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
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 Frequency (GHz) Bandwidth (at nadir) Instrument Sensitivity NEDT (K) 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
History 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 HSB instrument guide HSB data at NASA Goddard