Short_Name: NOAA-15
      Short_Name: AQUA
   End_Group
   Group: 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)
   End_Group
   Online_Resource: https://aqua.nasa.gov/content/amsu
   Creation_Date: 2007-04-16
   Group: 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
      Instrument_Owner: USA/NOAA
   End_Group
End_Group); 
update Definition (https://aqua.nasa.gov/content/amsu); 
""" ;
  ns0:altLabel [ ] ;
  skos:definition """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&#176; 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), the NOAA-18 polar orbiting satellite (launched 20 May 2005), the NOAA-19 polar orbiting satellite (launched 06 February 2009), and the METOP-B satellite (launched 17 September 2012). 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: &#177; 49.5&#176; cross-track from nadir
Instrument IFOV: 3.3&#176; (40.5 km at nadir) for both units
Scan Period: 8 s
Scan Sampling: 30 x 3.3&#176;, in 6 s
Design Life: 3 years


Group: Instrument_Details
   Entry_ID: AMSU-A
   Group: Instrument_Identification
      Instrument_Category: Earth Remote Sensing Instruments
      Instrument_Class: Passive Remote Sensing
      Instrument_Type: Profilers/Sounders
      Short_Name: AMSU-A
      Long_Name: Advanced Microwave Sounding Unit-A
   End_Group
   Group: Associated_Platforms
      Short_Name: METOP-B
      Short_Name: NOAA-19
      Short_Name: NOAA-18
      Short_Name: NOAA-17
      Short_Name: NOAA-16
      Short_Name: NOAA-15
      Short_Name: AQUA
   End_Group
   Group: 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)
   End_Group
   Online_Resource: https://aqua.nasa.gov/content/amsu
   Creation_Date: 2007-04-16
   Group: 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
      Instrument_Owner: USA/NOAA
   End_Group
End_Group"""@en ;
  skos:prefLabel "AMSU-A"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/4190ebdc-e89a-4f3f-bc74-b2af4c68d009> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/4190ebdc-e89a-4f3f-bc74-b2af4c68d009>
  skos:prefLabel "Profilers/Sounders"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/2a393a42-ecf9-4137-b1ea-1c25692384b4> .

