Humidity Sounder for Brazil

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The Humidity Sounder for Brazil (HSB) was an instrument launched on NASA's Earth Observing System satellite Aqua launched in May 2002. It was a four-channel passive microwave radiometer, with one channel at 150 GHz and three channels at 183 GHz. It was very similar in design to the AMSU-B instrument, except it lacked the 89 GHz surface sounding channel. It was intended to study profiles of atmospheric water vapor and provide improved input data to the cloud-clearing algorithms in the Unified AIRS Retrieval Suite, but the scan mirror motor failed on February 5, 2003. It worked with the Atmospheric Infrared Sounder and AMSU-A to form the AIRS Sounding Suite.

HSB was manufactured by Matra Marconi Space, Limited (MMS), in the United Kingdom under a contract with the Brazilian National Institute for Space Research (INPE).

Instrument characteristics[edit]

  • Heritage: AMSU-B
  • Swath: 1650 km
  • Spatial resolution: 13.5 km horizontal at nadir
  • Mass: 51 kg
  • Duty cycle: 100%
  • Power: 56 W
  • Data rate: 4.2 kbit/s
  • Field of View: ± 49.5 degrees cross-track
  • Instrument Instantaneous Field of View: 1.1 degrees circular

Table 1: Radiometric characteristics of the HSB

Channel Number AMSU-B

Channel Number




(at nadir)

Instrument Sensitivity


1 16 89.9 ± 0.9 DELETED DELETED
2 17 150 ± 0.9 4000 0.68
3 18 183.31 ± 1.00 2x500 0.57
4 19 183.31 ± 3.00 2x1000 0.39
5 20 183.31 ± 7.00 2x2000 0.30


HSB stopped scanning suddenly and without warning over the Pacific Ocean February 5, 2003 at 21:39 UTC. The most likely cause is an electrical failure in the scan electronics. By design AMSU-B and therefore HSB had very limited hardware redundancy and software update capability.

External links[edit]